Chapter 8 - Helping farmers to use optimal inputs: lessons from soil health cards in Bhoochetana experiment

Abstract

Poor understanding of soil quality and distortionary subsidies for urea are two big reasons for imbalanced use of chemical fertilizers in India. In 2009 the Government of Karnataka and ICRISAT launched a program called Bhoochetana to address both these problems. More than 90,000 soil samples were collected from all 220 taluks of the state and tested for macro and micronutrients, pH values, and salinity. 50%–62% of all soil samples were found to be deficient in boron, sulfur, and zinc. These test results were disseminated to farmers and the state government incentivized the use of these micronutrients by selling them at 50% subsidy. We analyzed data from crop cutting samples collected from a random sample of more than 3700 farmers and found that application of micronutrients led to an average increase in crop yields by 0.5 tons. The yield response was even higher in good rainfall years and for crops like sugarcane, maize, sorghum, sunflower, and pearl millet. However, there is large heterogeneity in the impact of micronutrients, which is not systematically correlated with native properties of the soil. Farmers seem to compensate for nutrient deficiencies in their soil. However, this compensation does not take the form of applying larger quantities of nutrients when the deficiency is higher. The average level of nutrient deficiency in a taluk is not systematically correlated with the average quantity of micronutrients applied by farmers. We may not be getting significant results because of attenuation bias caused by high measurement error in average values. Having farmer level data on nutrient deficiency and fertilizer application will give us more precise results.