To explore the feasibility of the application of coated urea in the cultivation of rubber trees, the nutrient release characteristics of coated urea were studied in the rubber plantation soil with a buried bag experiment. Relationship between cumulative nitrogen release rate and accumulated temperature of soil was fitted by equations. Results showed that the nutrient accumulation-release rate of sulfur coated, resin coated, vegetable oil coated urea was 51.01%, 95.32% and 82.91%, respectively; the initial release rate was 4.89%, 1.71% and 2.07%, respectively; the cumulative nitrogen release rate of 28 d was 36.30%, 39.94%, 43.33%, respectively. Relationship between cumulative nitrogen release rate and accumulated temperature of soil was fitted by a quadratic equation, and the values of r were 0.940, 0.998, 0.984. Therefore, according to the soil accumulated temperature during the fertilization period, and the nitrogen cumulative release rate of coated urea was calculated using the fitting equation, to determine the scientific fertilization measures of the coated urea. It is helpful for the reasonable application of coated urea in rubber tree.
Chinese Journal of Tropical Crops
nutrient release characteristics