氮肥底追比例对超高产栽培中小麦光合特性和干物质积累与分配的影响

Effect of Nitrogen Fertilizer Ratio of Base and Topdressing on Photosynthesis Characteristics,Dry Matter Accumulation and Its Distribution in Wheat with Super High Yield

为给小麦超高产栽培中氮肥的合理运筹提供依据,2009-2010年小麦生长季以济麦22为材料,在超高产栽培条件下设置4个试验处理:N0(不施氮),N1(在总施氮270 kg.hm-2的条件下,底施70%、拔节期追施30%)、N2(底施50%、拔节期追施50%)、N3(底施30%、拔节期追施70%),研究了不同氮肥底追比例对小麦光合特性和干物质积累与分配的影响。结果表明,在总施氮量相同的条件下,随氮肥追施比例的增加,旗叶净光合速率和气孔导度升高,细胞间隙CO2浓度降低,小麦群体净光合速率先升高后降低;N2处理提高了开花后干物质的积累量和对籽粒的贡献率,以及成熟期干物质向籽粒的分配比例,籽粒产量最高(达到11 698.94 kg.hm-2),氮肥生产效率和氮肥农学利用率亦最高;氮肥追施比例过多(N3),则开花后干物质的积累量及对籽粒的贡献率、成熟期干物质向籽粒的分配比例、籽粒产量和氮肥利用率均降低。在本试验条件下,底追比例为5∶5的处理是兼顾高产和高氮肥利用效率的运筹方式。

Application of nitrogen（N） fertilizer is one of the most important cultivation measures to increase wheat grain yield in production.In order to offer theoretical basis for application of nitrogen（N） fertilizer for super-high-yield winter wheat production,the effect of nitrogen fertilizer ratio of base and topdressing on photosynthesis characteristics,dry matter accumulation and its distribution was conducted with the cultivar Jimai 22 in 2009-2010 winter wheat growing season.The study were set with four nitrogen treatments of without applying N fertilizer（N0）;N application rate of 270 kg·hm-2 with fertilizer ratios of base to topdressing as 7∶3（N1）,5∶5（N2） and 3∶7（N3）.The results showed that with the increasing of nitrogen amount for topdressing,the net photosynthesis rate（Pn） and stomatal conductance（Gs） enhanced,but the intercellular CO2 concentration（Ci） decreased.The canopy apparent photosynthesis（CAP） of treatment N2 showed a changing trend of up at first and then down.The dry matter accumulation amount and its contribution to grains after anthesis increased in treatment N2 with the highest yield of 11698.94 kg·hm-2,the Nitrogen productive efficiency and N agronomic efficiency also increased.With excessive topdressing amount of nitrogen（N3）,dry matter accumulation amount and its contribution to grains after anthesis,distribution ratio of dry matter to grains,the yield and nitrogen use efficiency were all significantly lower.In conclusion,the most appropriate nitrogen applying regime recommended was treatment N2 with ratio of base fertilizer to topdressing as 5∶5.