果园夏季杂草数量生态学研究

2009年夏季采用1m×1m样方法对山西省太谷县的山西省农业科学院果树研究所果园夏季杂草群落进行调查，分析不同样地杂草群落的发生规律，并在此基础上，采用双向指示种分析法（CTWINS—PAN）和除趋势对应分析法（DCA）对群落进行了数量分类和排序分析。调查共发现73种杂草，属于27科62属，其中入侵杂草最多的为菊科（14种）和禾本科（11种）。TWINSPAN等级分类将该果园66个样方划分为11个群丛，分类结果较好地反映了该果园夏季杂草群落类型与环境梯度之间的关系，并在DCA二维排序图上得到较好的验证，即DCA第1轴主要反映了土壤水分的变化情况，从左到右土壤水分逐渐增多；第2轴主要反映了土壤养分的变化趋势，从上向下土壤养分逐渐减少，说明杂草群丛的分布格局与土壤水分和养分的密切关系，组成果园夏季杂草的优势种群能客观反映群落的生境特征．

Quantitative Ecology of Summer Weeds in Orchard

Quadrats of 1 m×1 m were used for the investigation of summer weeds communities in the orchard of Pomology Institute of Shanxi Academy of Agricultural Science in Taigu County during Summer 2009.Meanwhile,two-way indicator species analysis(TWINSPAN) and detrended correspondence analysis(DCA) were conducted to the summer weeds.There were 73 species of summer weeds belonging to 27 families and 62 genera in the orchard.The main families were Compositae(14 species) and Gramineae(11 species).A total of 66 quadrats were divided into 11 groups by TWINSPAN.The classification results better reflected the relationships between the 11 summer weeds communities and environmental gradients,and had been tested by DCA-dimensional map.DCA first axis mainly reflected changes in soil moisture,gradually increasing soil moisture from left to right.The second axis mainly reflects the trend of soil nutrients,gradually reducing the soil nutrient from the top.DCA illustrated the close relationship among the distribution patterns of the summer weeds communities,soil moisture and soil nutrient.The results showed that the dominant species of summer weeds in the orchard can objectively reflect the communities' habitat characteristics.