Studies On The Effect Of Contour Vegetative Hedges On Moisture Conservation, Growth And
Yield Attributes Of Millets, Cotton And Pulses Under Rainfed Conditions.
S. Balasubramanyan and S. Senthilvel. Regional Research Station, Kovilangulam - 626 107
Tamilnadu, INDIA
To ascertain the performance of pulses, millets and cotton with different hedging systems
on a slopey land under rainfed condition, a study was conducted with vetiver, subabul,
cenchrus grass and desmathus as hedges. The results revealed that the growth of the
cotton, redgram and greengram were best influenced by cenchrus hedge followed by vetiver
hedges. Vetiver hedging system has shown very good effect on the yield of annual crops.
The vetiver hedges conserved 21.80%, 20.98%, and 19.77% soil moisture at various stages of
growth, and thereby helped all annual crops to produce higher yield. In dryland farming,
hedging with vetiver is recommended for moisture conservation and higher yield of the
intercrops.
Suitable Techniques For Establishment Of Vetiver Hedgerows In Semi-Arid Region Of
Rajasthan-India
S.C. Manhot & P.C. Chaplot. College of Technology and Agricultural Engineering,
Rajasthan Agricultural University, Udaipur, Rajasthan 313001, India.
Investigations were carried out in semi-arid region at Udaipur during 1991-1995 to study
the effect of plant spacing, densities, polymers, manures, planting methods and time gap
between uprooting from nursery and planting in field for effective establishment of
Vetiver hedgerows on alfisols belonging to land use capability Class VI (non arable). and
Class IV (arable). The soils are low in N, medium in P and rich in K content. Wider spaced
(15 to 20 cm) planting proved significantly superior in respect to growth compared to 10
cm: presently in operation. Planting of 2 or more than 2 slips/hill recorded highest
increase in survival and growth. Among the polymers and manures. application of agrosoke
polymer 30 g/m row length in furrows at planting recorded highest survival (95%) and
significantly higher number of tillers/plant (116) and clump girth (79 cm): closely
followed by FYM application - 600 g/m row length. Planting of vetiver in furrows opened at
bottom of 'V' ditch is found suitable method as it recorded maximum survival as compared
to planting on top of bund of 'V' ditch and on berm. Planting of polybag raised vetiver
recorded maximum survival (98%) over field nursery raised (17%). Polybag raised vetiver
also gave significantly better growth. In a two year (1992 & 1993) study planting of
vetiver immediately or within 24-36 hours after uprooting from nurseries was found
effective in better establishment of vetiver hedgerows.
Effect Of Applying Vetiver Grass On Sloping Lands In China.
Chen Xuhui and Ronald D. Hill, Guizhou Academy of University of Hong Kong, Agricultural
Sciences, P.R. CHINA.
Planting grasses or shrubs along the contours is extremely effective for erosion control
on slopes. In order to explore measures for speeding up the growth of vetiver grass, a
fertilizer trial was conducted. According to observations, the growth of vetiver grass in
the first year after being transplanted could the divided into three stages: the recovery
stage, the rapid-growth stage and the trimming and gathering stage.
On farmland, the vetiver grass in the control plots survived very well and formed
hedgerows rapidly, whereas the treatment of applying fertilizer showed no obvious effect.
As most fertilizer disturbed the recovery of vetiver, if we must apply some fertilizer to
farmland in order to multiply seedlings of vetiver, we had better use fertilizer after
manure.
On sloping bare land, the organic manure is better than the chemical fertilizer, and
treatment NPK + FYM had a more obvious effect. The lack of phosphorus would seriously
disturb the survival, growth and grass-yield of vetiver. If we apply the NPK fertilizers,
we had better apply them in split applications which is better than applying the whole NPK
at transplanting.
Comparative Study Of Vetiveria zizanioides, Vetiveria nigritana, And Andropogon
gayanus In A Trial Of Soil And Water Conservation.
Thiombiano L. R. Zougmore and F. Kambou. Agricultural Institute, Burkina Faso. (INERA) Bp.
476 Ouagadougou, Burkina Faso.
Using vegetation in a trial of soil and water conservation is an important challenge in
arid and semi-arid zones. The objective of the study is to obtain data on the comportment
of three grass species, V. zizanioides (unknown in the country), the local Vetiver
(V.nigritana) and A. gayanus. On a bare ferrugineous soil (Lixisol), three stone lines
were built along the micro-topography with a distance of 33 meters. The three species were
used for vegetatization of the stone lines.
The results obtained show a few mortality of V. zizanioides (3%) compared to the local
grass (18% for V.nigritana and 34% for A.gayanus) in terms of growing after plantation.
Concerning plant height, local grass (A. gayanus) have a total longer of 203 cm when
Vetiver grass (local and exotic) have just 103, 5 cm after 103 days. The weight of dried
material is respectively 7570 g for Andropogon, 3548 g for V. zizanioides and 866 g for V.
nigritana. The coverage of the soil in amount of the stone line is about 80 - 90% for
Andropogon and 50 to 60% for Vetiver grass. The soil moisture evaluate ponderal method is
twice more under A. gayanus comparatively to V. nigritana. V. zizanioides maintained more
moisture in the soil than the local Vetiver. These data revealed the potential of
Vetiveria zizanioides growing in soudano-sahelian zone and the possibility to use it for
stone line vegetalization to combat erosion.
Studies On A Biological Erosion Control System Integrating Tree And Grasses To Manage
Degraded Soils Of Foot-Hill Himalayas.
S.S. Grewal and J.S. Samra. Central Soil and Water Conservation Research Centre, 27 A,
Chandigarh, 160027, India.
Soil erosion is the single largest factor responsible for degrading quality and
productivity of land in India. It is estimated that 45% of forest, 56% of farm, 86% of
cultivable wastes and 95% of pasture lands suffer from erosion related problems. Though 39
million hectares have since been treated in the last 30 years, but each year area degraded
far exceeds the area rehabilitated. Unless massive efforts are made to mobilize farming
communities, the march of degradation cannot be contained. This would, however, require
the development of cost effective and easily adaptable packages linking conservation and
production to motivate farmers. High cost and questionable performance of mechanical
measures have also shifted emphasis to biological measures of land amelioration. It is
planned that 40 million ha of wastelands be developed with vegetation models designed for
each agro-ecological region integrating multi purpose trees and sod-farming, conservation
effective perennial grasses having inherent ability to thrive on degraded sites and
provide usable biomass and economic returns.
In the Himalayan foot-hill ecosystem of north India, Acacia nilotica is the most favored
multipurpose tree species, Bhabar (Eubiopsis binata) and Kana (Saccharum munja) are
important sod forming natural perennial grasses. Dub grass (Cynodon dactylon) also
commonly thrives and meet conservation and forage needs. Vetiver grass (Vetiver
zizanioides) occurs naturally in wet pockets and was strongly recommended in many of the
internationally funded projects on conservation of natural resources. The research
information on the integration of these remarkable plant species in a silvipasture system
was lacking. Hence the study.
In a replicated and randomized field experiment started in July 1990 on a 1.2 ha of
degraded gravelly soil near Chandigarh (30� - 45' N, 76� - 15' E, 350 m MSL) typically
representing semi-arid climate; Acacia nilotica was uniformly planted from nursery raised
tube plants at 8m x 5m spacing in 30 cm3 pits. Four understorey grasses namely Bhabar,
Vetiver (0.5m x 0.5m), Kana (1 m x 1 m), natural dub grass were raised in the interspace
and compared with control having no grass. Interplot earthen bunds of 20 cm height were
made to conserve rainwater. Runoff and soil loss was measured using Ramser samplers. The
root system of the 3 planted grasses was studied by excavating soil monoliths at one and
two years of age. Grasses were harvested twice a year in June and November and air dry
weights recorded.
All the four understorey grasses affected the survival (except Vetiver) and growth of
Acacia nilotica seedlings as compared with no grass treatment (Table 1). The depressing
effect amongst grasses were non-significant. All grasses tended to reduce runoff and hence
soil loss. The lowest water loss (2.2%) was recorded under natural grass followed by
planted Vetiver grass (5.8%). The residual soil moisture left in 0 - 30 cm soil profile at
harvest was highest (9.1%) in Vetiver grass. S. munja provided the maximum biomass, when
Bhabar and Vetiver were almost at par. The roots of Kana were relatively more sturdy and
thick but the root density was low. The roots of Bhabar and Vetiver grass were more fine,
spongy, larger in number and hence their root density was much higher. The results of 3
years of study indicated that Vetiver was more conservation effective, Sacrum gave more
biomass and Bhabar grass provided more of economic returns. The emergence of clear picture
about their relative merits would take few more years of study.
Comparative Study Of Hedgerow Of Vetiver And Other Grasses With Mechanical Measures On
Erosion Losses At 4% Runoff Plots
S.P. Bhardwaj, Principal Scientist and Head of Division, Central Soil & Water
Conservation Research & Training Institute, Dehra Dun-248 195, India.
Mechanical measures namely bunding (earthen embankment), terracing, trenching etc. used to
stabilize high slopes have been found costly, area consuming and unstable structures
needing maintenance cost on agriculture lands up to 4 percent slope. Therefore, erosion
control measures of conservation agronomy and grass barrier were tried on runoff plots
(l00 x 20m) on 4 percent slope equipped with H flume, stage level recorder and Coshocton
Silt Sampler. Three grasses namely, Khus grass (Vetiveria zizanioides), Bhabar grass
(Eulaliopsis binata) and Guinea grass (Panicum maximum) were planted in 60 cm wide strips
on contour at 100 cm vertical interval. The soil loss (52 t/ha) and runoff (45%) of
rainfall from cultivated fallow were reduced to 18 t/ha and 51 percent respectively by
following contour cultivation of corn. There was further reduction in soil loss (10-12
t/ha) and runoff (40 %) by adopting strip cropping, intercropping, zero tillage and
bunding. Introduction of vegetative barriers (live bund) gave and average (7 years) soil
loss 5-6 t/ha and runoff 33% of rainfall. The performance of bhabar grass was
comparatively poor. Corn yield in most cases remained unaffected (23-24 q/ha) due to minor
variations in erosion losses. Dry matter production was highest from guinea grass (1540
kg/ha). The yield of following rainfed wheat was visibly higher in the upper reaches up to
5 m. due to deposition of fertile sediment (40 t/ha) and better moisture regime. Thus
grass barriers were more effective than other measures of conservation agronomy and
engineering. There is a tendency to change the slope into Puerto Rican terraces due to
grass barriers.
Performance Of Vetiveria zizanioides In Rainfed Areas Of Vindhyan Plateau Of Madhya
Pradesh, India.
Khandwe, Rupendra; Vyas, M.D. and Saran, R.N. J.N. Krishi Vishwa Vidyalaya, Jabalpur,
India.
The seven year study since 1987-1994, on the performance of vetiver was carried out under
World Bank aided Watershed Development Project at Rafi Ahmad Kidwai College of
Agriculture, Sehore (M.P.) India. The seeds of vetiver from different locations in
different years were tested under laboratory and field conditions for their germination.
The viability of vetiver seeds reduce as the increase in storage period. Relatively higher
germination 28.33% was observed in laboratory compare to 11.66% in field condition. The
naturally germinated number of vetiver plants was observed 16.22 and 17.44/m2 with up and
down stream on existing vetiver hedge row respectively when the field was cultivated
during winter and rainy season. While in uncultivated field during both crop season, the
vetiver plant was 48/m2.
In a study on application of fertilizer doses on the establishment of vetiver hedgerow. It
was found that the application of 20 kg N + 20 kg P205/ha as basal dose was most
effective. The vetiver barrier caused higher soil deposition in upstream with the average
soil deposition from 6.78 cm in two rainy season to maximum of 21.15 cm in seven rainy
seasons. Four to five percent higher moisture conservation on upstream was recorded than
the down stream.
In the screening of various locally available grasses in comparison to vetiver for
establishing soil and moisture conservation. It was found that the vetiver recorded higher
survival percent and higher soil particle binding capacity.
Environmental Considerations In Erosion Control: Use Of Vetiver Grass In Soil Moisture
Conservation Program In Sardar Sarovar (Narmada River) Catchment In India.
Pawan Kumar and A.K. Malhotra. Narmada Control Authority, Indore - 452 010 Madhya Pradesh,
India.
Soil and land form an integral part of the fragile life supporting system basic to mans
existence. However excessive soil erosion with consequent high rate of sedimentation in
the man made water bodies and decreased land fertility have become serious environmental
problems with disastrous socio economic consequences. For reversing the trend, there is an
urgent need for adapting economically viable techniques of soil moisture conservation.
Quick method of erosion control through construction of engineering structures have
neither significantly stopped erosion nor have significantly increased yields of crops
through improved moisture conservation. They also do not work in the long run. While
vegetative systems in conjunction with appropriate cultivation practices were in most
cases found suitable.
The present paper discusses the use of Vetiver as an economically viable method in erosion
control of arable lands and its usage in catchment area treatment program in Narmada river
basin in India where 175,000 ha area is being treated with erosion control measures.
Socio-economic problems associated with planting of vetiver on large scale in Narmada
river basin are analyzed. Based on the experiences drawn, planting, of vetiver as an
integral component of interactive subwatershed planning, is recommended for low cost
erosion control in extensive areas of a river basin to mitigate the stresses on the local
environment.
Use Of Vetiver Grass As A Filter In The Process Of Ground Water Recharge Through Open
Wells.
Y.M. Kool1, R.N. Saran2, S.L. Dandir3
1 & 2 Head Engineering Section and Dean College of Agriculture, Indore (M.P.)INDIA.
3 Chief Engineer, Public Health Engineering Department, Indore Zone, Indore, INDIA.
To solve the vital problem of constantly receding ground water in the plateau regions of
Malwa & Nimar (Western Madhya Pradesh), an attempt has been made to collect surface
runoff water filtering the water at various stages in to an unconfined aquifer
specifically by passing through the network of vetiver grasses provided as biological
filter on the bed and side of the drains. The studies were performed from 1990-95 at
Jawaharlal Nehru Agricultural University campus Indore. Integrated Soil & Water
Conservation Techniques were used to maintain the water level in the open wells viz.,
technique of water spreading and recharge through direct water injection. Water spreading
techniques contributed 23% to the ground water recharge while injective techniques
contributed 77%. An average annual recharge for the five hydrologic years (1990 - 91 to
1994 - 95) was 60308 m3. Total amount of water drawn from the ground water sources
(average annual value was 56554 m3) for an average annual rainfall 0.977m during this
period. Similarly. two year's average annual rainfall and draft of water from ground water
sources recorded during 1988 - 89 to 1989 - 90 was 852 m3 and 21710 m3 respectively. After
adoption of integrated water conservation techniques 34844 m3, about 1.6 times increase in
the water reserves in the wells was achieved. It was found that out of 50308 m3 water
additionally recharged 34844 m3 could be recouped which forms 69% of the average recharge
value. Vetiver grass has provided an excellent filtering effect.
Constraints Of Using Vetiver In Watershed Management In Sub-Mountain And Scarcity Zone
Case Study Of Nashik District (India).
Prakash Pawar. Government of Maharashtra, Department of Soil & Water Conservation,
India.
Soil and water are the most vital natural resources for the survival of mankind. Proper
management of this natural resources on watershed basis gives excellent results.
Engineering structure for managing, is expensive. Vegetative measures by use of Vetiver is
quite inexpensive and it is promoted in a centrally sponsored scheme in India.
Accordingly, twelve watersheds comprising two Agro Climatic Zones are undertaken in Nashik
District, with a geographical area 52,952 Ha. Since 1991 - 92, 4855 tonnes of Vetiver
slips (Vetiveria zizanioides) are used for drainage line and land treatment of watershed
management. A case study of Vetiver in the use of soil and water conservation attributes
are taken up.
The results of the case study indicate that the establishment of Vetiver and its survival
percentage are directly correlated to rainy days, depth of soil and other managerial
factors like, the problem of stray cattle. In scarcity zone the use of Vetiver as a
conservation measure failed except in a few drainage line treatments. In sub-mountain zone
drainage line treatments like live check dam and loose boulder structure show excellent
results while land treatment has only limited success. Instead of planting vetiver merely
as a barrier, a minor engineering support would give better result.
In sub-mountain zone, the survival percentage of Vetiver is the highest in live check dam,
supported by minor engineering structure (65.50%). It is followed by loose boulder
structure which is reinforced by Vetiver at 47.75%. Thirdly, land treatments named as
contour vegetative hedges give the lowest survival at 41.50%. From the case study it is
clearly observed that planting material plays an important role in the survival of
Vetiver, in addition to managerial factors like the problem of stray cattle. The overall
conclusion is that dry spell adversely affects the survival percentage of vetiver. The
average rainy days in sub-mountain zone are 75 while in scarcity zone it is only 25. The
dry spell thereafter and the problem of stray cattle causes the mortality of vetiver.
However, vetiver in good survival situations gives excellent results in terms of soil
erosion control and moisture conservation, which account for good land returns i.e. crop
production.
An attempt is made in this case study to compile all available information and its
correlation to field situation.
Effect Of Vetiver Hedge On Runoff, Soil Loss, Soil Moisture And Yield Of Rainfed Crops
In Alfisol Watersheds Of Southern India
C.Nagender Rao, M. Singa Rao, A. Padma Raju and R. Prabhu Prasadini. Division of Soil
Science, Andhra Pradesh Agricultural University, Rajendra Nagar, Hyderabad - 500 030,
India.
Runoff and soil loss are the twin problems threatening the security and sustainability of
crop production in the Deccan plateau of Peninsular India. Low cost and easily adoptable
technologies need to be developed for conservation of natural resources. Experiments were
conducted on shallow gravelly Alfisol having 2.5% slope during 1990 - 95 to study the
effect of vetiver (Vetiveria zizanioides) hedges on soil and water conservation, and yield
of rainfed crops, sorghum + redgram and castor. Vetiver hedge on contour reduced the
runoff and soil loss by 65.75 and 75.59% (1993-94) and 66.65 and 76.98% (1994-95),
respectively over contour cultivation alone. Vetiver + dead furrows (deep furrows) at 3.6
m interval reduced runoff and soil loss by 56.33 and 70.48% (1993-94) and 58.33 and 70.77%
(1994 - 95), respectively over dead furrows alone. Vetiver hedge on contours increased
mean soil moisture (up to 45 cm depth) by 5.13 to 8.55% over contour cultivation alone.
The increase in soil moisture content with vetiver + dead furrows was 6.96 to 10.85% over
dead furrows alone. The average soil moisture content 2 m above vetiver hedge was higher
by 8.61 to 16.25%, compared to the soil moisture below (2m) Vetiver hedge. The percent
increase crop yields due to vetiver hedge ranged from 7.04 to 22.37 over that of contour
cultivation. Vetiver + dead furrows recorded 3.79 to 8.29% increased yields over dead
furrows alone. The crop yield above vetiver hedge was higher by 15.55 to 17.98% over that
below the vetiver hedge.
Growing of vetiver hedges on contours and adopting conservation tillage practices between
them can thus be an effective method to reduce runoff and soil loss, and increase in-situ
moisture thereby obtain higher crop yields in rainfed Alfisols of the central parts of
Southern India.
Vetiver Vis-A-Vis Indigenous Plant Species For Conserving Soil And Water In Arid Lands
S.K. Saxena, K.D. Sharma, N.S. Vangani and H.P. Singh Central Arid Zone Research
Institute, India.
Study on the performance of contour vegetative barriers as soil and water conservation
measures has been initiated during 1991 on the farmer's field covering an area of about 50
ha near Jodhpur. The area receives an average rainfall of 360 mm per annum. Eight species
of grasses, 3 shrubs and 3 under shrubs were tried on contours at 1 m vertical interval in
3% slopey fields. Vetiver was used as control. This grass though survived on few fields
but failed to make an effective barrier due to adverse climatic and edaphic conditions.
Locally adapted grasses such as Cymbopogon jwarancusa, Cenchrus ciliaris and Cenchrus
setigerus performed exceedingly well and formed effective barriers against soil erosion in
a span of 2 years.
Significant reduction in peak flow and runoff volume have been recorded in the barrier
fields over control. The runoff volume reduced between 22 and 71 %. The barriers do not
channelise runoff and allow greater opportunity time for the rainwater infiltration. The
barrier fields store 12 to 16% of soil moisture as against 6 to 10% in the control fields.
The soil loss reduced from 530 kg /ha in the barrier fields. Also the sheet and rill
erosion were checked to a greater extent. All these resulted between 37 and 51% more yield
of guar (Cyamopsis tetragonoloba) over control.
The contour vegetative barriers of local grasses were more acceptable to the farmers as
these are less expensive, easy to raise, less labor intensive and provide fodder in the
lean period.
The Function Of Vetiver In Agriculture Ecosystem
Xia Hanping, Ao Huixiu, Liu Shizhong and the Daoquan. South China Institute of Botany,
Chinese Academy of Sciences, People's Republic of China, P.R. China.
The experimental results showed that vetiver could efficiently ameliorate many properties
of soil. For example, it could lower the acidity and exchangeable Al of strongly acid soil
by 0.5 - 0.7 and 0.3 - 0.6 cmol.kg, respectively. A significant increase in soil organic
matter, total N, available N and K, and porosity was found after planting vetiver for 29
months. However, vetiver didn't enhance soil P. After vetiver was established, the
moisture of soil was increased by 20.3 - 42.3% in 0 - 20 cm depth and by 4.2 - 13.4% in 20
- 40 cm depth, respectively. Furthermore, vetiver distinctly slowed down the dropping
speed of soil moisture. The vetiver treatment averaged 60% and 93% less runoff and soil
loss than the control, respectively, in 2 years. Vetiver also improved the microclimate of
agricultural ecosystem, which increased the relative humidity by approximately 5%, and
declined the air temperature by 1 - 2� C.
Studies On The Effects Of The Soil And Water Conservation Of Vetiveria Zizanioides In
Eucalyptus Plantations
Liao Baowen The Research Institute of Tropical Forestry, Chinese Academy of Forestry, P.R.
China.
In the new afforestation land of Eucalyptus ABL No.12 plantation, at Yangxi county,
Guangdong Province, China, three experiment plots, included a row of vetiver grass in two
rows of trees, a row of stylo grass in two rows of trees and only trees without any grass
(the control plot) were set up in April 1991. The runoff plot had been established in each
plot and the laws of changes in rain, height, surface loss rate of soil and water were
observed and studied. The three-year observation results indicated that the surface runoff
rate in vetiver grass was 20351 t/hm2, which was 15.2% lower than that of stylo grass and
58.5% lower than of the control plot. The soil loss was 68.2 t/hm2, which was 28.2% lower
than that of stylo grass and 51.1% lower than that of the control plot. The loss rate of
the solid and liquid nutrients were also much lower than that of the stylo grass and
control plot. The vetiver grass hedge can not only resist erosion, but promotes tree
growth as well.
Hedgerows And Mulch As Soil Conservation Measures On Steep Lands.
Oscar S. Rodriguez P. College of Agronomy, Central University of Venezuela, Venezuela
A summary of the experience with vetiver and other grasses used in soil erosion research
in Venezuela is presented. The need for accelerated data production through simulated
tests in the field is highlighted. Four experiments were conducted under field simulated
rainfall conditions at 1800 masl. in the mountain coastal range of Venezuela, with 5 m
length and 0.5m width plots and an average rainfall intensity of 556 mm/h using a double
nozzle rainfall simulator, on an Aquic Paleudult soil with different humidity contents and
two 15% and 26% slopes respectively. In order to evaluate the efficiency of five different
hedgerow conditions: 50 cm wide Vetiveria zizanioides 0 (Vetiver), Agapanthus africanus
(Lily). Nephrolepis sp. (Fern). Andropogon citraturn (Lemon grass) and no hedgerow. and
five levels of pine needles: 0 Mg/ha. 0.5 Mg/ha. 1.5 Mg/ha, 3 Mg/ha and 5 Mg/ha used as a
mulch. Overland flow was simulated in order to obtain equivalent slope lengths using a 0
1/mm, a 2 1/mm, a 6 1/mm and a 14 1/mm flow, representing a 2 1/mm flow equal to an 80%
rainstorm runoff similar to that obtained under humid and saturated conditions on a 5 m
length bare plot.
Hedgerows and mulch are good conservation measures, especially when they are combined. The
residue requirements are less when the slope is protected by hedgerows. and larger
intervals between hedgerows are possible provided there is mulch on the surface of the
soil between hedgerows. Soil losses in wet conditions were reduced to less than 1 Mg/ha by
combining any residue cover and a Vetiver hedgerow against almost 8 Mg/ha on the bare 5 m
length plot. Equivalent slope lengths increased soil losses up 25 Mg/ha on a 40m
equivalent length bare plot. For the same slope equivalent length condition there was a
soil loss of only between 1- 2 Mg/ha with the highest residue level applied and a loss
less than 1 Mg/ha when the residues and the hedgerows were combined. Vetiver grass and
Nephrolepis (Fern) were the most efficient hedgerows because of their high density
vegetative structure. Under dry soil and humid soil, slope effect was considerable but
under saturated soil the slope effect was not evident. Runoff was also diminished by the
residue cover and hedgerows but efficiency was poor under saturated conditions. Simulated
rainfall allowed to reduce time and costs of experiments as compared with natural rain. A
table is presented as a semi-quantitative model to design spacing between hedgerows taking
into account rainfall erosivity, soil erodibility, crop-management intensity and a minimum
distance between hedgerows of 10 m.
A Test Of Planting Vetiver Grass At Different Vertical Intervals Of Soil And Water
Conservation On Sloping Land.
Niras Tangtumniyom, Chaichan Chalothorn and Piroj Prasitnork. Land Development Department,
Ministry of Agricultural and Cooperatives, Bangkok, Thailand.
The study of planting vetiver grass at 7 different vertical intervals for soil and water
conservation was conducted in Huay Sai Royal Development Centre, Petchaburi Province on
Hup Kapong soil series at 5% slope. It was found that when planting vetiver grass at the
vertical interval of 0.5, 1 and 2 m. compared with no vetiver grass treatment, vetiver
grass treatments can reduced soil loss to 43.55, 39.72 and 22.89% respectively. However
they can reduced soil loss up to 53.98, 50.85 and 37.13% when comparing vetiver grass
treatments with the treatment of planting cassava up and down slope after land
preparation.
Establishing Vetiver Hedges To Alleviate Soil Erosion In The Rubber Replanting Area Of
Southern Thailand
Sayan Sdoodee. Department of Plant Science, Faculty of Natural Resources, Prince of
Songkla University Hat Yai, Songkhla, Thailand.
A rapid increase in rubber plantation in southern Thailand, has lead to the movement of
plantation area on marginal land, often steep land where the damage of soil erosion is
great during heavy rainfall. To alleviate this impact, an experiment was established in a
farmer's rubber-replanting area under traditional intercropping in Songkhla Province.
Rubber seedlings are grown (spacing 3 x 7 m.) on a highly erodible sandy loam soil on land
with slope of 12%. A randomized block design was used with 5 treatments (1 - sole cropping
of rubbers or control; 2 - establishing vetiver hedges between rows of rubbers (R+V); 3 -
rubbers intercropped with upland-rice (R+P); 4 - establishing vetiver hedges between rows
of rubbers intercropped with upland-rice (R+V+R); and 5 - establishing vetiver hedges
between rows of rubbers intercropped with Pueraria phaseoloides) and (P + V + P) in 3
replications. Total plots were 15, each plot (5 x 1 2 m) consisted of 4 rubber seedlings.
During the experimental period (October - December 1993) there was heavy rainfall of 1061
mm. In the control treatment, amount of runoff (649.88 lit/m and eroded soil (3.40 t/ha.)
were highest, and they was a significant difference from the remaining treatments. There
were no significant differences among the treatments of P + V, H + P, H + V + H and P + V
+ P. The highest percentage of the reduction of runoff and eroded soil occurred in the
treatment of H+V+P, and they were 40% and 52%, respectively. Analysis of nitrogen (N).
phosphorus (P) and potassium (K) in eroded soil, results showed that the removal of N and
K were significantly highest in the control treatment. The results of the tests suggested
that the occurrence of surface runoff during the rainy season should be counteracted by
establishing vetiver hedges and adequate plant cover.
Effects Of Vetiver Grass And Leucaena For Soil Erosion Control In Sugarcane, Maize And
Cassava Crop Practices
Somchai Anusontpornperm, Winal Supattanakul and Prayuth Kawilaves. Agro-Technology
Department, Thailand Institute of Scientific and Technological Research, Thailand.
Four experiments on the effects of vetiver grass and leucaena in sugarcane, maize and
cassava (grown early and at nearly the end of rainy season) crop practices were conducted
during 1993-1995 in a farmer's field at Tambon Huai Bong, Amphoe Dan Khun Thot, Changwat
Nakhon Ratchasima. The experimental plots were in a soil with sandy loam surface on three,
four, five and six percent slope respectively. The experimental design of all experiments
was randomized complete block with four replications. Each replication consisted of four
treatments: one and two-rows of vetiver grass strip, one-row of leucaena strip and the
control.
Results obtained from the experiments revealed no significant difference among treatments
in the amount of soil loss due to erosion in the first and second year in sugarcane. On
the other hand, in maize, the control treatment showed the highest amount of soil loss
with an average of 7.236 ton/ha which was significantly higher than that of the one-row of
vetiver grass strip treatment in the first year. In the second year, the control still
showed the highest amount of soil loss with an average of 16.753 ton/ha. This was highly
significant different from all other treatments. For cassava grown in early rainy season,
the different treatments did not show any significant difference in the amount of soil
loss in the first year. However, in second year the amount of soil loss obtained from the
control was 44.107 ton/ha which was about six times higher than that from the other
treatments. In another cassava plot grown near the end of rainy season, the data showed no
significant difference in the first year, however, in the second year the control gave the
highest soil loss with an average of 23.03 ton/ha. This was significantly higher than that
of the two-row of vetiver strip treatment. In these experiments it was found that the
yields of sugarcane, maize and cassava in different treatments were not significantly
different.
Vetiver Grass Hedgerows For Soil And Water Conservation In Tea Lands In Sri Lanka -- A
Success Story
R. Navaratnam. Natural Resources Management Centre. P.O. Box. 52. Dept. of Agriculture,
Peradeniya, Sri Lanka.
Soil erosion is severe in high rainfall Mid and Upland regions of Sri Lanka where the
major crop is tea; 80% of this is seedling tea (tea from seeds). The old 'Up and Down'
planting system adopted and absence of vegetative protection to existing mechanical
measures results in severe soil erosion. Studies reveal 115 cm top soil lost during last
century. This relates to 40 MT/Ha/yr. Unplanned land clearing causes 250 MT/Ha/yr soil
loss. Land rested 2 yr. under Managrass (Cympobogon confertiflorus) without mulching
results in 120-160 MT/Ha/yr. soil loss. New contour planted VP tea during 4 year growth
exhibits 75 MT/Ha/yr. to 20 MT/Ha/Yr. soil loss mainly due to insufficient mulching.
Mechanical measures are generally not accepted due to high cost, repeated reconstruction,
high maintenance, while Vetiver grass hedgerows popularly accepted due to low cost, easy
application, low maintenance, permanency once established. No detailed research done on
Vetiver hedge rows in tea, but significant results visually observed in its high
efficiency of soil and water conservation. This is proved by its increasing adoption by
tea estates for this purpose in Sri Lanka.
Vetiver -- A Promising Grass For Soil Conservation In Vietnam
Tran Thi Tam, Thai Phien and Nguyen Tu Siem. National Institute for Soils and Fertilizers,
Vietnam
In Vietnam the upland areas account for 25 million ha, which are located mainly on slopes
of 25% to 45%. So soil erosion presents a real threat for agricultural production and
environment. on the upland.
Studies showed that the anti-erosive measures based on imported "modern
techniques" appeared to be less acceptable by farmers than improved traditional ones
using living barriers. Among the plants used for this purpose, Vetiver is considered one
of the most suitable one.
This poster paper describes the present status of Vetiver use for soil and water
conservation.
Both advantages and disadvantages of this plant are also discussed based on the farmer
feedback and field observations.
In Vietnam Vetiver can be grown either from seeds or by vetiver "splits", but
the latter way vetiver is propagated vegetatively, by "splits" and not by seeds.
Vetiver is planted along the contour at 15 - 20 cm interval of the sloping land. The
vetiver grass grows very fast and does not compete with trees for nutrients. Within two to
tree years the plant grow together, forming vegetative hedge. Vetiver puts down a dense
curtain of deep roots and, being so well anchored, a hedge can withstand even a shed of
water flowing over it. Vetiver hedge can block the passage of soil, keep topsoil in site
limit runoff, and over time, retard most surface erosion and in many cases can filter out
the soil particles.
Since most of cropping systems on the upland retrieve nitrogen amendment, growing vetiver
in mixing with some leguminous ones is highly recommended.
A Test On The Use Of Vetiver Grass With Some Soil Conservation And Improvement Measures
For Sustainability In Cassava - Based Cropping (Sword Bean)
Chumpol Konsilp and Adul Srisupan . Land Development Department, Ministry of Agricultural
and Cooperatives, Bangkok, Thailand.
The test on the use of vetiver grass with some soil conservation and improvement measures
for sustainability in cassava based cropping was carried out on Nam Pong soil series at
Mahasarakam Province during 1993-1995. The treatments were: (1) Cassava without any soil
conservation or improvement measure: (2) Cassava with sword bean as cover crop; (3)
Cassava with sword bean and vetiver grass without seedbed; (4) Cassava with sword bean and
vetiver grass with seedbed; (5) Cassava with sword bean and mango in vetiver row without
seedbed; and (6) Cassava with sword bean and mango in vetiver row with seedbed.
The results indicated that treatment 3 and 4 which including soil conservation by vetiver
grass and soil improvement by sword bean showed good result in reducing soil loss and
increased the cassava's yield from 30 - 43% in the first year and 46 - 48% in the second
year. There was a potential to plant mango in the system but termites had to be
controlled.
Study On Optimum Rows And Different Plant Spacings Of Vetiver Grass For Soil Erosion
Control On Sloping Land.
Wenus Charoenrungrat, Nakorn Thawornwong, Anusornjit Sangknamarn, Solot Sae-Lim and
Surawuth Klinkhajai. Land Development Department, Ministry of Agricultural and
Cooperatives,
Bangkok, Thailand.
The experiment was conducted in Saraburi Province during August 1993 - March 1995, at
about 10% slope on Muak Lek soil series which is shallow and erosive soil. The treatments
were comparing between with and without vetiver grass as soil erosion control. The results
showed that there were significant differences in reducing soil loss and crop yield
between with and without vetiver grass, but there were not significantly difference in
reducing soil loss and crop yield among difference spacing of vetiver.
Vetiver Grass As Erosion And Land Productivity Control
Syahrul Donie and R Sudradjat. Watershed Management Technology Center, Indonesia
The use of vetiver as erosion and land productivity control was investigated in Boyolali
(Central Java) from 1990 to 1992. The method used were:
(1) Grass barrier with Vetiveria zizanioides; (2) Grass barrier with Setaria spacelata;
(3) Bench terrace with Setaria spacelata; and (4) Control : Bench terrace without grass
barrier.
Those treatments used as a strip cropping along border line of 1500 m plot area for each
treatment. Corn, Sesamur indicum and bean were planted for two harvesting periods in the
plot area. The result showed that the use of vetiver as a grass barrier could reduce
erosion of 72.7% and stream coefficient of 12.5% compared to control. Moreover, corn
production was increased by 104.7% at harvesting period I and 122% at harvesting period
II, as for Sesamur indicum, it increased by 89.3% and bean production by 142.9%. Among the
three grass barriers, only vetiver could produce brangkasan mucuna and give the highest
grass height.
Use Of Vetiver In Soil Conservation In The Black And Red Soil Areas Of India.
P.K. Thomas. 'Ponvanibhom', Prasant Nagar Junction Medical College P.O.,Trivandrum,
Kerala, India.
Mr. Greenfield of the World Bank initiated the 'Vetiver technology' of soil and water
conservation in 1986, on the Black (Vertisol) and the Red (Alfisol) soils of India, which
cover more than 15 million ha of arable land and which for generations, have been subject
to severe erosion (6 to 15 T/ha annually). Since then, through a series of field studies,
the characteristics of this grass and the effectiveness of the technology have been
evaluated. As compared to the existing technology (bunding), the Vetiver technology was
observed to reduce soil erosion up to 65 percent, reduce run off loss from 50 to 60
percent and increase crop yields up to 25 percent, apart from being the cheapest.
However, even with all the ideal characteristics of the plant itself and the evidences in
favor of the technology, it is not getting acceptance in the officially sponsored soil
conservation programs in India. It is believed that the real causes are the extensive
field coverage needed to achieve annual financial targets and the reduced scope for 'cuts'
by officials. and contractors. Extensive awareness campaign among farmers and adoption of
group farming system are suggested.