【作者】 胡迎春；

【导师】 廖允成； 秦晓梁；

【作者基本信息】 西北农林科技大学 ， 作物学， 2019， 硕士

【摘要】 黄土高原是中国重要的粮食产区,春玉米是该地区主要的粮食作物之一。针对黄土高原春玉米生产中过量施肥和效益较低的问题,本试验研究了氮肥减量下缓释肥（Slow-release Urea,简称C）和尿素（Urea,简称U）配施对土壤水分、土壤养分、春玉米生长发育以及效益的影响,试验于2017年和2018年两年在中科院长武生态试验站进行。以平作半膜覆盖下的春玉米为研究对象,采用随机区组设计,设置不施氮肥（CK）、常规施肥模式为全尿素施肥(100%U,施氮225 kg·hm^-2)、缓释肥和尿素7:3配施(100%CU,施氮225 kg·hm^-2)、氮肥减量20%下的缓释肥和尿素7:3配施(80%CU,施氮180 kg·hm^-2)、氮肥减量40%下的缓释肥和尿素7:3配施(60%CU,施氮135 kg·hm^-2)五种处理,旨在提出适合黄土高原地区高效的减氮施肥模式。主要研究结果如下:（1）两年的0²00 cm土壤贮水量在春玉米整个生育期内呈现出高-低-高的趋势。与CK相比,氮肥的施用增加了春玉米对土壤水分的消耗,降低了土层含水量,增加了春玉米对土壤40 cm以下水分的消耗,在春玉米生长的灌浆期较为明显。而土壤含水量和土壤贮水量以及不同生育阶段的水分消耗量在缓释肥配施处理与常规施肥之间的差异并不显著。（2）0¹00 cm土层的土壤硝铵态氮含量、全氮含量在灌浆期和成熟期都随土层深度的增加逐渐降低。缓释肥和尿素配施显著增加了收获期0⁴0 cm土层的硝态氮含量,80%CU处理的表层土壤有机质含量和100%U处理之间并无显著差异,而60%CU处理却造成了土壤有机质含量的降低。土壤铵态氮在各施肥处理间没有显著差异。（3）与常规施肥相比,氮肥减量下缓释肥和尿素配施并没有造成春玉米灌浆期SPAD值、成熟期株高以及成熟期籽粒氮素含量的降低。和100%U处理相比,80%CU处理的灌浆期叶面积指数,成熟期的干物质量、植株氮素积累量没有显著差异,但是增加了单株玉米籽粒干重,提高了籽粒灌浆速率;而60%CU处理的灌浆期叶面积指数、灌浆速率和成熟期的植株干物质量以及植株氮素积累量有所降低。（4）80%CU处理两年均收获了较高的产量,分别为12068 kg·hm^-2和13214kg·hm^-2,比100%U处理高出了4.68%和4.63%,并且没有造成春玉米籽粒品质降低。从经济效益来看,80%CU处理的利润最高,平均为11122 CYN·hm^-2,平均每年比100%U处理增加189 CYN·hm^-2。同时,80%CU处理的籽粒水分利用效率和降水利用效率在两年里都最高,氮肥减量下的缓释肥和尿素配施处理均显著提高了氮素农学效率、氮肥利用率、氮肥偏生产力和氮素吸收效率。因此,在黄土高原地区氮肥减量20%下缓释肥和尿素配施（80%CU处理）可以实现减氮增效的目标。更多还原

【Abstract】 Loess Plateau is one of the most important grain-based areas in China,and spring maize is the main food crops in this region.Aimed to the excessive and inefficient application of nitrogen fertilizer（N）and lower benefit in the planting of spring maize in Loess Plateau,a two-year field experiments were conducted in the southern of the Loess Plateau to investigate the effects of a mixture of conventional urea（U）and slow-release fertilizer（C）and N application rates on soil moisture,soil nutrients,spring maize growth and benefits with semi-film flat covering in a randomized complete block design.The experiment included five treatments:（a）no N application,CK;（b）the conventional fertilization mode with N application rate of 225 kg·hm^-2（100%U）;（c）the combination of C and U with N application rate of 225 kg·hm^-2（100%CU）;（d）the combination of C and U with N application rate of 180 kg·hm^-2（80%CU）;（e）the combination of C and U with N application rate of 135 kg·hm^-2（60%CU）.The above three treatments had the same C:U ratio of 7:3.The main results are as follows:（1）The two-meter soil water storage showed a trend of high-low-high during the whole growth period of spring maize in two years.The application of nitrogen fertilizer increased the soil moisture consumption,especially the water consumption in the depth under 40cm,which was more obvious in the filling periods of spring maize,but it was not obviously different between slow-release fertilizer treatments and conventional fertilizer mode in soil water content,soil water storage and water consumption at different growth stages.（2）The soil ammonium nitrogen,nitrate nitrogen,and total nitrogen in 0¹00 cm soil layer gradually decreased with the increasing soil depth during the filling period and mature period.The combination of slow-release fertilizer and urea significantly increased the nitrate nitrogen content in the 0⁴0 cm soil layer during mature period,organic matter content in 0²0 cm soil layer had no significant difference between 80%CU and 100%U,but 60%CU decreased organic matter content.The difference of ammonium nitrogen in different fertilization treatments was not significant.（3）Compared with conventional mode,the combination of slow-release fertilizer and urea did not cause the decrease of SPAD value in filling period,plant height and grain nitrogen content in mature period.Compared with 100%U,leaf area index at filling period,dry matter and plant nitrogen accumulation at mature period of 80%CU were not significantly different,but it`s dry weight of maize kernels and grain filling rate increased.Moreover,leaf area index,grain filling rate at grain filling period,dry matter content and nitrogen accumulation at mature period in 60%CU decreased（4）The highest grain yields(12068 kg·hm^-22 and 13214 kg·hm^-2)were achieved in the treatment of 80%CU,increased by 4.68%and 4.63%in comparison with the treatments of100%U in two years.And 80%CU obtained the highest net revenue among all treatments,with a 2-year average of 1,1222 CYN·hm^-2,which was 189 CYN·hm^-2 higher than 100%U.Moreover,water use efficiency and precipitation use efficiency of 80%CU were the highest in all treatments.And the N agronomic efficiency（NAE）,N using efficiency（NUE）and partial factor productivity of applied（NPFP）in 80%CU and 60%CU were significantly improved compared with 100%CU,but no significant difference was found in 100%CU.Besides,80%CU has no significant difference in grain quality compared with conventional fertilization mode.The results demonstrated that moderate amount(180 kg·hm^-2)of application of the combination of slow-release fertilizer and normal urea is recommended for greater net revenue and nitrogen use efficiencies in Loess Plateau.更多还原