Influence of Cow and Chicken Manure on Soil Fauna Abundance and N Uptake by Rice in Conversion from Conventional to Organic Farming System

Abstract

This research aimed to determine the effects of cow manure and chicken manure on the abundance of soil fauna and N uptake by rice as well as determining the best dose of fertilizer for plant treatment in early conversion of conventional to organic farming. Soil sampling was done three times: before planting and in the vegetative and generative phases of the plant. The abundance of soil fauna observed were earthworms and nematodes (parasitic and nonparasitic), and soil respiration was also observed. Earthworm population abundance was observed with ring samples of PVC, parasitic and nonparasitic nematodes were observed with a modified Whitehead tray technique, and soil respiration was observed by measuring the CO2 in sealed bottles. Total soil N content was analyzed by the Kjeldahl method, available soil N was analyzed by the Cottenie method, and total N in plant tissue was analyzed by wet digestion with sulfuric acid and peroxide acid. The results of this research showed that cow manure and chicken manure significantly affected the cation exchange capacity (CEC) of the soil, total soil N, abundance of worms, abundance of nonparasitic nematodes, soil respiration, N uptake by rice in the vegetative and generative phases, and rice production. The combination of the type and dose of fertilizer based on N uptake in the vegetative and generative phases, as well as plant height and the number of clumps, showed that treatment P3D3 (cow manure 5 t · ha−1 + chicken manure 5 t · ha−1) was optimal in the beginning of conversion from conventional to organic farming systems, with productivity reaching 2.04 t · ha−1.