Changes in nitrogen under submerged and well drained conditions of paddy soil.

摘要

A laboratory incubation experiment was conducted to investigate the changes in the ammoniacal extractable N under submerged and well-drained conditions of paddy soil with the use of Parthenium and Chromolaena as green manure and their compost. Soil samples were collected from Typic Paleustalf, paddy growing areas of Mudigere, Chickmagalur district, Karnataka, India. Based on the content of total C, plant organic material was applied at the rates of 0.5, 1.0 and 2.0% level of organic C. The highest carbon and nitrogen contents were observed in Chromolaena followed by Parthenium. In general, NH< sub>4+-N increased with the period of submergence. Ammoniacal-N content of soil decreased rapidly in all treatments. Ammoniacal-N of Mudigere soil (MS) alone and T13 (MS+parthenium compost) at 20% C at 30 day of sampling recorded 61.10 and 77.25 mg/kg, respectively. Nitrate-N concentration increased with time in all the treatments. Nitrate-N was 39.70 (T13: MS+chromolaena compost at 2.0% C) on the 30th day and increased to 41.50 on the 60th day. During the aerobic decomposition process, ammoniacal-N content decreased with time in all treatments, with concomitant increase in nitrate-N content.