Effects Of Different Nitrogen Fertilizer Types On Soil Nitrogen Supply Characteristics And Growth And Yield Of Maize

The combined application of controlled release nitrogen?N?fertilizer?CRF?and common nitrogen fertilizer can effectively improve the N fertilizer use efficiency?NUE?and economic benefit.Humic acid urea can promote crop growth,thereby improving crop yield,NUE and economic benefit,This study investigated the effects of different application ratios of CRF to common N fertilizer,its reducing application levels and humic acid urea on NUE by spring maize and soil available nutrients,which would guide the scientific application of N fertilizer in Northeast China.Results are as follows:1.Clarified the effects of CRF on soil N supply characteristics and growth and yield of Maize?1?The combined application of CRF and common N fertilizer improved the N accumulation in leaves,enhanced the photosynthesis ability and yield of maize,and increased the economic benefit.The maize yield and economic benefit were significantly higher with the application of CRF combined with common N fertilizer than that with single application of CRF.Treatment of CR4 showed the highest maize yield of 14695.40 kg·hm^-2,which was25.68%higher than the CK.?2?The combined application of CRF and common N fertilizer increased the contents of soil ammonium N and nitrate N by 0.947-2.718 mg·kg^-1 and7.375-9.421 mg·kg^-1,respectively,and decreased the contents of soil available phosphorus and available potassium relative to CK.This indicated that the application of CRF promotes the absorption of nutrients by crops.?3?N use efficiency,N Agronomic efficiency and N partial factor productivity of CR3 were significantly higher than others and increased by21.79%,14.17 kg·kg^-1 and 23.68 kg·kg^-1,respectively,compared with CK.The application of CRF combined with common N fertilizer increased the NUE by 18.23%-19.11%and decreased the apparent N loss by 35.04%-40.01%.There was no significant difference in the apparent N loss among the treatments of reducing N fertilizer and the treatments of combined application of CRF and common N fertilizer.?4?The maize yield,economic benefit and different N fertilizer use indices in the CR4 treatment were significantly higher than those in the CR1 treatment.The N fertilizer agronomic efficiency and partial factor productivity in the CR4 treatment were significantly higher than in the CR6 treatment.The CR4 and CR5treatments showed the highest N balance index,which was not significantly different between them.2.Clarified the effects of different types of humic acid urea on soil N supply characteristics and growth and yield of Maize?1?Humic acid urea improved the N accumulation in leaves,enhanced the photosynthesis ability and yield of maize,and increased the economic benefit.The yield of UHAIII was the highest,reaching 16024.52 kg·hm^-2,which was increased 37.05%,compared with CK,the yield of RUHAIII was significantly higher than CK,which was 4463.39 kg·hm^-2.?2?Humic acid urea significantly increased the contents of soil ammonium N and nitrate N by 3.75-7.56 mg·kg^-1 and 8.39-15.76 mg·kg^-1,respectively and decreased the contents of soil available phosphorus and available potassium relative to CK,This indicated that the application of humic acid urea promotes the absorption of nutrients by crops.?3?Humic acid urea significantly improved the NUE.NUE of RUHAIII was highest,which was 27.91%higher than that of CK.The agronomic utilization rate and nitrogen partial productivity of UHAIII were the highest,which were 169.32%and 38.08%higher than that of CK.Compared with CK,NUE of humic acid urea increased from 15.80%to 27.91%,the apparent N loss rate of humic acid urea decreased by 28.86%to 49.65%.The apparent N loss rate of UHAIII was 6.26%,which was significantly lower than other treatments.?4?UHAIII is superior to other treatments.In summury,humic acid urea and controlled release nitrogen fertilizer are environmentally friendly new nitrogen fertilizers.The best nitrogen application methods in the two parts of the experiment were CR4 and UHAIII,respectively.Compared with CR4,yield and nitrogen fertilizer utilization indexes of UHAIII were better.In the apparent balance indexes of N fertilizer,the apparent N residual rate of UHAIII was lower than that of CR4,the apparent N recovery rate and the apparent loss rate were higher than that of CR4.The highest economic benefit was also UHAIII.