Soil physical and chemical characteristics influencing Meloidogyne incognita density in long-term continuous tobacco growing fields in Enshi, Hubei

In order to clarify the soil physical and chemical characteristics that affect the Meloidogyne incognita density in the long-term continuous tobacco cropping fields in Enshi, and to reduce the damage of Meloidogyne incognita on tobacco, 23 soil samples were collected from Xuan'en areas in Enshi, Hubei Province, where the disease was serious and typical. The physical and chemical characteristics of the soil and the density of Meloidogyne incognita were analyzed by stepwise regression, correlation and path analyses. The results showed that the contents of available phosphorus, exchangeable potassium and magnesium in soils had significant effects on the density of Meloidogyne incognita, with the comprehensive effects in the order of exchangeable potassium > exchangeable magnesium > available phosphorus. Exchangeable potassium content (mass fraction) had positive effects, while available phosphorus and exchangeable magnesium contents had negative effects on the density of Meloidogyne incognita. Therefore stabilizing potassium, increasing phosphorus and supplementing magnesium were suggested measures for controlling Meloidogyne incognita in the long-term continuous tobacco cropping fields in Enshi.