Effects of organic and inorganic manures on maize and their residual impact on soil physico-chemical properties

Organic and inorganic nutrients are important for crop productivity and soil health. Present study investigated the effects of organic and inorganic manures on maize and their residual impacts on soil physico-chemical characteristics. Sheep manure (SM), poultry manure (PM) and farmyard manure (FYM) were applied as organic nutrient source while urea, diammonium phosphate (DAP) and sulphate of potash (SOP) were used at different concentrations as inorganic nutrients source viz., T 1 : Unfertilized control; T 2 : NPK at 250-150-125 kg ha -1 ; T 3 : SM at 15 t ha -1 ; T 4 : FYM at 16 t ha -1 ; T 5 : PM at 13 t ha -1 ; T 6 : NPK at 150-85-50 + 8 t ha -1 SM; T 7 : NPK at 150-85-50 + 8.5 t ha -1 FYM and T 8 : NPK at 150-85-50 + 7 t ha -1 PM. Results showed that growth and yield of maize were substantially improved by fertilizer application alongside organic manures whereas soil total organic C and total N, P, K contents increased when inorganic fertilizers were applied alone or in combined with organic manures. However, soil pH and soil bulk density decreased due to application of organic fertilizer and showed a negative correlation with grain yield. Further, a significant and positive correlation (R 2 = 0.52, 0.91 and 0.55) was observed among maize grain yield and available N, P and K contents, respectively in the soil. Conclusively, integration of inorganic fertilizers with organic manures can be used with optimum rates to improve crop productivity on sustainable basis. This study will be helpful in crafting sustainable nutrient management programs in future to enhance crop productivity with high efficiency and minimum nutrient loss.