Study On Mineral Nutrition Law And Nutritional Diagnosis Of Jackfruit Leaves In Hainan "Malaysia No.1"

With the increasing popularity of jackfruit products among consumers around the world,jackfruit industry has brought increasing economic benefits,while the yield and quality are uneven.In the past,the production of jackfruit in our country was lack of management and cultivation techniques.Improper use of chemical fertilizers and lack of standardized fertilization techniques lead to fertilizer waste,imbalance of nutrients absorpted by plant,and uneven yield and quality.In order to solve the above production problems,this study selected the"Malaysia No.1"jackfruit medium and high yield garden in Nanyang Town,Wenchang City,Hainan Province,Dalu Town,Qionghai City,and Huangliu Town,Ledong County in two years,and collected leaf samples at fixed points and at fixed times.The contents of 9 kinds of mineral elements such as N,P,K,Ca,Mg,Fe,Mn,Cu,Zn in leaves were determined at fixed point and time,and the dynamic change law of mineral elements in the whole year was studied.Analysis of the deviation,coefficient of variation and significant difference of the mineral element content in the leaves and determine the suitable nutrition diagnosis time.The diagnostic index of nutrition in leaves of‘Malaysia No.1’was preliminarily established by using‘standard value method’to diagnose and evaluate the nutrient law in different orchards.The main results are as follows:1.The order of annual average contents of nutrient elements in leaves of‘Malaysia No.1’jackfruit is:N>Ca>K>P>Mg>Mn>Fe>Zn>Cu.2.Based on the phenological and nutritional characteristics of jackfruit in actual production,the growth cycle of jackfruit is divided into two batches and six periods:the first batch of tree-growing period（November-December）,flower bud differentiation period（January-February）,fruit swelling period（March-April）,the second batch of tree-growing period（May-June）,the flower bud differentiation period（July-August）,and fruit swelling period（September-October）.3.The variation coefficient and mean deviation of‘Malaysia 1’jackfruit were small in June,which could be used as the suitable sampling time for nutritional diagnosis.4.Nutritional diagnostic indicators of mineral nutrients:N,20.87～23.71 g·kg^-1;P,1.97～2.25 g·kg^-1;K,13.56～18.48 g·kg^-1;Ca,14.84～17.32 g·kg^-1;Mg,2.27～3.97 g·kg^-1;Fe,55.96～82.60 mg·kg^-1;Mn,578.08～802.96 mg·kg^-1;Cu,2.97～4.40 mg·kg^-1;Zn,14.13～19.51 mg·kg^-1.5.The nutrient prediction model established by the partial least squares regression method can better predict the N,P,K,Ca,Mg,Fe,Mn,Cu,Zn and other nutrients in jackfruit leaves,indicating that the established near-infrared spectrum of jackfruit leaves The model has certain practical value in detecting total nutrient content.Conclusion:This study obtained the regularity of nutrient changes in jackfruit leaves during the growth cycle,determined the key fertilizer-requiring period and the appropriate period for sampling and diagnosis of jackfruit trees,and obtained the appropriate value for nutritional diagnosis,which provided theoretical support for fertilization and nutritional diagnosis of jackfruit.The establishment of mathematical model of NIRS lays a foundation for rapid diagnosis of nutrition in jackfruit.