秸秆还田与氮肥管理对稻田杂草群落和水稻产量的影响

为了研究秸秆还田和氮肥管理对稻油轮作夏季稻田杂草群落分布特征和水稻产量的影响，试验设5个处理：常规施肥NPK+秸秆不还田，N基追肥比例为6：2：2（F₀NS，CK）；常规施肥NPK+秸秆全量还田，N基追肥比例为6：2：2（F₀S）；常规施肥NPK+秸秆全量还田+秸秆腐解剂，N基追肥比例为6：2：2（F₀SA）；常规施肥NPK+秸秆全量还田+秸秆腐解剂，N基追肥比例为7：2：1（F₁SA）；常规施肥PK，N减量15%+秸秆全量还田+秸秆腐解剂，N基追肥比例为6：2：2（F₂SA）。记录杂草种类、数量、密度、生物量等指标，并于2016年9月底进行水稻实收测产。结果表明，与CK相比，F₀S、F₀SA、F₁SA和F₂SA处理的杂草总密度分别降低50.3%、29.2%、20.3%和6.8%，秸秆还田可以有效降低稻田杂草密度、生物量和杂草多样性；与F₀S相比，F₀SA、F₁SA和F₂SA处理的杂草发生数量和发生密度差异不显著，但禾本科和莎草科杂草不同程度地减少，柳叶菜科和玄参科杂草显著增加，配施秸秆腐解剂对农田杂草种类影响显著。在秸秆腐解剂和不同施氮措施下，与F₀SA相比，F₁SA和F₂SA处理杂草种类、生物量增加，杂草相对密度降低，但差异不显著；各处理间优势杂草种类和种群数量减少，但F₂SA处理下生物多样性指数明显高于F₀SA和F₁SA处理。与CK相比，F₀S、F₀SA、F₁SA和F₂SA处理的水稻产量分别提高7.13%、16.55%、17.80%和10.67%，其中F₁SA处理作物产量增幅最高。研究表明，秸秆还田和氮肥管理能有效降低稻田杂草的发生密度、总生物量和和生物多样性，有利于提高水稻产量。

Effects of straw return and nitrogen fertilizer management on weed community and rice yield in paddy field

The purpose of this study was to demonstrate the effect of straw return and nitrogen fertilizer management on distribution characteristics of weed community and rice yield in summer rice field. The experiment was conducted in five treatments:Conventional fertilization NPK(F₀NS, CK); conventional fertilization NPK + straw returning(F₀S); conventional fertilization NPK + straw returning + straw microbial inoculant(F₀SA); conventional fertilization NPK,N fertilizer proportion increase in early growth period of rice+straw returning+ straw microbial inoculants(F₁SA); conventional fertilization PK, N reduce 15% + straw returning + straw microbial inoculants(F₂SA). The weed species, number, coverage and biomass were recorded and the rice yields were measured at the end of September, 2016. The results showed that compared with CK treatment, the total weed density of F₀S, F₀SA, F₁SA, and F₂SA treatment decreased by 50.3%, 29.2%, 20.3%, and 6.8%, respectively, the total weed density, weed biomass and weed diversity were reduced effectively by straw returned; Compared with F₀S treatment, there was no significant difference in the number and density of weeds of F₀SA, F₁SA, and F₂SA, the grass of Gramineae and Cyperaceae decreased in different degrees, and the grass of Onagraceae and Scrophulariaceae increased significantly, the effect on weed species was significant by application of straw microbial inoculants. Compared with F₀SA treatment, the weed species, and biomass were increased and weed relative density were decreased in F₁SA and F₂SA treatment, which were no significant difference among treatments; The species and population of dominant weeds decreased among the treatments, and biological diversity index of F₂SA treatment was significantly higher than F₀SA and F₁SA treatments. Compared with CK treatment, the rice yield of F₀S, F₀SA, F₁SA, and F₂SA treatment increased by 7.13%, 16.55%, 17.80%, and 10.67%, respectively, of which crop production of F₁SA treatment was the highest increase. Straw return and nitrogen fertilizer management could effectively reduce the density, total biomass and biodiversity of weeds of paddy fields and was beneficial to rice yield improvement. Adjustment of agricultural management measures, can effectively reduce the growth of dominant weeds in farmland, improve the competitive relationship between weeds and crops, to maintain the balance of farmland ecosystem and biodiversity, and promote crop production.