冬绿肥覆盖对土壤团聚体及有机碳和AMF多样性的影响

为探究冬绿肥覆盖对土壤AMF（丛枝菌根真菌）群落和团聚体及其有机碳含量的影响.以坡耕地红壤为研究对象，采用Illumina MiSeq高通量测序、湿筛法和重铬酸钾外加热法分别测定AMF群落组成、团聚体和有机碳含量.研究了苕子覆盖（VC）、豌豆覆盖（PC）和冬季休耕（WF）这3个处理下AMF群落组成及多样性和有机碳含量与团聚体稳定性的关系.结果表明，VC和PC处理的>2 mm团聚体含量和团聚体稳定性显著高于WF,0.25～1 mm和<0.25 mm团聚体含量则相反；VC处理的0.25～1mm团聚体和全土有机碳含量较PC、WF分别显著提高了33.21%、27.10%和25.68%、58.45%,PC处理的<0.25 mm团聚体有机碳含量则显著低于VC和WF;VC、PC的ACE和Chao1指数分别较WF处理分别显著提高了252.03%、158.55%和243.75%、158.33%;Glomus（球囊霉属）为各处理的优势属，PC和VC处理下Claroideoglomus（近明球囊霉属）的相对丰度较WF显著降低了76.29%和71.21%,PC处理下Acaulospora（无...

Effects of Winter Green Manure Mulching on Soil Aggregates, Organic Carbon, and AMF Diversity

To investigate the effects of winter green manure mulching on a soil arbuscular mycorrhizal fungi （AMF） community and aggregates and their organic carbon content, Illumina MiSeq high-throughput sequencing, the wet sieve method, and potassium dichromate external heating method were used to determine AMF community composition, aggregates, and organic carbon content in red soil of sloping farmland. The relationship between AMF community composition and diversity, organic carbon content, and aggregate stability under the three treatments of vetch mulching （VC）, pea mulching （PC）, and winter fallow （WF） was studied. The results showed that the content of >2 mm aggregates and the stability of aggregates treated with VC and PC were significantly higher than those of WF, whereas the content of 0.25-1 mm and <0.25 mm aggregates showed the opposite. The organic carbon content of 0.25-1 mm aggregates and whole soil in the VC treatment was significantly increased by 33.21% and 27.10% and 25.68% and 58.45%, respectively, compared with those in PC and WF. The organic carbon content of <0.25 mm aggregates in the PC treatment was significantly lower than that in VC and WF. The ACE and Chao1 indexes of VC and PC were significantly increased by 252.03% and 158.55% and 243.75% and 158.33%, respectively, compared with those in the WF treatment. Glomus was the dominant genus in each treatment. The relative abundance of Claroideoglomus under the PC and VC treatments was significantly lower than that of WF by 76.29% and 71.21%, respectively. The relative abundance of Acaulospora under the PC treatment was significantly higher than that of the VC and WF treatments. PCoA analysis showed that the PCoA1 and PCoA2 axes explained 57.76% and 30.07% of the differences in the AMF community composition, respectively. Spearman correlation analysis showed that 0.25-1 mm aggregates and total soil organic carbon content were significantly positively correlated with R_0.25, MWD, and GMD. RDA analysis showed that the content of >2 mm aggregates, R_0.25, MWD, and GMD were positively correlated with the diversity （Chao1, ACE, and Shannon） index and the relative abundance of Glomus, Gigaspora, and Scutellospora. AMF community richness （ACE and Chao1 index） and Gigaspora were the main factors affecting the stability of soil aggregates under winter green manure mulching （P<0.05）. SEM analysis showed that AMF community richness affected the formation and stability of soil aggregates by changing SOC content. The results showed that winter green manure mulching during the fallow period could further improve the stability of aggregates by increasing the richness of the soil AMF community and the content of organic carbon in aggregates, which could provide a theoretical basis for the implementation of winter green manure mulching mode and the prevention and control of soil erosion in red soil sloping farmland in southern China.