Processes Regulating Grass Straw Composting
Published 1996 · Materials Science
We have been able to successfully compost high C/N ratio materials such as grass straw. The straw composting was examined by using an on-farm windrow approach, different quality straw materials, and different number of turns. Temperatures typical of thermophilic composting (> 50°C) were commonly observed in the turned windrow treatments. The magnitude of culturable microorganisms varied little among treatments and windrow depth (30 cm and 100 cm). except that thermophile populations increased in the turned windrow treatments at all depths midway through the 200 day composting process. Hydrolytic enzyme activity showed no definable pattern for all treatments and windrow depths. The loss of lignin fraction C indicated that extensive lignin degradation occurred in all treatments including the control. The increased need for C and reduced requirement of N of the thermophilic biomass and the release of soluble N and ammonium during the mesophilic to thermophilic transition explains the extensive decomposition of high C to N ratio (50–60 to 1) grass straw during windrow composting. Upgrading of agricultural wastes through composting is a viable residue management alternative that may be important for developing sustainable cropping systems.