沿黄灌区饲用油菜与苏丹草间作对土壤酶活性及细菌群落结构的影响

为探究沿黄灌区饲用油菜与苏丹草间作对土壤酶活性及细菌群落结构的影响，于2022年在内蒙古鄂尔多斯市达拉特旗，采用高通量测序技术结合土壤酶活性，比较分析饲用油菜单作、苏丹草单作、饲用油菜苏丹草间作3个种植模式下的土壤细菌群落结构及酶活性的差异。结果表明：饲用油菜苏丹草间作显著提高土壤脲酶、蔗糖酶活性，较饲用油菜单作和苏丹草单作分别提高了8.09%~13.93%和13.01%~58.02%。饲用油菜苏丹草间作使土壤细菌OTUs数目和细菌群落多样性指数提高。不同种植模式下土壤细菌群落组成和相对丰度表现不同，其中变形菌门、拟杆菌门、放线菌门、芽单胞菌门为优势菌门，Salinimicrobium、海杆菌属、革兰菌属为优势菌属；间作种植模式提高了变形菌门、放线菌门、芽单胞菌门、革兰菌属的相对丰度。相关性分析表明：土壤脲酶、蔗糖酶与变形菌门相对丰度呈显著正相关关系，与酸杆菌门相对丰度呈显著负相关关系；土壤碱性磷酸酶与蛭弧菌门相对丰度呈显著正相关关系，与放线菌门相对丰度呈显著负相关关系；土壤过氧化氢酶与蛭弧菌门相对丰度呈显著正相关关系，与厚壁菌门相对丰度呈极显著负相关关系。综上可知，饲用油菜苏丹草间作改变了土壤细菌群落结构，提高土壤酶活性和有益菌物种丰度，可作为改善沿黄灌区盐碱土壤微生态环境的有效措施。

Effects of intercropping forage rape with Sudan grass on soil enzyme activity and bacterial community structure in the irrigation areas along the Yellow River

To explore the effects of intercropping of forage rape and Sudan grass on soil enzyme activity and bacterial community structure in the Yellow River irrigation area, high|throughput sequencing technology was used in Dalate Banner, Ordos City, Inner Mongolia in 2022, combining with soil enzyme activity. The differences of soil bacterial community structure and enzyme activity under three planting modes of monoculture of forage rape, monoculture of Sudan grass and intercropping of forage rape and Sudan grass were compared and analyzed. The results showed that the activities of soil urease and sucrase were significantly increased by 8.09%~13.93% and 13.01%~58.02%, respectively in the intercropping of forage rape and Sudan grass compared with the monoculture of forage rape and Sudan grass. The intercropping of forage rape and Sudan grass increased the number of soil bacterial OTUs and bacterial community diversity index. The composition and relative abundance of soil bacterial communities under different planting patterns were different. Proteobacteria, Bacteroidota, Actinobacteriota, and Gemmatimonadota were the dominant phyla, and Salinimicrobium, Marinobacter, and Gramella were the dominant genera. The intercropping planting pattern increased the relative abundance of Proteobacteria, Actinobacteriota, Gemmatimonadota, and Gramella. Correlation analysis showed that soil urease and sucrase were significantly positively correlated with Proteobacteria and significantly negatively correlated with Acidobacteria. Soil alkaline phosphatase was significantly positively correlated with Bdellovibrionota, and negatively correlated with Actinobacteria. There was a significant positive correlation between soil catalase and Bdellovibrionota, and a significant negative correlation with Firmicutes. In summary, the intercropping of forage rape and Sudan grass changed the soil bacterial community structure and increased the soil enzyme activity and the abundance of beneficial bacteria species, which could be used as an effective measure to improve the saline|alkali soil micro|ecological environment in the Yellow River irrigation area.