Review of research progress on the influence and mechanism of field straw residue incorporation on soil organic matter and nitrogen availability

Straw residue incorporation, as a key practice of global organic agriculture, was critical for maintaining soil fertility, reducing fertilizer use and improving soil carbon sequestration in farmlands. Straw residue incorporation has improved farmland environments for safe and high production capacity by increasing soil organic matter and reducing nitrogen fertilizer application. Effective straw residue incorporation improved soil microbial conditions by supplying abundant carbon, stimulating microbial activity and enhancing soil fertility. Also mineralization of straw residue promoted normal soil nitrogen cycle and mineralization and improved nitrogen efficiency. Straw residue incorporation maintained normal carbon-nitrogen ratio with intensive high nitrogen input in farmland ecosystems, reduced nitrogen loss via leaching, loosened up hardened soil structures and mitigated obstacles related with continuous cropping. Recent straw residue incorporation rate in China was under 50% while it was over 90% in European and American countries. This implied that there was still plenty of room for China to make a full use of straw residue incorporation potential. Thus it was possible to improve straw residue incorporation rate in China which will gradually enhance soil organic matter content and prevent nitrogen loss and soil quality decline in farmlands. It was beneficial to refocus intensive research on the mechanisms of soil organic matter and nitrogen availability. It was also beneficial to compare long-term monitoring experiments with various technological methods of straw residue incorporation in order to develop suitable local straw residue incorporation techniques. Such efforts had the potential to promote sustainable agricultural ecosystem and agricultural production in China.