棉秆生物质炭添加对棉田土壤理化性质及根际微生物群落结构的影响

Effects of Biochar Addition on Soil Physicochemical Properties and Rhizosphere Microbial Community Structure in Cotton Fields

摘要:

以新疆滴灌棉田为研究对象，研究生物质炭施用对棉田土壤理化性质和棉花根际土壤微生物群落特征的影响。试验采集了不施生物质炭(CK)、施生物质炭3 t/hm²(BC1)、施生物质炭6 t/hm²(BC2)和施生物质炭9 t/hm²(BC3)4种处理棉花根际土壤，分析土壤理化性质和根际土壤微生物群落结构和组成的变化。结果表明，生物质炭施用后土壤pH和电导率分别下降了5.58% ~ 9.18%和5.38% ~ 18.04%；与CK相比，生物质炭施用使土壤有机质、全氮、全磷、碱解氮和有效磷含量均显著增加，且BC3增加效果最好，但生物质炭施用导致土壤钾含量显著降低。生物质炭施用显著降低了浮霉菌门(Planctomycetota)、芽单胞菌门(Gemmatimonadota)、厚壁菌门(Firmicutes)和被孢霉门(Mortierellomycota)相对丰度，但增加了子囊菌门(Ascomycota)、斯克尔曼氏菌属(Skermanella)、苔藓杆菌属(Bryobacter)、毛壳菌属(Chaetomium)、头束霉菌属(Cephalotrichum)、金孢属(Chrysosporium)和拟棘壳孢属(Pyrenochaetopsis)的相对丰度。另外，生物质炭施用降低了根际土壤微生物多样性和细菌丰富度，但根际土壤真菌的丰富度提高。生物质炭施用显著影响根际土壤微生物特别是真菌的群落结构，电导率、速效钾和pH是根际土壤微生物群落的主要影响因子。研究表明，生物质炭施用可以改善棉田土壤理化性质进而影响根际土壤微生物群落组成和结构，9 t/hm²为本试验的推荐施用量。

Abstract:

Focusing on the effects of biochar application on soil physicochemical properties and the microbial community in the rhizosphere of cotton fields in Xinjiang, cotton rhizosphere soils were collected from four treatments: Control (CK), biochar 3 t/hm²(BC1), 6 t/hm² (BC2) and 9 t/hm² (BC3). The changes in soil properties and rhizosphere soil microbial community structure and composition were analyzed. After biochar application, soil pH and electrical conductivity (EC) decreased by 5.58%-9.18% and 5.38%-18.04%, respectively. Compared with CK, biochar application significantly increased soil organic matter contents (SOM), total nitrogen (TN), total phosphorus (TP), alkali hydrolyzed nitrogen (AN), and available phosphorus (AP), among of which, BC3 had the best effects, but biochar application significantly reduced soil potassium content. Biochar application significantly reduced the relative abundance of Planctomycetota, Gemmatimonadota, Firmicutes and Mortierellomycota. However, the relative abundance of Ascomycota, Skermanella, Bryobacter, Chaetomium, Cephalotrichum, Chrysosporium, and Pyrenochaetopsis were increased. In addition, biochar application reduced microbial diversity and bacterial richness but increased fungal richness in the rhizosphere soils. Applying biochar significantly affected the community structure of rhizosphere soil microorganisms, especially fungi. Soil EC, available potassium (AK), and pH were the main factors affecting the rhizosphere soil microbial community. In conclusion, biochar application can improve the physicochemical properties of cotton field soil, thereby affecting the composition and structure of rhizosphere soil microbial communities, and 9 t/hm² biochar application is recommended in this experiment.