Cereal-legume intercrops, a typical model for using biodiversity to enhance the resources use efficiency (i.e. phosphorus), was commonly adopted in Sichuan province. For a long time, the studies on microbial processes for improving phosphorus use focused on microbial community level because of the limited  molecular tools. Studies carried out so far on the improvement of rhizosphere phosphorus availability by plants have neglected to take into account the relationships between the roots and soil microorganisms, especially the bacterial communities. We proposed to explore the importance of the interactions between microbial processes and root-soil interface processes, together with the effect of microbial loop occurring in the rhizosphere between bacteria and their microfaunal grazers (protozoa or nematodes). The present study focuses on multiple trophic interactions between bacteria and their microfaunal grazers (protozoa or nematodes) and microbial strengthening effects of root-soil interaction in terms of efficient phosphorus acquisition and use for cereal/legume intercropping system in purple and paddy soil of Sichuan province through field trials and pot experiment in green house. Some key methods and techniques for monitoring dynamic processes and related parameters in the root-soil interface are adopted, including in situ research methods for rhizosphere processes, new generation gene sequencing technology, a novel non-invasive optical method for quantitative visualization of pH dynamics and fluorescence probe detection combined with molecular biological techniques. The main objectives of the present study are to systematically investigate the spatio-temporal changes of rhizosphere microbial community and its effect on microbial biomass phosphorus, clarify mechanisms of the predations of microfanua on microbial P turnover for efficient use of phosphorus, reveal the mechanisms of rhizosphere functional microbial groups that mediate or modify root growth on efficient use of phosphorus, thus develop the strategies for rhizosphere/root zoon management to enhance phosphorus use efficiency in cereal/legume intercrops. This study will provide scientific basis for improving phosphorus use efficiency in intercropping and achieving sustainable production of saving fertilizer and increasing efficiency in farmlands.