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, 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.