梨树枝条粉碎覆盖对梨园土壤养分和微生物组的影响

梨树整形修剪枝条是一类重要的生物质资源，将其粉碎后覆盖于树下土壤是资源化利用的有效途径。为了科学评估梨树枝条粉碎覆盖对土壤理化性状及微生物群落结构的影响，采集了贵州毕节、河北昌黎、黑龙江哈尔滨、湖北枝江和河南许昌5个不同纬度梨典型种植区梨园枝条覆盖1~2年后的土壤样品，检测了土壤基础理化特性及土壤细菌、真菌和原生生物群落。结果发现，与不覆盖枝条的对照相比，总体而言覆盖能有效提高土壤有机质和有效磷含量，土壤细菌、真菌和原生生物群落结构也发生了显著变化，但对群落多样性无显著影响；覆盖处理显著富集了土壤细菌中的变形菌门、酸杆菌门和真菌中的担子菌门以及原生生物中的孔虫界和囊泡虫类等类群的相对丰度。进一步利用随机森林模型挖掘了不同采样点枝条覆盖后的关键物种，模型预测准确率高达94.44%，关键物种以细菌为主，包括Acidibacter、Xanthobacteraceae、Nitrosomonadaceae等与有机残体降解有关的微生物，还发现土壤有效磷含量是土壤微生物群落结构差异的主要驱动因子。相关研究结果初步评估了梨树枝条覆盖对土壤养分和微生物组的影响，挖掘了潜在的关键微生物。

Effects of Pear Pruning Branches Mulching on Soil Nutrition and Microbial Community Structures

【Objective】As a by-product of fruit tree shaping and pruning, pear branches are important biomass resources. The use of crushed branches for soil mulch under trees is one of the effective ways to utilize waste resources, which is conducive to increasing soil organic matter and improving soil fertility in pear orchards. 【Method】In order to assess the effects of short-term pear branch mulching on soil properties and structure of microbial community, soil samples were collected from five pear orchards in different latitudes (Bijie City of Guizhou Province, Changli City of Hebei Province, Harbin City of Heilongjiang Province, Zhijiang City of Hubei Province and Xuchang City of Henan Province) after 1-2 years of mulching. Soil basic physiochemical characteristics of the soil and the bacterial, fungal and protist communities were detected. 【Result】Results showed that the soil organic matter and available phosphorus content were significantly increased in pear branches mulching treatment in general, and the soil bacterial, fungal and protists community structure also changed significantly. Specifically, the mulching of pear branches significantly enriched the relative abundance of taxa such as Proteobacteria and Acidobacteria in bacteria, Basidiomycota in fungi, and Rhizaria and Alveolata in protists. The model prediction accuracy was as high as 94.44%, and the key species were mainly bacteria, including Acidibacter, Xanthobacteraceae, Nitrosomonadacee and other microorganisms related to the degradation of organic residues. Soil-available phosphorus content was found to be the main driver of variations in soil microbial community structure. 【Conclusion】The study preliminarily assessed the effect of pear tree branch mulching on soil nutrients and microbiome and excavated potential key microorganisms. The findings can serve as a reference for managing the health and fertility of orchard soils.