尿素硝铵溶液对黑土区春玉米产量和氮素吸收利用的影响

Effects of Urea Ammonium Nitrate Solution on Grain Yield and Nitrogen Uptake of Spring Maize in Black Soil Region

【目的】尿素硝铵溶液(urea ammonium nitrate solution,UAN)是集硝态氮、铵态氮和酰胺态氮于一身的液体氮肥品种,兼有3种氮源优势。本研究目的在于明确黑土区春玉米施用UAN的肥效和氮素利用效率,为进一步科学应用及推广提供依据。【方法】2015和2016年在吉林省黑土区设置大田试验,施肥处理包括:不施氮(N0)、尿素一次性基施200 kg N·hm^(-2)(U200)、UAN一次性基施200 kg N·hm^(-2)(UAN200)、尿素基施80 kg N·hm^(-2)+追施120 kg N·hm^(-2)(U80-120)、UAN基施80 kg N·hm^(-2)+追施120 kg N·hm^(-2)(UAN80-120)、尿素基施64 kg N·hm^(-2)+追施96 kg N·hm^(-2)(U64-96)、UAN基施64 kg N·hm^(-2)+追施96 kg N·hm^(-2)(UAN64-96),追肥时期为拔节—大喇叭口期,施肥深度均为12 cm。测定指标包括籽粒产量、产量性状、植株吸氮量、土壤无机氮含量,并计算土壤-作物系统的氮素平衡、氮素的表观利用、残留和损失状况。【结果】2015和2016年施氮处理的玉米产量、植株吸氮量相比不施氮处理显著提高,均以UAN200处理最高(10.3、11.9 t·hm^(-2)和187.4、288.2 kg·hm^(-2)),而U64-96处理最低(9.14、10.2 t·hm^(-2)和159.1、243.8 kg·hm^(-2))。相同施氮量、施用方式条件下,UAN处理的玉米产量均等于或高于尿素处理。2015年UAN在200 kg N·hm^(-2)一次性、分次施用和160 kg N·hm^(-2)分次施用条件下相比尿素分别增加6.1%、2.0%和5.3%,2016年分别增加0.1%、7.8%和7.4%,其中UAN80-120处理显著增产。UAN增产的主要原因是减少果穗秃尖长度而增加单穗粒数。UAN处理的植株氮素吸收量在相同施氮量、施用方式条件下均高于尿素处理,而收获后土壤无机氮残留量和氮素表观盈余量相对较低,因而获得较高的氮素利用率。与UAN200处理相比,UAN64-96处理在减氮40 kg N·hm^(-2)条件下两年玉米产量分别达到9.6和11.0 t·hm^(-2),其中2015年干旱条件下与UAN200处理无显著差异。而且,UAN64-96处理的土壤氮素表观残留率最低,2015和2016年分别为2.4%和4.4%,而氮素表观利用率最高,分别达到42.6%和52.0%。【结论】相同用量和施用方式下,黑土区玉米施用UAN可获得与尿素相同甚至更高的产量和氮素吸收量,同时土壤氮素残留和盈余较少,氮素利用率明显较高,环境效应较好。从施氮量、产量和氮素利用及损失等方面综合考虑,黑土区春玉米推荐施用160 kg N·hm^(-2)的UAN,以基肥40%和拔节-大喇叭口期追肥60%分次施用。

【Objective】Urea ammonium nitrate solution(UAN)is a liquid nitrogen(N)fertilizer with nitrate-N,ammonium-N and amide-N and owns advantages of these N sources.This study aimed to investigate maize yield responses and N use efficiency of UAN in black soil region,and thereby provided scientific references for application and promotion of UAN in local maize production.【Method】Two field experiments were conducted in black soil region of Jilin province in 2015 and 2016,including seven fertilization treatments,i.e.No N fertilizer application(N0);200 kg N·hm^-2 of urea as base fertilizer(U200);200 kg N·hm^-2 of UAN as base fertilizer(UAN200);80 kg N·hm^-2 of urea as base fertilizer with 120 kg N·hm^-2 of urea as topdressing(U80-120);80 kg N·hm^-2 of UAN as base fertilizer with 120 kg N·hm^-2 of urea as topdressing(UAN80-120);64 kg N·hm^-2 of urea as base fertilizer with 96 kg N·hm^-2 of urea as topdressing(U64-96);64 kg N·hm-2 of UAN as base fertilizer with 96 kg N·hm^-2 of urea as topdressing(UAN64-96).All the topdressing were applied at jointing-bellbottom stage,and the fertilization depth was 12 cm below soil surface.Grain yield,yield characteristics,N uptake in plant,and soil mineral N content were measured at harvesting,as well as further N balance and the percentage of apparent recovery,residual and loss were also calculated.【Result】The results showed that N fertilization increased significantly grain yield and N uptake of maize in 2015 and 2016.In these two years,both the highest yields(10.3 and 11.9 t·hm^-2)and N uptake(187.4 and 288.2 kg·hm^-2)were observed under UAN200 treatment,while the lowest values were obtained under U64-96 treatment,which were 9.14,10.2 t·hm^-2 and 159.1,243.8 kg·hm^-2,respectively.With same application rates and methods,grain yields under UAN treatments were generally higher than those under urea treatments.Yield advantages was 6.1%for UAN200,2.0%for UAN80-120 and 5.3%for UAN64-96 compared with the responding urea treatments in 2015,and these were 0.1%,7.8%and 7.4%in 2016,respectively.The yield advantage in UAN treatments was mainly attributed to increased kernels number per ear and reduced bare tip length at maturity.With same application rates and methods,UAN treatments showed higher N uptake in plant but lower mineral N residual and surplus in soil after harvesting,thus obtained higher N use efficiency.UAN64-96 treatment reduced N input of 40 kg·hm^-2 compared with UAN200 treatment,but it still obtained grain yields of 9.6 and 11.0 t·hm^-2 in the two years,respectively,and which was similar with UAN200 treatment in 2015.Moreover,both the highest N recovery rates and lowest N loss rates were observed under UAN64-96 treatment,the former was 42.6% in 2015 and 52.0% in 2016,and the latter were 2.4% and 4.4%,respectively.【Conclusion】Compared with urea treatments,UAN treatments showed equal or higher maize grain yields and plants N uptake in black soil region when applied with same rates and methods,meanwhile soil N residual and surplus were relatively lower,and thereby resulting in higher N use efficiency and better environmental effect.Based on the integrated consideration of N application rate,grain yield,N use and loss,160 kg N·hm^-2 of UAN was recommended to be applied for maize production in black soil region with two splits,i.e.40% before planting and 60% at jointing-bellbottom stage.