Nitrogen release and dynamic fo controlled relase fertilizer studied with rice

Pot experments wer ocnducted to investigate the effects of controlled relase fertilizer (CRF), applyed as only one basal, on nitrogen release and rice absorbing dynamic. It was observed that th maximum N releasing date of the CFR treatment appeared by 8th to 10th day, and the perild of sufficient N supply was maintiained for 40-50d for late crops and 50-60d for early crops after peak date. However, the maixmum N relaeasing date of teh rice special fertilizer as only one basal treament occurred at first day to third day, and the date of sufficienc N supply was maintained for 30-35d after peak date. In addition, the CRF miantiened relatively higher N supply than the specieal ric efertilizer treaments at late stages. N supplying levele the the CRF treament in the late crops was higher than that in the early crops. In comparison to the special fetilizer either in splits or as one basl, the rate of absorption for N and P the CRF treatment was ghiher at whole rice growth satge, and the K absorbing rate of the CRF treatment was higher at early growth stage, but lower at medium and late growth stage. The amount of acumulating absorpion for N, P and K of the CRF treatment reached maximum in the 3 fertilization treatments at harvest stage. The results slso showed that the CRF treatment trached maximum in the 3 fertilization treatments of harvest stage. THe results also showed that the CRF treatment hightened significantly fertilizer N utilization efficiency, and N utilization efficiency fo CRF was increased by 12.2-13.5% and 20.0-22.7% respectively, comparing to the special rice fertilizer in splits and as basal. Apart from N, and apllication of the CTRF aslo increased the utilization efficiency of P and K.