Influence of long-term use of inorganic and organic manures on soil fertility and sustainable productivity of rainfed groundnut in alfisols

Long-term integrated nutrient management trial in rainfed groundnut on red sandy loam soil (Alfisols) conducted for 18 years at Agricultural Research Station, Anantapur revealed that judicious use of chemical fertilizers along with groundnut shells improved the sustainability yield index (SYI) to 0.320 as compared to 0.306 and 0.285 for the usage of inorganic fertilizers or FYM alone, respectively. However, the mean pod yield was not significantly influenced by different nutrient management practices except in case of control (no manures and fertilizers) and organic manures alone treatments. This indicates that present recommended fertilizer dose to rainfed groundnut grown on Alfisols of Anantapur district can be cut down to 50% without reduction in yield. The continuous application of recommended dose of P fertilizer (17.5 P kg ha⁻¹) to groundnut every year resulted in substantial build-up of available P up to to 54 kg P ha⁻¹ from initial level of 20 kg P ha⁻¹. Organic manures alone could not sustain crop yield vis-á-vis soil quality.