Gao Huan, Li Sen, Wu Fengzhi
Department of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, China.
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, China.
Front Microbiol. 2021 Mar 31;12:630302. doi: 10.3389/fmicb.2021.630302. eCollection 2021.
Diazotrophs are important soil components that help replenish biologically available nitrogen (N) in the soil and contribute to minimizing the use of inorganic N fertilizers in agricultural ecosystems. However, there is little understanding of how diazotrophs respond to intercropping and soil physicochemical properties in cucumber continuous cropping systems. In this study, using the gene as a marker, we have examined the impacts of seven intercropping plants on diazotrophic community diversity and composition compared to a cucumber continuous cropping system during two cropping seasons. The results showed that intercropping increased the abundance of the gene, which was negatively correlated with available phosphorous in the fall. Diazotrophic diversity and richness were higher in the rape-cucumber system than in the monoculture. Multivariate regression tree analysis revealed that the diversity of the diazotrophic communties was shaped mainly by soil moisture and available phosphorous. were the dominant genera in all of the samples, which increased significantly in the mustard-cucumber system in the fall. There was no effect of intercropping on the structure of the diazotrophic community in this case. Non-metric multidimensional scaling analysis showed that cropping season had a greater effect than intercropping on the community structure of the diazotrophs. Overall, our results suggest that intercropping altered the abundance and diversity rather than the structure of the diazotrophic community, which may potentially affect the N fixation ability of continuous cropping systems.
固氮菌是重要的土壤成分，有助于补充土壤中生物可利用的氮（N），并有助于减少农业生态系统中无机氮肥的使用。然而，对于黄瓜连作系统中固氮菌如何响应间作和土壤理化性质，人们了解甚少。在本研究中，我们以该基因作为标记，在两个种植季节中，对比黄瓜连作系统，研究了七种间作植物对固氮菌群落多样性和组成的影响。结果表明，间作增加了该基因的丰度，其在秋季与有效磷呈负相关。油菜 - 黄瓜系统中的固氮菌多样性和丰富度高于单作。多元回归树分析表明，固氮菌群落的多样性主要受土壤湿度和有效磷的影响。在所有样本中，是优势属，在秋季的芥菜 - 黄瓜系统中显著增加。在这种情况下，间作对固氮菌群落结构没有影响。非度量多维尺度分析表明，种植季节对固氮菌群落结构的影响大于间作。总体而言，我们的结果表明，间作改变了固氮菌群落的丰度和多样性而非结构，这可能潜在地影响连作系统的固氮能力。
