Purpose To investigate the differences of soil rhizosphere microenvironments between healthy and tobacco bacterial wilt affected plants in different soil types (loam and sandy loam) in Baoshan, Yunnan Province.
Methods Based on field surveys and soil sampling, the nutrient content, pH value, physical properties, and biological characteristics of rhizosphere soils from both diseased and healthy tobacco plants in typical tobacco-growing areas of Baoshan were analyzed.
Results In both soil types, the rhizosphere soil of healthy tobacco plants exhibited significantly higher levels of dissolved organic carbon, organic matter, exchangeable calcium, and pH compared to those of diseased plants. Specifically, in loam soil, these parameters were higher by 116.28%, 87.89%, 39.98%, and 11.62%, respectively; while in sandy loam soil, the increases were 77.81%, 28.20%, 301.76%, and 8.16%, respectively. The porosity of healthy soils was significantly higher, and the bulk density was significantly lower than that of diseased soils in both soil types. Soil texture analysis indicated that coarse silt was the dominant particle fraction in both healthy and diseased soils, accounting for 29.90%-30.97% in loam and 36.18%-38.03% in sandy loam. Principal component analysis demonstrated extremely significant differences between healthy and diseased soil in overall characteristics, primarily attributed to variations along the first principal component (PC1). PC1 was mainly driven by indicators such as bulk density, porosity, organic matter, dissolved organic carbon, superoxide dismutase, microbial biomass nitrogen, catalase, microbial biomass carbon, ammonium nitrogen, and pH value.
Conclusion The rhizosphere soil of healthy tobacco plants is characterized by higher porosity, organic matter content, dissolved organic carbon content, microbial biomass nitrogen, superoxide dismutase activity, catalase activity, and pH, as well as lower bulk density and microbial biomass carbon.
DownLoad: