Relationship Between Soil Chemical Properties And Canker Disease Of Carya Cathayensis

This research is based on a survey of soil productivity in the main production areas of Carya cathayensis,and a comprehensive survey of the soil chemical properties of forest land.It is to explore the relationship between soil chemical properties and the occurrence of canker disease,so as to provide a scientific theoretical basis for optimizing the soil management methods of forest,controlling the occurrence of canker disease and improving the yield and quality of Carya cathayensis.The main results as follows:?1?The dominant factor affecting the soil comprehensive fertility is the pH-based adaptive fertility comprehensive factor,comprehensive nutrient fertility factor of micro-fertilizer based on Cu and Zn,basic nutrient fertility comprehensive factor based on hydrolytic N and organic matter,comprehensive stress-resistant factor based on K and B.?2?At the current level of cultivation techniques,the comprehensive soil fertility determines the soil productivity,and the comprehensive index of the two shows a very significant linear relationship.Among them,soil pH,available Ca,available Mg,available Cu,available Zn and available K are significantly positively correlated with soil productivity index.The critical parameters of the above six key fertility factors are:pH?5.19,5.70?,K(87 mg·kg^-1,129 mg·kg^-1),Ca(817 mg·kg^-1,1374mg·kg^-1),Mg(93 mg·kg^-1,145 mg·kg^-1),Cu(1.36 mg·kg^-1,4.39 mg·kg^-1),Zn(0.78 mg·kg^-1,2.33mg·kg^-1).?3?Soil pH,hydrolytic N and available K are the three main fertility factors affecting the occur-rence and severity of canker disease.When the pH value is constant,the corresponding balance of soil N and K contents is the main soil environmental condition for preventing canker disease.?4?When the soil pH value is lower than 5.2,or the soil average available K is lower than 80mg·kg^-1,the risk of canker disease is significantly increased.When the soil pH value is higher than 6.0,the available K is higher than 130 mg·kg^-1,the risk is significantly reduced.?5?Human management methods and intensity significantly affect the occurrence and severity of canker disease.In strongly acidic soil?pH value less than 5?,the strength of nitrification is the main factor affecting the occurrence and severity of canker disease.The stronger the nitrification,the higher the conversion efficiency of N,the more serious the canker disease;long-term and excessive fertilization leads to serious acidification of the soil,which leads to the sharp leaching of K⁺and other cations.The supply of soil available K is insufficient,and the N accumulation is too high,which is the root cause of the high incidence of canker disease;the traditional model of biological self-fertilization can effectively and safely solve the problem of soil N supplementation.In strongly acidic soil,combined with single application of K fertilizer,can effectively reduce the risk of canker disease,but the soil hydrolytic N is too high will lead to further acidification of the soil,thereby increasing the risk of canker disease.