Effects Of Urea-formaldehyde And Urea In Different Proportions On Growth Of Main Grain Crops And Soil Nutrients

Urea-formaldehyde slow-release fertilizer?SRF?is increasingly applied to economic crops due to slow release rate of nitrogen minerized.However,little is paid more attention to the performance of SRF in the field crops.In this study,three field experiments were conducted to study the SRF's nutrient release characteristics and its effect on crops yield,nitrogen use efficiency?NUE?,and economic outputs for winter wheat,maize,and rice.Five application rates of SRF to total N(as definded by:30,40,50,60,and 70%?SRF1,SRF2,SRF3,SRF4,and SRF5?were used for each crop.The main findings are as follows:?1?There shows a change trend with decrease-increase-decrease for releasing SRF-nitrogen during wheat growth period.The SRF2 and SRF3 are recomended in the N fertilization management for providing more nitrogen mineralized for plant growth and yield formation.?2?The plots applied with SRF2 or SRF3,relative to conventional fertilization control plots?all N was applied to the field prior to sowing?,significantly improved wheat grain yield by11.36%and 12.01%and signicantly increased economic output by 1359 and 1350 RMB·hm^-2.NUE in these treatments was also improved by 22.95%and 9.68%.As compared to another conventional fertilization control plots,the SRF2 or SRF3 leads to yield increases of 13.01%to 13.67%and economic output increase of 1591 RMB·hm^-22 and 1582 RMB·hm^-2.NUE in these treatments was also improved by 31.58%and 18.31%.However,there were no signiciantly different in SRF1,SRF4,SRF5 treatments,and control plots in terms of crop yield,economic output,and NUE.Neither SRF2 nor SRF3 is an alternatively recomonded into winter wheat production for improving NUE,yield,and economic output.?3?As compared to conventional N fertilization plots,the plots with SRF1,SRF2,and SRF5 all did not affect yield harvested.In contrast,in the plots applied with SRF3 and SRF4increased maize yield by 9.01%¹7.76%and economic output by 1889.0⁴641.2 RMB·hm^-2and NUE by 9.40%to 23.00%.The SRF3 or SRF4 plots applied in maize cropping system could be an effective and efficient practice to improve maize yield and facilitate the effective utilization of P and K by plants.?4?The SRF1 and SRF2 treatments provide the reasonable N uptake by rice plants during the early crop growth period,improving P and K uptake by parts of plant aboveground duiring mid-late crop growth period.The yield and grain number were also improved in both treatments.These treatments,relative to conventional N control plots,improved rice grain yield by 6.2%¹3.5%,increased economic output by 1445.8 to 4119.9 RMB·hm^-2,enchanced NUE by 5.7%²7.5%,whereas the SRF3 and SRF4 treatments did not change these measurements.Both SRF1 and SRF2 treaments are worthing recommending for high efficienct yield and higher economic output in the rice production.?5?According to soil column simulation leaching test,the nitrogen leaching amount of conventional fertilization treatment accounted for 23.44%and 16.38%of the total nitrogen application rate,which was higher than that of urea-aldehyde slow-release blending fertilizer and sulfur-plus-resin urea compound fertilizer.Compared with coated fertilizer,under the same proportion of conventional nitrogen,the nitrogen leaching rate of urea-aldehyde slow-release blending fertilizer was lower than that of coated fertilizer,indicating that urea-aldehyde sustained-release blending fertilizer treatment was not susceptible to nitrogen leaching.Ammonia volatilization losses were small in each treatment and there was no significant difference.