烟草青枯病发病烟株根际土壤营养状况分析

Nutritional status of rhizosphere soil around bacterial wilt diseased tobacco plant

为探究烟株根际土壤营养状况与青枯病发生的关系,摸清影响烟草青枯病发生最关键的土壤养分因子,以从重庆市烟草青枯病发生十分典型的黔江植烟区采集的177份根际土壤样品为供试材料,测定并采用t检验、因子分析、判别分析等方法分析了土壤pH、有机质、碱解氮、速效磷、速效钾、交换性钙和镁、有效铁、有效锰、有效铜、有效锌、有效硼、有效钼13项指标。结果表明:土壤pH、有机质、速效钾、交换性钙、有效硼、有效钼含量偏低以及土壤碱解氮、交换性镁、有效锰含量偏高均有可能降低土壤的抑病效果,导致青枯病严重发生;烟草青枯病发病烟株根际土壤的钙镁比(4.04)明显低于健康烟株根际土壤的钙镁比(9.86);因子分析结果显示,土壤中低水平的有效钼、交换性钙可能是导致青枯病发生流行最主要的因子;通过判别分析可知,烟株根际土壤中速效钾、交换性钙、有效钼、有机质、有效硼5个成分的含量情况可能是判别青枯病发病与否的关键因子。

177 soil samples were collected and analyzed in order to study the relationship between nutritional status of tobacco rhizosphere soil and bacterial wilt. Results showed that lower levels of soil pH, organic matter, rapidly available potassium, convertible calcium, available boron and molybdenum, and higher levels of convertible magnesium and available manganese could weaken soil resistance to disease, resulting in serious bacterial wilt. The Ca/Mg value （4.04） of rhizosphere soil around tobacco plant with bacterial wilt disease was significantly lower than that of healthy ones （9.86）. Factor analysis showed that lower levels of available molybdenum and exchangeable calcium in tobacco-growing soil were the overriding factors for bacterial wilt epidemic. Discriminant analysis showed that rapidly available potassium, convertible calcium, active molybdenum, organic matter and available boron in tobacco rhizosphere soil might be key factors to cause tobacco bacterial wilt.