In soil micro-foodwebs, resource-transfer links between bacteria, fungi and microbivorous nematodes govern the transformation and cycling of soil organic carbon and for the quality, productivity and sustainability of soil ecosystems. However, changing the amount and frequency of stover mulching affects the resources available for the bacterial versus fungal decomposition pathways of soil micro-foodwebs. Therefore, we investigated the responses of the soil micro-foodweb to maize stover mulching amounts (33% and 67% of the stover remaining at harvest) and frequencies (high frequency had continuous mulching every year; low frequency had mulch applied once every three years) during a 10-year mulching experiment in a no-tillage system. Soil microorganism and nematode communities were affected significantly by the frequency, but not the amount of stover mulching. Greater abundance of bacterial PLFAs that were correlated with bacterivores occurred in the high frequency mulching treatments. In the low frequency mulching treatments, the abundance of fungal PLFAs and their correlations with fungivores were higher. Greater nematode enrichment index in the high frequency mulching indicated more carbon flow from mulch into the soil micro-foodweb, whereas low frequency mulching tended to develop a relatively stable soil micro-foodweb. We conclude that trophic interactions regulate the binary coupling between bacteria and bacteriovores with high frequency mulching and between fungi and fungivores with low frequency mulching. Consequently, the structure and activity of decomposition pathways in these soil micro-foodwebs are determined by the bottom-up effect of stover mulching.

在土壤微食物网中，细菌，真菌和微食线虫之间的资源转移联系决定着土壤有机碳的转化和循环，并控制着土壤生态系统的质量，生产力和可持续性。但是，改变秸秆覆盖的数量和频率会影响土壤微食物网的细菌与真菌分解途径的可用资源。因此，我们调查了土壤微食物网对玉米秸秆覆盖量（收获时剩余秸秆的33％和67％）和频率（每年高频连续覆盖；低频每三年施用一次）的响应）在免耕系统中进行了10年的覆盖试验。土壤微生物和线虫群落受到频率的显着影响，但不覆盖秸秆。在高频覆盖处理中，与细菌噬菌体相关的细菌PLFA的含量更高。在低频覆盖处理中，真菌PLFA的丰度及其与真菌的相关性较高。高频覆盖下较高的线虫富集指数表明，有更多的碳从覆盖层流向土壤微食物网，而低频覆盖倾向于形成相对稳定的土壤微食物网。我们得出结论，营养相互作用调节高频覆盖下细菌与细菌之间以及低频覆盖下真菌与真菌之间的二元偶联。因此，这些土壤微食物网中分解途径的结构和活性取决于秸秆覆盖的自下而上效应。