清江流域烟区烟草青枯病发生的土壤营养因素分析

目的]明确清江流域烟区中影响烟草青枯病发生的土壤营养因素,为更好地进行该烟区烟草青枯病的合理防控提供理论依据.方法]2016年度在湖北省恩施州宣恩县选择两种类型烟田(病田和非病田),于烟草青枯病全面暴发期(移栽后97 d左右)采集土样,测定根际土壤营养元素含量,采用多种统计分析方法研究烟草青枯病发病率、病情指数与根际土壤营养元素含量的关系.结果]t检验结果表明,16项土壤营养元素指标中,有10项指标在两种类型烟田中存在显著(P<0.05)或极显著(P<0.01)差异.典型相关分析结果显示,在一定范围内,适当提高土壤pH、阳离子交换量及交换性钙含量,降低土壤有机质、有机氮、有机碳和有效铁含量等可减轻烟草青枯病的发病率和病情指数.分组分析结果表明,抑病的土壤营养条件为土壤pH 5.0~7.0,有机质含量1.5%~2.5%,阳离子交换量、交换性钙含量及钙镁比分别高于20.0 cmol/kg、1000 mg/kg和15,有机氮、有机碳及有效铁含量分别低于0.15%、1.0%和50 mg/kg.结论]在清江流域烟区中,烟草青枯病发生程度与土壤营养元素含量间存在密切联系.

Soil nutrient elements affecting the occurrence of tobacco bacterial wilt in Qingjiang River Basin

Objective]The study was conducted to survey the soil nutrients that affected occurrence of tobacco bacte-rial wilt in Qingjiang River Basin,and provide theoretical basis for the rational prevention and control of tobacco bacterial wilt in the area.Method]The soil samples from two kinds of fields(bacterial wilt field and non-bacterial wilt field)were collected during full outbreak period of tobacco bacterial wilt(97 d after transplanting)in Xuan'en,Enshi,Hubei Province in 2016.The contents of nutrition elements in rhizosphere soil were determined,then the relationship between incidence of tobacco bacterial wilt disease,disease index and nutrient elements in rhizosphere soil was researched using a variety of statistical analysis methods.Result]t test showed that,among the 16 soil nutrient elements indexes,10 indexes presen-ted significant difference(P<0.05)or extremely significant difference(P<0.01)in two kinds of fields.The results of canoni-cal correlation analysis indicated that increasing of pH and contents of cation exchange capacity,exchangeable calcium content,and reducing the contents of soil organic matter,organic nitrogen,organic carbon,effective iron could reduce the morbidity and disease index of tobacco bacterial wilt within certain extent.Group analysis revealed that the appropria-te soil nutrient condition for inhibiting the disease were pH at 5.0-7.0;the organic matter content 1.5%-2.5%,the contents of cation exchange capacity,exchangeable calcium and calcium/magnesium ratio were higher than 20.0 cmol/kg,1000 mg/kg and 15 respectively,and contents of organic nitrogen,organic carbon and effective iron lower than 0.15%,1.0% and 50 mg/kg respectively.Conclusion]The occurrence of tobacco bacterial wilt is closely bound up with soil nutrients in Qingjiang River Basin.