Changes in nitrogen resources with increases in temperature during production of mushroom compost.

The rise in temperature is an important event during the composting of lignocellulosic materials and has to be controlled and regulated to improve the biodegradation. Phase I mushroom composts were incubated under environmentally controlled conditions. When the temperature was pre-set at 65°C and then later at around 80°C, the microbial respiration and the biodegradations were hardly affected. However residual activities due to thermoresistant bacteria were still measured after 68 h at a constant temperature of 80°C. Significant changes in nitrogen resources were observed: loss of nitrogen from microbial products, an increase in the proportion of nitrogen in non-hydrolysable and stable forms, and an increase in volatilisation of ammonia. These changes were mainly due to physico-chemical mechanisms associated with disturbances in the structure of the microbial community.