氮肥减施下添加硝化抑制剂对夏玉米灌浆期叶片生理特性的影响

Effect of Nitrification Inhibitor Application in Nitrogen Rate Reduction on the Leaf Physiological Characteristics in Grain Filling Stage of Summer Maize

为明确氮肥减施条件下添加硝化抑制剂对夏玉米灌浆期叶片生理特性的影响,本研究设置氮肥正常施用量、氮肥不同减施量及其添加硝化抑制剂处理,研究玉米灌浆期叶片SPAD值、荧光特性、氮素代谢关键酶活、籽粒产量及氮效率的变化。结果表明,氮肥减施20%时添加硝化抑制剂处理能够显著增加果穗粒数,籽粒产量为11.59 t·hm^(-2),达到正常施氮量水平。与正常施氮处理相比,氮肥减施30%和20%时添加或不添加硝化抑制剂,氮效率均显著提高,其中氮吸收效率和氮利用效率在各处理间表现不一致,氮吸收效率以氮肥减施30%处理最高,为0.72 kg·kg^(-1),氮利用效率以氮肥减施30%添加硝化抑制剂最高,为72.23 kg·kg^(-1)。玉米灌浆期,氮肥减施20%并添加硝化抑制剂处理下穗位叶SPAD值优势明显,最大荧光和PSⅡ综合性能指数等荧光指标明显提高,氮素代谢关键酶硝酸还原酶(NR)和谷氨酰胺合成酶(GS)活性显著增强。综上,在本试验条件下,氮肥减施20%并添加硝化抑制剂能增强玉米灌浆期氮素代谢能力,协调碳氮代谢之间的关系,提高氮效率,增加玉米籽粒产量,达到玉米节本增效的目的。本研究结果为在夏玉米生产上推广施用硝化抑制剂提供了理论依据。

To investigate the effects of nitrification inhibitor application in reduced nitrogen rate on the leaf physiological characteristics in grain filling stage of summer maize,normal nitrogen(N)rate,N application reduced with or not nitrification inhibitor treatments were conducted to analyze the variation of SPAD,fluorescence characteristics,key enzyme activity about N metabolism of ear leaf,yield and N efficiency in this study.The result indicated that N reduced by 20%adding nitrification inhibitor treatment could increase the kernel number,and grain yield in this treatment was 11.59 t·hm^(-2),achieved the normal N level.Compared with normal N rate treatment,N reduced by 30%and 20%,with or not nitrification inhibitor,significantly increased N efficiency.Nitrogen uptake efficiency and nitrogen utilization efficiency were significant different in each treatment,respectively.Highest nitrogen uptake efficiency was found by 0.72 kg·kg^(-1) in N reduced by 30%and highest nitrogen utilization efficiency was obtained by 72.23 kg·kg^(-1) in N reduced by 30%adding nitrification inhibitor treatment.In the grain filling stage,N reduced by 20%adding nitrification inhibitor treatment got the higher SPAD,Fm and PI and enhanced activity of NR and GS.Thus,in this study,N reduced by 20%adding nitrification inhibitor could strengthen the N metabolism capacity,coordinate the relation of N and C,increase N efficiency and grain yield,to reduce cost and increase efficiency,and could be theoretical basis for widely promoting nitrification inhibitor in the maize production of this region.