Evaluation of hydrothermal treatment in enhancing rice straw compost stability and maturity

In order to evaluate the hydrothermal treatment (HTT) in enhancing compost stability and maturity of lignocellulosic agricultural residues, a bin-scale (90 L) composting of rice straw with and without HTT was performed. The rice straw compost product with HTT after 6 weeks of composting can be considered stable and adequate for field application as expressed by pH of 8.4, EC value of 2.96 dS m(-1), C/N ratio of 12.5, microbial activity of <8.05 mg CO2 g(-1), Om d(-1), NH4+-N content of 93.75 mg kg(-1) DM and finally, by GI of >83%. However, compost may prove phytotoxic if used as growing media for EC sensitive plants. As for rice straw compost product without HTT, the high microbial activity (>12.28 mg CO2 g(-1), Om d(-1)) even after 14 weeks of composting suggests that the residue has not stabilized yet and is far away from stability and maturity, although a higher GI (>100%) was observed. (C) 2013 Elsevier Ltd. All rights reserved.