Effect of Side Bar Fertilization Technology Based on Slow-release Fertilizer on Rice Yield and Nitrogen Losses

ZHANG Ai-ping1,LIU Ru-liang1,2,YANG Shi-qi1,ZHANG Qing-wen1,LI You-hong2,YANG Zheng-li1 *(1.Institute of Environment and Sustainable Development in Agriculture CAAS,Beijing 100081,China;2.Ningxia Agriculture and Forest Academy,Yinchuan 750002,China)

side bar fertilization technology;slow release fertilizer;nitrogen losses;water environment

Side bar fertilization technology based on slow-release fertilizer is recognized as being the most mature environment-friendly technology and having good operability by the experts in Japan,but there's little application in China.Focusing on the effect on water quality of such typical pollutants like nitrogen(N) from the irrigated areas in the upper reaches of the Yellow River,we studied the effect of side bar fertilization technology based on slow release fertilizer on rice yield and nitrogen losses.There were 5 treatments in this experiment,no fertilizer treatment(CK),low quantity of slow-release fertilizer treatment(LF),middle quantity of slow-release fertilizer treatment(MF),high quantity of slow-release fertilizer treatment(HF) and conventional fertilizer treatment(FP).The slow-release fertilizer was used as basal which was provided by ShiKeFeng Chemical Industry CD,LTD and the nitrogen content was 23.0%.We used side bar fertilization machine which was introduced by Japanese experts to transplant rice on June 14 and the harvest time was September 26.The results were as follows:the side bar fertilization technology based on high quantity of slow-release fertilizer treatment(HF) reduced the amount of nitrogen applied by approximately 40% compared to conventional fertilizer treatments(FP) but had no remarkable effects on rice yields while the number of ear and the weight of thousand ear of rice were increased 17.0% and 16.6% respectively.The nitrogen recovery of slow-release fertilizer treatments were from 54.5% to 63.5% which were higher than conventional treatment.The concentration of NH+4 and TN in surface water peaked before the third day after fertilizer application.The NO-3 amount in surface water of high quantity of slow-release fertilizer treatment(HF) brought down to the lowest level after 30 d.When compared with high quantity of slow-release fertilizer treatment(HF),conventional fertilizer treatments(FP) decreased even more rapidly with the time.When urea used as nitrogen sources,the first 9 d after urea applied was the critical period to reduce nitrogen loss,and within one month was important time to prevent nitrogen loss as use slow-release fertilizer.The critical occurrence time of leaching and nitrogen loss was within early stage,and NO-3-N was the main form of nitrogen loss,which accounted for from 64.8% to 70.3%.Total nitrogen loss amount of high quantity of slow-release fertilizer treatment(HF) was 8.57 kilogram fewer than conventional fertilizer treatments(FP) per hectare.Considering the rice yield and environmental effects,side bar fertilization technology based on slow-release fertilizer is one of environment-friendly technology that can be applied in rice cultivation.