In-situ water harvesting: a farmer’s systematic approach for managing drylands

In the changing climate, untimely rains and prolonged dry spells are putting agriculture under risk. While not much change in the total rainfall is seen in a year but the distribu- tion is badly hit with more heavy rainy days and prolonged dry spells. Rain water harvesting at the farm level is one of the best solu- tions as the crops need only soil moisture and not water for its growth. An integrated approach for this will help rainfed farm- ers to save their crops.

Every farm receives about one lakh litres of rain water per hectare for every 1 cm of rain received. If we account for 30% of it evaporates, remaining 70,000 litres can be harvest- ed for every 1 cm rain received. If 80% of this can be har- vested we will have about 56,000 lit. So even in areas which have about 500 mm rainfall (which is average rainfall of dri- est districts like Jodhpur and Ananthapur) at least 1.5 lakh lit of water can be harvested per hectare which is sufficient to save a crop.

Subash Sharma, an Innovative farmer from Yavatmal Dist, Maharashtra has integrated several approaches togeth- er to harvest most of the rain received on his farm.

Increasing the soil organic matter: increasing the soil organic matter improves the moisture holding capacity of the soil by over 30%. The crop residue is converted into compost he calls ‘Go Sanjeevani’ 1 ton of dung+1/2 ton of tank silt, sprayed with 50 kg oil cake + 25 kg jaggery solution and com- posted for a month. This can be applied for 2 ha.

Micro Locking in deep furrows: In summer the field is ploughed and furrows (1 ft deep) are made. The furrows are again locked for every 8 ft (this can vary with the slope of the land – if the land has 1/2 inch slope locking can be for 15 feet, for 8 ft in 1 inch slope and for 5 ft in 2 inch slope lands). When it rains the water stays back in each of this furrow and sinks inside. If there is a heavy rain the locking can be removed by 6 inches so that water can flow out. Towards the lower end of the farm a channel is made which takes the excess water into a trench.

Trenches: On the lower end of the farm, a trench of 4 ft wide and 6 feet deep is made into which all the field channels flow. The trench is also locked for every 80 ft so that water can per- colate. Any over flow from the trenches leads into a farm pond.

Farm Pond: for every hectare of a small farm pond of 10 ft x 10 ft x 10 ft is dug into which the water flows if there is excess rain in a season.

Cropping systems: in addition to managing water and soil, appropriate cropping systems with shallow and deep root systems is important to use the available soil moisture judi- ciously. Last season Redgram and Soybean were taken up in 1:3 ratio. Other cropping systems tried were 1:3 red gram and Bendi, 1:3 red gram and Sesame. In case delayed rains short duration crops like bajra, mung, or leafy vegetables like palak and mung are taken up. Integrating trees (including fruit trees) in the farm or bunds will help to reduce the winds and provide biomass.

4.5 lakh lits of water harvested per hectare: Yavatmal receives about 900 mm annual rainfall and per acre at least

4.5 lakh litrs of water can be saved which is sufficient in the form of soil moisture to support two crops. The excess water which percolated also increased the ground water levels.

Establishing trees: In rainfed areas having more trees on farm sustainable incomes for small and marginal farmers. Lemon or citrus plants with 6 m x 6 m spacing or seethaphal with 4 x 4 mt spacing is ideal and space in between can be used for the intercropping with annual food crops. But major problem they face is in establishing the trees in the initial stages. A simple approach evolved by Sri. Subash Sharma ji can help to establish a tree with use of 180 lit/tree/yr.

Within 6 inches of the place where the sapling would be planted insert a plastic pipe of 1 ft long and 3 in diameter Fill it up with small pebbles and remove the pipe

When water is applied here it directly goes into the sub- surface and helps the sapling to survive.

2 lit of water for every 4 days for two years will help the saplings to establish themselves and later the in situ water harvesting is sufficient for the trees to survive and give sus- tainable incomes.

In situation like what we are in today, due to El Nino effect, this kind of integrated approach will reduce the risk of crop failures. An integrated approach to rain water harvest- ing and crop planning is very important which needs support from the government.

For further information Contact Sri. Subash Sharma, Choti Gujjiri Mohalla, Yavatmal dist. Farm is in Tiwasa village, Yavatmal district. Mobile no. 09422869620