Influence of plant residues, farm yard manure and inorganic fertilizers on soil N and P mineralization and growth ofAbelmoschus esculentusLinn.

Abstract

Management of crop residues can have important implications apart from the desired maintenance of soil organic matter and improving plant growth. In order to test this hypothesis, field experiments were conducted to evaluate the effects of plant residues, farm yard manure and inorganic fertilizers on soil N and P mineralization and growth of Abelmoschus esculentus Linn. A randomized complete block design consisting of nine treatments including the control was used with three replications each. ‘Okra’ was selected as the test crop. The source of N, P and K was urea (containing 45% N), superphosphate (16% P), muriate of potash (60% K). The application of full NPKand half NPK doses recorded 72 and 84 germination percentage. Nevertheless, the plots amended with half NPK and full NPK doses did not significantly (F= 0.067, n< 0.05) increase the growth of crop. The regression analysis of shoot and root biomass shows positive correlation in each treatments.The study revealed that NPK amended soils showed two times more fruit biomass production than the plant residue amended soils. Net N mineralization in different treatments ranged from 0.112 to 0.410 mg g−1 day−1. N mineralization significantly varied among the plots with inorganic fertilizers having the highest mineralized N followed by residues applied soils and controls the least. On the other hand, phosphorous mineralization was higher in fertilizer amended soils. Over all, crop residue management with supplementary chemical fertilizer loading could help have better yield response under ‘`business as usual’ climate scenario.