The Phosphorus Release Through Rice Bran Decomposition of the Lowland Rice and Vegetable Soil in Santa Cruz, Laguna Classified as Alipit Series

Abstract

INTRODUCTION

With the growing population there is a need to increase food production especially in terms of rice which is the staple food in the Philippines. Of the major contribution of rice biomass to plant growing is organic matter which is rice and rice bran. Both of which has an initial negative effect on organic matter decomposition due to its high carbon nitrogen ratio that renders the immobilization of nitrogen. This study aims to initially collect data that will show the contribution of organic matter decomposition of rice bran to improvement of phosphorus of soils grown to lowland rice and vegetables in Sta. Cruz, Laguna.

METHODS

Rice bran was mixed with the soil for treatment 4-6, the treatment 1 served as the control and treatment 2 and 3 had inorganic fertilizer added a week before obtaining the most recent sample. They were transferred to pots, each containing 10 kg of soil. It took almost 2 ½ months to know the decomposition of rice bran and its phosphate release. After that, the researchers used two testing -qualitative and quantitative for better analysis. The testing on the soil samples obtained on the on the middle of the decomposition period were tested on the soil test kit to measure if there was already decomposition and phosphate release occurring. Soil samples taken as a basis and the most recent samples were submitted to the Analytical Services Laboratory of the Division of Soil Science, Agricultural Systems Institute, College of Agriculture and Food Science, UPLB for phosphorus determination.

RESULTS

The qualitative results showed that the treatments with rice bran had gradual increase in phosphorus as the application of rice bran increases. The quantitative results showed that there is 15% and 21% increase in amount of phosphorus when rice bran amount were added at 100% and 150% higher than the control. There is also 9% increase in 50% rice bran application.

DISCUSSIONS

Results showed that increasing the amount of rice bran applied produces increasing phosphorus content of the soil. Applying 50% rice bran computed based on the inorganic chemical fertilizer requirement gave an increase of phosphorus content by 9% compared with the control (9.58 vs. 8.73 ppm). Accordingly, 15% and 21% increase in amount of phosphorus was computed when rice bran amount were added at 100% and 150% higher than the control, respectively.