Correlation between Soil pH and Main Nutrient Content and Macrophoma caryae

In May and June 2016, investigations were carried out on Macrophoma caryae status and degree on 15-35-year Carya cathayensis distributed in production area of Zhejiang. In December 2015, collection of soil at 0-20 cm was conducted for determination of pH, alkaline hydrolysis nitrogen, available phosphorus, available potassium. The results showed that it had extremely significant negative relation of M. caryae with soil pH and AK, but extremely positive with soil N/K ratio. The investigation demonstrated that M. caryae occurrence decreased with the increase of pH and AK, but increased with the increase of soil AN. Analysis revealed that soil pH, AN and AK was main factors of M. caryae occurrence. Regression model was established by logical regression for main factors of M. caryae and quantitative relationship which had prediction accuracy of 91.01%.