Kinetics of N Mineralization during Rice Straw Decomposition in the Soils

A laboratory experiment was conducted with three soils under five treatments [Control, rice straw alone, rice straw + N (@ N factor), straw + Paecilomyces fusisporus and straw + Trichurus spiralis) to determine the kinetics of N mineralization during rice straw decomposition in the soils. Mineralized nitrogen was significantly reduced due to rice straw and straw inoculated with cellulose decomposing fungi in the soils during first two weeks of incubation, whereas, application of nitrogen with rice straw was able to reduce the initial immobilization of nitrogen. The mean nitrogen mineralized during 12 weeks was significantly increased due to inoculation of P. fusisporus and T. spiralis over rice straw. Inoculation of cellulose decomposing fungi significantly increased the potentially mineralizable nitrogen (N_o) and nitrogen mineralization rate constant over control and rice straw treatments. The half time required (t_½) to mineralise half of the N_o was increased due to rice straw, but addition of inorganic nitrogen along with straw and use of fungi generally reduced the t_½ values.