作物轮作对甘薯田土壤微生物群落的影响

为缓解甘薯连作障碍,探究甘薯不同轮作方式对土壤微生物群落的影响,设置甘薯连作、甘薯―花生轮作、甘薯―小麦轮作3个处理,利用磷脂脂肪酸（PLFA）和Biology生态板方法,研究甘薯不同轮作方式下土壤微生物群落结构、碳源利用能力、多样性指数的变化规律。结果表明,与甘薯连作相比,甘薯―花生轮作显著（P<0.05）提高了土壤微生物细菌、放线菌、革兰氏阳性菌（G⁺）、革兰氏阴性菌（G^-）生物量,降低了真菌生物量及真菌与细菌比值,甘薯―小麦轮作降低了土壤细菌、放线菌、真菌、革兰氏阳性菌和革兰氏阴性菌生物量,提高了真菌与细菌比值;甘薯―花生轮作提高了土壤微生物对羧酸类化合物、碳水化合物、氨基酸和胺类化合物的利用能力,甘薯―小麦轮作提高了土壤微生物对碳水化合物、氨基酸和胺类化合物的利用能力,其中甘薯―花生轮作对羧酸类化合物、芳香化合物和碳水化合物的利用能力显著高于甘薯―小麦轮作;甘薯―花生、甘薯―小麦轮作均提高了土壤微生物丰富度指数（Shannon index）、均匀度指数（Mclntoch index）和优势度指数（Simpson index）,其中甘薯―花生轮作的均匀度指数高于甘薯―小麦轮作,而丰富度指数和优势度指数显著降低;冗余分析（RDA）表明土壤微生物群落结构、碳源利用能力和多样性指数与不同土壤养分存在相互促进或相互制约的关系。综上所述,甘薯与花生、小麦轮作能够改变土壤微生物群落结构及功能多样性。

Effects of Crop Rotation on Soil Microbial Community in Sweet Potato Field

In order to alleviate the obstacle of sweet potato continuous cropping, we explored the effects of different rotation patterns (sweet potato continuous cropping, sweet potato-peanut rotation and sweet potato-wheat rotation) on soil microbial community by PLFA and biology ecological plate method, and the changes of soil microbial community structure, the utilization ability of carbon source and diversity index under the different rotation patterns of sweet potato were determined. The main results were as follows: compared with the continuous cropping of sweet potato, sweet potato-peanut rotation significantly (P<0.05) improved the contents of the biomass of soil microbial bacteria, actinomycetes, Gram-positive bacteria and Gram-negative bacteria, reduced the biomass of fungi and the ratio of fungi to bacteria, sweet potato-wheat rotation reduce the biomass of soil microbial bacteria, actinomycetes, fungi, Gram-positive bacteria and Gram-negative bacteria, and improved the ratio of fungi to bacteria. Sweet potato-peanut rotation improved the utilization ability of carboxylic acid compound, carbohydrate, amino acid and amine compound in soil microorganism, sweet potato-wheat rotation improved the utilization ability of carbohydrate, amino acid and amine compound in soil microorganism, the utilizations of carboxylic acid compounds, aromatic compounds and carbohydrates in sweet potato-peanut treatment was significantly higher than that in sweet potato-wheat treatment; Sweet potato-peanut and sweet potato-wheat rotation improved the Shannon index, Mclntoch index and Simpson index, The Mclntoch index of the sweet potato-peanut treatment was higher than that of sweet potato-wheat treatment, while the Shannon index and Simpson index decreased significantly; The redundancy analysis (RDA) showed that there were promotion or restriction relationships among the soil microbial community structure, the utilization ability of carbon source and diversity index with the soil nutrients. In conclusion, the rotation of sweet potato -peanut or -wheat can change the structure and functional diversity of soil microbial community.