玉米残体分解对不同肥力棕壤团聚体组成及有机碳分布的影响

  目的  为了对土壤资源的合理利用与管理提供指导，研究不同土地利用方式土壤有机碳组分和微生物群落对植物残体的响应。  方法  以枣树林、撂荒地和玉米地为研究对象，分别设置添加沙达旺、苦豆子、二者混合植物残体及空白共计12个处理，并进行室内培养试验，测定了土壤总有机碳（TOC）、可溶性有机碳（DOC）、微生物量碳（MBC）、颗粒有机碳（ POC）以及微生物群落含量等指标。  结果  在三种土地利用方式下，沙打旺、苦豆子和混合植物残体输入后土壤TOC、DOC、MBC及POC均显著增加，枣树林地 > 玉米地 > 撂荒地。不同利用方式的土壤总磷脂脂肪酸、革兰氏阳性细菌（G⁺） 、革兰氏阴性细菌（G⁻）及放线菌含量在植物残体输入下均呈现不同程度的增加。三种植物残体对不同土地利用方式下PLFAs含量的影响表现为：枣树林地 > 玉米地 > 撂荒地。土壤G⁺/G⁻的比值范围为0.96 ~ 1.15。在三种土地利用方式下，植物残体输入并没有显著影响G⁺/G⁻的比值。  结论  植物残体输入改变了三种土地利用方式的土壤有机碳组分及微生物群落的含量，土壤TOC、DOC、MBC和POC等有机碳组分含量与土壤G⁺、G⁻ 、放线菌和真菌数量呈显著正相关关系，而与土壤G ⁺ /G⁻无明显相关关系。本研究结果为不同土地利用方式的土壤肥力提升与绿色可持续利用提供了科学参考。

Effect of integrated nutrient management practice on soil aggregate properties,its stability and aggregate-associated carbon content in an intensive rice-wheat system

  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.