QUANTITATIVE ANALYSIS OF WEED COMMUNITIES IN THE WHEAT FIELDS OF JIANGSU PROVINCE

摘要

The outputs of the principal component analysis (PCA) were ecologically interpreted, after the overall weed infestation indexes of all weed populations occurred in 150 sampling sites amounted to 147.2hm~2 wheat fields in Jiangsu Province were assessed by visual scoring the level of weed infestation to wheat in seven scales. The results showed that the main factors determined the weed communities and infestation in the wheat fields were soil moisture and other ecological factors determined by latitude. According to the result of PCA, 150 sampling sites could be divided into four groups in wheat fields all over the province. The southern dry-land group rotated with dry crops in hilly region of the south of Jiangsu Province had such dominants as Galium aparine var. tenerum, Veronica persica and Avena futua while the dominant weeds of the northern dry-land group in the north of Jiangsu Province were Galium aparine var. tenerum, Veronica persica, Descurainia sophia and Lithospermum arvense. Sclerochloa kengiana and Polypogon fugax were the two main weeds occurred in the group of rotated with rice in the north of Jiangsu Province. The rice group rotated with wheat in the south of Jangsu Province had three dominant weeds as follows: Alopecurus japonicus, Alopecurus aequalis and Beckmannia syzigachne. The suggestion for the integrated weed management was also put forward according to weed distribution pattern.