氮肥施用方式对耐盐冬小麦干物质积累和氮素吸收利用的影响

【目的】耐盐冬小麦作为盐渍化地区的先锋作物，结合适当的轮作方式，既可以提高盐碱地的当年生产力，又可以改良盐碱地土壤耕层的盐分状况，然而在施肥管理方面，耐盐冬小麦没有形成统一的管理技术模式，其营养特征尚不明确，为了探索耐盐冬小麦科学合理的氮肥施用技术模式，本文对冬小麦开展了不同氮肥施用方式对其干物质积累和氮素吸收利用的影响研究。【方法】基于冬小麦区域施肥状况调查和冬小麦不同生育阶段的氮素吸收量，设置4种施肥方式；采用田间小区试验，在不同时期采集冬小麦植物样品，收获期进行产量测定，并对采集的样品进行氮素吸收和干物质量的测定，再通过相关公式计算，获得冬小麦的氮素吸收量和干物质积累量，用SPSS统计软件做统计分析，研究处理间的差异。【结果】 1）从返青到孕穗期，各处理间干物质积累量和氮素积累量差异最大，N300/2（农民习惯施肥）和N210/3（氮肥分三次施用，基肥、拔节肥和穗肥各占1/3）处理干物质积累量和氮素积累量明显高于N150/3和不施氮（N0）处理； 2）在返青期、孕穗期和收获期，N0处理的氮素含量最低，与施氮处理间差异显著，而所有施氮处理间差异不显著； 3）N300/2与N210/3处理的干物质累积量和氮素累积量以及产量无显著差异； 4）N210/3处理的氮素利用效率最高达40.7%，显著高于N300/2处理。【结论】耐盐冬小麦干物质积累均表现为苗期返青期很慢，返青期孕穗期迅速增大，孕穗后期成熟期缓慢增加，整个过程呈现慢快慢的趋势；耐盐冬小麦的氮素积累量在返青期至孕穗期最大，对氮肥的需求最为迫切。生育期少量多次施肥方式，在不降低耐盐冬小麦产量的情况下可以减少氮肥施用量，并能够提高氮肥的利用效率。

Effects of nitrogen application patterns on the dry matter accumulation and nitrogen uptake in salt-tolerant winter wheat

【Objectives】Salt tolerant winter wheat as salinization area pioneer crop, combined with proper rotation, can not only increase the productivity of saline soil, but also improve the plough layer features of saline alkali soil. In the fertilizer management, however, salt tolerant winter wheat does not form a unified management pattern, its nutrition status is unclear. In order to explore the scientific and reasonable salt tolerant winter wheat nitrogen fertilization technology pattern, the effect of different nitrogen fertilization patterns on the accumulation of dry matter and nitrogen absorption and utilization was studied.【Methods】Based on winter wheat regional fertilization condition investigation and nitrogen uptake of winter wheat in different growing phases, four fertilization patterns were tested using field plot trail. Samples were collected in different periods of winter wheat plant for the determination of nitrogen absorption and dry matter weight and the output. The winter wheat nitrogen uptake and the dry matter accumulation were calculated using related formula.【Results】1) The largest differences in the dry matter accumulation and nitrogen accumulation in all treatments were observed from the greening to the booting stages. The accumulation amounts of dry matter and nitrogen accumulation in N300/2 (farmers used fertilization) and N210/3 (210 kg/ha, three times application, basal 1/3, jointing fertilization 1/3 and earing fertilization 1/3) treatments are significantly higher than those of N150/3 and N0(no N applied) treatments. 2)In greening, booting and the harvest stages, the nitrogen content of CK is the lowest, significantly lower than those of nitrogen treatments, but the differences are not significant among all the nitrogen treatments. 3) There are not significant differences in dry matter and nitrogen accumulation of wheat between treatment of N210/3 and the farmers'practice. 4) The nitrogen utilization efficiency of N210/3 reaches 40.7%, significantly higher than that of N300/2. 【Conclusions】The accumulation of dry matter of salt tolerant winter wheat during seedling and greening period is slow, increases quickly from the greening to booting stage, slowly from the booting to the mature stage, showing a tendency of slow-fast- slow. The largest amount of nitrogen is accumulated from the greening to the booting stage, demanding the most urgent nitrogen supply from fertilizer. For the same yield of salt tolerant winter wheat, applying nitrogen fertilizer in different development stages enhances the efficiency of nitrogen utilization.