International Journal of Plant & Soil Science

A long term field experiment has been initiated in 2008-09 on permanent site at Organic Farming Research Station, MARS, UAS, Raichur with sunflower-rabi sorghum cropping system of two years rotation under rainfed condition. The five crop rotation cycles were completed in the year 2020-21. The experiment consisted five different nutrient management practices viz., 75% organic, 100% organic, integrated (50% organic + 50% inorganic), 100% in organic and RDF+ FYM. In the experiment strip plot design was followed. The organic system and recommended package were on par with each other (368, 411 and 398 kg/ha) and superior over inorganic package (321 kg/ha) with respect to seed yields and net returns (24316 Rs/ha). The soil fertility status (OC%, Available N, P₂O₅ and K₂O kg/ha) were improved substantially with organic (0.68%, 164.0, 66.2 and 865.0 kg/ha, respectively) and integrated management practices (0.60%, 162.5, 63.2 and 805.0 kg/ha). Whereas, integrated application of nutrient sources like organic and fertilisers resulted in significantly higher available N, P₂O₅ and K₂O than chemical fertilizers alone (0.46%, 154.2, 48.5, 775.0 kg/ha, respectively) and 75% organic (0.55%, 143.3, 51.3 and 785.0 kg/ha, respectively) nutrient management practices. The net and B:C ratio was found to be on par with RDF+FYM and integrated management practices over the years. The organic nutrient management recorded increasing net returns and benefit cost ratio over the years compared to inorganic and 75% organic nutrient management treatment.