作 者 ：徐明杰 董娴娴 刘会玲 张丽娟 巨晓棠
期 刊 ：植物营养与肥料学报 2014年 20卷 5期 页码：1084-1093
Keywords:15N, winterwheat, managementpattern, anthesis, fateofnitrogen,
摘 要 ：【目的】随着氮肥在农业生产中的广泛应用，已有许多通过不同施氮水平调控，分析作物养分吸收，提高氮素利用率的相关研究，但是关于高产体系下作物花前花后氮素利用、转移规律的研究相对较少。本文探讨传统（CT）和优化（YH）两种栽培体系对冬小麦氮素吸收、分配及去向的影响。分析高产条件下化肥氮的“作物吸收—土壤残留—损失”的新变化，解析小麦花前花后氮素利用、转移规律，探讨肥料氮、土壤氮与作物氮之间的关系。【方法】在传统和优化两种栽培体系定位试验中设置15N 微区，采用将15N 标记的尿素表施的方法，通过测定植株、土壤样品分析氮素利用特征。新鲜土壤 NH+4-N和NO-3-N 含量采用TRACCS 2000型流动分析仪测定。15N土壤及植物全氮用美国THERMO finnigan 公司的稳定同位素质谱仪Delta plusXP 测定。【结果】在该试验条件下，优化管理小麦籽粒产量和吸氮量均显著高于传统处理，分别比传统管理高35%和34%。优化管理15N利用率比传统管理高，差异达显著水平。小麦各器官中氮素的累积量及向籽粒中的转移量均表现为来自土壤氮高于来自肥料中的氮，说明土壤氮是小麦生长的主要氮源。传统管理籽粒氮素大部分来源于花前累积，转运氮的贡献率为81.65%，优化管理为62.14%。优化管理土壤硝态氮及15N含量显著低于传统管理；开花期传统管理土壤表层硝态氮及15N大量累积；收获后40—60 cm土层15N 出现累积峰，氮肥随水向下运移。两种管理方式的小麦当季化肥去向均表现为土壤残留>作物吸收>损失；传统管理土壤氮肥残留率高达 69.33%，优化管理较低，为39.17%。【结论】在优化栽培体系中冬小麦施氮量为139 kg/hm2 时，小麦籽粒产量达到高产且氮肥高效利用。合理调控氮素投入量以及适度的水分胁迫可以实现水氮高效前提下的作物高产。
Abstract:【Objectives】Nitrogen fertilizer having been widely used in agricultural production, many studies illustrated the efficiency of nitrogen, however, few studies showed the nitrogen accumulation and transport at the anthesis and maturity stages of winter wheat in high-yielding system. A field experiment was conducted to determine effects of different management patterns on uptake, distribution and fate of nitrogen in winter wheat. We indicated impacts of optimizing nitrogen and water management on “N uptake-soil residues-loss”, explored nitrogen accumulation and transport at the anthesis and maturity stages, and identified fate of nitrogen.【Methods】Two management patterns ［i.e., conventional pattern (CT) and optimized pattern (YH) in nitrogen and water management］ were designed through establishing 15N-micropolt experiments in the field. We analyzed the characteristics and nitrogen utilization by measuring soil and plant samples. NH+4-N and NO-3-N in the fresh soil samples were analyzed using continuous flow analysis (TRAACS 2000) in laboratory. 15N in the soil and plant were determined using the Delta plusXP.【Results】Under the experimental conditions, the differences in grain yields and nitrogen uptakes of wheat between the optimized and conventional treatments are significant. Compared to the conventional treatment, the grain yield and nitrogen uptake under YH are increased by 35.23% and 34.39%, respectively. The rate of 15N utilization of the conventional treatment (18.19%) is significantly lower than that of the optimized treatment (34.81%). The amounts of accumulated nitrogen in the crop aboveground organs and the amounts of transferred nitrogen to grain from soil nitrogen are significantly higher than those from fertilizer nitrogen. Therefore, soil nitrogen is the main nitrogen source of wheat. The nitrogen in seed mostly comes from the accumulation before the flowering, and the contribution rates of transporting nitrogen by organs of the conventional and optimized patterns are 81.65% and 62.14% respectively. After the wheat harvest, the contents of nitrate and 15N in 0-100 cm soil of the optimized pattern are significantly lower than those of the conventional pattern. The 15N contents under CT with soil depth increase at the first and then decrease, with the accumulation peak in 40-60 cm. The amount of nitrogen fertilizer is as follows: soil residual> crop uptake> loss. The residual nitrogen rate in soil of the conventional pattern is up to 69.33% which is significantly higher than that of the optimized pattern (39.17%).【Conclusions】It can be reached that high levels of grain yield and use efficiency of nitrogen with nitrogen controlled at around 139 kg/ha. Thus, we conclude that less nitrogen and reasonable water stress not only raise the efficiency of nitrogen fertilizer but also increase food production.
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