Abstract:A location-fixed field experiment was carried out for 2 years under double cropping rice in Nanchang, Jiangxi Province of Southern China. Four treatments were designed which included no nitrogen fertilizer (CK), optimization of nitrogen fertilization application split by three times (OPT), slow/controlled release fertilizer all used as basal fertilizer (100CRF), and 80% slow/controlled release fertilizer all used as basal fertilizer (80CRF). Each treatment had three replicates. Rice grain yield, nitrogen absorption and utilization, soil mineral nitrogen accumulation and nitrogen balance in soil-crop system were investigated. The results showed that compared with OPT, 100CRF and 80CRF did not changed the rice yield significantly, but 100CRF increased nitrogen uptake of rice significantly (P<0.05). Nitrogen uptake increased by 32.58% (P<0.05) in early rice and 15.41% (P<0.05) in late rice in 2013, respectively; while no difference existed in nitrogen uptake between 80CRF and OPT. Compared with OPT, CRF improved utilization rate of nitrogen of rice and thus reduced loss of soil nitrogen. Soil mineral nitrogen was higher in early rice than in late rice in the same growth period, no significant difference existed in soil mineral nitrogen between different treatments in tillering, heading and mature stages, but soil nitrate nitrogen in late rice under 100CRF was significantly higher than that of OPT in mature stage. Compared with OPT, the average nitrogen loss ratio of 100CRF and 80CRF reduced by 65.34 kg/hm2 (33.08%) in 2013 and 90.64 kg/hm2 (45.89%) in 2014, respectively. Therefore controlled release nitrogen fertilization can promote rice yield, increase nitrogen absorption of rice, maintain high soil nitrogen level, reduce soil nitrogen loss and improve utilization rate of nitrogen fertilizer. Reducing 20% of applied controlled release fertilizer is more reasonable under current situation because it can maintain high yield of cropping rice while has the highest utilization rate of nitrogen fertilizer and the lowest nitrogen loss at the same time.