| dc.description.abstract | Jak Nitrogen is one of the important soil nutrients needed in a large number. The released N from organic matter cannot be used directly by plant, it has to be mineralized and changed into available forms (N-NH4+ and N-NO3) for the plants. Nitrate is disappeared easily from the soil through denitrification, leaching and plant absorption. The objective of this research is to notify the availability of nitrogen in rice straw and compost of rice straw amanded to flooded soil as a result of N mineralization and its effect on soil pH.
The experiment was done in the Laboratory of Soil Chemistry and Fertility and Laboratory of Soil Biology, Department of Soil Sciences, Faculty of Agriculture, Bogor Agricultural University. The organic materials used in this experiment were rice straw (B₁), compost of rice straw 4 month (B2) and compost of rice straw 8 month (B3). Organic materials were applied at a uniform rate of 92 kg N ha¹. Organic materials were mixed with 1,000 g soil (oven 105 °C-dry basis) and then added aquades. The soil was plowed under flooded condition and the mixture was incubated for 120 days. Nitrogen mineral of N-NH4 and N-NO3 and soil pH were analyzed at 0, 7, 14, 21, 47, 70, 96 and 120 days.
The results showed that the form dominant N-mineral in the flooded soil is in the form of N-NH₄⁺. The availability of N-NH, from rice straw in flooded soil after 21 days of incubation period is much higher and faster than that of N-NH4 from compost of rice straw (4 month and 8 month composting). The concentration of N-NO; however in soil, sharply decreased in the initial of incubation period after flooding the soil. It might be due to the reduction of N-NO; in soil by immobilization and denitrification process. The addition of rice straw in the flooded soil increased soil pH higher than soil pH before a treatment... | id |
