Effects of Mulching Mode on Bacterial Wilt Disease Control in Soil Continuously Cropped with Tobacco

In order to explore the agricultural measures for controlling tobacco bacterial wilt disease,the effects of film mulching,rice straw mulching,and ryegrass planting on the disease were investigated with field plot trials in 2008 and 2009.The influences of tested treatments on Ralstonia solanacearum and the species and populations of soil culturable microbe,including bacteria,fungi and actinomycetes,were analyzed.The results indicated that the combination of film mulching and ryegrass planting and the mode of film mulching followed by rice straw mulching could effectively control tobacco bacterial wilt disease,their relative control effects in four weeks after transplanting and at the end of harvesting reached above 65%,while that of ryegrass planting or rice straw mulching only was 32%-62%.Different mulching mode influenced soil micro-environment differently.The relative inhibitory rates of film mulching and ryegrass planting were over 75% in one week and four weeks after transplanting;and that of film mulching followed with straw mulching was above 74% in the same durations.These two mulching modes could increase the species of soil bacteria,while had little effects on soil fungi and actinomycetes;they were of higher practical uses for tobacco bacterial wilt disease control.