Agricultural Development Officer, Nashik

Department of Soil Conservation and Watershed Management,

Maharashtra State, INDIA.

Land and water are the most important natural resources for the survival of life and mankind. Land is one of the most precious resources, where population pressure per unit of land is very high and is highly sensitive to human disturbances. Hence it is essential to adopt suitable conservation measures in order to get higher and higher agricultural production without deterioration of land. Conservation of soil and water for sustained production and restoration of environment is essential with the objective to achieve them with better benefit cost ratio. Among various methods of soil and water conservation vegetative methods are found very effective and cheaper. These methods are drawing greater attention during recent years. Grasses which form effective hedges check the speed of runoff water resulting in the settlement of soil particles at the live bunds. The live bunds particularly of grasses act as filters through which water with very less soil particles flow at reduced speed.

Research and studies in various countries and in the state of Maharashtra (India) clearly showed that Vetiveria zizanioides and a few local grasses are very effective in the formation of live bunds for soil and water conservation, deposition of silt and clay and development of soil under favourable rainfall conditions and effective management with good socio-economic response, vegetative hedges can be established within a crop season. Andhra Pradesh Agricultural University in India (1989) found that when Vetiver hedge established across the slope with castor—bean can reduce runoff water and improved crop yield. In China, Xinhao (1992,) reported that vetiver grass in potatoes areas can reduce runoff water and soil loss about 56% and 95% compared to farmers practice plot. Bharad (1990) observed that 55.4% , 28.5%, 14.49 % increased productivity of crops in very shallow soils (on farm), shallow soils (on station), medium deep soil (on station) respectively when cultivation and sowing was along contour vegetative hedge line. Surface runoff was also reduced by 46% in shallow soils and 16.7 % in medium deep soils.

Government of India has started National Watershed Development Project for Rainfed Areas (NWDPRA,1991) in which main emphasis is given to vegetative or biological methods for conserving soil and water as low cost techniques instead of using high cost techniques as mechanical / engineering measures which disturb the soil structure. The states and the central government are laying stress on vegetative methods, especially on the cultivation of Vetiver in soil and water conservation programs. Hence, it is essential to evaluate the efficiency of Vetiver planted during the last few years. Keeping this in view and the hydrology in a changing environment, the present investigation was undertaken.

This study is not based on research data. It is based rather on a huge practical and field experience, gained during the frequent field visits for technical inspection, guidance and assessment of the quality of works completed by the field staff working at watershed level. The study confirmed to NWDPRA and use of vetiver for soil and water conservation in Nashik district. Since 1991 — 92 twelve watersheds with a geographical area of 52,952 hectares is treated with 4855 tones of Vetiver slips for drainage line and land treatments. Up to the end of 1995-96 monsoon season, Contour Vegetative Hedges (CVH) are completed on 1 0466 hectares area; similarly 9320 numbers of Live Check Dam (LCD) and 2434 1 numbers of Loose Boulder Structures (LBS) are completed. Out of these on going watersheds, seven are selected for the study. These are Wadivarhe, Talegaon(T), Thanapada and Rashegaon from sub-mountain zone and Patpimpri , Karajgavan and Shingave from scarcity zone. The sub—mountain zone has an annual rainfall between 850 and 4 000 mm, the soil is reddish brown to black tending towards lateritic nature with varying depths and textures. The cropping pattern is mainly dominated by Kharif cereals mainly paddy (Oryza sativa) followed by Ragi Elusine coracana . The scarcity zone receives less than 750 mm of annual rainfall.

With uncertainty and irregular distribution the agriculture in this region is very unstable coupled with low productivity. Cropping is dominated by Pennisetum typhoides followed by Sorghum vulgare. By using randomised sampling techniques some treatments and areas are selected for observations, each from submountain and scarcity zone. Two identical small watersheds having about 15—41 ha. geographical area, from Thanapada, Rashegaon, Patpimpri are selected and named as T1 (non treated) and T2 (treated) for crop productivity, surface runoff and soil loss measurement.

Planting material plays an important role in the survival of Vetiver. It is recommended that the proper stage of Vetiver slips for transplanting is at the age of 16-23 weeks and transplanting should be completed within 24 hours after uprooting the slips from the nursery. It is observed from field experience that the Vetiver used for planting during the year 1991-92 was transported from a long distance and it was about one and half years old, which resulted in low survival percentage. The Vetiver used during 1991-92 is therefore omitted from the study. During the years 1992-93 to 95-96, the Vetiver slips used for transplanting were of proper stage and transplanting was completed within a couple of days. The survival was recorded during the month of January of the same year. Under almost all treatments the survival percentage was 75 (Table- 1). This clearly showed that tine age of the planting material and the time gap between uprooting and transplanting play a very important role in the survival of Vetiver

A) Submountain Zone

1. Year of Plantation - 1 992-93

1. Jan ‘93 75.00 75.00 56.25 68.74

2. Jan ‘94 50.00 62.50 37.50 50.00

3. Jan ‘95 37.50 56.25 31.25 39.58

4. Jan ‘96 37.50 50.00 31.25 39.58

2. Year of Plantation - 1993-94

1 Jan ‘94 75.00 87.50 75.00 79.16

2. Jan ‘95 50.00 68.75 50.00 56.25

3. Jan ‘96 50.00 68.75 50.00 56.25

3. Year of Plantation - 1994-95

1. Jan ‘95 75.00 100.00 81.25 85.41

2. Jan ‘96 62.50 75.00 43.75 60.41

B) Scarcity Zone -

1. Year of Plantation - 1 993-94

1. Jan ‘94 - - 50.00 50.00

2. Jan ‘95 - - 25.00 25.00

3. Jan ‘96 - - 25.00 25.00

2. Year of Plantation - 1 994-95

1. Jan ‘95 - 50.00 50.00 50.00

2. Jan ‘96 - 25.00 25.00 25.00

It is evident from the data regarding precipitation during the seasons that rainy days (Table -2) did not show any relationship with the survival of Vetiver. During the different years under study there were variations in the total rainfall and rainy days, however there were not many differences in the survival of Vetiver. Similarly the survival percentage in different watersheds in the sub-mountain zone were of the same order though there was maximum rainfall in Wadivarhe watershed and minimum in Rashegaon watershed. The number of rainy days also could not show any significant effect on survival. When the survival and maintenance of Vetiver were recorded in successive years it was observed that the survival percentage declined progressively though it was more pronounced during the period between January and May. It may be mainly because of higher atmospheric temperature and low residual soil moistures. The soil depths and soil types did play important role in the survival and maintenance of Vetiver during the succeeding years after plantation. The locations where soil depths were more and soils were medium with higher water holding capacity showed more survival compared to shallow and light soils. The soils in watersheds at Rashegaon and Thanapada are of better types with better water holding capacity compared to those of Wadivarhe and Talegaon (T) watersheds as a result of which rainfed crops are grown on large areas in Thanapada and Rashegaon Watersheds. The survival percentage of Vetiver are more than those of the remaining two watersheds, which shows the important role of soil types on survival

The rainfall in the scarcity zone is scanty and uncertain. The survival of Vetiver planted in three watersheds was found low i.e. about 50 percent compared to that in watersheds of sub-mountain zone. The survival after 2-3 years after planting was more than 50% in sub-mountain zone and only 25% in the scarcity zone.

When the treatment effects were compared it was observed that among the three treatments that of LCD supported by 0.18 sq.m. stone bund was better than the remaining treatments i.e. LBS amid CVH during all the observations in all the four watersheds in sub—mountain zone. The survival percentage under all treatments was the maximum in the month of January about six months after plantation. The survival was successively and progressively reduced further. However, the mortality of Vetiver was at a faster rate during summer i.e. between the period of January and May. After a period of about two years the survival percentage became steady. And in addition to these factor one more factor which plays a significant role in increasing the mortality of the established Vetiver is the free grazing of stray cattle which disturb and destroy the established Vetiver. All the watersheds under study are located in rainfed areas where there is Kharif oriented cropping system. In time watersheds of Rashegaon and Thanapada the soils are medium and medium deep with a better water retention potential and double cropping. Kharif and Rabi crops are sown in quite a substantial area in these two watersheds. In all these watersheds cattle are let free once the crop are harvested These animals are let free for grazing in all watersheds except those of Rashegaon and Thanapada from November - December onwards. These animals wander freely and destroy the established Vetiver mainly by trampling and partly by uprooting while grazing. As a result the survival of Vetiver in such areas is lower compared to that in watersheds of Rashegaon and Thanapada where Rabi crops are also grown on a large area where animals are let free for grazing only after harvesting of Rabi crops, i.e. after February. Thus uncontrolled grazing of cattle is a major constraint for maintenance of the established Vetiver and free grazing needs to be checked for the better survival and maintenance of established Vetiver in the succeeding years. It is clearly evident from the data (Table—1) that the survival of Vetiver six months after plantation is about 75 % which decreases progressively with the passage of time.

B. Effect of treatments on survival of vetiver :

It is observed that the overall survival percentage of Vetiver for the four years (1992-96) in sub-mountain zone was about 51.33%. From table 3 it is also observed that LCD supported by 0.18 sq.m. section small stone bund secured the highest survival percentage (64.56%). It is followed by LBS which is reinforced by Vetiver as 47.87%. Thirdly land treatment named CVH gave the lowest survival at 4 I .56%. In scarcity zone the survival percentage of all treatments are about 25 % due to low rainfall situations

C. Crop Productivity :

It is observed that (Table -4) the effect of Vetiver as conservation measures in the treatment of CVH the crop yield of Elusine coracana increased by 35.3% in submountain zone. In scarcity zone the crop yield of Pennisetum typhoides was increased by 32.52 % and Sorghum vulgare by 28.69 %.

(T1 - non treated, T2 - treated with vetiver, CVH)

D. Surface Runoff :

It is found that the surface runoff of shallow soils in submountain zone was reduced by 47% and in scarcity zone it was reduced only by 8% because of low intensity of rainfall. In medium deep soils runoff was reduced by 23% (Table -5)

E. Soil Loss :

The soil loss a long with runoff water as sediment was estimated . In submountain zone it was found that the soil loss in shallow soil was 24.30 tones/ha, while in deep medium soil it was 32.50 tones/ha. In scarcity zone soil loss was only 10.55 tones/ha as there was very low rainfall with less intensity and resulted in low surface runoff. Soil loss reduction in sub-mountain zone and scarcity zone was 42.68 % (mean) and 12.79 % respectively by treating watersheds with Vetiver. (Table - 5)

(T1 - non treated, T2 - treated with vetiver)

This practical field experience clearly shows that though vegetative barrier as a low cost technique plays an important role in —situ moisture conservation by conserving rain water as well as by arresting soil particle, there are some limitations.

Vetiver grass has root system that penetrates deep into the soil (up to 3 m.). the roots effectively act like a net, holding the soil in place and thus preventing eroding. Moreover the stalks of vetiver grass helps to control waterflow, regardless of the slope of the terrain, by restraining the silt that rainwater normally carries away.

The cultivation of crops along with CVH gives 35.30 % and 32.52 % increased productivity. respectively in submountain and scarcity zones. The surface runoff reduction due to use of vetiver in CVH is 35% (shallow soil 47%; medium deep soil 23%) and 8% in submountain and scarcity respectively. The soil loss that is arrested is a very remarkable amount when using Vetiver Hedge line. It is 31.35% in submountain and 12.79 % in scarcity zone.