The research advance on the influencing factors of crop water use effi-ciency （WUE） was reviewed in this paper. Based on the discussion on the conno-tation of crop WUE, the influencing factors of crop WUE, such as crop, environ-ment, chemicals, cultivation measures, cropping systems, etc, were elaborated. A-mong them, the species and varieties of crop, soil and chemicals were discussed in detail.
Field plot experiment was conducted to study the effects of two slow-re- lease fertilizers and balanced fertilization on dry matter accumulation, yield, fertilizer use efficiency, nitrogen, phosphorus and potassium uptake of peppers at Jiangna Town, Yanshan County, Yunnan Province in 2011. The results showed that the dry matter accumulation in dried pepper plant, pepper yield, nitrogen, phosphorus, potassium uptake in peppers were significantly increased in all the fertilizer treat- ments, compared with those in control （no fertilizer）. Compared with conventional fertilization, balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer significantly increased dried pepper economic output by 20.94%, 17.5% and 14.54%, nitrogen uptake in dried peppers by 21.53%,18.46% and 13.19%, phosphorus uptake in dried peppers by 14.08%, 15.76% and 10.44%, potassium uptake in dried peppers by 22.66%, 15.73% and 16.28%; they also in- creased nitrogen and potassium use efficiency, but reduced potassium use efficiency due to the increased potassium addition. In treatments with balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer, the nitrogen utiliza- tion was 5.84%, 7.14% and 8.33% higher and the phosphorus utilization was 3.32%, 3.27% and 2.47% higher than those in treatment with conventional fertiliza- tion. In addition, the nitrogen application could be reduced by 20%-50% by bal- anced fertilization and the two slow-release fertilizers, thereby reducing environmen- tal pollution. Slow-release fertilizers could also reduce the frequency of fertilization and labor costs.
