Enhancement of no tillage, crop straw return and manure application on field organic matter content overweigh the adverse effects of climate change in the arid and semi arid Northwest China
Abstract Soil organic matter (SOM) is important for sustainable agricultural production. Agricultural management can directly or indirectly affect SOM content and associated soil organic carbon (SOC) stocks. The SOM content and crop productivity are generally low in the farmlands in the arid and semi arid regions of China, and are highly sensitive to climate changes. An improvement in SOM content may greatly enhance the efficiency of fertilizer and water use, thereby increasing the resilience of agricultural systems to climate change. However, little information is available on the response of SOM to the interactions of cultivation measures and changing climate in the regions. Here we analyzed the effects of climate and long term management practices on SOM content at three sites in the arid and semi arid regions of China using the SOM data monitored under a range of management practices. We showed that the manure application, crop residue return and no tillage had significantly increased SOM content from 12.1% to 127.5% in the long term experiment at three sites. We also used the DayCent model to simulate the effects of these management practices in combination with future climate changes on the SOM content, and found that climate changes in the near future would not increase SOM content, and even decrease SOM content under conventional agronomic management, but the possible adverse impact of climate change on SOM can be outweighed by the enhancement of agronomic management. Our results provide important information for improving management to maintain SOM content and sustainable production under future climate changes.