恩施烟区烟草根结线虫发生与土壤理化性状的关系

为探究恩施烟区烟草根结线虫发生与土壤理化性状的关系，明确影响烟草根结线虫病发生最关键的土壤理化因子，在病害发生最为典型的宣恩烟区分别采集了25个健康和发病烟田根际土壤，测定了有机质、土壤团聚体平均质量直径（MWD）、含水量、容重、毛管持水量、pH、碱解氮、有效磷、速效钾、交换性钙、镁、钠、有效铁、锰、铜、锌和硼17项指标，采用t检验、相关性分析和主成分分析等方法，系统分析了健康与发病烟田土壤上述指标之间的差异。结果表明，健康烟田土壤MWD、含水量、毛管持水量、交换性钙、有效铁、锰、铜、锌和硼比发病烟田土壤分别显著高出54.76%、6.45%、7.61%、64.90%、37.25%、50.62%、56.67%、60.14%和33.33%（p<0.01），而容重显著低于发病烟田土壤4.00%（p<0.01）；因子分析结果表明，上述10项差异显著指标对烟草根结线虫病发生的累积贡献率达68.62%，并能分别反映土壤供给营养元素、水分条件特征2个主成分；结合参考指标相关关系建立了包括有效锰和毛管持水量2项因子影响烟草根结线虫病发生的最小数据集。

Relationship between the Occurrence of Tobacco Root-knot Nematode and Soil Physiochemical Properties in Enshi Tobacco-growing Area

In order to explore the relationship between the occurrence of tobacco root-knot nematode and soil physiochemical properties, 25 typical healthy and 25 typical diseased rhizosphere soil samples collected from Xuan’en Conunty, the typical tobacco root-knot nematode region in Enshi City of Hubei Province, were detected for organic matter, mean weight diameter of aggregates, water content, bulk density, capillary moisture, pH, alkali-hydrolyzale nitrogen, available phosphorus, rapid available potassium, changeable Ca2+, Mg2+, and Na+, available Fe, Mn, Cu, Zn and B. The most critical soil factors of tobacco root-knot nematode were identified by the t-test, correlation analysis and principal component analysis were used to systematically analyze the differences in the above 17 indicators between healthy and diseased soils. The results showed that the content of MWD, water content, capillary moisture capacity, exchangeable Ca2+,, available Fe, Mn, Cu, Zn and B increased significantly by 54.76%, 6.45%, 7.61%, 64.90%, 37.25%, 50.62%, 56.67%, 60.14% and 33.33%, respectively(p<0.01), but the bulk density reduced significantly by 4.00%(p<0.01). The results also showed that the cumulative contribution rate was 68.62% from the above 10 indicators with significant differences, and the soil nutrient supply and water condition is the two principal component. According to the results, the available Mn and the capillary moisture capacity was established as the minimum data which could affect the occurrence of root-knot nematode disease.