Nutrient Release of Controlled-Release Fertilizer and its Effects on Rice Growth and Development

Pot experiment was conducted to investigate the effects of controlled-release fertilizer (CRF), applying as only one basal, on rice growth and nutrient release. It has been observed that the release of N was controlled at early growth stage immediately after transplanting for the CRF treatment. Release peak of N appeared at the 9th day and kept sufficient N supply from the 9th day to the 50th day after application. In addition, the CRF maintained relatively higher N supply than the specific fertilizer treatments at late stages. This N release model indicated that one basal application of the CRF could satisfactorily meet the demand of N nutrition throughout the growth and development of rice. In comparison with the same rates of the specific fertilizer either in splits or as one basal, the CRF resulted in greater primary tillers thus increasing effective panicle by 16.7% and 8.3% respectively. Application of the CRF significantly increased yield of rice grain by 10.1% and 18.2% respectively, probably due to better N nutrition, which increased chlorophyll concentration of blade, resulting in more effective photosynthesis and carbohydrate accumulation at late growth stages. The utilization efficiency of fertilizer N of the CRF as basal significantly increased by 13.5% and 22.7% respectively, comparing to the rice special fertilizer in splits and as basal. Apart from N, application of the CRF also increased the utilization efficiency of P and K.