Kutch in Gujarat is an area of scanty and erratic rainfall. It is surrounded on three sides by the sea, which results in strong winds. Ambient temperatures are very high, and can go upto 42oC in September and October. The combination of strong winds and high temperatures results in very high evaporation. This is counteracted to some extent by dew in the early hours of the day caused by the sea. About 10% of the area is under agriculture, mostly irrigated. Intensive irrigation has led to declining water tables. This has resulted in the seepage of sea water laterally, through the porous sandstones, resulting in soil salinity.
Kutch has a short rainy period with a low annual rainfall of 350-400mm. Very intense rain of upto 150mm in one day is not uncommon. As the total rainfall is low and evaporation high, and rainfall distribution is erratic. Farmers have depended on open wells and borewells for heavy irrigation for two decades. So though the irrigated area is about 2% of the arable land, groundwater tables are falling. Now borewells more than 200 feet deep have to be sunk to reach reliable sources of water.
Excessive irrigation has resulted in impervious salt deposits on the topsoil as a result of the high evaporation rates. Consequently these saline soils have low infiltration rates. Salinity, together with the high intensity of rainfall causes rapid run-off on the easily erodable soils.
Since 1994 I have been experimenting with organic farming and water recycling techniques to rehabilitate the degraded environment and soils on my 40 hectare farm in Kutch. Forty head of cattle and two stall-fed goats are reared on the farm. Annual crops and several multi-purpose tree varieties are grown.
Wheat, bajra and pulses such as moong arhar and pigeon pea are grown for food. Carrot and jowar are grown as fodder crops. These are cultivated during the rainy season. To save groundwater, only protective irrigation is given to arable crops during dry spells in the rainy season and no crops are grown in the dry season.
Sesbania grandiflora, Sesbania sesban, Indian coral tree, drumsticks, Kydia calycina and mulberry provide fodder for the cattle. Nitrogen fixing trees like Glyricidia sepium, Casuarina but also non-nitrogen fixing trees like Cassia alata, neem, Pongamia pinnata provide biomass for compost making. Fruit bearing trees like mango (1000), Indian gooseberry (2000) and custard apple (500) generate income.
To control erosion and surface run-off, trees were planted at intervals of 16 feet. Mangoes were watered at the rate of 2 litres per tree per fortnight during the establishment phase of four years. In most of this area mangoes were dying because of accumulation of salts. Application of mulch remedied the situation to a limited extent. We then tried drenching the mulch material with a slurry of 5 kg cowdung in 100 litres of water. This has improved the soil condition by neutralising salts, releasing the nutrients, and improving the soil structure, thus increasing infiltration and aeration. In the mulched area, trees which helped in trapping the early morning dew were planted. The soil temperature of 27oC under the mulched areas has increased microbial activity. (In contrast, the temperature of untreated soils can be as high as 67oC.)
Plant growth improved considerably, using the same quantities of water and nutrients. Soil rehabilitation has proven to be successful since yields and product quality have improved, leading to better income. The shelf life, taste and appearance of mangoes have improved through this practice. At present yields stand at 3 tonnes (from one thousand 4-year old trees) but are expected to rise to 50 tonnes in the coming 5 years. The price fetched is Rs 20/kg of mangoes.
Feeding cattle with the fodder grown organically on the farm has improved their health. this has the quality of milk and butter, which sells at one and a half times the normal market prices. At present 2 kg of butter at Rs. 150/kg is being sold daily to Mumbai.
To improve the groundwater situation, seven wells are recharged from road side and farm lands. The TDS (Total Dissolved Solids) has gone down from 2300 to 900. Open well recharge is a better option in Kutch than creating percolation ponds, as the fine silt deposits create impervious layers and prevent recharge of the groundwater; most of the water evaporates. Open well recharge has the advantage that layers of sandy soils are interspersed between the impervious layers and lateral recharge becomes possible. Silt settles only at the bottom of the well.
Moolchand Haria
