沼液施用对辣椒疫病的防治效果及对土壤生物学特性的影响

摘要

[目的]研究猪粪、牛粪及其沼液配合化肥施用对辣椒疫病的防治效果以及对土壤生物学特性的影响,探讨施用沼液对植物土传病害防治的机制及其农用价值.[方法]利用连续3季的盆栽试验,研究等氮下,50％猪粪、牛粪及其沼液N替代比例配合化肥施用对辣椒疫病的防治效果及土壤酶活性的影响,并采用PCR-DGGE方法研究土壤微生物区系的变化.[结果]猪粪沼液配合施用化肥对辣椒疫病防治效果最好(平均防治效果为79.3％),其次为牛粪沼液(平均防治效果为38.5％),施用猪粪、牛粪对辣椒疫病无显著防治效果；2种沼液处理辣椒生物量显著高于猪粪、牛粪处理及阴性对照处理；施用猪粪沼液处理土壤荧光素二乙酸酯(FDA)水解酶活性、过氧化氢酶活性及多酚氧化酶活性分别比阴性对照高出3.44倍、66.7％和76.7％.此外,2种沼液处理均可增加根际土壤的细菌、真菌、放线菌、荧光假单胞菌及木霉的数量,提高土壤细菌、真菌的多样性指数.[结论]猪粪沼液对辣椒疫病的防治效果较好,体现出良好的农用价值.调控土壤微生物群落结构、提高土壤肥力可能是其抑制植物土传病害的机制之一.%[Objective] The objective of this study is to evaluate the effects of application of anaerobically digested slurry (ADS) on reduction of the incidence of Phytophthora blight of chilli pepper and soil biological characteristics.The potential mechanisms of plant disease suppression by ADS application was also proposed.[Method] Three consecutive batches of pot experiment were carried out to study the control of Phytophthora blight of chilli pepper by substitution of 50％ N input with raw pig slurry,raw dairy slurry,anaerobically digested pig and dairy slurry.The variations in activities of soil enzymes were analyzed.And the changes in soil microbial diversities and microbial structures were studied by PCR-DGGE.[Result] Application of anaerobically digested pig slurry resulted in the best control efficacy against pepper blight and the disease incidence rate was decreased by 79.3％,followed by combined application of anaerobically digested dairy slurry with chemical fertilizer (38.5％ of control efficacy).Application of raw pig and dairy slurry had no significant suppressive effect on pepper blight.Plants treated by anaerobically digested pig and dairy slurry showed significantly higher shoot biomass of pepper plants than those treated by corresponding slurry and negative control.The fluorescein diacetate (FDA) hydrolase activity,catalase activity and polyphenol oxidase activity of soil treated by anaerobically digested pig slurry were 3.44-fold,66.7％ and 76.7％ higher than those of positive control,respectively.In addition,application of ADS significantly increased the numbers of soil bacteria,fungi,actinomycete,and antagonistic microorganisms including Pseudomonas fluorescents and Tricoderma spp..The PCR-DGGE analysis showed that the bacterial and fungal diversities in the ADS treatments were improved.[Conclusion] The combined application of anaerobically digested pig slurry with chemical fertilizer obtained great achievement in reducing pepper blight incidence and had immense potential in agricultural production.Regulation of microbial diversity in rhizosphere and improvement of soil fertility might be one of the possible mechanisms on disease suppression of pepper blight by ADS application.