Soil test-based nutrient balancing improved crop productivity and rural livelihoods: case study from rainfed semi-arid tropics in Andhra Pradesh, India
Widespread multinutrient deficiencies in the semi-arid tropics (SAT) are among major factors for large gaps between farmers current crop yields and potential yields. In this study, we adopted stratified soil sampling method to assess soil fertility-related constraints in farmers fields in eight districts of Andhra Pradesh in the semi-arid tropics of India. Most of the fields across all eight districts were critical in sulphur (61 to 98% deficient fields); and up to six districts each in boron (83 to 98% deficient fields), zinc (50 to 85% deficient fields) and soil organic carbon (55 to 97% deficient fields). Low soil organic carbon specifically indicates nitrogen deficiency. Phosphorus deficiency was critical in three districts (60 to 84%) while potassium in general was adequate. Soil test-based nutrient balancing through application of sulphur, boron and zinc in addition to farmers practice of adding only nitrogen, phosphorus and potassium increased crop productivity by 8 to 102%. Benefit-cost ratio (1.60 to 28.5) proved favourable to scale-up balanced nutrition. Better postharvest soil health and residual benefits of sulphur, boron and zinc up to four succeeding seasons indicated sustainability of the practice. Results showed that balanced nutrition is a way forward for sustainably improving farm productivity and livelihoods.