河北省夏玉米田杂草群落数量分析

采用改良的倒“W”9点取样法对河北省夏玉米田的杂草群落进行调查，比较了杂草的相对优势度和杂草群落物种多样性指数，通过系统聚类分析对杂草群落进行相似性测度，采用主成分分析对杂草间相关性和分化方向进行分析。结果表明，夏玉米田的优势杂草主要是马唐等禾本科杂草，杂草群落可分为马唐+狗尾草+牛筋草+反枝苋+铁苋菜+打碗花和马唐+狗尾草+牛筋草+铁苋菜+马齿苋两类，分别属于冀中南山前平原和黑龙港地区两个地理区域。对杂草群落的生物多样性进行分析，黑龙港地区杂草群落中优势杂草的相对优势度高于冀中南山前平原，杂草群落结构的复杂程度和物种分布的均匀度低于冀中南山前平原。主成分分析表明，冀中南山前平原的各杂草种在群落中的分布比较均匀，黑龙港地区的各草种在群落中的分布则比较集中，且优势杂草间的相关性较高。

Quantitative analysis of weed community in summer maize in Hebei Province

The field survey was conducted using inverted W pattern with 9 sampling points. Relative abundance and species diversity indices of weed communities were compared. The community similarity was measured by hierarchical cluster. Correlation between weed species and differentiation direction of weed community was analyzed by principal component analysis. The results showed that the dominant weeds belonged to Poaceae. The weed communities could be divided into two groups, Digitaria sanguinalis + Setaria viridis + Eleusine indica + Amaranthus retroflexus + Acalypha australis + Calystegia hederacea and Digitaria sanguinalis + Setaria viridis + Eleusine indica + Acalypha australis + Portulaca oleracea. The two weed groups distributed in Hebei middle and south piedmont and Heilonggang region, respectively. The proportion of dominant weeds in Heilonggang region was higher than that in Hebei middle and south piedmont. The complexity level of community structure and species evenness in Heilonggang region were lower than those in Hebei middle and south piedmont separately. The correlation between weed species in Heilonggang region was higher than that in Hebei middle and south piedmont, and the weed species were concentrated in three directions.