中文摘要：

为协调冬小麦个—群体间关系,建立适宜的群体结构,充分发挥旱作条件下垄沟栽培优势,以小偃22为材料,采用二元二次旋转组合设计,通过2年田间试验研究了垄沟覆膜、垄下集中施肥模式下种植密度与施氮量对冬小麦个—群体间干物质累积及产量的影响。结果表明,个体干物质累积量随种植密度的增加呈降低趋势。2008~2009年群体干物质累积量随种植密度的增加而减小;2009~2010年群体干物质累积量随种植密度的增加而增加。花期单茎干物质累积量不受施氮量的影响;而成熟期个体干物质累积量随施氮量的增加而增加。冬小麦群体干物质累积量均随施氮量的增加而增加。冬小麦能够通过分蘖调节自身的群体结构,不能盲目地通过增加播种量增加小麦群体密度;适量的增施氮肥有利于个体与群体发育。本试验条件下,冬小麦品种小偃22在中等密度（112 kg/hm2）与较高施氮量（N 201~214 kg/hm2）配置时,个—群体关系比较协调,个体发育健壮,群体干物质累积量和产量较高。

英文摘要：

The aim of this study was to harmonize the relationship between individual and population,and establish a suitable community structure,and fully apply the advantages of furrow and ridge cultivation in rainfed land areas.The successive two year field experiments were conducted to investigate the effects of sowing density and N rate on yield,and dry matter accumulation of individual and population of winter wheat in the furrow and ridge film mulching planting system.The central composite rotatable design with two factors of seeding density and N rate was used in the experiments.There were five levels of sowing density,75,85.95,112.5,139.04 and 150 kg/ha,and five N levels of N rates,120,137.57,180,222.43 and 240 kg/ha.The tested cultivar was Xiaoyan 22.The results show that the dry matter accumulation of individual winter wheat is significantly affected by sowing density,and the accumulation is decreased when the sowing density is increased.There are significant different dynamics of the dry matter accumulation of population in the two year experiments owing to difference weather.The dry matter accumulation of population is decreased as the sowing density is increases in 2009,while that is increased in 2010.Although there are no effects of nitrogen application on individual biomass at the anthesis stage,there are significant effects of N on biomass at the maturity stage.The nitrogen fertilization could increase the dry matter accumulation of population remarkably at the two stages.These results indicate that there are some effects of the sowing density and nitrogen rate on the dynamics of plant individual and population,the winter wheat has capacity to regulate their population according to environmental condition.Therefore,it could not to increase the population with higher sowing density blindly.The efficient nitrogen application is benefit to the individual and population growth.Under this experiment condition,the medium sowing density（112 kg/ha） and the higher nitrogen rate（201-214 kg/ha） are benefit to