中文摘要：

在半湿润地区的土垫旱耕人为土上，以冬小麦品种‘小偃22’为指示作物，通过田间小区试验研究了不同施肥条件下冬小麦田间杂草种群的组成以及在4个生育期（越冬期、返青期、拔节期、成熟期）田间杂草密度和生物量的变化。结果表明：（1）在冬小麦全生育期内共发现以猪殃殃、麦家公、婆婆纳、播娘蒿、泽漆、荠菜等为主的17种杂草，不同生育期杂草的优势种群不同，而且杂草总密度表现为越冬期〉返青期〉拔节期，生物量表现为拔节期〉返青期〉越冬期；（2）与不施肥处理（P0N0）比较，单施氮肥增加了杂草密度和生物量，在氮磷配施条件下，氮肥对生物量有极显著影响且随施氮量增加表现为减小趋势，其中PN45处理的杂草生物量最大并比P0N0增加51．8％；施磷对杂草生物量有极显著影响，其中单施磷比P0N0处理增加44．0％，PN135处理比P0N135处理增加24．0％。（3）低密度播种比正常密度播种能显著增加杂草生物量，平均增加幅度达82．9％。结果表明，通过增施氮肥和适当增加种植密度，可在一定程度上控制杂草发生，促进作物良好生长。

英文摘要：

Plot trials were carried out to study effect of fertilization and sowing density on community and biomass of field weed. The results showed that. 17 species field weeds were found during the winter wheat growth stage,and the dominant species,weed biomass,weed density varied at different growth stage. Comparing with P0 No ,the density and biomass increased with only N application, and there was a remarkable effect of N application on weed biomass in NP treatments. The weed biomass reached the maximum in low N application treatment. The biomass of PN45 was the greatest which increased by 51.8% comparing with P0 No ,and the biomass decreased with the increase of N application. There was a remarkable effect of P application on weed biomass. The biomass of only P application increased 44.0^ comparing with P0N0, and PN135 increased 24.0% comparing with PoN135, Weed biomass of low density treatment was greater than that of normal density, and biomass increased 82. 9%. The results indicated that weed biomass and density could be controlled to promote growth of crop by applying N fertilization and increasing cultivation density.