摘要
在黄土高原南部旱地,采用田间试验研究了氮肥用量对冬小麦生长、产量及氮素累积和吸收利用的影响,确定不同施氮量条件下,冬小麦生长后期地上部干物质和氮素向籽粒转移的差异,明确合理的氮素用量。供试土壤在有效氮缺乏,肥力中等偏下。试验设不施氮(N1),每公顷分别施80,160和240 kg N(分别以N2,N3和N4表示)。试验期间分期测定了地上部及各器官(茎叶、穗、颖、籽粒)生物量的变化和吸氮量变化。结果表明:氮肥用量合适,小麦增产效果特别突出,每公顷施80 kg N,每kg N增产小麦籽粒33 kg,几乎达最大增产值。小麦由氮肥中吸收的氮素远高于由土壤中吸收的氮素。随施氮量增加,同一生育期小麦植株含氮量升高,而后期降低幅度增大;吸氮量显著增加,至灌浆期或收获期达峰值。施用氮肥对后期籽粒氮素累积有十分重要的作用,籽粒累积的氮素大部分来源于生长前期累积在营养体中氮素在灌浆期间的转移。从氮素效率和氮对环境影响来看,每公顷施用80kg N是最佳选择。
A field experiment was conducted to study the effect of N rate on wheat growth,yield,N accumulation and uptake and utilization efficiency with an aim to determine the differences of the transfer of dry matter and N from shoots to seeds at the late stages of winter wheat and the rational N rate.The soil used for the trial was deficient in available N and thus it had good response to N fertilizer.The experiment included four treatments： control（without N application） and addition of 80,160 and 240 kg N per ha,respectively.During the experimental period,changes of dry matter of different organs（stem and leaf,ear chaff and seed） and N in the aboveground part were measured.The results showed that when N rate was adequate,wheat yield was remarkably increased.Application of 80 kg N per ha had the highest efficiency,and 1 kg N increased 33 kg of wheat grain,almost reaching the highest limit of N function.There was no significant effect of application of N fertilizer on N harvest index.The biomass of wheat was increased with wheat developing time,and the peak value occurred at grain filling stage.Wheat took up much higher N from N fertilizer than from soil.At the same growing stages,the N content or concentration in plants was increased with the rise of N rate while at the late stages the concentration was declined higher for the higher N rate than for the lower N rate.However,the N uptake amount was continuously increased until grain filling stage when peak values were reached.Application of N fertilizer played a great role for grain to accumulate N and a large part of N in grains was originated from the transfer of N accumulated in plants during the grain filling stage.Evaluated by N utilization efficiency and its impact on the environment,application of 80 kg N per ha was the best choice for the soil used in the trial.
出处
《干旱地区农业研究》
CSCD
北大核心
2010年第5期65-70,91,共7页
Agricultural Research in the Arid Areas
基金
科技支撑计划子课题(2006BAD25B09)
关键词
氮肥用量
冬小麦
生物量
籽粒产量
氮素吸收
累积
分配与转移
nitrogen fertilizer rate
winter wheat
biomass
grain yield
N uptake
distribution and transfer
