Mineralization of nitrogen from 15N labeled crop residues at varying temperature and clay content

Abstract

A laboratory incubation experiment was carried out for 85 days to monitor the N mineralization during the decomposition of 15N labeled wheat and rice straws incorporated at 5 g kg-1 soil at varying temperatures and with soils of varying clay content. Results have shown that N mineralization surpass immobilization 40th day onwards. Irrespective of temperature and clay content, mineralization of rice residue N was found to be significantly higher than that of wheat residue throughout the incubation period. Increasing temperature and clay content both had positive effect on residue N mineralization. At 85th day after incubation N mineralization from the residues was found to be 13 - 14%. Clay content, temperature, composition of the residues are important factors controlling plant residues decomposition under laboratory conditions.   Key words: Rice and wheat residues, straw, N-mineralization, immobilization.