不同轮作制度下施肥对冬小麦田间杂草群落及小麦生长的影响

摘要

为探讨不同轮作制度下长期施肥对冬小麦Triticum aestivum L.田间杂草及小麦生长的影响，我们在三个长期田间肥效试验定位点，研究3种轮作制度下（冬小麦-大豆Glycine max (L.) Merr.（WS）、冬小麦-夏玉米Zea Mays L.(WM)、冬小麦-中稻Oryza sativa(WR)）长期不同施肥模式对冬小麦田间杂草群落及小麦生长的影响。研究表明，在3种轮作制度下，平衡施加N、P、K肥或者NPK肥配施有机肥均可以显著降低冬小麦田杂草密度、地上生物量和田间光照透过率，促进冬小麦生长，并提高冬小麦产量和地上生物量；而且在冬小麦-大豆轮作和冬小麦-中稻轮作的冬小麦田中平衡施加N、P和K肥可以在控制杂草密度的同时保持一个较均一的杂草群落。3种轮作制度下各指标相对值比较发现，3种轮作制度改变施肥对冬小麦田间光照透过率影响程度的顺序与3种轮作制度改变冬小麦田中施肥对杂草密度和地上生物量影响程度的顺序相同；另外，在冬小麦-大豆轮作和冬小麦-中稻轮作制度下杂草密度与冬小麦田间光照透过率之间的相关系数也很高（R≥0.7906）,说明施肥对冬小麦田间光照透过率的改变可能是施肥影响冬小麦田间杂草群落的主要途径之一。轮作制度改变冬小麦田中施肥对优势杂草种类数和杂草生物多样性影响的程度差别不大，这可能是因为轮作改变施肥对田间杂草的影响并没有达到引起田间杂草物种消亡的程度。结果表明，在3种轮作制度中施肥对冬小麦田间杂草群落及小麦生长的影响虽有差异，但都显示出施肥在抑制田间杂草发生、维持杂草生物多样性和提高作物产量上的作用。%The effects of long-term fertilization on weed communities and growth of winter wheat (Triticum aestivum L.) were investigated under three cropping rotations: winter wheat−soybean [Glycine max (L.) Merr.] (WS), winter wheat−summer maize (Zea Mays L.) (WM) and winter wheat−mid-rice (Oryza sativa) (WR). Results showed that under the three crop rotations balanced fertilization with NPK or NPK plus manure could significantly reduce the population and biomass of the aboveground parts of weeds and light transmittance in the wheat field, and promote growth, yield and aboveground biomass of winter wheat under the three cropping systems. Moreover, the balanced NPK treatment could maintain relatively uniform weed communities in the WS and the WR. In comparison among the relative values of the indicators measured from the three cropping systems, it revealed that the light transmittance as affected by different fertilizer treatments in the fields followed the same sequence and quantity as the changes in weed populations and the aboveground biomass in the three cropping systems. In addition, the correlation coefficients between the weed population and the light transmittance in winter wheat field were also significant (R≥0.790 6) in the WS and the WR, indicating that the change of the light transmittance by improved fertilizer practices can be one of the main approaches to adjust the weed communities in winter wheat field. Different cropping rotations had less impact on number of dominant weed species and weed biodiversity in the winter wheat fields, which might be the reason why the same fertilizer treatment under different cropping rotations could not completely get rid of the weed species from the field. The results further indicated that although there are differences in the effects of fertilization on weed communities and wheat growth in winter wheat field under the three cropping rotations, one thing is definite, that is, balanced fertilization can effectively suppress weed growth, maintain weed biodiversity and increase crop yield.