Effect of organic and inorganic nutrient sources and their integrated nutrient management on productivity, economic efficiency, available N, P, K and microbial population in soybean (Glycine max)-onion (Allium cepa) cropping sequence

A field trial was conducted during 2010–2015 at Parbhani, Maharashtra, to study the effect of organic, inorganic and integrated nutrient management on yield, economics and soil health in soybean [Glycine max (L.) Merr.]-onion (Allium cepa (L.) cropping sequence for central plateau zone of Maharashtra. The experiment was laid out in a randomized block design (RBD) during 5 years with 3 replications and 7 treatments. Out of 7 nutrient treatments, 5 had organic sources and one each having 100% fertilizer and integrated nutrient management (50% through organic and 50% inorganic). The higher value of soybean grain yield (2.67 t/ha), onion bulb yield (23.9 t/ha), soybean-equivalent yield (9.66 t/ha), production efficiency (110.0 kg/ha/day), economic efficiency (510.7 /ha/day) and sustainable yield index (0.64) in soybean-onion cropping sequence were recorded by NPK recommended dose of N: P: K with secondary and micronutrients based on the soil test (ZnSO₄ 10 kg + S 25 kg/ha) followed by 50% recommended dose of N: P: K combined with 50% N through FYM as compared with other treatments. The mean maximum net monetary returns (186.4 × 10³/ha) and benefit: cost ratio (3.35) over 5 years experimentation were recorded by 100% recommended dose of fertilizer with secondary and micronutrients based on the soil test (ZnSO4 10 kg + S 25 kg/ha) followed by 50% NPK recommended dose combined with 50% N through FYM. Among the organic treatments, different organic sources each equivalent to 1/3 of recommended nitrogen through FYM + vermicompost + neem-cake + biofertilizer containing N and P carriers recorded the highest value of soybean grain yield (2.23 t/ha), onion bulb yield (19.3 t/ha), soybean-equivalent yield (7.83 t/ha), production efficiency (89.7 kg/ha/day), economic efficiency (377.0?/ha/day), sustainable yield index (0.54), net monetary returns (137.6 × 10³/ha), benefit: cost ratio (2.14) over other treatment of organic. Soil properties and microbial population were markedly influenced by different treatments over the 5 years of experiment.