A novel fungal agent for straw returning to enhance straw decomposition and nutrients release

Straw returning is a promising option to alleviate environmental pollution caused by the excess usage of chemical fertilizers. However, the straw decomposition by local microorganisms in the soil is often very slow. Herein, a new straw decomposition agent of fungi was prepared by Trichoderma viride, Penicillium, and Phanerochaete chrysosporium burdsall (PCB) for lignin, cellulose, and hemicellulose decomposition. The highest efficiency was achieved by mixing the three fungi at a mass ratio of 1: 1: 1. Results indicated that the straw decomposition rate was preferably 45.2% in a 10-day continuous reaction. It was found that the depth of straw in soil and the application of composite fertilizer played an important role in straw decomposition. More importantly, the nutrient release from straw decomposition was observed. After 90 days of reaction, the maximum N, P, and K release rates reached 48.3%, 60.3%, and 72.1%, respectively. By comparing the novel straw decomposition agent with two different commercial straw decomposition agents, the novel straw decomposition agent showed matched performance in straw decomposition under the same conditions, indicating that it has great potential in practical applications.