The input of exogenous organic carbon is an important factor affecting soil organic carbon (SOC) dynamics in farmland. It improves the level of SOC and is a major carbon source for soil biota. Returning straw (stover) to soil is one of the major measures adopted worldwide to enhance soil fertility. However, the amount and quality of stover application directly and indirectly affect decomposition pathways of soil micro-food webs, and thus the productivity and sustainability of farmland ecosystems.  

To examine how the amount and frequency of stover mulching regulate decomposition pathways of soil micro-food webs, KOU Xingchang, MA Ningning, ZHANG Xiaoke, XIE Hongtu and other members of the Special Research Team on Conservation Tillage from the Institute of Applied Ecology (IAE), Chinese Academy of Sciences, conducted a study at Lishu experimental base.  

The researchers found that the frequency of stover mulching had significant effects on the structure of soil micro-food webs. The high-frequency mulching significantly increased the interactions between bacteria and bacteria-eating nematodes, and enhanced the role of bacterial decomposition pathway in organic matter decomposition. The low-frequency mulching increased bacterial PLFAs and the relationship between fungi and fungi-eating nematodes, and strengthened the role of fungal decomposition pathway.  

They thus concluded that the frequency of stover mulching regulates the interactions between soil microorganisms and nematodes and drives the flow of carbon among different functional groups of soil micro-food web.  

They also pointed out that the bottom-up effect of stover mulching plays a determinant role on soil micro-food web structure. The study provides a soil biological explanation of the roles of stover mulching on maintaining the sustainability of no-tillage farmland. 

The study entitled "Frequency of stover mulching but not amount regulates the decomposition pathways of soil micro-foodwebs in a no-tillage system" has been published in Soil Biology and Biochemistry. 

This study was funded by the National Natural Science Foundation of China, the National Key Research and Development Program, and Kuangcheng Wong Education Fund Program, etc.