TOLERANCE OF VETIVER TO TOXIC CHEMICALS


Vetiver Hedgerows And Agrochemical Residues: A Case Study In The Cabbage Fields At Nong Hoi Development Center Chiang Mai, Northern Thailand.
J.Pinthong1, S. Imphitaks2, M. Udomchoke2, A. Ramlee1
1Research Division, Royal Project Foundation
2Department of Agriculture Technology, THAILAND

The main objectives are to investigate the fate of agrochemicals used for growing cabbage in between the vetiver hedgerows (VHRs) and to evaluate the effectiveness of hedges in reducing the over supply amount of pesticides and nitrate fertilizer. The experiment has been conducted in the area of 15 x 72 square meters on 60 per cent slope. Split-plot in randomized complete block is assigned with three replications (blocks). Each block consists of six plots with and without VHRs at 3 and 6 meter vertical intervals and also agrochemicals at zero, one and double doses were applied. Seedlings were transplanted on July 13, and harvested in September 29. Random samplings were later taken from the lowest VHRs of the three whole plants at each plot; and from soils to one meter depth in between and at one meter behind the lowest VHRs. Included were sediments from the collection tanks below. From the analytical data, the three pesticides were taken up into vetiver grass at different rate and contents. Those applied were in soil cooperated as Carbofuran insecticides. Alachlor herbicides sprayed 7 days after planting cabbages and Monocrotophos spraying twice at 34 and 42 day during the growing stage. Carbofuran was found in vetiver grass about 0.001 - 0.006 per cent; Alachlor 0.01 - 0.08, and Monocrotophos 0.19 - 0.53 per cent of the total fresh weight. In soils, the only Alachlor has been detected around 3.38 to 7.69 per cent. It is believed that over 90 per cent of Carbofuran and Monocrotophos had decomposed and could have not been detected by the method employed. Probably, the same decomposition happened for Alachlor after spray to harvesting when the cabbage was about 78 days old. Alachlor and Monocrotophos were found both below and over Maximum Residue Limit, i.e.>0.02 and 0.20 ppm respectively. Carbofuran at normal and double close was lower according to FAO/WHO CODEX (<0.5 ppm). Losses of soil through VHRs of 5 months old found at the moderate rate of 22.4 ton per hectare. There was only Alachlor found in sediments about 0.02-0.5 per cent. The influence of nitrate fertilizer could not be possible as to have been detected by this period. A conclusion can be made at this stage that VHRs have substantially contributed to a process of captivating over supplying of agrochemicals as the living walls. As a result detoxification should have been possible and the better downstream water quality. This study is a preliminary one, thus it still needs further detailed investigation.


The Capability Of Vetiver Hedgerows On Decontamination Of Agrochemical Residues: A Case Study On The Production Of Cabbage At Nong Hoi Development Center Chiang Mai, Thailand.
Pinthong J.1, Impithuksa S2., Udomchoke M2., Ramlee A.1.1 Research Division, Royal Project Foundation.
2 Division of Agricultural Toxic Substances, Department of Agriculture.


The study was conducted in a cabbage field at Nong Hoi Development Center, Chiang Mai, in order to determine the movement and degradation of agrochemicals applied on cabbage which focused on their impacts on soil sediment and especially in vetiver. Split-plots in RCB was designed in the area of 15x72 in2 at sixty per cent slope. Each block consisted of cabbage and vetiver hedgerows (VHRs) lined vertically at 3 and 6 m apart. Before and after transplanted on July 13, the pesticides, i.e. carbofuran, monocrotophos, and alachlor were applied in single and double doses. On September 29, an approximate 78 days after transplanted the cabbages were harvested and were brought to the laboratory together with soil, sediment (from the small reservoir below the experimental plots). and vetiver grass for analysis.

The analytical data revealed that most of the tested pesticides applied on cabbages could be translocated and up taken by crops, adsorbed by soil as well as sediment in different amounts. The vetiver was capable of pesticide absorption as indicating by the residues of carbofuran, monocrotophos and alachlor found at the percentage of 0.001 - 0.006, 0.09 - 0.25 and 0.01 - 0.08 of the total amount of active ingredient application, respectively. In soil, only alachlor was detected between 3.69 - 7.56 per cent. While, the percentage of residues found in cabbage for carbofuran, monocrotophos and alachlor were 0.005 - 0.01, 0.75 - 0.91 and 0.01 - 0.09, respectively. Moreover, alachlor residues detected from the single and double doses were exceeded the maximum residue limit (MRL). This event was also occurred in the cabbage applied with the double dose of monocrotophos. The loss of surface soil by run-off which could be evaluated in term of sediment was at the medium level 22.5 ton per hectare. Aside from the rate of leaching the sediment was also an accumulation site for alachlor and carbofuran residues at the percentage of 0.02 - 0.5 and 0.002 of the total active ingredient admitted, respectively. No data were available for the absorption of nitrate fertilizer by vetiver in the experiment. The study concluded that the vetiver hedgerows played an important role in contribution to the process of captivity as well as decontamination of agrochemicals especially pesticides and preventing them from contamination and accumulating in crops, streams and other ecosystems. Due to the lacking of data upon the relationship between vetiver and agrochemicals, altogether with this study which is a preliminary one, therefore further study for more details is still needed.


In Vitro Induction Of Salt Tolerance In Vetiver Grass
M. Nanakorn1, S. Surawattananon1, C. Wongwattana2
K. Namwongprom1 and S. Suwannachitr1
1Department of Botany, Faculty of Science, Kasetsart University, Bangkok, THAILAND.
2Department of Biology, Faculty of Science, Srinakharinwirot University, Bangkok, THAILAND.

Vetiver grass (Vetiveria zizanioides Nash) ecotype Sri Lanka was induced for salt tolerance by culturing calli from young inflorescence on MS medium supplemented with 5 M 2,4- D and 0.5 -3.0% NaCI, at 0.5% intervals for 45 days. At 0.5-1.5% NaCI, 100% of calli survived. At 2, 2.5, and 3.0% NaCI, their survival percentage dropped to 82.5, 25, and 0%, respectively. The surviving calli regenerated to plantlets when transferred to hormone and NaCI free MS medium for 30 days. However, the regeneration percentage declined with an increased concentration of NaCI. The 1.0 - 2.0% NaCI treated calli regenerated only 10 - 20% while there was no regeneration in 2.5% NaCI. All obtained plantlets were tested for their salt tolerance by culturing on MS medium with NaCI at the same level as their calli were treated, in comparison with the untreated plantlets. The result showed that the survival percentage of treated plantlets at each concentration of NaCI was higher. They tolerate up to 15% NaCI while the normal plant can tolerate nothing higher than 1.0% NaCI.


In Vitro Selection Of NaCl Tolerance In Vetiveria Species
M. Nanakorn1, S. Surawattananon1, K. Namwongporm1
K. Sangnil2 and S. Suwannachitr1
1Department of Botany, Faculty of Science, Kasetsart University, Bangkok, THAILAND.
2Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, THAILAND.


The NaCl tolerance of vetiver grasses were examined in vitro. There were 5 ecotypes of Vetiveria zizanioides Nash: Surat Thani, Songkhla 3, Chiang Rai, Sri Lanka and Indonesia; and 5 ecotypes of V. nemoralis A. Cam US: Kampaeng Phet 1, Prachuap Kin Khan, Nakhon Sawan, Huay Diag and Gudbaak. The calli from young inflorescence were cultured on MS medium supplemented with 5 ILM 2,4-D and 0-4% NaCI at 1 % interval for 45 days. The Kampaeng Phet 1 clearly showed maximum degree of salt tolerance. The NaCI concentration that gave 50% reduction in callus growth was 1.95% and followed by Prachuap Kin Khan at 1.31 %. The surviving calli of the Kampaeng Phet 1 were regenerated to plantlets on hormone and NaCI free MS medium for retesting of NaCI tolerance.


Vetiver For Sodic Land Reclamation
H. M. BEHL & A. K. SINGH, Tree Biology, National Botanical Research Institute Lucknow
226 001, India

National Botanical Research Institute (then NBG), Lucknow in Uttar Pradesh was a pioneer for using vetiver (in 1956) for amelioration of sodic sites. However, it is only recently, after 40 years, that vetiver has again been opted for large scale trials under a World Bank programme in the state. High concentration of salts in the root zone of soil limit the productivity of 950 million hectares of otherwise productive land around the world. In India alone, there are 8.1 million hectares of sodic land, where productivity is limited. We have been able to grow Vetiver successfully in the soils with high levels of exchangeable sodium in the root zone with high pH (9 to 10.6) throughout the profile, poor water intake, occasional anaerobic stress due to water logging, poor availability of phosphorus that limits the growth, and low fertility.

Agro-techniques were developed for growing vetiver as hedgerow and flat beds in barren uncovered lands. The agro-techniques included developing quality planting material selected for tolerance to high pH, optimum root formation, mycorrhizal association and vigorous vegetative growth. The nursery was raised in a poly house with mist irrigation. Application of endomycorrhizae cultures (Glomus fasciculatum) facilitated root growth and P uptake. Such selected and tailored slips are being used for hedge under sodic land afforestation and development programme. Capacity to provide planting material in commercial quantities has been developed.

Farmer are yet slow to accept the technology, however, a marketing strategy with appropriate training is being planned. Initial training is provided by "motivators" while technical tips are provided by experts. Key persons are being trained for faster dissemination to end users. Vetiver along with other aromatic grasses such as lemon grass and palma rosa are gradually gaining cognizance and acceptability.

Effects Of Some Adverse Soil Conditions On The Growth Of Vetiver Zizanioides L.
P.N.V.Truong and D.E. Baker
Resource Management Institute, Queensland Department of Primary Industries, Melers Road, Indooroopilly 4068, AUSTRALIA.

It has been widely reported that vetiver grass can be established and flourish under a wide range of conditions including some very hostile environments. However very few quantitative data have been reported to support these anecdotal observations. In a series of glasshouse and field experiments, it was shown that vetiver can thrive under a wide range of pH, it is highly tolerant to saline and sodic soil conditions, and Al and Mn toxicities. When adequately supply with N and P fertilizers, Vetiver can flourish between pH 3.3 and 9.5. The saline threshold level is ECse = 8 dS/m and for 50% yield reduction, ECse = 17.5 dS/m. These results include vetiver in a group of highly salt tolerant crop and pasture species grown in Australia. Its growth was also not adversely affected by soil with exchangeable sodium percentage of 33%. With adequate moisture, N and P supply vetiver can flourish at soil Al and Mn higher than 68% saturation and 578 ppm respectively.

These results support observations that vetiver can be established under highly hostile environment and indicating that it is highly suitable for land stabilization and reclamation of extremely hostile environment such as mining and industrial wastes.