| Through field experiment,we studied the application of the mixture experiment of the simplex centroid design of release-controlled urea and normal urea of watermelon,checked the growth situation and yield structure of watermelon and analyzed the field nutrient and the quality of watermelon,then we summarized the utilization of coated urea and nitrogen on watermelon.The results showed that: the method of using coated urea would lower the position producing fruits,enlarge the thickness of aerial stem,turnip length,leaf number and improve the single fruit weight obviously.This method would improve the safety and nutrient quality of watermelon.It's not very obvious for the coated urea to improve the OM of the field,but the total nitrogen and alkaloid N of field improve a lot,and plays a long-time utility on field.The method of using U-D60-D90 would improve the utilization ratio of the field,which is 98.58% higher than normal urea,D60-D90 would be 85.09% higher and U-D90 62.17% higher than normal one.So,we can choose two methods: U-D60-D90 and D60-D90 in the yield of watermelon,both would improve the production and quality of the watermelon. |