Dick Grimshaw (The Coordinator, The Vetiver Network, USA)
The Vetiver Network has been instrumental in disseminating information, world wide, on vetiver grass technology used for soil and water conservation as well as for land rehabilitation and stabilization. It disseminates information through newsletters and a home page on the world wide web. In this past year (1996) the Vetiver Network has supported the establishment of five new regional networks and two national networks. These networks will play an important role in vetiver technology dissemination. The Vetiver Network has supported a number of NGOs and other groups to develop vetiver operations in the field, primarily with small farmer groups. The Vetiver Network has been able to provide this support through its special funds amounting to about $500,000. The Vetiver Network will seek more funds from international donors so as to assist others in establishing new networks.
Xu Liyu (The China Vetiver Network, NanJing 210008)
Although it was introduced into China as early as the 1950's as a plant for extracting oil from its roots the valuable grass vetiver (Vetiveria zizanioides) was also identified in the late 1980's as a plant to assist the formation of soil erosion control hedges. Since the 1980's, vetiver grass has been experimented with or tested in most provinces in southern China, as in JiangXi, FuJian, SiChuan, HuNan, GuiZhou, HaiNan, GuangDong, GanSu, HeNan, ShanDong, and ZheJiang. Recently, great progress has been made in accelerating vetiver technology extension throughout China. This work was coordinated by the China Vetiver Network (CVN) in cooperation with numerous institutions in various disciplines. Some examples of work conducted by the CVN include:
(1). National information service. The national information service focused attention on the southern part of China where tropical and subtropical climates dominated. The vetiver publications (newsletters, fact sheets, and a journal) were distributed to many national universities, research institutions, government offices, provincial institutions, and also many county level and some township level extension stations.
(2). Field surveys and investigations. Aimed at disseminating vetiver technology, discovering new users and exploring new vetiver applications, field surveys and investigations were carried out in FuJian, JiangXi, GuangDong, HuBei, HuNan, and AnHui Provinces. These investigations were organized by the China Vetiver Network in cooperation with numerous multi-disciplinary institutions at national, provincial, prefectural, county, and township levels. Through these investigations team members learnt experiences from established vetiver application models and proposed new applications. In addition, with the distribution of more and more publications and with increasing discussion among vetiver extensionists, local technicians and farmers, more people were becoming familiar with vetiver grass.
(3) Supporting partners to test vetiver grass. The China Vetiver Network has supported partners who tested and utilized vetiver grass by providing micro-grants and information services. The followings are some examples:
--The FuZhou Soil and Water Conservation Station, FuJian Province
--The Botanical Institute of South China, GuangDong
--The reproduction base in the DaBie Mountains, AnHui Province
(4). Encouraging different institutions to use vetiver. Since the establishment of the CVN in 1996, more and more people expressed their interests in applying vetiver grass based on their own budget and existing project conditions. The CVN has provided them with information, documents, and/or planting materials and encouraged them to use and extend vetiver grass technology.
(5). Preparation of new development proposals through joint efforts. Based on multiple surveys, investigations and exchange programs, several proposals or concept papers were prepared. These played and will continue to play an important role in accelerating the dissemination and development of vetiver technology throughout the country and will keep the CVN young and vigorous.
Xia HanPing and Ao HuiXiu (South China Institute of Botany, Academia Sinica, GuangZhou 510650)
Vetiver (Vetiveria zizanioides), an excellent hedgerow for soil and moisture conservation, is being widely disseminated and applied in the tropics and sub-tropics. Generally speaking, China's vetiver was introduced in the middle 1950s from Indonesia and India. The Vetiver Network has never reported any wild vetiver distribution in China, nor have any of the pertinent monographs. Our investigations, however, indicate that there have been natural distributions of vetiver communities in GuangDong and HaiNan Provinces.
As early as 1936, a botanist named Liu XinQi collected wild vetiver samples in HaiNan, and specimens have been preserved in the Herbarium of the South China Institute of Botany(SCIB). Later, in 1960, ecologists from SCIB made a survey of vegetation types in HaiNan and found natural distributions of the plant near lagoons.
A natural vetiver community with a total area of about 6,667 ha. (100,000 MU) was also found in WuChuan County of GuangDong by the same scientists in 1957 when they conducted a provincial vegetation survey. The community was situated on an alluvial plain at the juncture of 3 counties, WuChuan, MaoMing, and DianBai, within the lower reaches of the JianJiang River. This was a hygrophytic-mesophytic tropical grassland, that flooded from April through September, and was dry from October to March. During the flood period, the whole plain was inundated, while during the drought, it became an ideal place for a large multitude of Emberiza aureoba to live through the winter.
In the 1950's, the local people utilized the vetiver community mainly for forage and thatch, which did not alter its composition. Later, utilization and development through human activities created tangibly severe changes. These activities included digging up vetiver roots for refining oil in the 1960's, building canals and dams in the 1970's, and especially large scale reclamation for fishponds and residential areas since the 1980's. Thus, the whole grassland ecosystem has seriously deteriorated over the past 40 years. The remaining area consists only of several hundred hectares, its landscape has become discrete pieces; and vetiver coverage has dwindled from 30-40% in the 1950's to 10-15% even lower by May 1997. Obviously, the precious wetlands will be completely obliterated due to excessive development if not protected at once.
In order to preserve the highly valuable plant and germplasm resources of vetiver, therefore it is suggested that a reserve should be immediately delineated in the largest original native habitat of vetiver, WuChuan of GuangDong. If this is established, then the valuable local resources, such as Emberiza aureoba mentioned above and the vetiver ecological environment with its biodiversity will be effectively conserved. In addition it will provide it provide a perfect base for carrying out studies on wetlands and biodiversity in South China.
Yan LiJiao, Zheng ZhiMing and Wang ZhaoQian (Institute of Agricultural Ecology, ZheJiang University of Agriculture, HangZhou 310029, China)
Qian JianDong, Xu QinLao and Jia XiangChi (JinHua City Office of Red Earth, ZheJiang Province, JinHua 321000, China)
According to worldwide investigations and experiments, vetiver grass, a perennial that originated in tropical and subtropical areas such as India, Sri Lanka and Myanmar, is considered a useful plant for soil erosion control. It reproduces mostly by vegetative means. With a 3 m long, thick and intertwining root system, the 2 m high grass is able to fix the soil tightly. Besides having great endurance to drought, waterlogging, high temperature and cold, the grass is easy to plant and manage and grows well in any type of soil, in high latitudes (up to 42( N), at high altitudes (up to 2,600 m) and on steep slopes (up to 31(). Vetiver planted on sloping land functions well in soil erosion control by slowing down runoff and reducing soil losses. Planted on dikes along ditches it helps to prevent the dikes from collapse and to minimize siltation.
Vetiver planted on river banks, pond dikes and reservoir embankments may control embankment erosion and mud siltation. Even when planted on a roadside it may help to consolidate the road base. Experience in India showed that vetiver hedgerows may help to reduce runoff by 30-47%, to decrease alluvial sand discharge by 43-74% and consequently to increase cereal yield by 6-26%. Experiments in Malaysia showed that compared with a control, runoff and soil loss in sites with vetiver grass decreased by 73% and 93% respectively. People in India began using vetiver in soil erosion control about 200 years ago. However, the Indian people only started their research on the effectiveness of vetiver for soil erosion control a little more than 10 years ago. In spite of this they still remain first in the world in this research fields. Due to the recommendation of Mr. R. G. Grimshaw Director of the Agricultural Technology Division, Asian Technology Bureau of the World Bank, vetiver technology was introduced into China and initially applied to the red earth projects in JiangXi and FuJian Provinces in early 1989. Later, the technology was extended to HuNan, ZheJiang, SiChuan, HaiNan and GuiZhou Provinces. Today more multidisplinary research and extension work remains to be done. With the collaboration of technicians and farmers more scientific data and technical support can be provided for further extensive application of vetiver technology. More demonstrations in hilly or mountainous areas are needed to show farmers the effectiveness of vetiver on soil erosion control and on the growth of crops.
Dr. M. Matiur Rahman (Director Bangladesh National Herbarium, VARC Complex, Farmgate, Dhaka-1215)
This paper presents the findings of a survey on vetiver grass in Bangladesh during a fifteen-month period in 1995/96. The survey records information on the ecological distribution, morphological variation, and the present use of vetiver grass obtained on study visits to all of the 64 districts in Bangladesh. The study indicates that the only species found in Bangladesh is Vetiveria zizanioides (L.) Nash, and it is very common in a variety of habitats. Three botanical "forms" of vetiver have been identified though no ecotypic variation has been found. Several large areas dominated by vetiver grass have been identified. The present findings reveal that vetiver grass has many traditional uses including its great potential for use as a vegetative means of protection on river and coastal embankments in Bangladesh.
Ricardo Hernandez, William McDowell and Joaquin Santamaria
El Salvador is a Central American country with a high population density (270 people/km2), a high rate of rural poverty, intensive competition for arable land, and severe environmental problems. More than three-fourths of the national production of basic grains occurs on small farms on marginal hillside soils.
Degradation of soil and water resources affects the household income of thousands of farmers, hydroelectric systems, sources of potable water and coastal zones. There have been increased investments in soil conservation practices in response to these problems, which has created a strong national demand for vetiver.
NOBS Anti-erosion, is a private company that promotes vetiver grass for soil conservation on hillsides. Established in 1994, it works with 140 institutions on 110 projects nationwide. The main activities include the transfer of technology, and the sale of vegetative material for living hedges. These activities are implemented through aggressive communications programs and by a team of extension specialists.
A case-study is presented on the transfer of vetiver technologies by NOBS in an area in the southwest region of E1 Salvador. A select group of small-scale farmers was trained to grow and manage vetiver for sustainable soil conservation. The farmers were given vegetative material for two years to establish replication plots. They then began transferring vetiver technologies to their neighbors. Currently, a group of 220 farmers is testing the vetiver technologies. Seventy-one percent of the farmers say that vetiver controls erosion. Eighteen percent of the farmers have observed that vetiver is increasing crop production due to increased soil moisture content. Eighty-two percent of the farmers will continue using vetiver for soil conservation.
Narong Chomchalow (Office of the Royal Development Projects Board, Bangkok, Thailand)
The creation of the Pacific Rim Vetiver Network (PRVN) was the result of a proposal made by Mr. Richard Grimshaw, President of the Vetiver Network at the First International Conference on Vetiver (ICV-1) held in Chiang Rai, Thailand, on 4-8 February 1996. Mr. Grimshaw suggested that Thailand act as the core of the PRVN with the principal objective of serving as a center to collect and disseminate information in the form of newsletters, occasional publications as well as a homepage on the internet on the use of vetiver grass. homepage on the internet. in the form of newsletters, occasional publications as well as a on the. Thailand is considered suitable because it is the site of the world's largest vetiver project, known as the Doi Tung Development Project, which has been implemented under the supervision of the Office of the Royal Development Projects Board (ORDPB), the organizer of the Conference. Subsequently, the ORDPB submitted the proposal to His Majesty the King, a keen supporter in the use of vetiver grass and an awardee of the Vetiver Network's specially-commissioned bronze vetiver sculpture, in order to obtain his comments and approval. His Majesty agreed with the proposal and commissioned the setting up of the PRVN under the supervision of the Committee on the Development and Campaign for the Utilization of Vetiver under His Majesty's Initiatives, to be administered by ORDPB.
In order to facilitate the effective implementation of the network with a common view and flexibility, the Committee established a Working Team to take care of the PRVN. It has the responsibility to manage and supervise the Network which aims to promote the cultivation and use of vetiver through the issuance of a newsletter and the homepage. The PRVN intends to serve the countries of eastern Asia and the Pacific. These include Australia, Brunei, Cambodia, the Cook Islands, China, Fiji, Indonesia, Japan, Korea, Lao PDR, Malaysia, New Zealand, Papua New Guinea, the Philippines, Singapore, the Solomon Islands, Taiwan, Thailand, Tonga, Vanuatu, Western Samoa, and Vietnam.
Narong Chomchalow, (Office of the Royal Development Projects Board, Bangkok, Thailand)
In Thailand, the present state of land degradation caused by soil erosion as a result of top soil being washed away after heavy rains and the resultant runoff is quite devastating. His Majesty King Bhumibol Adulyadej has realized the urgency of the problem and its cause. After careful consideration of the potential of vetiver grass , a versatile plant that can help prevent soil erosion and conserve soil moisture, His Majesty has adopted the idea of using vetiver for soil and water conservation. A simple technology will first be introduced to the hilltribes in the highlands of northern Thailand, and later to all others who suffer from the same problem of soil erosion. The vetiver grass technology (VGT) has been found to be quite effective, with little or no expense, and it requires minimum care once its growth has been established.
His Majesty started to implement his concept in June 1991 upon information received from the World Bank. This has proven to be so effective that a great deal of progress has been achieved in a relatively short time. The Office of the Royal Development Projects Board (ORPDB) has been assigned to coordinate the R & D activities on vetiver in Thailand from the very beginning. Their achievements include the following:
1. The organization of the First International Conference on Vetiver (ICV-1) in Chiang Rai, Thailand, on 4-8 February 1996, to commemorate the 50th anniversary of His Majesty's accession to the throne. It was one the most successful meetings ever organized with about 400 participants, including 102 from foreign countries.
2. The (National) Committee on the Development and Campaign for the Utilization of Vetiver under His Majesty's Initiative was established under the administration of the ORPDB. The Committee is charged with the duty of coordinating all R & D activities for all agencies in Thailand that are working on vetiver in order to ensure that they follow the policy set forth in the master plan and to evaluate the results obtained. This Committee also helps these agencies by requesting their annual budget from the Budget Bureau. A Sub-committee on Technical Issues, Planning and Evaluation has also been set up by the Committee.
3. During the first phase (1993-96), a master plan was developed giving emphasis to the following activities: (i) investigation and research, (ii) transfer of technology, (iii) demonstration and extension, and (iv) other means of vetiver utilization. There were 27 agencies cooperating under the scheme in the first phase, with considerable success in each, especially in research, although there are a number of issues which have to be monitored more effectively.
4. The Committee has already prepared a master plan for the second phase of the programme (1997-99), with the objective of coordinating activities among various agencies, arranging the budget, and evaluating the work accomplished in order to satisfy His Majesty's Initiative.
A few success stories from the results of the research and development work during the past phase will be highhlighted in the present paper.
Lu ShengLuan, He XiangYi, Xiong GuoGen and Xie MeiGen (JiangXi Provincial Institute of Red Earth, JinXian, JiangXi 331717, China)
Zhen QiFang (Soil and Fertilizer Division, Bureau of Land Administration, JiangXi Province)
This paper deals with the growth and adaptability of vetiver on bare, severely eroded low hills composed of red earth. Vetiver grasses are more drought resistant, cold hardy and perform better with infertile soils than all local wild grasses. They are very effective in soil and water conservation due to their quick growth, numerous tillers and fast hedge formation. Their thick leaves and stems, once returned to the soil, are advantageous to soil physical properties and soil fertility. These as well as other benefits, make vetiver grass suitable for growth on the vast red earth hill areas in southern China and are worth extending to new locations.
Ao HuiXiu, He DaoQuan and Xia HanPing (Laboratory of Ecology, South China Institute of Botany, Academia Sinica, GuangZhou 510650, China)
In the experimental sites at WuHua, XingNing and other counties in GuangDong Province, vetiver grass, though planted in various eroded gullies, or dams or on slopes with thin and infertile soils, usually grew vigorously. Those planted in XingNing reached a height of 1 m by the sixth month after transplanting, with a average tillering rate of 10-15 slips, and a maximum of 50-60 slips per clump. Vetiver could form a closed belt in a timely manner and therefore could function well in soil and water conservation. Experiments showed that vetiver grass grew normally in eroded areas in GuangDong Province and could be extended to more areas in the future. However, further extension requires more profound research.
Huang BuHan and Zhang JingXi (South China Institute of Botany, CAS, GuangZhou 510650, China)
This paper introduces the series of investigations, studies and experiments conducted by the authors and others in the late 1950's, on wild vetiver grass found in large areas around HuaZhou, GuangDong Province, China.
1. A great deal of information was obtained through a large scale field survey, including details of the morphological features of vetiver, distribution and the estimated reserves of wild vetiver.
2. Studies were conducted on the vetiver growing environment, i.e. landform, climate and soil conditions. Research showed that vetiver grass grew well in special local environments with alternating dry and moist conditions, growing in moist summers while flowering and fruiting in dry winters. It has shown that vetiver being a mesophyll-mesophyte type of plant with a wide range of adaptability could tolerate both water-logging and drought.
3. Research on the extraction, analysis and perfume test of wild vetiver oil and on the identification of wild vetiver fibre quality for paper making have verified the value of utilizing vetiver. As a result, vetiver grass has been put into industrial use. Tests have also proven that the quality of oil and fibre derived from wild vetiver is as good as that derived from common vetiver. The authors consider wild vetiver as a new kind of vetiver with a fine prospect for development and suggest that the authorities concerned should pay more attention to it.
4. Impacts of local environmental conditions on the oil content of vetiver roots and paper production of vetiver fibres were analyzed. Research showed that vetiver grass grew more luxuriantly in moist fields than in dry lands. However, perfume concentration of vetiver found in dry locations was higher than that from moist fields. In short, the content of available ingredient and utilization value of vetiver from dry sites was higher than that from moist fields. Research also showed that the rate of paper production for wild vetiver grass fibre grown in moist or wet depressions was lower than that found in aerated soils with less water logging. It is therefore suggested that vetiver grass be planted in loose soils without water logging to obtain higher fibre quality for paper production and superior perfume oil quality.
Paul Truong (Leader, Erosion Control and Slope Stabilisation Group, Resource Sciences Centre, Department of Natural Resources, Brisbane, AUSTRALIA)
The application of the Vetiver Grass Hedge System (VGS) was first developed to protect farmlands from soil erosion. While this application of the VGS still plays a vital role in agricultural lands, its tolerance to highly adverse conditions will have a key role in the increasingly concerned field of environmental protection.
Research and development to date have shown the VGS is highly efficient in soil and water conservation in farmlands which can lead to crop yield improvement and more productive land use practices.
The vetiver plant is highly tolerant to extremely adverse growing conditions and possesses some physical characteristics which can be used for engineering purposes. The three main applications of the VGS are considered to be in the areas of:
1. Agricultural Lands: The VGS is the most efficient, low cost and effective soil and water conservation system available. Its thick growth has hydraulic properties that can be used to protect flood prone areas from flood erosion. Its roots are highly resistant to nematode attacks thereby providing some protection to horticultural and agricultural crops.
2. Engineering Applications: With a tensile strength equivalent to one third that of mild steel reinforcement, the VGS is highly effective in steep slope stabilisation. The porous barrier and hydraulic characteristics of the vetiver hedges result in a very effective diversion barrier for high water flows.
3. Environmental Applications: A very effective filtering system resulting from the vetiver hedges provides an ideal natural barrier to trap both coarse and fine sediments. In addition, its tolerance to highly adverse growing conditions such as extreme pH or unfavorable levels of Al, Mn, As, Cd, Cr, Ni, Cu etc. provides an ideal plant species for a bio-remedy and rehabilitation of toxic and contaminated lands.
The extent and results of these applications in the Asia-Pacific and southern African regions will be presented.
Xia HanPing and Ao HuiXiu (South China Institute of Botany, Academia Sinica, GuangZhou 510650, China)
Almost all studies and observations on vetiver grass (Vetiveria zizanioides) from around the world during the previous 12 years have indicated that this perennial has a widespread adaptation to diverse environments and a strong resistance to adversity. It is also easy to establish and maintain. Apart from its great success as a biological measure for soil and moisture conservation, vetiver also has a multitude of other functions. It can increase nutrients and moisture in the soil, enhance agricultural microclimates, aid in the recovery of deteriorated eco-systems, ameliorate polluted lands and rehabilitate them vegetatively. Planted in strips vetiver can, also, protect fishponds, orchards, dams, reservoirs, and highway prevent hills from landslides, and so forth. Vetiver itself also has many uses. For example, its tender leaves are a good fodder for livestock, and its old leaves and stems can be used as paper pulp, mulch, manure, fuel, animal bedding thatch, making handicrafts, and so on. The roots of this plant are used to refine an aromatic oil, for use in medicines and pesticides. Therefore, extending vetiver engineering, particularly in mountain villages, is an efficient measure to assist in rural sustainable development. Agricultural ecosystems in which vetiver has acted as a pivot may produce tangible ecological, economic, and social benefits.
For over 10 year now, scientists from home and abroad have conducted a great deal of research on vetiver, and attained many achievements. These will provide a staunch theoretical basis for the large scale application and spread of this biological technique in the future. Obviously, vetiver engineering is an important step toward realizing sustainable agriculture. It has a wide application in soil and moisture conservation and in establishing complex agroecosystems in the tropics and subtropics as well as in mountainous areas of southern China. It is necessary, however, to ensure that publicity, popularization, development, and utilization of this technology be more quickly and extensively spread.
Challenges and Problems in the Use of Vetiver for Watershed Management in the Sub-Mountainand Scarcity Zones of Nashik District (Maharashtra, India)
Prakash B. Pawar (Divisional Soil Conservation Officer (S.C.) Nashik, Department of Soil Conservation and Watershed Management, Maharashtra, India)
Soil and water are the most vital natural resources for the survival of mankind. Proper management of these natural resources on a watershed basis gives excellent results. Otherwise soil degradation is a serious environmental, social and economic problem for the agriculturist. Soil degradation is closely associated with constrained agricultural production and sustainable development. A key component of soil degradation is erosion by rain water i.e. runoff. Vast areas of fertile agricultural land are damaged every year through soil erosion caused by rain water especially in dry areas. There are major challenges in the scientific, technological and financial approaches to finding solutions. Engineering structures for managing catchments are expensive. Vegetative measures such as the use of vetiver is quite inexpensive, and it is promoted through centrally sponsored schemes in India. Accordingly, twelve watersheds comprising two agroclimatic zones with a geographical area of 52,952 hectares were identified for improvement in the Nashik District. Since 1991-1992, 4,855 tones of vetiver slips ( Vetiveria zizanioides) were used for drainage lines and land treatment in watershed management. From this a case study of vetiver for soil and water conservation was conducted.
The results of the case study indicated that the establishment of vetiver and its survival rate were directly correlated to type of soil, depth of soil, quality of planting material and other managerial factors like the problem of stray cattle. In a scarcity zone the use of vetiver as a conservation measure failed except in a few cases of drainage line treatment. In the sub-mountain zone drainage line treatments like live check dams and loose boulder structures showed excellent results while land treatment had only limited success. Instead of planting vetiver merely as a barrier, addition of a minor engineering support gave better results. Vetiver enhanced the infiltration rate of a nearby plantation, arrested fertile slits resulting in profuse growth of vetiver. Besides, the vetiver hedges served as boundry marks which helped tillage operation, especially in dry areas.
In the sub-mountain zone, the survival rate of vetiver was highest with live check dams, supported by minor engineering structures (64.6%). This was followed by loose boulder structures reinforced by vetiver (47.9%). Thirdly, land treatment called contour vegetative hedges had the lowest survival at 41.6%. From the case study it was clearly observed that planting material played an important role in the survival of vetiver, in addition to managerial factors such as stray cattle. The overall conclusion was that a dry spell adversely affected the survival rate of vetiver. The average number of rainy days in the sub-mountain zone was 75 while in the scarcity zone it was only 25. The dry spell after establishment and the problem of stray cattle caused the mortality of vetiver. However, vetiver in high survival situations gave excellent results in terms of soil erosion control and moisture conservation, which accounted for good returns from the land i.e. crop production. In the present study it was found that sowing along the contour with vegetative hedges gave a 35.3% increased yield of Eleusine caracana in the sub-mountain zone and 32.5% more yield of Sarghrmvulgare, Pennisetum typhoides in the scarcity zone as compared to non treated areas. There was also a significant increase in financial returns for farmers.
An attempt was made in this case study to compile all available information about the personal, social and economic characteristics of farmers and their association with the use vetiver in a watershed management unit.
Paul Truong and Dennis Baker (Leader, Erosion Control and Slope Stabilisation Group, Resource Sciences Centre, Department of Natural Resources, Brisbane, AUSTRALIA)
Research conducted in Queensland has established that vetiver has an extremely high level of tolerance to adverse soil conditions.
Soil conditions Levels
Acidity pH 3.3
Alkalinity pH 9.5
Al ( Sat.%) Between 68% - 87%
Mn > 578 ppm
Salinity (50% yield reduction) 17.5 mS cm-1
Salinity (survived) 47.5 mS cm-1
Sodicity 33% (exchangeable Na)
Magnesicity 20 Cmol/kg (Mg)
Vetiver can also withstand very high levels of heavy metals in the soil.
Arsenic 100 - 250 ppm
Cadmium 20 ppm
Copper 50-100 ppm
Chromium 200 -600 ppm
Nickel 50 -100 ppm
These characteristics make vetiver highly suitable for the rehabilitation of toxic and contaminated lands.
Results on the use of vetiver in the rehabilitation of an old landfill site overburden (contaminated with heavy metals) as well as tailings of coal and gold mines will be discussed.
Ao HuiXiu, Xia HanPing, Liu ShiZhong and He DaoQuan (South China Institute of Botany, Academia Sinica, GuangZhou, 510650)
Vetiveria zizanioides, a perennial grass, has broad adaptations and a strong resistance to adversity. This plant grows rapidly and produces a strong and massive root system. It has been widely demonstrated that vetiver can effectively prevent soil erosion. Introduced by the World Bank and the Vetiver Network, the South China Institute of Botany (SCIB) since 1989 has begun to carry out experiments with vetiver hedgerows, with good results on erosion control and rehabilitation of deteriorated ecosystems on slopes. In order to magnify and spread the achievements, the SCIB collaborated with the GuangDong Provincial Highway Bureau(GPHB) in 1995 to conduct a trial on prevention of highway embankment landslides with vetiver hedgerows along National Highway No. 105. After six months, the hedgerows turned the barren road embankments green, and distinctly reduced soil erosion and water runoff. SCIB and GPHB were both satisfied with the results and were willing to continue cooperating with each other. Thus, in 1996 both sides continued conducting a similar experiment with this biological treatment on a dangerous and unstable section along the First-Ring Highway around GuangZhou. Vetiver grew to 150-200 cm high and produced 18-20 tillers per clump after being planted 5-6 months. Neat and luxuriant hedgerows formed which effectively slowed down and more evenly distributed the runoff. This prominently halted the soil erosion and ended the threat of a landslide. On the opposite embankment of the highway, Mimosa sepiaria was planted to "protect" the slope and acted as the control treatment. However, the whole slope, during the same period, was severely destroyed. Six large gullies with an average depth of 1-1.3 m by 20 m long along with a dozen small rills formed as a result of the impetus of rain water and the impotent protection from M. sepiaria. The two measures formed a sharp contrast.
The trial indicates that it is absolutely imperative to plant vetiver along contour lines and less than 15 cm apart between clumps to ensure that hedgerows can effectively protect slopes. It is best to apply fertilizer to the plants, including basal manure and top dressing, for highway embankments are usually very infertile. Certainly, cutting back the tops to 30-40 cm above the ground before flowering is also a good management practice, which can reduce the consumption of nutrients and promote tiller formation. As a matter of fact, civil engineering such as sand bags and dams are usually indispensable when trying to establish the vetiver technology. Biological hedgerows can be established more rapidly and efficiently in conjunction with civil engineering.
It is much better to combine vetiver with trees, shrubs and creepers that are adapted to the local environment when employing biological engineering. This combination can make roadsides not only more stable, but more beautiful as well. There are several kinds of plants, including Acacia auricuiformis, A. mangium, Pinus elliotii, Lespedeza formosa, Milinis minutflora, and so on, which behaved well in the trials.
Applying biological measures for protecting and beautifying highways has produced positive ecological, economic and social benefits. The vetiver technology certainly has a broad development perspective for the whole of southern China.
Zheng ChunRong, Tu Cong and Chen HuaiMan* (Institute of Soil Science, Academia Sinica, NanJing 210008)
The possibility of purifying eutrophic water with vetiver was tested and described in the present paper. Vetiver was grown in river water polluted by domestic sewage, in pond water and in tap water using the "floating island" technique. During a 4 week culture, vetiver grew normally in these three water bodies, but did the best in river water. Net increases in plant height were 80 cm, 60 cm and 50 cm with tillers numbering 4, 1 and 0 for river water, pond water and tap water, respectively. The sight characteristics of river and pond water were apparently improved and transparency increased after planting vetiver. For river water, the total N and water-soluble P removed was 34.1%, and 68.1% after 1 week of growth, respectively; the removal rate was up to 99% for P after 3 weeks, and 82% for total N after 4 weeks. The removal of N and P was not as obvious in pond water because of fewer contaminants (0.014 mg N/ L and 0.70 mgP/L). These findings suggested that vetiver is a good plant for purifying eutrophic water and has application potential. Changes in COD, BOD and dissolved oxygen, the optimum growth period, and treatment capacity of vetiver need further study.
* Corresponding author.
Hu JianYe (Agriculture Development United Co., JiangXi Province, NanChang 330002, China)
Xue HuiXian (JiangXi Provincial Institute of Red Earth, JinXian, JiangXi, 331717, China)
Zhou CaiWen (Red Earth Development Bureau, ChongRren County, JiangXi, 344200, China)
This paper deals with the effects of vetiver application on red soil development. Experiments of 3 cultivation models, i.e., 1) contour vetiver hedgerows, 2) contour terrace cultivation, and 3) non-contour cultivation along the slope, were located on slopes with red soil derived from Quaternary clay. Comparison among the 3 models showed the effects of vetiver on conserving soil and water, lowering surface runoff, resisting drought when used as a mulch and maintaining soil moisture in sloping red soils under different rainfall conditions.
Experimental results showed that: (1) The effect of water and soil conservation by vetiver hedgerows established on the upper part of slopes with red soil was better than that of both contour terrace cultivation and non contour cultivation along the slope. The former model reduced runoff by 11.6% and 23.9% and reduced sediment by 24.0% and 36.1% compared to that of the latter two models. The same effects were also found in the following 2 years. (2) The minimum runoff was found after rainfall in the model with the vetiver hedgerow, regardless of whether rainfall was less than 9.9 mm or a of rainstorm was more than 25 mm. Generally speaking, runoff was 1/3 and 1/4 less than those in the contour terrace model and in the non-contour cultivation along the slope, respectively. Experiments also revealed remarkable differences in sediment yields due to variation in the amount of surface runoff. The sediment yield with the vetiver hedgerow (472.7 t/km2(yr) was close to the allowable amount (500 t/km2(yr). This was 0.6 and 1.9 times lower than those in models of contour terrace cultivation and non-contour cultivation along the slope, respectively, while the runoff coefficients were 0.16 and 0.5 times lower, respectively. The reduction of sediment build up minimized nutrient losses in the vetiver hedgerow case. (3) Soil moisture storage at depths of 0-60 cm with a surface mulch of vetiver leaves was obviously higher than with a surface mulch of rice straw or without a surface mulch. A slow and stable loss of moisture was found in soil with vetiver leaf mulch due to slower moisture evaporation. This resulted in drought being delayed by 6-10 days when compared to soils with no mulch, while a delay of only 2-5 days was noted with rice straw mulch. Moreover, fresh vetiver leaves with certain content of crude protein and fat could be used as fodder for cattle.
These experiments were the first successful efforts toward extension of vetiver technology in phase 1 of the red soil project. The provided a good example for red soil development in southern China as well as the soil and water conservation projects in the Yangtze River Basin.
Guo TingFu (Department of Rural Water Conservancy and Soil and Water Conservation, Ministry of Water Conservancy, BeiJing 100761, China)
During his visit to China in 1988, Richard G. Grimshaw, the Chief of the Agricultural Technology Division, Asian Technology Bureau of the World Bank described the function of vetiver in soil and water conservation. It was through his active promotion that vetiver was introduced to some areas in southern China.
This paper summarizes the planting efforts, experimentation and effects of vetiver in China's JiangXi, FuJian and other provinces. In order to accelerate erosion control and the development of agriculture with forestry and pastural production (agroforestry) so as to better serve the national economy and enhance people's lives, the author appeals to authorities concerned to pay more attention to the introduction and cultivation of plants, which are good for water and soil conservation, such as vetiver.
Chen Kai and Hu GuoQin(Department of Horticulture, NanJing University of Agriculture, NanJing, 210014)
Rao HuiMao, Xu LinHua and Wu HuaQing (County's Office of Foreign Capital Projects, LinChuan, JiangXi Province)
Vetiver grass (Vetiveria zizanioides) planted in lines along contour furrows in sloping citrus groves of red soil grew and developed quickly and vigorously with an annual yield of fresh plant matter of about 15t/hm2. The grass was cut and used as a mulch to cover the surface soil under the citrus trees such that the air temperature and soil temperature in the citrus groves were both effectively decreased. At the same time, the relative humidity and moisture content of the soil both increased during periods of high temperatures and drought. In the summer, the strong solar radiation was partly shaded by the vetiver grass fence. There were remarkable benefits in water and soil conservation, as well as improvement in soil structure and fertility. The soil bulk density decreased, while its porosity, pH, organic matter contents, total N, hydrolytic N, available P and K, Ca, Mg, Fe, Mn, Zn, Cu, B, Mo and 20 kinds of amino acids all increased. The citrus trees, therefore, also grew and developed vigorously. Some new information was provided for regional development and comprehensive utilization of red soil resources to obtain sustainable high yields, superior citrus quality, and efficient productivity with low cost in southern China.
Chen LongJiang (Bureau of Water Resources and Electric Power, XingNing 514500)
The County Bureau of Water Resources and Electric Power planted vetiver grass on ridges of sloping farmland as a form of slope protection to test its effect on preventing soil erosion and soil fixation. Two runoff plots were designed on the ridges, one with vetiver grass and the other as a control. During the period from July to December, when the rainfall was 411.8 mm, the runoff modules was 183.2 dm3/m2 for the vetiver plot and 259.4 dm3/m2 for the control, or 29% less for the vetiver plot. The amount of soil erosion was 1.6 kg/m2 for the vetiver plot and 4.8 kg/m2 for the control, or 67% less for the vetiver plot. Within the 0-20 cm soil layer depth, the average water holding capacity was 22.8% for the vetiver plot, and 16.3% for the control. The results showed that vetiver grass acted well in preventing soil erosion and maintaining ridge stabilization. It also aided the soil moisture holding capacity thereby enhancing soil moisture. In addition, the actual dry weight of the grass was up to 55.6 kg/ha (834.0 kg/mu). The grass could therefore also be used as a fertilizer suitable for the fruit tree.
Chai Zong and Zhang Ning (ChengDu Institute of Mountain Disaster and Environment, The Chinese Academy of Sciences, The Ministry of Water Conservation, ChengDu 610021, China)
The authors briefly introduced the results and benefits of the application of vetiver hedgerows in soil and water conservation as well as the application of vetiver leaves as soil mulch in 1) India and 2) FuJian and JiangXi Provinces in China. However, they also pointed out some problems remained to be solved when planting of vetiver grass. For example, vetiver grass returned much fewer economic benefits than other cash crops in populated areas with limited land resources when their roots could not be used to make the perfume extract. Moreover, vetiver grass planted together with other crops or fruit trees might compete for soil moisture and nutrients creating a detrimental growth effect on the other crops. Finally, vetiver grass proved to be susceptible to pest and disease attacks.
Considering the weaknesses of vetiver, the authors suggested that the following could improve vetiver development:
1. Vetiver should be planted in areas south of a line formed by the QinLing-FuNiu Mountains in Central-China at elevations < 2000 m.
2. Vetiver should be extended stressing its advantages on bare hillsides in populated areas with limited land resources.
3. Mixed hedgerows composed of vetiver and other cash crops should be developed.
4. Focus should concentrate on studies to eliminate pest and disease attacks upon vetiver.
Liao BaoWen, Zheng DeZhang and Zheng SongFa(Institute of Tropical Forestry, Chinese Academy of Forestry,GuangZhou 510520, China)
Three experimental sites were arranged in an artificial Eucalyptus (E. ABL No. 12) forest afforested in April, 1991 in YangXi County, GuangDong Province, China. They were: (1) lines of vetiver planted between 2 lines of Eucalyptus; (2) lines of stylosanthes guianensis planted between 2 lines of Eucalyptus, and (3) a control with no grass planted under the trees. The runoff field was arranged to observe rainfall, surface soil and water losses. Results of a 3-year observation showed that surface runoff in site 1 was 20351 t/hm2, 15.2% less than that in site 2 and 51.1% less than that in control site 3. Similar results were found in cases of nutrient loss in solid and liquid. It was concluded that vetiver was not only good for soil and water conservation but also good for forest development.
Contribution of Vetiver Grass to Sustainable Agricultural Development in the Hilly Red Soil Region
Lu ShengLuan and Zhong JiaYou (Red Soil & Hill Comprehensive Experiment Station, DongXiang County, JiangXi Province, 331800)
Soil erosion and soil degradation is a serious problem existing in the hilly red soil region of southern China, where an area of soil erosion has increased from 71,000 km2 in the 1950's to 200,000 km2 in the 1980's. Statistical data reveal that 0.7 billion tons of topsoil, 160,000 tons of organic matter and 100,000 tons of mineral nutritional elements are lost every year in the nine provinces of southeastern China which are located in the subtropical region. Massive soil erosion, which leads to declines in soil fertility and crop yield, is one of the principal obstacles to sustainable agricultural development in hilly red soil regions. Surveys and studies in JiangXi Province show that vetiver grass contour hedgerows offer one practical technology to address this problem.
1. Vigorous hedgerows of vetiver grass with their dense root system formed 1 or 2 years after the grass was planted. They constituted a biological soil moisture retention system effective for soil erosion control by fixing soil particles and conserving soil moisture. Observations at standard runoff sites in farmlands with a slope of 5-6 % showed that, compared to a control, there was a 32.7% decrease in runoff. This was a 21.4 t/hm2/yr decrease in soil loss resulting from vetiver hedgerows of 1 m in height. Soils could be preserved in this way, providing a base for sustainable agricultural development in hilly red soil areas.
2. In fields with a vetiver hedgerow arrangement, with dry and high temperature conditions, air and soil temperature decreased and surface water evaporation decreased while humidity increased.. In cold winters adequate temperatures could be maintained and frost damage could be minimized as the convection and diffusion of cold air could be buffered by the hedgerows. An improved ecological environment with stabilized hydrothermal conditions therefore formed to promote the sustainable agricultural development in hilly red soil areas.
3. Large quantities of biomass were generated with the quick tillering of vetiver grass. As a result an increased amount of organic matter accumulated in the soils as a large quantity of vetiver materials, naturally decayed or artificially applied, entered the soil layers. Fertile soils formed in this way constituted a fertility base for sustainable agricultural development.
4. Vetiver grass does not threaten the growth of crops as most weeds do because they develop without rhizomes or creeping stems and do not propagate by seeds. Therefore, they may be planted in orchards and crop fields using appropriate designs and forming sustainable multilayered integrated agricultural systems such as fruit-grass or crop-grass combinations.
Fu DongYue and Wei XiChun (ShaWu City Office of Soil and Water Conservation, FuJian Province)
Vetiver grass was introduced in 1988 for two soil erosion control trials in a newly cultivated orchard in YueWang-Long, ShuiBe Township and in an integrated small watershed management project in DaFuGang. 1) In the former case, vetiver grass was planted in holes along contour lines, between 2 adjacent tree lines with a hole interval of 10-15 cm. A clump consisting of 3-5 slips of vetiver was planted in each hole with a small amount of compound fertilizer (at a rate of 450 kg/ha). Eight months later, vetiver clumps had grown to an average height of 120 cm, with a maximum of. 200 cm. By August, vetiver clumps, planted in early April had tillered to 25 slips each and formed a continuous hedgerow, stopping the mud carried in the runoff. A remarkable earth ridge, consisting of mud and sand was found on the rear side of each hedgerow. It was expected that a terrace would form on these newly formed earth ridges in 5-6 years.
(2) In the latter case, vetiver grass was planted on contours of eroded sloping surfaces using the following characteristics: a) line interval: 30 cm, b) clump interval (holes): 10-15 cm, c) number of slips for each clump: 4-7, and d) amount of compound fertilizer applied in each hole while planting: 450 kg/ha. As the grass grew, sloping surfaces were largely covered by thick grass clumps thereby effectively controlling splash and sheet erosion. Moreover, soil erosion-resistance was greatly increased as the soil was fixed by the strong vetiver root system.
Three years of experiments showed that the quick growing vetiver grass was indeed an ideal and effective plant for soil and water conservation. The grass height increased an average of 1.3-1.8 cm/day when local temperatures were 22°C or above and reached 1.5-2.0 m by the end of the first year of growth. The hedgerows formed the same year that the grass was planted and were vigorous enough to stop soil losses caused by runoff. Being adaptable to harsh conditions, vetiver grew well in very infertile and severely eroded red soils with very little fertilizer and management even after undergoing a drought lasting for 60 days and a cold period with -7.5°C. The tender leaves of vetiver can be used as cattle fodder while old leaves can be used for perfume extraction for roof thatch, for orchard mulch or for fuel.
Diti Hengchaovanich (Director, Erocon Sdn Bhd P.O. Box 10639, Kuala Lumpur, Malaysia)
Use of vegetation (grass and trees) for erosion mitigation and slope stability enhancement has been implemented since time immemorial, mostly based on successful applications of preceding cases. The increasing popularity in the last decade of a vegetative ("soft") approach by using trees for slope stabilization has gained favour over a "hard" approach of using inert man-made materials. This has been due to the concern over the degradation of the environment caused by development, coupled with the fact that more knowledge and information on vegetation have now come to light to aid in engineering designs.
Vetiver, until very recently a relatively unknown plant, possesses some unique features of both grasses and trees by having a profuse, deep penetrating root system that can offer both erosion prevention and can control movement of surface earthen materials, a precursor to slope stability solutions. Parameters obtained from recent experiments revealed that vetiver grass roots are very strong with an average tensile strength of 75 MPa or one-third that of mild steel. The massive root system also increases the shear strength of the soil, thereby enhancing slope stability appreciably. Engineers or designers working with sloping land will find it more helpful now to have some quantitative data available to provide an engineering 'answer' to stability issues, when employing vetiver grass. Successful application models of vetiver grass for slope stability enhancement and erosion mitigition measures for highway projects in Malaysia are described.
Zheng ZhongDeng and Huang XiuSheng (FuJian Academy of Agricultural Sciences, FuZhou, FuJian 350013)
This topic is one of the research projects from the "Second Chinese Red Soil Project" in FuJian Province. By establishing special plots for runoff experiments, the effects of different cropping systems and biological practices on soil and water conservation have been studied. There were 4 treatments including: 1): no forage grasses planted on terraces; 2) vetiver grass planted on terrace banks; 3) no forage grasses planted on slopes; 4) 50 cm wide Premier Fingergrass strips planted between tree rows on the slopes. In the treatments with grasses, terraces were planted with Pinto peanut or Wynn cassia in Two replications. The area for each plot was 4¡Á25 m2 and a 500¡Á500¡Á25 mm prefabricated cement block was placed between two plots. A water-collecting (or sand-collecting) pool, for water storage was built in each plot. Also a set of meteorological observation instruments was installed in the experimental area. Plum seedlings as well as various grass species were planted before April, 1995. Since January, 1997, formal observations have been performed. Meteorological observations on the main components, run-off amounts of soil and water, and moisture content in the soil layers were measured according to the requisites issued by Chinese Agricultural Ministry.
The preliminary results of a half-year's observation showed that planting on slopes without any biological practices caused serious run-off; planting grass strips on slopes and covering the terrace surface with Pinto peanut may prevent the soil surface from erosion; not planting forage grasses on the terraces with frontal banks and rear-ditches, although eliminating serious run-off ended up with the front bank being leveled and the rear-ditches being filled with soil in the one and half year's observation. Soil erosion occurred when the torrential rains came. In the treatment where forage grasses were planted on terraces, grass barriers formed on the banks. In a half-year's time, the terraces were covered by grass, the banks and ditches were well maintained, and the run-off loss did not occur, especially in plots where vetiver grass was planted. The ground surface and soil layer temperatures were directly affected by the vegetation on the soil surface. In the treatments covered by plants and grasses, the temperature was lower in the summer and higher in the winter compare with treatments not covered by plants and grasses. Since January 5, 1997, the moisture content in different treatment plots was tested every 5 days. Data taken 39 times showed a regular pattern in which the moisture content in plant-covered plots was higher than that in the bare plots. The upper, middle and lower soil layers showed the same tendency. The nutrition loss in the run-off experiments will be analysed soon.
Ding GuanMin (FuJian Experimental Station of Soil and Water Conservation)
Vetiver was introduced to northern FuJian Province, as well as JianYang, and ShaoWu Counties from HaiNan Province, China, in the 1950's, when it was used as a perfume crop, with economic benefits. Afterwards, however, it reverted to a kind of wild grass. Recently, Mr. Grimshaw, Agricultural Department Chief from the World Bank, introduced the grass for soil and water conservation. FuJian Experimental Station of Soil and Water Conservation then began to conduct a study using vetiver to harness soil and water loss in JianYang County in the north, AnXi County in the south, and coastal PingTan County. The results showed that vetiver is suitable for planting throughout the province, because of its acid and alkali tolerance. It has significant effects in harnessing eroded laterite slopes, especially on controlling rock slides in granite areas. Vetiver hedges can protect the cultivated land on slopes; moreover, it can also play a role in wind protection and sand stabilization along the highways and rivers as well as in the coastal areas. The stems and leaves of vetiver can be used in the cultivation of edible fungi, which can bring direct economic benefits. At present, however, vetiver extension is still in the preliminary stages, and it is necessary to do further studies.
Cheng Hong (NanChang Water Conservancy and Hydro-Power College, Ministry of Water Conservancy, NanChang 330029, China)
Analysis of 6 experiments introducing vetiver grass, in northern China, southern China and their transition areas, showed that: (1). Regardless of high or low latitudes, vetiver grasses, planted in a standardized way, all grew normally, with a survival rate ranging from a the maximum of 100% (GuiXi, JiangXi Province) to a minimum of 61% (ChangShan, ZheJiang Province). (2). Vetiver grasses grew quickly, with 2 growth peaks during their growing period. Among the 4 experimental sites, the quickest growth was found in HaiNan while the slowest was found in ChangShan. (3). The maximum tillering number was over 20 while the minimum was greater than 6. Study also showed that the increase in the number of tillers on vetiver roots could be represented by the equation
where a and b varied at different latitudes. Finally, (4) adequate pruning of the parts above the ground of vetiver in a suitable season promoted root tillering.
Xia HanPing, Ao HuiXiu and He DaoQuan (South China Institute of Botany, CAS, GuangZhou 510650, China)
The authors deal with the impacts of some environmental factors, shading fertilization and pruning on the growth of vetiver grass.
1. Impacts of shading on the growth of vetiver. The growth and development of vetiver were remarkably inhibited by shading. Measurements of the net growth in height of vetiver grass showed a difference of 90.8 cm between grass inhibited by shading compared to no shading. This resulted even though shading was only applied for 3.5 months during the 9 month long growing season lasting from March to November. Measured during the peak of the growing season, the average dry weight of slips without shading was 2.43 times more than with shading. The number of tillers per clump without shading was 82.9% more than with shading. Experiments also showed that the removal of shading during the growing season may quicken the growth of vetiver grass. However, recovery of both height and accumulated dry matter was slower and that of tillering was quicker.
2. Impacts of fertilization and pruning on the growth of vetiver. Experiments showed that vetiver grass could grow on infertile laterite and that fertilizer (urea) application increased plant height and number of tillers. According to the second set of measurements after fertilization, the number of tillers in the fertilized clumps averaged 90% more than those without fertilization. However, ceasing fertilizer application reduced the growth rate of the originally fertilized grass clumps to the same level as those without any fertilization. Also no remarkable increase in dry matter accumulation due to fertilization was noted over this short time. Therefore, accelerating vetiver tillering will be an important topic in vetiver study.
Vetiver tillering may be promoted by moderate pruning at appropriate times. Pruning before earring could aid vetiver growth and tillering. Only limited pruning, i.e. conducted in early spring and early autumn, was considered beneficial for vetiver development.
Zhang Jing (FuZhou City Office for Soil and Water Conservation, FuZhou 350005, China)
Situated off the east coast of FuJian Province, PingTan Island ranks 5th in size among China's islands. It often suffers from natural disasters, such as Typhoons and severe rainstorms. Since 1991, vetiver grasses have been successfully planted on the island to prevent wind damage, to fix sand dunes and to protect the coastal seashore.
1. Setting up seedling nurseries
In March and April, 1992, 555 clumps of vetiver, each including 3 slips were planted at 20 x30 cm intervals between clumps, in the forest at ChengGuan, PingTan. A full four months after planting, in addition to through watering, liquid manure was applied to the vetiver. By the end of July, the vetiver grass was pruned to 30 cm. According to observations in November of the same year, most of the grass had grown to a height of 180 cm and some to more than 200 cm. The clumps had tillered to as many as 117 slips each. In addition a layering trial was successful. Clumps layered on July 16 were more than 100 cm tall in November. This nursery provided a material base for further development of vetiver in PingTan.
2. Vetiver hedges as a windbreak
The windbreak hedge experiment in wind channels showed that a hedge could be formed in a short time due to the excellent growth of vetiver in adverse conditions. Vetiver could be developed even in very marginal climatic conditions.
(1). In order to form a closed vetiver hedge as quickly as possible, in the early stage of planting it was necessary to set up an artificial windbreak in the wind stream to weaken the force of the wind.
(2). In places with the strongest wind, it was suggested that vetiver rows be parallel to the wind's direction so that the wind resistance of the hedge would be strengthened. A sheltering windbreak formed as soon as the hedges closed.
In addition, technicians have succeeded in planting vetiver in cash crop gardens to minimize the wind speed and to fix drifting sands. Vetiver hedgerows have also been used to protect embankments and slopes of hills.
Xia HanPing (South China Institute of Botany, Academia Sinica, GuangZhou 510650)
Vetiver grass (Vetiveria zizanioides) was introduced to China in the middle 1950's. Since then some multiplication, cultivation and management experiments on this plant have been conducted. The purpose for introducing vetiver was the production of essential oil from the vetiver roots. Seedlings were quite scarce at that time; so experiments concentrated on two aspects: firstly, on the rapid multiplication of seedlings, and secondly on breeding roots that yielded oil of high quality and high content. This paper summarizes these two aspects of the experiments and surveys.
Besides the general practice of propagation by division of roots, other successful propagation methods included: 1)multiplication by stem-culm cuttings, 2)multiplication by pedicel-culm cuttings, 3)multiplication by longitudinal-slit stems, and 4)multiplication through pruning tops. Cultivation techniques that promoted rapid field establishment were: 1)water-cultivation to accelerate root growth, 2)heeling-in to improve root establishment, 3)dipping roots, 4)oblique planting, and 5) retaining mother tillers left in the soil.
Management measures developed from experiments that enhanced tillering rates consisted of: 1)intensive cultivation while strengthening management, 2) proper pruning, and 3)rational close planting.
In addition, several unanswered questions remained: 1)How deep should vetiver be planted, shallow or deep? 2)How long should vetiver roots be kept, long or short? 3)How many tillers per clump should be planted, one, two, three or more?
Obviously, these successful propagation, cultivation, and management methods can play an instructive role and be used as a reference for future work.
Gao WeiSen, Zhang Ning and Zhang XinBao(ChengDu Institute of Mountain Disaster and Environment, The Chinese Academy of Science and the Ministry of Water Conservation, ChengDu 510021, China)
Experiments introducing vetiver were allocated to different regions in the SiChuan Basin, i.e., DeYang in the plains area, JianYang in the hilly area, PingShan and DuJiangYan in areas around the basin as well as HuiLi and PanZhiHua in mountain areas of southwestern SiChuan. Comparison analyses were conducted on growth including the date the grass turned green and tillered, growth height, etc. in 4 types of soils in the 4 different types of locations.\
Results showed that: (1). Vetiver grew best in sandy alluvial soils with high fertility and good aeration; it grew fairly well in cultivated sandy yellow soils and the red soils; and it grew poorly in cultivated yellow clay soils. (2). Vetiver seedling growth varied greatly in different temperature regimes. For example, in the trial sites in DuJiangYan, a continuous rainy period with low temperatures resulted in a prolonged period of 34 days after transplanting before the vetiver turned green. Meanwhile at the HuiLi sites with adequate temperatures only a short 12 day period was needed after the vetiver was transplanted in March, before it turned green resulting in a survival rate of 70%. Moreover, an even short period of 6 days was needed with a 95% survival rate, for grass transplanted in July at higher temperatures. Experimental results showed that the optimum average daily temperature for vetiver transplanting was 17.1°C. (3). These hydrothermal conditions directly influenced the net growth of vetiver. For example, vetiver in PanZhiHua grew under the worst hydrothemal conditions and produced less than half of the biomass of grass grown in the JianYang region which had adquate temperature and plentiful rainfall. (4). In the first year of introduction, better management including sufficient water and fertilizer application was needed to pass safely through this period of adaptation.
Chen XuHui and Xia JinHui(Institute of Soil and Fertilizer, GuiZhou Provincial Academy of Agriculture, GuiYang 550006, China)
Ronald D. Hill (Department of Ecology and Taxonomy, University of Hong Kong)
Severe soil and water losses are found in GuiZhou Province where 97% of the territory is covered by mountains and hills. Experiments showed that soil erosion might be effectively controlled and sloping fields may be gradually transformed into terraces by arranging contour lines of shrubs or perennial grasses. Aimed at accelerating vetiver growth and promoting the formation of hedgerows for soil erosion control, a study on vetiver was jointly started in 1995 by the GuiZhou Provincial Academy of Agriculture and the University of Hong kong.
The study showed that no remarkable differences were found between the vetiver hedgerows with fertilization and those without fertilization on farmlands where vetiver grew vigorously and hedgerows formed quickly. Furthermore, it was found that the time necessary for vetiver grass to turn green after transplanting might be lengthened and survival rate of the vetiver might be reduced by fertilization at transplanting. It is suggested that fertilizer as a dressing be applied on vetiver planted on farmlands after transplanting.
As for vetiver planted on infertile sloping farmlands, organic manures were found to be much better than chemical fertilizers, but organic manures applied together with N, P and K fertilizers proved to be the best. A trial of various fertilizer prescription showed that the survival rate, the growth vigor and the biomass yield of vetiver were negatively affected by a lack of phosphorus. It was also found that when applying N, P and K, it was better to apply them separately at multiple times than to apply them together at one time with transplanting.
Fertilization was found to be helpful in promoting the formation of contour vetiver hedgerows on infertile sloping lands. According to data in 1996, surface runoff could be reduced by 25% and soil erosion could be reduced by 55% from hedgerows with the fertilization treatment in comparison to those without fertilization. It was concluded that soil and water losses on infertile sloping lands could be effectively controlled by fertilized vetiver hedgerows.
A. Muthusankaranarayanan, U. Solaiappan and S. Senthivel (Regional Research Station, Agricultural University, Arnppukkottan 626107, Tamilnadu, India)
Field investigations were carried out at a Regional Research Station, Tamilnadu Agricultural University, Arnppukkottan on various planting techniques for vetiver slips in rainfed vertisols during the rainy seasons of 1991-92, 1993-94 and 1994-95. The treatment combinations comprised four planing methods viz 1) single row planting with an Azospirillum root treatment, 2) zig-zag planting with an Azospirillum root treatment, 3) single row planting without Azospirilllum and 4) zig-zag planting without Azospirillum in the main plot with three spacing distances between the plants viz. 10 cm, 15 cm and 20 cm in the subplots. The experiment utilized in a split plot design with three replications.
The mean tiller counts were observed at both the vegetative (30.3 tillers/hill) and the flowering stages (32.4 tillers/hill) when vetiver slips were planted in the zig-zag manner with an Azospirillum root treatment. The Azospirillum treated vetiver slips planted in a zig-zag manner maintained a high level of soil moisture and produced higher seed cotton yield (352 kg/ha) compared to other planting methods.
Among the various planting intervals, a wider spacing (20 cm intervals) recorded higher mean tiller numbers at the vegetative (29.4 tillers/hill) and the flowering stages (31.0 tillers/hill). This was comparable to 15 cm spacing which maintained a higher level soil moisture profile.
Hence, it can be concluded that for better establishment of vetiver and for getting favourable benefits from the vetiver hedge, vetiver slips may be planted in a zig-zag manner with roots dipped in an Azospirillum solution, then planted at a 15 to 20 cm spacing between the slips, in rainfed vertisols.
U. Solaiappan, S. Senthivel and A. Muthusankaranarayanan (Regional Research Station, Tamilnadu Agricultural University, Aruppukkottan 626107, Tamilnadu, India)
Field experiments were conducted at the Regional Research Station, Tamilnadu Agricultural University, Aruppukkottan on different agro-techniques for establishment of vetiver slips in rainfed vertisols during the rainy seasons of 1993-94 and 1994-95 using a split plot design with three replications.
The main plot treatments consisted of six planting times for vetiver slips after uprooting viz., 6 hours, 12 hours, 18 hours, 24 hours, 30 hours and 36 hours and the subplot contained three root dipping techniques viz., 1) Azospirillum, 2) a 5% glucose solution and 3) a 5% jaggary solution. It was observed that the establishment of the vetiver slips was higher when they were planted within 18 hours after uprooting and gradually decreased with further delay in planting time. Establishment was 97.9% when planting was done within 6 hours of uprooting, while it was 81.4% when planting was done after 36 hours of uprooting. There was not much difference in the establishment rate when considering root dipping in nutrient solutions.
The mean tiller count and plant height were observed 8 months after planting. All the biometric observations were higher when planting the vetiver slips within 6 hours. Vetiver slips planted 6 hours after uprooting had a higher mean plant height (107.8 cm), and number of tillers (26.2 tillers/hill), where as, the vetiver slips planter 36 hours after uprooting had the lowest mean plant height (96.2 cm) and number of tillers (24.1 tillers/hill). Among the root dipping techniques, roots of vetiver slips dipped in the Azospirillum solution had a higher tiller number (27.9 tillers/hill), while roots dipped in the 5% glucose solution had higher plant height (110.0 cm) than the other treatments. Lesser plant heights (94.1 cm) and tiller numbers (21.5 tillers/hill) were recorded with the roots of slips dipped in the jaggery solution.
Hence, it can be concluded that the vetiver slips should be planted within 24 hours of uprooting for better establishment and the roots may be dipped either in Azospirillum or in a 5% glucose solution for better growth in rainfed vertisols.
Ding GuangMin(FuJian Provincial Soil and Water Conservation Experiment Station)
Fang HouDe (JianYang County Office of Soil and Water Conservation, FuJian Province)
Vetiver, a perennial grass, usually reproduces by tillers. Procedures for raising seedlings in various vetiver nurseries in FuJian Province are as follows: (1) Nursery preparation: nurseries are to be arranged in sand along gentle flowing rivers and in flat or slightly sloping fields with convenient transportation and a plentiful water supply. (2) Seedling cultivation: seedlings are cultivated in flat nurseries without a table or ridge arrangement. Clumps of vetiver, 3-5 slips each, pruned to a stem and leaf height of about 20 cm with roots about 10 cm long, are planted along contours in V-shaped holes, 10-15 cm in depth and spaced at 30 x30 cm. The planting season lasts from March to June with the optimum time being in March. Maximum survival rate and the most vigorous growth are found in vetiver seedlings planted in March while a decreased survival rate is found in those planted after June. About 300 kg/ha of fertilizer (urea) are dressed in holes, 15 cm deep and 5 cm from vetiver clumps, when the newly planted seedlings are turning green. (3) Management: timely planting and adequate management are helpful to ensure seedling growth with a survival rate of 100%. For more tillering and higher yields, the following management measures are needed: (a) timely irrigation in the first 15 days of green up, (b) irrigation 1-2 times during drought periods; weeding and (c) fertilizing at the peak of tillering in August and September. (4) Transplanting: seedlings will be ready for transplanting the following spring. Before being taken out of the nursery, vetiver grass should be pruned as seedlings with roots 10 cm long and stems and leaves 20 cm high. A 1 ha nursery needs 7,500 kg of seed vetiver grass and can produce 52,500 kg of seedlings as well as provide protection for 40-60 ha of terraced fields or 70-100 ha of sloping fields.
Zhou FuJian(Water and Soil Conservation Station of FuJian Province)
Xu LiYu (Institute of Soil Science, Academia Sinica, NanJing)
FuJian Province is located in the southeast area of the country, 23°33'-28°19' N, 115°50'-120° 43°E, with an area of 120,000 sq km and a population of 30,000,000 (1990). About 85% of the area is mountainous or hilly. In this southern subtropical climate, a deep weathered, red crust several meters to dozens of meters thick has formed.
In addition, there is a long coast line in FuJian Province, (3,324 km) and there are more than 1,200 islands. Most of these areas are covered by white sands which contain a high level of salts and are subject to wind erosion. Therefore, plants rarely grow well or even survive.
In the late 1980's the Red Soil Project supported by the World Bank introduced vetiver technology to southern China. Since 1988, vetiver has spread to a large area involving many counties such as JianYang, ShaoWu, GuangZe, ShunChang, AnXi, ChangLe, PingTan, SongXi, PuCheng, etc. About 200,000 kg of plant materials were produced of which some were exported to the neighboring provinces of JiangXi, HuNan, SiChuan, ShanDong, AnHui, and ShanXi. Besides the National Vetiver Conference held in ShaoWu in 1989, a workshop was held in SongXi organized by NanPing Prefecture. Vetiver planting was mainly organized by the local Agricultural Foreign Investment Offices involved in the Red Soil Project and also water and soil conservation stations.
Experience showed that vetiver could grow in extreme soil conditions such as the semi-weathered granite materials covering a large area in southern China, where the soil was almost completely eroded. The vetiver in these areas was planted along contour-line where other plants could not survive. The trial in AnXi County showed that after 3-5 years the barren land accumulated some litter, and other grasses, shrubs, and trees gradually took hold. At last, the barren and gullied land was completely covered by multiple layers of plants, shrubs and in particular trees, Meanwhile it was difficult to find the vetiver. So, farmers called vetiver a pioneering grass.
Vetiver was used to protect orchards by the JianYiang Water and Soil Conservation Station and Agricultural Foreign Investment Office. They made 'hill-side ditches' surrounding the hills using a width so that a walking tractor could be operated in a screw thread fashion. Along the ditch embankments vetiver was planted in double-line at a spacing of 20¡Á30 cm without fertilizer application. The next year the grass grew up to 3 m in length, while the roots were 1.5 m deep. The grass was cut 2-3 times a year, which promoted better growth and produced more tillers. The cuttings were used for ground mulch or pulp. About 1-2 years after planting the runoff decreased considerably. Three years after planting, the soil particles were efficiently detained by the vetiver hedges. As the outer-side of the ditches was a little higher than the inner side, the ditches effectively retained the water.
Another use of vetiver grass was with Chinese chestnut widely planted in areas of northern FuJian Province and many other provinces as well. Because of soil erosion the soil fertility declined once the original plantation had been cleared and the young chestnut trees planted. To solve this problem, the HuShan Orchard Plantation in JianYiang County established a vetiver fence on land with a slope of 12% They cleared the degraded Masson's pine and planted chestnuts at a 3 x3 m spacing. In December 1990 instead of establishing terraces, they planted vetiver grass to build hedges along the contours at every 2-3 meters of altitude.. The results showed that vetiver hedges could control soil erosion very efficiently and saved the costs of building terraces.
In FuJian Province, with its long coast line and numerous islands there was also a critical problem with wind erosion. The soil, primarily a coarse white sand, contained very little organic mater and many salts, which made it difficult for most plants to survive. The cultivated lands were frequently buried by sand, while rivers and ditches were continously blocked. Since the 1990's farmers in these areas have planted vetiver under the guidance of technicians. They planted vetiver along ditches, roads, and seashores. In addition, they built windbreak nets of trees with vetiver surrounding the plots to control the wind and sand. Inside the plots they planted the profitable shrub hohoba to produce seeds from which a lubricating oil was extracted. Many other crops and vegetables could also be cultivated in the plots.
It is obvious that vetiver grass can be widely used for cultivation on sloping lands, for wind erosion control, and for the protection of riversand ditches in southern China.
Xu LiYu (Institute of Soil Science, NanJing 210008, China)
Zhang HuaSen (ChangPu Township Forestry Station, YueXi County, AnHui Province,
The HuaiHe River Basin, one of the important grain production bases in China, is located within N 32° - 36°, E 112°- 120° with a total area of 270,000 km2. There are altogether 143,680,000 people in the area with 125,990,000 involved in agriculture. Following population increases, forests have been felled for food production resulting in a seriously deteriorating ecological environment. Dry springs and summer flooding are critical problems in this area as the HuaiHe River is one of the most disaster prone rivers in the country. For example, during the 500 years from 1400 to 1900, there were 350 disastrous floods and 280 droughts. To solve this problem, in the most recent 40 years, thousands of reservoirs were constructed with a total storage capacity of up to 25,000 million cubic meters. However, due to a lack of biological measures the life expectancy of many reservoirs was drastically reduced. The annual sediment deposition in the large and middle reservoirs amounted to 48 million cubic meters.
The DaBie Mountains are one of the principle mountain ranges located in the upper and middle reaches of the HuaiHe River with a total area near 100,000 km2. Most of the parent materials are granite consisting of coarse-particles. Due to various factors, the DaBie Mountain areas remain underdeveloped with a mean annual per capita income of less than 400 Yuan RMB (about US $50). Here there are more than a dozen counties identified as poverty stricken counties by the central government.
In recent years following the national economic reform, farmers and government officers cleared the original vegetation, built earthen terraces and planted tea, mulberry, and chestnut and other commercial trees on a large scale, calling it the "second forestry revolution". Because this kind of production management lacked protection measures, it usually led to more soil erosion, resulting in decreased soil fertility. Consequently, the commercial trees have not grown well. More often, serious soil erosion occurred before commercial trees and new vegetation matured.
Field trials in YueXi County of AnHui Province showed that: (1) vetiver grass could grow well in the proposed project area; and (2) the output of well-protected chestnut orchards on earthen terraces could reach more than 80,000 Yuan (US $10,000)/ha/yr by the 8th year after replanting, while the production value for a control forest was only 27 Yuan (US $3.3)/ha/yr.
The proposed project would introduce and extend vetiver grass to sloping lands, in particular these with commercial tree plantations in reservoir areas of the southern DaBie Mountains in AnHui and HuBei Provinces by: (a) introducing and improving the awareness of the importance of vetiver in soil erosion control, earth work stabilization, disaster prevention, sustainable farming, and other numerous multiple uses, among policy makers, farmers, extension workers and scientists; (b) establishing 14.3 ha (215 mu) of vetiver nurseries; (c) promoting demonstration sites of vetiver protected commercial trees on 66.7 ha (1000 mu); (d) organizing farmer-to-farmer visits and discussions; (e) training extensionists from forestry, from soil and water conservation, from soil and fertilizer stations; and master farmers from villages to grasp vetiver technology used with commercial tree management and related agroforestry technology by organizing training courses and field practice sessions for disseminating training materials; and (f) helping farmers, along with township and county extension stations to produce planting materials through establishment of permanent or temporary nurseries or by using existing vetiver hedges to produce planting materials.
Zhang ZhongYi (Red Soil Station, Liu Jia Zhai, 335211 JiangXi, China)
Xu Liyu (China Vetiver Network, P.O.Box 821, NanJing 210008, China).
PoYang Lake, the largest fresh water lake in China is a lake where all the major rivers of JiangXi Province converge. The lake basin's total drainage area includes an area of 162,225 km2, accounting for 97.2% of JiangXi Province. The depth, area and volume of the lake water fluctuates dramatically with the different seasons. According to investigations, each year sandy sediments from the 5 main rivers into the Yangtze River amount to 10.52 million tons.
In the PoYang Lake area the climate is characterized by strong winds. Due to water and wind power, sandy hills and mobile dunes have formed. According to satellite information there are altogether 17,600 ha (264,000 mu) of sandy land and mobile dunes, covering more than 12 counties. Most of these areas have very little, if any, vegetation. The people in the area have been suffering from windblown sand for years. For example, there were 253 ha (3,800 mu) and 500 houses buried by mobile dunes from 1736-1949 in XingZi County. In XingJian County, about 20 km west of NanChang the capital of JiangXi Province, there were 1,000 ha (15,000 mu) damaged by dunes, and 2 villages were forced to relocate.
In the PoYang Lake area, forest land covers 352,000 ha (5,288,000 mu) with a tree coverage of only 17.8%. In many places, the forestry lands are covered only by sparsely distributed shrubs or young trees with a biomass of 7,500 kg/ha (500 kg/mu). The per capita wood volume is only 0.97 cubic meter.
Fuel shortage is a serious problem in the area. According to partial statistics for 10 counties or cities, there are 686,000 families lacking fuelwood, which is equivalent to 1,114,000 tons of fuelwood. In HuKou County, 85% of the families lack fuelwood, and there are 700,000 workdays spent collecting firewood. In some places, farmers have to travel for 30-40 km, from early morning to late evening, to collect firewood. This is about two months each year for fuelwood collection.
Production trials in PingTan Island, FuZhou City of southern China showed that vetiver grass grew well on coastal dunes in an area where there was once a disaster called "18 villages were buried in one night". Vetiver grass not only stabilized the mobile sands but also acted as a windbreak to protect economic crops, such as hohoba beans, from wind damage. In some areas -- coastal sands and wetlands for instance -- where trees can not grow, vetiver grass grew well due to its deep and strong root system. It has been proven that on sandy land vetiver grew much better and faster than on red clay soils. Seven months after planting two slips of vetiver produced 117 tillers with an average height of 2 meters.
Vetiver can not only withstand different environmental conditions but also produces significant volumes of biomass. Reports from Mississippi in the USA (P.E.Igbokwe, et al, 1991) indicate that the combined root and shoot biomass production after 6 months of regrowth can range from 176,798 kg/ha for one of the accessions to 353,596 kg/ha for another when the plant spacing is 20.3 cm ¡Á 20.3 cm. Experiments in GuangDong Province of China show that vetiver can withstand seasonal flooding and waterlogging which indicates that the grass is quite suitable for sand dune stabilization in the PoYang Lake area where ground water is usually high. Also vetiver can be used for shore line reinforcement where it will survive seasonal waterlogging caused by fluctuating lake water levels. Therefore, it is reasonable to plant vetiver grass on sandy land to stabilize dunes, and at same time to relieve fuel shortages in the PoYang Lake area.
The proposed project will include establishment of a vetiver nursery, a demonstration, training, and extension. The demonstration site will be at FuShan Township, NanChang County where there is some sandy land that covers 667 ha (10,000 mu). The components of the project will include: (a) 6 ha (90 mu) for a vetiver nursery; (b) 40 ha (600 mu) for a demonstration; (c) training courses for extension purposes; and (d) production and dissemination of training materials and posters.
Environmental Group (The Institute of Soil Science, Academia Sinica, P.O.Box 821, NanJing 210008 China)
TaiHu Lake, one of the largest lakes in China is located at around N31(20' and E120(16' with a total area of 2,420 km2, a total volume of 4,870 million cubic meters, and an input flow of 195.0 cubic meters/sec. It is situated in JiangSu Province, ZheJiang Province, and the ShangHai Municipality. With intensive land cultivation in the area farmers have been harvesting their crops 2 to 3 times a year under a high chemical fertilizer input annually averaging 345 kg/ha N and 18 kg/ha P.
Based on research from 1982-1990, the agricultural non-point nitrogen pollution in TaiHu Lake was as high as 35,000 t N/yr, accounting for 25.2% of the total annual N application and resulting in water eutrophication. The water eutrophication was usually concentrated in the closed or semi-closed lakes and slow-flowing rivers (flow rates less than 1 m/min.), which included about one third of all of TaiHu Lake. The eutrophication led to a high content of elemental N, P, and C in the water and nearby soils and resulted in the rapid growth of blue algae, green algae, etc. Consequently, algal blooms occurred while the water transparency and soluble oxygen content declined, leading to the death of many aquatic animals. In many places, a terrible smell was released from the water, influencing people's daily lives.
Studies showed that in the period for 1981-1988, the content of NO3-N in the water of TaiHu Lake doubled. The content of NO3-N in the water of wells and rivers during the dry seasons increased 5-10 times. In the main lakes TaiHu Lake consisting a series of lakes, such as Tai Lake, YiangCheng Lake, Dushu Lake, JinJi Lake, Ge Lake and Jiu Lake, the mean annual inorganic nitrogen content in the water was more than 0.25 mg/L, which was 2.5 times the national safety standard for surface water. As a result, controlling water eutrophication in TaiHu Lake has become a critical environmental issue in the region.
Research indicated that vetiver can survive and grow well in wetlands. It can grow much faster in soils rich in nitrogen. Vetiver as mentioned, with its dramatic biomass growth potential can consume a considerable amount of nitrogen from the soil along the lake and in the areas where the water surface fluctuates seasonally. Because the high nitrogen content is concentrated in the water near the banks of rivers and lakes, planting vetiver grass in wetlands along rivers and around lakes can relieve the eutrophication problem as vetiver contains a certain content of N and P. The vetiver grass planted on banks and slopes along rivers and around lakes can reduce soil erosion caused by backwash generated from boat traffic. In addition, the grass can be harvested for pulp at 80 Yuan RMB /ton of dry matter (about USD10), which can increase farmers' income.
The proposed project will include field trials and a laboratory analysis, a vetiver nursery, a demonstration, training and extension. These will be coordinated by the China Vetiver Network in cooperation with the environmental institute and agricultural extension stations in JiangSu, ShangHai and ZheJiang. A trial plot of 150 m2 will be set up in SuZhou, JiangSu Province to determine the effect of vetiver on the N content in water and waterlogged soils.
Xie FuXin (Agricultural Foreign Investment Department, JianYang County, FuJian Province 354200)
In the past decade, following the national economic reform, highways with different grades have been developed very rapidly throughout the country. For example, in FuJian Province 4,000 km of highways were established from 1992-1996. In FuJian Province the highways were usually constructed on heavily weathered granite, from a few meters to several dozens of meters deep, and were subject to soil erosion and collapse, leading to damaged highways. To protect the highways engineers have had to use rocks and concrete to protect critical sections of the road embankments. There are 2.6 million m2 of road embankment slopes that need to be protected in FuJian Province, however due financial constraints, only a very small percentage of these slopes are reinforced. Therefore, finding a new method of highway construction and protection which is both effective and economical, is an urgent task.
Many examples show that vetiver has a strong fibrous root system that penetrates and binds the earth to a depth of up to 3 m and can withstand the effects of tunneling and cracking. The grass is more effective than hardwood roots as root reinforcement on soil slopes, as clearly demonstrated on extremely unstable and massive highway embankments and cuts in Malaysia (Diti Hengchaovanich and Nimal S. Nilaweera Erocon, 1996). Vetiver quickly forms a dense, permanent hedge, and is therefore an excellent plant for road embankment stabilization. It is much cheaper using vetiver grass than using rocks. For example, in FuJian Province, it costs 30 Yuan/m2 using rocks to protect a road embankment, while only 3 Yuan/m2 using vetiver.
The proposed program will include:
(1) Demonstration: Demonstration sites will be established at JianYang City of FuJian Province, where some vetiver plant experience was obtained over the past decade and where planting materials are available. In 1996, 83.9 km of highway were constructed in JianYang City with cut and fill slopes of 59,000 m2 needing protection. Of this 28,000 m2 are already protected by rocks and concrete, with 31,000 m2 still needing to be stabilized but awaiting funds. The proposed program will use vetiver to stabilize road embankments as a demonstration site for southern China, and FuJian Province in particular. Vetiver will be planted using two models, i.e., A) contour aligned vetiver hedges and B) square mesh planting which combines vertical and horizontal hedges like a honeycomb. To ensure fast and vigorous of the grass as well as effective protection, fertilizers, P in particular, will be applied in some places where the soil is extremely poor. Also the stems will be cut at a height of 30 cm from the ground surface to promote tillering and subsequent hedge strength.
(2) Extension: Field visits and discussions will be organized annually for extension purposes. Lectures will be presented to introduce the basic technology of vetiver planting, and extension materials will be released. The participants will be mainly scientists, engineers, and policymakers, etc. coming from FuJian and other Provinces in southern China. More than 50 participants are expected in 1997 and again in 1998. The proposed program will last two years.
Gu YePing, Wei Xiang and Liu FuCheng (Geography Department of AnHui Normal University, WuHu 241000)
Hill regions of southern AnHui lie to the south of the Yangtze River passing through 15 counties or cities in AnHui Province. The land area of the whole region is 29,000 km2, accounting for more than 1/5 of the total land area of the province. The cultivated land is very limited (about the 10% of the total land area of the region), and the land used for forestry comprises 64% of the region. Also, the population is 491,500, making up less than 1/10 of the total population of the province. The serious soil erosion area covers 1/4 of the whole province.
Necessity of the research work includes:
Firstly, the hill regions of southern AnHui are historically an important forestry base for the province and one of the important tea-producing regions in China. It holds an important position in the economy of the province.
Secondly, the research meets the urgent need to restore and to develop economic forests with forest products or a fruit tree base with traditional special local products.
In the region, there are more than ten products with interregional significance and development potential, such as tung oil, Chinese tallow, Chinese chestnut, loquat and so on. Generally speaking, their output accounts for 50-90% of the output from the whole province. Many species, such as SanTan loquat, ShangFeng snow pear, ShuiDong candied date and HuangShan Chinese chestnut, are special local products once famous in the domestic and international markets. At present, these resources are in decline, their fame is decreasing; and their economic benefits are quiet low. Planting vetiver is urgently needed to protect the production of these economic forest products and fruit trees.
Thirdly, the application of vetiver is a necessity to help control floods, to decrease sediment deposits and to prevent and control siltation of rivers and reservoirs. Since the founding of New China, the soil conservation work has achieved a great deal. However, as a result of the destruction of forest resources, the periods between droughts and floods have been shorten. For example, a dam across a river was built in GuangDe County in 1984. Now, the top of the dam is only 3 m higher than the riverbed. The riverbed of the middle and lower reaches of the QingYi River and the ShuiYang River, main rivers in southern AnHui, have 1-1.5 m of silt deposits. Landslides and mud-rock flows on a large scale have occurred frequently there. So, it is extremely important to establish vetiver hedges in the area.
Fourthly, the application of vetiver can meet the needs of sustainable economic development in the southern AnHui hill regions and can have a profound and lasting effect on the improvement of the ecological environment on the middle and lower reaches of the Yangtze River.
The project will demonstrate and spread vetiver planting in economic forests, with fruit trees, in reservoir areas and on river banks, thereby enabling vetiver to be extended to all of the southern AnHui hill areas.
He XiangYi, Ye Chuan and Huang QianRu (JiangXi Provincial Institute of Red Earth, JinXian 331717, China)
An experiment on the adaptability of vetiver and its effects on soil protection and fertilization was conducted from 1990 to 1992. The experiment showed that vetiver characterized by high survival rates on infertile soils, acid tolerance, drought-resistance and cold hardiness, grew and performed far better on sloping hilly red soils and severely eroded land than any other kind of grass tested. With a strong root system over 2 m long, vetiver grass grew quick enough to form hedgerows in a short time resulting in excellent soil erosion control, i.e., a 50% reduction of surface runoff with a 60% decrease in soil particle erosion. In addition, soil was greatly improved by mixing into it vetiver leaves and stems, increasing a corn yield by 10-30% or more. Further research work will be done, as follows, to clearly define the functions of vetiver in development and management of subtropical hilly red soils and the proper arrangement of the grass for increased production.
1. Management on sloping land. Several kinds of red soils in southern and northeastern JiangXi derived from different parent materials and found in slopes with different degree, are to be chosen for the experiments concerning the natural formation of terraces by hedgerows. These will consist mainly of vetiver technologies. The aim is to explore the possibility of creating adequate hedgerow technology to replace the routine engineering method of constructing terraces. The proposed experimental programs will include the terracing speed, characteristics, effects, and benefits of vetiver technology as well as the reasonable vetiver ratio of land to grass and allocation.
2. Management on severely eroded land. Model management sites with an area of 6.6 ha each, are to be set up in granite and Quaternary Clay areas, respectively, to conduct experiments in (1) soil erosion control and (2) soil fertility recovery on severely eroded bare lands. This will be accomplished by constructing multi-stratified vegetative cover, consisting of trees, shrubs, grasses and especially vetiver grass.
3. Sand dune management. Sand dune control sites are to be established in XinJian and XingZi Counties in northern JiangXi to test vetiver's ability to control sand dunes. Experimental programs will include vetiver adaptability, sand dune fixing ability, adequate use of key technologies and a fairly large scale demonstration.
4. Slope protection for highways, reservoirs and ponds. Demonstration sites of a pre-determined size are to be set up to show the effectiveness of vetiver, in combination with other creeping grasses using proper arrangements for highway embankment and slope protection.
Zhou DunWang and Dai GuoQiang(MaCheng City Station for Soil and Water Conservation, MaCheng HuBei, 431600, China)
Over 70% of the total territory of MaCheng City, situated in the DaBie Mountains, is covered by mountains and hills. Severe soil erosion hinders the development of agricultural and industrial production as well as economic advancement. In order to promote the development of the city's economy by controlling soil erosion, vetiver grass is to be introduced to improve vegetative conditions, and to provide effective protection for the newly built Beijing-Kowloon railway. A series of experiments will be conducted as follows:
1. Improvement of the monocultured pine forest. Severe soil erosion is found under 17,000 ha. of a pure pine (Pinus massoniana) forest with a single sparse crown layer. A pine tree-vetiver grass interplanting experiment is to be conducted to determine if the planting combination is mutually beneficial for increasing biomass and for forming a multilayered crown cover to control soil and water losses.
2. Infertile land improvement. Plants grow poorly on 6,600 ha of bare land in marginal conditions. It is a very difficult land use problem in this area. Vetiver grass is choosen as a pioneer plant to improve the habitat conditions through decreased soil erosion, for slope protection and land improvement.
3. River bank protection. Most of the 90 km long banks along the JuShui River, one of the first grade tributaries of the Yangtze River, are constructed with clay and course sands derived from weathered granite. They are loose and susceptible to destruction. Vetiver grass is to be planted on the banks, forming hedgerows to prevent the banks from being damaged by floods.
4. Contour planting on sloping fields. There are 6,600 ha of sloping farmland and 6,000 ha of sloping mulberry fields in the area that suffer from severe soil erosion. Much labour and investment are needed to change them into terraced fields using engineering measures. It is easier and much less expensive to form contour living vetiver hedgerows than to build terraced fields with engineering methods. Contouring vetiver hedgerows are actual important for improvement of sloping land in the area because they help to control soil erosion and tend to level the sloping fields.
Chen ShangWen (Faculty of Forestry GuangXi University, NanNing 530001, China)
Located in the southern part of China, the GuangXi region covers an area of 23.76 million ha. Its annual average temperature ranges from 17.9(C to 22.6(C and yearly rainfall ranges from 1,380 mm to 2,100 mm.
By 1997, 3.06 million ha of land in the region were subject to soil erosion and the most severe cases were found in 10 counties of southern GuangXi.
In our first consideration, vetiver grass is to be introduced as a pioneer plant to control soil erosion in the southern counties. It will be planted first on dams and dykes of reservoirs as well as highway and railway embankments to prevent them from eroding. Second, vetiver grass will be interplanted in timber and cash crop forests to test their ability to control pests and weeds. Third, it will be planted in orchards, city gardens and seashores to beautify and protect the environment.
However, problems and difficulties exist with the introduction of vetiver. First, lack of funds slows down the process. Second, farmers do not immediately accept vetiver because they worry that vetiver grass can not compete with the large quantity of weeds. Besides, even some technicians think that if vetiver can not bring economic benefits to farmers, for example by selling extracted oils from their roots, it will be viewed as nothing but weeds harmful to the forest ecosystem.
Despite the problems mentioned above, some pilot experiments supported by foreign funds will be useful to help encourage people in GuangXi to accept vetiver. It is believed that vetiver grass holds a bright prospect for forest protection, the forest chemical industry and horticulture in GuangXi.
HuangGang Institute of Soil and Water Conservation and Farmland Water Conservation (LuoTian, HuBei, 436612 China)
The land area in the southern slopes of the DaBie Mountains is situated in the northeastern part of HuBei Province. Most of the soils in this area are derived from granite or gneiss, resulting in a loose sandy soil cover. Due to sparse vegetation, severe soil erosion takes place during the rainy season with the heavy rains. As a result, up to 80% of the total area suffers from moderate or severe soil erosion. Erosion damage leads to infertile sandy hill; land degradation; fertility reduction; sparse vegetation on the hill; very low yields from hillside fields; silting and raising of river bed, reservoir and canal bottoms, an increase of cold waterlogged fields due to the raised river beds; landslides; as well as damage to highways and buildings from mud-rock flows.
In order to effectively control soil erosion in the mountain areas the following 5 new vetiver technologies as key biological control methods in integrated projects are to be extended throughout the DaBie Mountains:
1. Vetiver hedges are to be arranged in scattered wood lands with newly planted timber trees, in orchards, in fuel-wood plots and in between pasture and crop fields, to help increase vegetative cover.
2. Biological control technologies, i.e., vetiver hedges, instead of engineering control, i.e., field terracing, are to be adopted to improve sloping farmland conditions.
3. Vetiver technologies are to be applied to dikes along the Yangtze River to test their endurance to waterlogging, and to determine their effectiveness for dike protection.
4. Vetiver technology is to be applied to river dikes, canal embankments and reservoir dams to research vetiver's ability to minimize flood damage.
5. Research on the effectiveness of vetiver technology for the protection of road embankments along railways and highways is to be conducted.
In addition to the 5 projects mentioned above, integrated evaluation of the ecological, economic and social benefits of vetiver are to be conducted along with the integrated management of small watersheds on the southern parts of the DaBie Mountains.
Chen YiBing(Institute of Soil and Fertilizer, SiChuan Provincial Academy of Agriculture)
The purple hills of SiChuan Province, with an area of 121,000 km2, a population of 68,000,000 and farmlands of 244,000 ha, 21%, 60% and 56% of the province's total, respectively, constitute a major agricultural base producing 60-80% of the provinces total cereals, edible oils, cotton, pigs and citrus. However, severe soil erosion has taken place in the area due to hills, steep slopes, irrational farming and excessive rainfall. According to data from ZiYang County Soil and Water Conservation Station, a yearly erosion model averaged 2,500 T/km2 with up to 10,000 T/km2 in some places. Soil erosion accelerated the deterioration of the agricultural environment and increased potential environmental damage to rivers and reservoirs, especially the Yangtze's Three Gorges Reservoir under construction. It is necessary to introduce advanced soil erosion control technology to ensure sustainable agriculture development in the areas concerned.
The proposed project includes the introduction of vetiver technology to about 700 ha of fields in SiChuan's ZiYang and JianYang Prefectures over the next 3 years. The experiments will be as follows: vetiver grass will be planted at the edges of earthen embankments on sloping fields and interplanted along contours with fruit tree lines at defined intervals on steeply sloped lands. In the latter case, vetiver grass will be pruned in a timely manners to form hedgerows 30-40 cm in height. This is designed to stop sand and mud from washing away while causing no negative influence to the growth of the fruit trees. It is expected that the agricultural production environment will improve and farmers' income will increase after 3 years when hedgerows form and fruit is harvested.
Huang ShaoLing and Wang ZhenChun(Teaching and Study Group of Genetics, Biology Department, GuangZhou Education College, GuangZhou,510050)
Vetiver (Vetiveria zizanioides) is a perennial which belongs to the grass family. It can tolerate both waterlogging and poor soil conditions, while exhibiting strong adaptability, a developed root system, and rapid growth. It has proven to be an excellent plant which can form a green hedge thereby conserving soil and water, and is considered a new hope in overcoming soil and water losses in GuangDong Province and southern China. In recent years, experiments harnessing soil and water losses, conducted by the South China Institute of Botany, show that vetiver ecological benefits are unsurpassed by other plants. However, planting of vetiver in both GuangDong and GuangXi show it only blossoms, but fails to bear fruit. In general, it spreads only by asexual reproduction of tillering, which is too slow to supply enough young plants to large areas. This restricts its distribution.
Therefore, a tissue culture study was conducted on vetiver in 1995. So far, a proper formula for the culture medium has been chosen. The next step is to try to find a feasible method for industrial production of vetiver test-tube plants using rapid asexual reproduction. At the same time new varieties which can bear fruit, are being cultivated and attempts to find the cause of its failure to fruit are being made so that this property can be altered through biological technology.
Qiu ShiJun (Department of Geography, South China Normal University, GuangZhou, 510631)
There are three types of soil and water losses on the slopes of the red weathering mantle in GuangDong Province classified as sheet erosion, gully erosion and landslides. Great achievements have been made through more than 20 years of erosion control. However, some problems still exist. For instance, because an ideal plant to stabilize the soil has not been found, sheet erosion occurring on the slopes of the weathered red-rock mantle in the hills of northern GuangDong Province cannot be effectively controlled. Several years ago, Milinis minutiflora was used to control landslides, resulting in marked improvement. However, investigations afterwards showed that most of the Milinis minutiflora withered three to five years later and no longer played a role in stablizing the slopes. Therefore, a new plant with a strong capability to stabilize the eroded slopes is urgently needed. Vetiver is a promising choice.
In order to spread the new method of using vetiver to control soil and water loss on the slopes of the red weathering mantle in GuangDong Province, NanXiong which represents a siliceous shale area and WuHua and DeQing, which represent granite areas, were selected as study sites to carry out experiments to harness sheet erosion and landslides, respectively.
Soil and Water Conservation Office, Water Conservation Department of HuBei Province (WuHan, 430071)
The BeiJing-Kowloon Railway passes through eight counties of HuangGang city, HuBei Province from the south to the north, including MaCheng, TuanFeng, HuangZhou, XiShui, JiChun, WuXie, HuangMei and Hong'An Counties with a total length of 275.6 km. Because of the urgency in construction of the railway, soil and water conservation has been neglected resulting in huge amounts of soil and water loss. Preliminary investigations showed that the area suffering soil and water loss reached 286.2 ha, the area with its original vegetation destroyed reached 1390.7 ha and the volume of eroded soil and residues reached 47.2 m3. Though measures to conserve soil and water have been taken in certain sections of the railway, in general, much work must still be done.
The railway departments always take protective measures such as digging road trenches, establishing road embankments and providing soil retaining walls. Although they are easily built and attain rapid results, the cost is relatively high and they are easily damaged after long-periods of operation. Meanwhile, because HuangGang is located at the southern foot of the DaBie Mountains, its dominant soil-forming parent rock is granitic gneiss, whose soil is loose and easily eroded. Moreover, the area is characterized by heavy precipitation and many violent storms. As a result, the engineering measures are not as effective as expected. Therefore, a study on using plants to control soil and water loss along the railway is of great significance.
According to the experts' recommendations and the scientific materials available: 1) vetiver has a strong adaptability to both the climate and soil conditions in the region; 2) with developed root systems, vetiver grows rapidly and forms hedges easily, which has an ideal effect on soil and water conservation; 3) because it does not fruit, vetiver cannot spread by airborn seeds, nor can it invade cultivated lands; 4) vetiver has economic value, and it can be used as fodder, fuel, or sources of perfume; 5) the environment along the railway will become more beautiful; and 6) to save on investment and to provide long term benefits, the program aims to select vetiver as a plant to use for soil and water conservation along the railway. This will be a study comparing vetiver planting models to try to find the best model to protect road embankments. There are three planting models: a) double rows of grass hedges for slope protection at the top and bottom of the slopes respectively; b) rows of grass hedges for slope protection at equal intervals; and c) grass covering the slope like scales.
Expected results: the dominant topographical features along the HuangGang section of the Beijing-Kowloon Railway are low hills and scattered mounds. With less digging and more filling during railway construction, the ratio of the former to the latter is 4:6. The length of the slope embankments on both sides is about 330 km. On the slope below 6 metres, in height vetiver is planted for protection; and on the slopes greater than 6 metres high, engineering support projects are to be established to stabilize the slope first. Then vetiver can be planted within gaps of the protection wall of the main engineering projects. In addition, vetiver can also be planted in green belts, at excavation sites, or in places where dumped earth and residues are piled. If the experiment planting vetiver is successful, a new way for afforestation and slope protection along the railway can be realized.
Zhao DingGuo (Institute of Environmental Science, Shanghai Agricultural Academy of Sciences, ShangHai, 201106)
The content of the vetiver study in ShangHai is as follows:
1. Study on establishing a production base for vetiver is young plants.
Vetiver is always propagated by transplants. Hence, a study on the cultivation of vetiver young plants is important for its dissemination. A small experimental nursery will be used as a base for the study and spread of vetiver.
2. Study on the feasibility of using vetiver in solid waste disposal sites
There are several large solid waste disposal sites in Shanghai. Because the moisture is not suitable for plant growth, natural grasses fail to grow long after the sites are covered with soil. Moreover, after the garbage ferments, it will give off heat and harmful gases, which makes it difficult for many animals and birds to inhabit the area, and fallen seeds to germinate. If the vetiver is planted in these sites, the ecological environment will be greatly improved, the landscape will be fundamentally changed, and the soil loss from runoff will also be reduced. Meanwhile, vetiver will also play a role in decomposing harmful components in the garbage.
3. Study on the role of vetiver for embankment protection in large water conservation projects.
Many large water conservation projects are now carried out in Shanghai. Because of the lashing from waves caused by motor-driven boats after rivers opened to navigation, the new river banks cannot support plants, resulting in soil loss. If vetiver can play an effective role in river bank protection, not only will it protect the river banks from earth loss, but it will also help to form a new landscape along the river side.
4. Study on vetiver role in highway embankment protection.
With the rapid development of highways in Shanghai, especially the establishment of many provincial level expressways, the investment in road embankment protection is large. The research available shows that vetiver can play an important role in the protection of road embankments. An experiment planting vetiver on the slopes along roadsides will be carried out in order to strengthen the protection of these slopes and to reduce the expenses of road maintenance.
5. Study on vetiver use as fodder
Vetiver produces a large amount of biomass. The use of vetiver as a green fodder or a grass powder, which will be studied, not only increases the fodder resource, but also helps dispose of the stems and leaves clipped during pruning.
Xiang ChiZong (Institute of Agricultural Science, PeiLing, ChongQing, 648000)
Based on the capabilities of vetiver, this program aims to study the introduction and spread of vetiver in order to solve the problem of soil and water loss in the Three-Gorges-Reservoir Region effectively and rapidly. The Three-Gorges-Reservoir region is located between 20010'-32012' N latitude and 105017'-110012' E longitude, and includes ChongQing, WanXian, and PeiLing Cities as well as QianJiang Prefecture. The dominant landforms are low-to-medium mountains and hills. The mean annual precipitation is between 1000-1700 mm, with a subtropical humid monsoon climate; the precipitation from May-October when most violent storms occur comprises 75% of the annual rainfall. The soils are labeled mountainous yellow soils, yellow-brown soils, sandy soils and some purple soils, which are derived from limestone, shale, sandstone, purple shale etc.
The soil and water loss in the Three-Gorges-Reservoir region is serious. The eroded area is 63.2% of the total. Because of erosion, often there is channels blockages, leading to frequent occurrence of floods and degradation of the ecological environment. Soil and water conservation in the Three-Gorges-Reservoir region not only can increase the volume in the reservoir, but it can also reduce the silting of the sand to guarantee the longevity of the Three-Gorges Project. In recent years, comprehensive measures have been taken, including biological, engineering and agricultural measures to establish ecological barriers to control the soil and water loss by blocking the silt on mountains and embankments. However, when employing biological measures, only trees have been considered, and not lower bushes + grasses. Thus, the benefits were not as high as expected. Therefore, the introduction of vetiver in the Three-Gorges-Reservoir Region is of significance.
The contents of the planned program include:
1. Establishment of a seedling base.
Experiments on the introduction and propagation of vetiver will be carried out in the region. The aim is to study vetiver propagation in order to breed its vigorous strains. The vetiver propagation base can provide large amounts of young plants for the spread and application of vetiveria in the region.
2, Experiments on embankment protection, slope stabilization and marsh utilization.
The aim is to use vetiver as a pioneering plant for embankment protection with trees. An experimental site with a defined area will be established, and different methods designed to observe the quantitative ecological benefits that vetiver will bring. In order to use vetiver to reform and utilize the marshes near river banks, it will be necessary to determine its ability to withstand high water levels. .
3. Experiments with road protection.
With the development of the economy, many new roads have been built in order to meet urgent demands. These roads intensify the soil and water losses. This experiment selects both the cut-away surface of the mountains above the roads and the loose piled earth at the roadsides as two typical study sites. The objectives are to observe the growth of vetiver planted in these sites, and to determine whether they can reduce in the short term the soil and water losses caused by the cutting and filling operations during road construction and maintenance.
4. Experimention on grass belts for soil and water conservation on farmed slopes.
The farmed slopes in ChongQing are sources of soil and water loss. Owing to a large population and small area of cultivated land, the cultivated area needs to be expanded by using sloped areas. For example, farming on slopes above 260 accounts for 56% of the total area under cultivation. In order to reduce the soil and water losses in these areas, many forest belts planted along the contours are to be established. These belts will combine trees with bushes and grasses. Thus, vetiver will be tried as an experimental grass to control soil and water loss effectively and rapidly.
Liao GuanRong (Institute of Soil Science and Ecological Environment, GuangZhou, 510650)
Li ShuYi (LeiZhou Forestry Bureau of GuangDong Province, 524348)
This program is aimed at using vetiver to prevent soil and water loss, and the spread of gullies formed by erosion. The study site is situated in the largest Eucalyptus plantation on LeiZhou Peninsula. Located between 20018'-21030' N latitude and 109039'-110038' E longitude, LeiZhou peninsula is situated in the northern fringe of the tropics, with an oceanic monsoon climate. Its mean annual temperature is 23.50C; its mean temperature in July is 28.90C and in January it is 15.20C with a temperature extreme not exceeding 380C. Its mean annual precipitation is 1610.6 mm; and its mean annual evaporation is 1764.9 mm. The frequent typhoons in August and September often bring storms. The dominant landforms are tablelands and low hills. The soil type is primarily laterite derived from sandy shale, granite, shallow sea sediments and basalt. Since 1954, some man-made forests, including a Eucalyptus plantation with an area of 42,000 ha and other plantations of Pinus and Acacia, have been established. Soil erosion and landslides are commonplace on most tablelands. The erosion begins with small rills. Then gradually ditches form and become large and deep. Finally a large amount of earth collapses, increasing the decline of soil fertility and removing vegetation. In order to prevent the plantations from further deterioration and to recover the vegetation, an experiment using vetiver to control erosion will be established in 1998. The contents are as follows:
1.To compare the roles played by different planting patterns of vetiver in preventing soil and water loss in Eucalyptus plantations.
(A) The different planting patterns include: 1) a green hedge planted along the fringe of forest blocks (the area of each forest block is 100 mu); 2) a green hedge planted every 20 metres in the forest block.
(B) The observations consist of: 1) investigating and recording the conditions of vetiver growth; 2) noting the changes in soil erosion; 3) recording the changes in runoff; 4) monitoring the changes of water conservation in the soil; 5) determining the biological yield of Eucalyptus; and 6) establishing nutrient levels in the soils.
Shui JianGuo and Lu YunFu (Soil and Fertilizer Institute, ZheJiang Academy of Agricultural Sciences, HangZhou 310021, China)
Situated in the west central part of ZheJiang Province, at 28°15'-29° 41' N latitude and 118° 15'-120°47''E longitude, the JinHua-JuZhou basin, in the north central part of the subtropical zone is one of the well-known basins with red soil in southern China. It abounds with water and its heat resources and its productive potential is high. Under the influence of a monsoon climate, there is uneven distribution, spatial and temporal, of precipitation with frequent and alternative occurrences of drought and flood. The areas suffering from annual drought and flood average 32.3% and 26.1%, respectively. The relatively intensive erosion in the hills, hillocks and valleys characterized by sloping and steep land where soil and water erosion is severe has resulted in wide spread land degradation. Development of farm production is also slow because of a relatively high concentration of people, a lack of arable land, abusive tillage, soil degradation and low productivity. In order to utilize the land resources rationally, to keep soil erosion under control and to effect speedy ecological reinstatement for sustainable agricultural development, a study to achieve these objectives by cultivation of vetiver grass is projected. Based on agricultural ecology, a program with 3 aspects will be undertaken:: studies 1) on techniques of high-yielding cultivation of vetiver grass on newly-reclaimed red soils; 2) on combinations of models of live vetiver grass fences alongside roads and steep slopes; and 3) on the linkages of vetiver grass in eco-models in connection with trees, bushes, grass and animal husbandry. With a view to setting up a germplasm bank of vetiver grass with simultaneous introduction, experimentation and demonstration, nurseries covering 5 ha of vetiver grass and live vetiver grass fences covering 150 ha are to be fixed. Likewise, 3-5 optimization models for speedy ecological reinstatement in low-hill red soil areas using vetiver grass cultivation are to be built aiming at an 85% vegetation coverage, a 70% decline in soil erosion and over a 50% rise in water resource availability. Emphasizing its practicability, this study will create an example to be widely followed in 52,400 km2 of red-soil areas in ZheJiang Province and serve as a guide for 2,180,000 km2 of red and yellow soil areas throughout southern China.
Li XiangDong (Forestry College of GuangXi University, NanNing)
GuangXi is one of the provinces in China suffering from serious soil and water loss. The area of soil and water loss is about 30,000 km2 with an annual soil erosion of more than 80 million tons, second only to that in the Loess Plateau Region. Though a lot of protective measures have been taken over a long period of time, no satisfactory results have been achieved. Therefore experiments with vetiver grass cultivation for water and soil conservation were conducted. The planned programs are as follows:
Program one: experiments using vetiver to reduce damage from typhoons and for sand fixation in the southern coastal region
The study site is in YingPan Township, BeiHai City. Located near BeiBu Gulf, its topography is characterized by beaches along the seacoast. With a northern tropical climate, its mean annual temperature is 22.6°C, its mean annual precipitation 1600 mm, and its mean annual sunshine 2100 hours. The soil is sandy and derived from shallow sea sediments, with a low moisture capacity and poor fertility. Because it is attacked by typhoons 2-3 times each year, the crops and houses are often damaged by the strong winds and the soil is severely eroded, resulting in sandy soils. Since the 1960's, forest shelter belts for wind protection have been established, however, the strong ventilation below the forests limits their effect as windbreaks. Therefore, the plan is to plant vetiver along the outside of the forests to observe its effects on wind reduction and sand fixation.
Program 2: experiments planting vetiver for slope protection along the central part of the 2nd-level NanNing-WuZhou Highway.
The study site is in the NanNing-BinYang section of the highway. The length of this section is 90 km and the dominant landform is hills with altitudes of 80-200m. With a southern subtropical climate, its mean annual temperature is 21°C; its annual precipitation is 1500 mm; and many storms occur during the rainy season from April to September. The soils are a red soil and a laterite soil derived from granite and sandy shale. As a result of a large amount of earth excavated and filled during highway building, a road slope of 50°-60° and 5-10 m in height was constructed. Though there have already been some protective engineering measures storms often cause landslides on these slopes, resulting in block's traffic. So, the plan is carry out experiments planting vetiver for slope protection.
Program 3: experiments planting vetiver for land protection and to provide fodder.
The study site is in SiCheng Township, LingYun County. It is located in the foot hills of the YunGui Plateau, in northwestern GuangXi Province, with an altitude of more than 300 m. Here there is a southern subtropical climate, with a mean annual temperature of 19.50C, with an annual precipitation of 1600 mm, and with many storms during the rainy season from April to September. Owing to the steep slopes and concentrated precipitation, soil and water loss is severe and landslides often occur. Although several protective measures have been taken such as planting trees and building terrace fields where soils permit or building soil and rock-retaining walls where the soil layer is shallow, slope protection still remains a problem. Therefore, the aim is to plant vetiver along the contours of the terrace fields and cultivated land, not only to protect the slopes and conserve soil and water, but also to experiment on using vetiver as fodder and a source of methane.