Objective  The response of soil organic carbon and microbial communities to plant residues under different land use patterns were studied, which is of great significance for guiding the rational utilization and management of soil resources.

  Methods  Three different land use patterns (jujube forest land, abandoned land and maize field) were selected as the research objects, and laboratory culture experiments were carried out with a total of 12 treatments (such as adding astragalus adsurgens residue, sophora alopecuroide residue, mixed plant residue and blank treatment under three land patterns). Soil total organic carbon (TOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC), particulate organic carbon (POC), and microbial community contents were determined.

  Results  The soil TOC, DOC, MBC and POC were increased after the input of astragalus adsurgens, sophora alopecuroide and mixed plant residues, which showed as below: jujube forest > corn field > abandoned land. The response of PLFAs content to plant residue input under different land use patterns varied with microbial types. The plant residues had significant effects on the contents of total PLFAs, gram-positive bacteria G⁺, gram-negative bacteria G⁻ and actinomycetes under different land use patterns. The effects of the three plant residues on PLFAs content under different land use patterns were as follows: jujube forest > corn field > abandoned land. The ratios of soil G⁺/G⁻ were 0.96-1.15, respectively. Plant residue input did not affect the G⁺/G⁻ ratio significantly under three land use patterns. Conclusion The plant residues changed the contents of organic carbon fractions and microbial communities under three land use patterns. The contents of soil TOC, DOC, MBC, and POC were positively correlated with the contents of soil G⁺, G⁻, actinomycetes and fungi, but there had an insignificant correlation with soil G⁺/G⁻. The results of this study provide a scientific reference for the improvement of soil fertility and green sustainable utilization under different land patterns.