棉隆熏蒸与微生物有机肥联用对西瓜枯萎病的防控研究

通过田间试验评估了土壤熏蒸和微生物有机肥联用对西瓜枯萎病的防控效果及对西瓜产量与品质的影响。试验设置3个处理:对照(CK)、棉隆熏蒸结合普通有机肥处理(OF)、棉隆熏蒸结合微生物有机肥处理(BOF)。结果发现:与CK相比,BOF处理和OF处理均显著降低西瓜枯萎病发生率,病害防治效果分别为65.8%和54.1%;BOF处理还显著增加连作西瓜产量(增幅达33.4%),提高西瓜中心糖含量(增幅达15.9%)和糖酸比(增幅达13.4%)。棉隆熏蒸处理土壤细菌和真菌数量均显著低于CK,尖孢镰刀菌数量下降3个数量级;土壤脲酶、蔗糖酶、荧光素二乙酸酯酶活性以及土壤微生物碳源利用多样性指数、均一性指数较CK均显著降低。棉隆熏蒸后施用有机肥可使土壤微生物数量、土壤酶活性及微生物碳源利用多样性逐步恢复,其中BOF处理土壤微生物数量和酶活性恢复速度和强度更大、病原菌数量及病原菌与真菌数量比最低、微生物碳源利用多样性指数最高。结果表明,利用棉隆对连作西瓜土壤熏蒸20 d能显著减少病原菌数量,配合施用微生物有机肥,能快速改善土壤微生物区系和恢复土壤酶活性,降低枯萎病的发生,并有效促进西瓜生长,提高西瓜产量及品质。

Prevention and Control of Watermelon Fusarium Wilt by Dazomet Fumigation Combined with Bio-organic Fertilizer

Fusarium wilt disease, caused by formae speciales of the fungus Fusarium oxysporum f. sp. niveum (FON) is a serious problem for the watermelon production around the world.Among the managements for controlling Fusarium wilt disease, pre-planted fumigation of soil is one of the most effective and stable means for the disease inhibition. In this study, the possibility of applying the fumigation agent, dazomet, to watermelon planting field with a novel bio-organic fertilizer (BOF) was investigated as a strategy for controlling Fusarium wilt of watermelon and improving the bio-chemical properties of a continuously cropping soil. Three treatments including control (CK), dazomet fumigation plus organic fertilizer (OF) and dazomet fumigation plus the bio-organic fertilizer (BOF) were set in the field experiment. Compared with CK, BOFand OF treatments significantly reduced Fusarium wilt disease incidence by 65.8% and54.1%, respectively. Watermelon yield in BOF treated plots was increased by 33.4%, the sugar content and sugar/acid were enhanced by 15.9% and 13.4%, respectively. Soil fumigation with dazometfor 20 days significantly decreased the numbers of soil microbial organisms when compared with pre-fumigation and non-fumigated control (CK). Through the estimation by realtime PCR method, the copy number of FON was decreased by 3 log units,the urease, invertase, fluorescein diacetate esterase activities were significantly reduced bydazomet fumigation. Principal analysis of the Biolog AWCD showed that fumigation altered the microbial community. The Shannon diversity index and evenness index were significantly reduced when compared with CK.The amendment of organic fertilizer or the bio-organic fertilizer after dazomet fumigation restored the numberof mcrobial organism, the activity of soil enzymes and microbial functional diversity. Maximum soil enzymes inBOF treatment appeared earliest.The FON population and FON/fungi in the soil were least in BOF treatment during the whole growing season. The highest Shannon indexwas found in BOF treatment. These results suggest dazomet fumigation could significantly reduce the number of FON and if combined with bio-organic fertilizer application, soil microbial florarecovered faster and enzyme activities were enhanced to a larger extent compared with traditional organic fertilizer co-corporation. Thus watermelon plants could be prevented from being re-infected by FON and Fusarium wilt disease incidence could be reduced significantly and thuscan effectivelyincrease the yield and quality of watermelon.