磷肥和生物炭配施对杉木林地土壤微生物的影响

Effects of Combined Application of Phosphate Fertilizer and Biochar on Soil Microorganism in Chinese Fir Woodland

以二代杉木林地土壤为供试土壤,进行室内培养试验来探讨P肥与生物炭配施对杉木林地土壤养分和微生物结构的影响,为施用生物炭和P肥对我国经营南方杉木人工林的可持续性提供合理的依据。试验设置4组处理,进行150 d室内生物培养试验后测定土壤基本养分状况,同时采用高通量测序技术分析土壤细菌、真菌的群落组成,并对土壤主要养分与微生物类群的相关性进行分析。结果表明,与单施P肥处理组(P)相比,在施加P肥的条件下,配施的生物炭在氧化前后均能促进土壤全C、全N、全P,速效K的含量增加,同时也降低了硝态氮和速效P的含量,其中与施生物炭处理组(WBCP)相比,氧化生物炭处理组(OBCP)对速效P和溶解性有机碳的含量有显著的抑制作用;与原土(CK)相比,P处理组中土壤细菌相对丰度以及群落结构差异较小,而其他处理中土壤的细菌相对丰度以及群落结构差异较大;WBCP和OBCP处理组对土壤真菌种类影响弱于P处理组,不同生物炭的添加培养分别降低子囊菌门的相对丰度,提高了毛霉亚门的相对丰度;土壤基本养分含量与门、属水平下主要微生物类群具有密切的相关性。因此在施用P肥的土壤中添加生物炭,能够有效改善杉木人工林土壤的主要养分状况,总体上促进土壤微生物物种数的增加,但生物炭氧化后其改善效果减弱,在对主要微生物类群相对丰度的调节上具有差异。

Second generation fir woodland soil was used for indoor cultivation experiments to identify the effects of phosphate fertilizer and biochar on soil nutrients and the microbial structure to provide a reasonable basis for the application of biochar and phosphate fertilizer in the fir plantations in southern China.Four groups of treatments were set up.The basic nutrient status of the soils was analyzed after 150-day indoor biological cultivation.Simultaneously,high-throughput sequencing technology was used to analyze the community composition of soil bacteria and fungi and the correlation between main soil nutrients and microbial groups.Compared with the phosphate fertilizer treatment group(P),the combined addition of biochar after the application of phosphate fertilizer increased the content of soil total carbon,total nitrogen,total phosphorus,and available potassium and reduced the content of nitrate nitrogen and available phosphorus.Compared with the biochar treatment group(WBCP),the contents of available phosphorus and dissolved organic carbon were significantly inhibited jion oxidized biochar treatment group(OBCP).Compared with the original soil(control),the relative abundance and community structure of soil bacteria in the P treatment group were more similar,while the relative abundance and community structure of the soil in other treatments differed more.The effects of the addition of WBCP and OBCP on the species of soil fungi were weaker than those of the P treatment group.The addition of different types of biochar reduced the relative abundance of Ascomycota and increased the relative abundance of Mucoromycota.The content of basic soil nutrients was closely related to the main microbial groups at the level of phylum and genus.In conclusion,adding biochar to the soil in which phosphate fertilizer has been applied can effectively improve the main nutrient status of soil in the Chinese fir plantation.The overall performance promotes an increase in the number of soil microbial species,but the ability of biochar to increase the number of species weakens after oxidation,and there is a difference in the adjustment of relative abundance of the main microbial groups.