Physicochemical Properties and Microbial Community of Soil and Crop Yield under Rice-Tobacco-Milk Vetch Rotation Cropping

  Objective   Regulatory functions of milk vetch on soil fertility and microbial communities were studied to determine the potential of incorporating the shrub plant in rotation cropping with tobacco and rice for further land use improvement.

  Method   Soil samples were collected from a field practicing tobacco-rice-milk vetch rotation cropping for 5 years and one of tobacco-rice as control. Physicochemical analysis on the soil using spectrophotometry and metagenomic sequencing on the microbial community were conducted.

  Result   With milk vetch added to the tobacco-rice rotation cropping, the field soil increased significantly on the available nitrogen and phosphorus, rose slightly on the organic matter, total nitrogen, and total potassium, maintained a same level of total phosphorus, and reduced significantly on the available potassium. The yield of tobacco rose 2.74% and that of rice 4.67% in 2023. And the microbial diversity became significantly enriched by 8.67% and 3.10% but declined by 11.57% over control on the dominant kingdoms of Proteobacteria, Nitrospira, and Acidobacteria, respectively. The microbes in the soil were largely associated with carbohydrate, energy, and amino acid metabolisms.

  Conclusion   By incorporating milk vetch in the rotation cropping of tobacco and rice, aside from the increased yields on the crops, the physiochemical properties of field soil were significantly improved as well.