Nitrogen Balance Studies in Rice-Growing Wetland Soil

Nitrogen balance in the wet land soil growing rice in different seasons as well as at the end of three cropping seasons were worked out using different sources of Nat 0, 51, 102 and 153 kg ha⁻¹ levels. Soil N content (total) as well as the volatilization and leaching losses of N were higher during warmer season as compared with cold season. A positive N balance of about 55 kgN ha⁻¹ was observed during warmer (summer and kuruvai) seasons while it was negative (−31 kg N ha⁻¹) during the cold thaladi season. The N balance was positive under lower levels of applied N (up to 102 kg N ha⁻¹) and negative at higher N level (153 kg N ha⁻¹). The overall net N balance at the end of the three crop seasons was 78 kgNha⁻¹ year¹.