Effects of Alien Earth Soil-improving on Soil Nutrient Status and Tobacco Bacterial Wilt

The sandy soil suffers serious tobacco bacterial wilt in Nanxiong tobacco growing areas, Field trials were conducted by blending natural weathered red sand (purple soil) at different ratios in the tillage layer of the sandy soil. The changes of soil nutrient and control effects to bacterial wilt after mixture were analyzed. The results showed that after blending red sand in the tillage layer of sandy soil (which was prone to tobacco bacterial wilt) at 150-450 m³/hm², the pH value changed from acidic (4.78) to neutral (7.06), and the exchangeable calcium content increased by 3 to 4 times. The population of bacteria and fungi declined, while the actinomycetes increased. The bacterial wilt incidence and morbidity index decreased by 42.2%-73.5% and 51.4%-81.1% respectively compared with the control (sandy soil). The correlation analysis demonstrated that pH value and actinomycetes population showed a significant negative correlation with bacterial wilt incidence and disease index. In summary, mixing certain percentage of red sand in the tillage layer of the tobacco planting sandy soil (in which bacterial wilt was severe) could prevent or reduce tobacco bacterial wilt.