控释尿素基施深度对夏玉米产量和氮素利用的影响

Effects of Base Application Depths of Controlled Release Urea on Yield and Nitrogen Utilization of Summer Maize

【目的】探究控释尿素不同施肥深度对氮素吸收与利用的影响,明确控释尿素一次性基施在黄淮海夏玉米区实现高产、高效、稳产的适宜施肥深度。【方法】在大田条件下选用郑单958为供试品种,设置不施氮肥(CK)、地表撒施(DP0)、沟施深度5 cm(DP5)、10 cm(DP10)、15 cm(DP15)、20 cm(DP20)、25 cm(DP25)7个处理,系统研究控释尿素基施深度对夏玉米生长发育和产量及氮素利用的影响。【结果】在施用等量控释尿素条件下,施肥深度均对夏玉米产量存在显著影响。夏玉米产量随基施深度增加呈先增后减的趋势,并且2013年和2014年夏玉米产量与施肥深度间的关系符合二次曲线关系,二者的相关性均达到显著水平,2年获得最高产量的理论施肥深度分别为12.5 cm和12.2 cm,而实际生产中DP15处理产量最高,DP15和DP10处理产量差异不显著,较CK分别显著增产16.72%和16.50%(P<0.05)。与DP0处理相比,随施肥深度增加,夏玉米的氮素收获指数、氮肥偏生产力、氮肥农学效率、氮肥利用率均呈现出先增加后降低的趋势,其中氮肥农学效率、氮肥利用率均符合二次曲线关系,氮素收获指数和氮肥农学效率2年平均以DP10处理最大,分别为61.91%和6.68 kg·kg-1,而氮肥偏生产力、氮肥利用率以DP15处理最高,分别为47.27 kg·kg-1和46.97%。施肥深度在10 cm和15 cm较地表撒施(DP0)能增加土壤硝态氮和铵态氮含量并且减少氮素损失,花后氮素积累量2年均值增加38.93%和41.88%,促进了植株花后氮素积累量,并且分别显著增加夏玉米植株总吸氮量20.45%和22.36%。相关性分析可以看出,夏玉米产量与干物质积累量、氮素总积累量、氮肥偏生产力、氮肥农学效率和氮肥利用率均成显著正相关,与氮素籽粒生产效率成显著负相关。【结论】在施氮量为225 kg N·hm-2时,控释尿素一次性基施深度控制在10—15 cm可显著提高夏玉米的氮素吸收积累量,增加氮素利用效率,降低氮素损失,提高干物质积累量,最终获得较高籽粒产量,实现高产高效,可作为夏玉米控释尿素种肥同播的适宜施肥深度。

【Objective】The effects of different fertilization depths of controlled-release urea on nitrogen absorption and utilization were investigated,and then the suitable fertilization depth for achieving high,efficient and stable yield of controlledrelease urea in the Huang-Huai-Hai summer maize area was determined.【Method】Zhengdan958 was selected as the test variety under field conditions,and seven treatments were set,including no nitrogen fertilizer(CK),surface application(DP0),furrow dressing depth of 5 cm(DP5),10 cm(DP10),15 cm(DP15),20 cm(DP20)and 25 cm(DP25).The effects of urea application depth on growth,yield and nitrogen utilization of summer maize were studied systematically.【Result】Under the same amount of controlled-release urea application,the yield of summer maize was significantly affected by fertilization depth.The yield of summer maize increased at first and then decreased with the increase of basal fertilization depth.Moreover,the relationship between maize yield and fertilization depth in the summer of 2013 and 2014 conformed to the quadratic curve and the correlation between them reached a significant level as well.The theoretical fertilization depth that obtained the highest yield was 12.5 cm and 12.2 cm in 2013 and 2014,respectively.While in actual production,the DP15 treatment produced the highest yield with no significant difference between DP15 and DP10 treatment,with a significant increase of 16.72%and 16.50%,separately,compared with CK(P<0.05).Compared with DP0,nitrogen harvest index,partial nitrogen productivity,nitrogen agronomic efficiency and nitrogen utilization rate of summer maize all showed a trend of first increasing and then decreasing with the increase of basal fertilization depth.The agricultural efficiency of nitrogen fertilizer and the utilization rate of nitrogen fertilizer fit the quadratic curve.The nitrogen harvest index and nitrogen fertilizer agronomic efficiency were the largest under DP10 treatment in two years,achieving to 61.91%and 6.68 kg·kg-1,respectively,however,the highest nitrogen fertilizer efficiency was 47.27 kg·kg-1 and 46.97%under DP15 treatment,respectively.Compared with DP0,fertilization depth of 10 cm and 15 cm could increase soil nitrate and ammonium nitrogen content and reduce nitrogen loss.The mean value of nitrogen accumulation after flowering was 38.93%and 41.88%in 2013 and 2014,respectively,which promoted the post-flowering nitrogen accumulation and significantly increased the total nitrogen uptake above-ground by 20.45%and 22.36%,respectively.Correlation analysis showed that summer maize yield was significantly positively correlated with dry matter accumulation,total nitrogen accumulation,partial nitrogen productivity,nitrogen agronomic efficiency and nitrogen use efficiency,and significantly negatively correlated with nitrogen grain production efficiency.【Conclusion】In nitrogen application rate of 225 kg N·hm-2,controlled release urea one-time basal application depth in 10 to 15 cm could significantly improve nitrogen absorption accumulation of summer maize,increase nitrogen use efficiency,reduce nitrogen loss,improve the dry matter accumulation,eventually obtain higher grain yield.Furthermore,it also realized higher production and efficiency,and could be used as controlled release urea suitable fertilization depth for summer maize sowing and manuring simultaneously.