EFFECTS OF ORGANIC AND INORGANIC FERTILIZATION ON RICE CROP PERFORMANCE, SOIL ANIMAL POPULATION AND MICROBIAL DIVERSITY IN ORGANIC AND CONVENTIONAL SOILS

Abstract

A pot of experiment was conducted undergreenhouse to determine the crop performance and the effects of compost on soil animals and microorganisms in two lowland rice soils. The two soils were: (a) organic lowland soil that had been applied with carabao manure for about 12 years, and (b) conventional lowland soil that had been applied with chemical fertilizers for many years. The aim of the study was to determine the short-term effects of organic and chemical fertilizers application on rice crop performance, soil animal population and microbial diversity. The fertilizers used were decomposed commercial composts at 4.5 t ha^-1 and chemical fertilizers at recommended NPK level of 90-30-30 kg ha^-1 with a control and the experiment was laid out as completely randomized design. The compost used as organic fertilizer in this experiment was as effective as the commercial chemical fertilizer on crop growth and yield. The average crop yields per hill were not significantly different at 47.4 g hill^-1 and 41.1 g hill^-1 for the chemical fertilizer and compost, respectively. Moreover, the organic soil had higher diversity, number of soil animals and microbe counts than the conventional soil. There were gradual changes in microbial population during the three crop growth stages (initial, active to maximum tillering, and harvest). Application of organic materials stimulated the population of soil organisms, plant growth and development in both organic and conventional soils. The results indicate the potential of organic fertilizers in improving degraded conventional lowland rice soils.