Effect Of Slow-release Urea On Soil Inorganic N And The Yield Of Cotton And Maize

【 Object】 The new type fertilizer is the main way to realize "zero growth" chemical fertilizer.Slow-release fertilizer as an important component of its application is increasing widely. This field experiment was to determine the effect of slow-release urea on the soil inorganic N, crop yield, N uptake and utilization to provide reference for reasonable application of slow-release urea.【Method】This study was conducted at the Chemical Ecological Park of Tian Ye, Shihezi, Xinjiang, in 2015. Two field experiments including Slow-release urea application amount experiment and Slow-release urea base fertilizer application ratio experiment. The Slow-release urea application amount experiment were set Non-nitrogen fertilizer, urearecommended rate(310 kg N/hm2) and urea reduced 20% rate(248 kg N/hm2), Slow-release urea recommended rate(310 kg N/hm2), Slow-release urea reduced 20% rate(248 kg N/hm2). All deal with nitrogen as the basal one-time.In 20% of urea for contrast basal for conventional fertilization.Slow-release urea base fertilizer application ratio experiment under the N application rate of 310 kg N hm2.Slow-release urea as basal content of total nitrogen respectively 0, 20%, 50% and 100%, the rest of the nitrogen fertilizer supplementby ordinary urea.【Result】(1) Urea is 248 kg, 310 kg N/hm2 deal with 0 ~ 60 cm soil layer soil NO3--N content in cotton and maize 33 days after planting is higher than 248, 310 kg N/hm2 slow-release urea treatment. While the opposite trend from 50 days after planting, 310 kg N/hm2 slow-release urea treatment is the highest. Urea treatment 0 ~ 40 cm soil layer NH4+-N content higher than 33 days after sowing slow-release urea, but 83 days after planting at the highest of 310 kg N/hm2 slow-release urea. The soil inorganic nitrogen of 248, 310 kg N/hm2 slow-release urea treatments higher17.12% ~ 39.04% than urea 310 kg N/hm2, the N apparent loss is lower 29.27% ~ 72.07%.(2) Slow-release urea 248、310 kg N/hm2 cotton yields were higher 13% and 17%, nitrogen use efficiency higher 23.11 and 26.19, agronomic efficiency higher 68% and 85% than urea 248、310 kg N/hm2,respectively. The maize yields were higher 1.92% and 12.98%, nitrogen use efficiency higher 11.54 and 2.14, agronomy efficiency higher 4.32% and 28.62%, respectively. Administration of slow-release urea 310 kg N/hm2 can significantly improve cotton per boll weight and number of kernels per cob. Cotton and maize yield and fertilizer use efficiency is highest.(3) Slow-release urea 100% base processing in each soil layer soil NO3--N contents higher than 20% and 50% in 65 days after planting, and then gradually decline and lower than both. Slow-release urea 20% and 50% base processing 0 ~ 60 cm soil layer soil NO3--N contents higher than the control treatment in 83 days after planting. Slow-release urea 100% base processing soil NH4+-N content less than 20% and 50% basal application process from 65 days after planting. Slow-release urea base by 20%, 50% and 100% of soil inorganic nitrogen content in surplus accounted for 101%, 106% and 70% in cotton field. Soil nitrogen apparent of loss accounted for the N surplus 4.72%, 3.24% and 41.28% in maize field. With slow-release urea 50% base soil inorganic nitrogen content is the highest, N apparent of loss is the lowest.(4) Slow-release urea 50% base processing cotton yields were higher 11.00% and 23.88%, nitrogen use efficiency higher 3.15 and 8.94, agronomic efficiency higher 28.25% and 74.14% than Slow-release urea 20% and 100% base processing, respectively. And maize yield higher 11.00% and 4.81%, nitrogen use efficiency higher 2.22 and 10.84, and agronomy efficiency higher 22.47% and 9.31%. It can significantly increase the cotton per boll weight and maize 100-grain weight when 50% of the N fertilizer was applied as slow-release urea as planting. the cotton yield increasing 8.40% and maize yield increasing 8.53% Compared with control treatment.【Conclusion】 The results indicated that slow-release urea can be used on drip irrigated cotton and maize. And slow-release urea dosage for pure N 310 kg/hm2 is more reasonable. At the same time, the appropriate base proportion of slow-release urea not only ensures the growth of crops, reduces the loss of the fertilizer, and can obtain higher fertilizer use efficiency. Cotton and maize yield, N use efficiency were high and soil N loss was low when 50% of the N fertilizer was applied as slow-release urea as planting under these experimental conditions.