Organic recycling for soil quality conservation in a sub-tropical plateau region

The long-term effect of organic recycling on some aspects of quality in a l owland rice soil of an Indian plateau region was studied. The experiment wa s set up at the agricultural experimental farm of the Indian Statistical In stitute, Giridih, Bihar, India. Two rice cultivars, and treatments with fou r organic supplements (cowdung manure, Leuceana leaves, decomposed farm res idue and Sesbania), chemical fertilizers (urea, superphosphate and muriate of potash) and no input were arranged in a factorial randomized block desig n. Organic supplements improved soil quality parameters such as water holdi ng capacity, total organic C, microbial biomass C, urease and acid phosphat ase activities of soils in comparison to chemical fertilizers and no input. Among the organic supplements, cowdung manure gave significantly higher or ganic C (1.39%), microbial biomass C (276.46 mu g g(-1) dry soil), urease a ctivity (32.79 and 21.22 mu g urea hydrolized g(-1) dry soil h(-1) at 37 de grees C by the buffer and non-buffer method, respectively) and acid phospha tase activity (1.99 mu mol p-nitrophenol released g(-1) dry soil h(-1) at 3 7 degrees C) than the others. The conversion of organic C into biomass C (2 .46%) was highest in Leuceana-treated soil.