30) ICRISAT's Drought Research: Hope that Never Dries Up (May 2000)

Drought avoiding crops.For farmers in Gottipadu village, near Guntur in Andhra Pradesh, 1999 was a particularly harsh year: there were no rains at all after 21 October that year. In spite of this severe drought, farmers got as much as 1.7 tonnes per hectare that season. Their crop: chickpea, more precisely, chickpea varieties, Swetha (ICCV2) and Kranthi (ICCC37), short-duration varieties which mature in 85-100 days and therefore escape end-of-season drought.

In the semi-arid tropics, drought occurs roughly two out of every 5 years. And even when there is rainfall (varying from 500-1300 mm per annum), it is erratic, varying from year to year, and within seasons. Further, only 30-60% of this rainfall is used effectively for crop production; the remaining 40-70% of rainwater is lost as runoff, evaporation, and deep drainage.

It is against such a challenging background that ICRISAT has been researching for solutions for over a quarter-century now. And the combination of deep commitment and good science has given dividends. Besides, the silent chickpea revolution -- chickpea production in AP increased 9-fold in the last decade -- ICRISAT's groundnut program has distributed to national programs in Asia and Africa 45 drought resistant breeding lines. From the ICAR-ICRISAT groundnut releases in India, three varieties are tolerant of end-of-season drought, and two are tolerant of mid-season drought.

Efficient use of limited water. ICRISAT is fighting the battle against drought on a different front as well -- that of natural resource management. The basic strategy there is to conserve rainfall in community-managed watersheds. On-station and on-farm watersheds varying from 500 to 10 000 hectares are being used for the research. On-station results are very promising. Using an integrated watershed approach on deep black soils (90 cm and more), researchers at ICRISAT-Patancheru observed the following.

  • Achieved 4-4.3 tonnes per hectare as compared to 900 kg per hectare of sorghum grains from conventional system. 

  • Surface runoff of rainwater was reduced to 14% of rainfall as against 25% of rainfall in case of conventional system. 
  • Water loss through bare soil evaporation and deep drainage was reduced to 19% of rainfall as against 45%. 

  • Rainwater use efficiency for crop production was increased to 67% as against 30% in case of conventional system. 

  • Soil loss in case of improved system was reduced to 1.5 tonnes per ha as compared to 6.4 tonnes per ha.

  • In case of shallow black soils at Patancheru using integrated watershed management approach, ICRISAT researchers say:

  • Soybean + chickpea sequential system produced on an average 2.5 to 2.8 tonnes per hectare of grains and soybean pigeonpea intercrop produced 2 to 2.2 tonnes per hectare over the last 4 years. 

  • Improved land management decreased surface runoff by 40 mm (5 % of seasonal rainfall) and increased deep drainage of rainwater on an average by 5% as compare to the conventional system. 

  • Overall rainfall use efficiency on watershed basis ranged from 50 to 100 per cent on Vertic Inceptisols.  

  • In a drought year like 1999 intercropping systems performed far superior and produced 400 kg more grains per ha over the sequential system, in addition to the increased biomass production. 

  • Integrated nutrient management system followed in the improved system resulted in the balanced n nutrient budget for the improved cropping system. The Glyricidia loppings from the plants planted on bunds provided 25 kg N per ha. Legumes provided 42 to 89% of their requirements from BNF. 

Based on these achievements of ICRISAT in the area of integrated watershed development, the Asian Development Bank (ADB) has funded a project to evaluate this technology under farmers' conditions in India, Thailand, and Vietnam.

Evaluation through on-farm studies. For a task of this magnitude ICRISAT cannot -- and does not -- work alone. The Institute is evaluating this model in India in partnership with the farmers, non-governmental organizations (Bharatiya Agro-industries Foundation, Bhopal; MV Foundation, Hyderabad), National agricultural systems such as ICAR institutes (CRIDA; Indian Institute of Soil Science, Bhopal), and state agricultural universities (Jawaharlal Nehru Krishi Vishwa Vidyalay, Indore). On-farm evaluation is being done at Kothapally in Andhra Pradesh, and Lalatora and Solsinda watersheds in Madhya Pradesh.

At Kothapally in Ranga Reddy district of Andhra Pradesh during the first year of the program (1999) the rainfall received was only 480 mm. For the first time farmers grew soybean on 30 ha and harvested 400–1200 kg grains per ha depending on soil type. Improved cropping system with improved management produced 3.3 tonnes of grains in case of maize pigeonpea intercrop, and 1.5 tonnes grains in case of sorghum pigeonpea intercrop as compared to 900 kg per ha grains in case of traditional sorghum pigeonpea intercrop. The watershed committee of the villagers also undertook construction of water storage structures and gully control structures.

As ICRISAT Senior Scientist, Dr S P Wani says, "Through the community participatory approach we aim to develop simple and affordable technological and institutional arrangements with the help of local research and community institutions for managing the natural resources in the watersheds. These empowered farmers and community members in the watersheds will be equipped better to cope with the vagaries of the rains and to mitigate the adverse effects of drought without further degradation of natural resources."

With the diverse skill-sets of farmers, NGOs, and scientists all coming together, the battle against drought has seriously begun.

by ICRISAT. All rights reserved.