江苏茶园秋季杂草群落及外来入侵杂草的数量生态学分析
Multivariate analysis, description, and ecological interpretation of weeds and alien invasive weeds in the autumn tea gardens of Jiangsu Province, China

为明确除草剂使用、翻耕、树龄、坡度和郁闭度等杂草管理措施及环境因子对江苏茶园秋季杂草群落和外来入侵杂草物种组成、群落结构的影响,于2013年10月分别对江苏茶叶主产区仪征、金坛和宜兴3地共90个样地进行了杂草调查。通过主成分分析和典范对应分析,90块样地可以依据优势杂草种类和杂草丰富度被分成3个类群。类群Ⅰ为荩草、野老鹳草、酢浆草、狗尾草、蓬蘽、麦冬杂草群落,该类群翻耕和化学除草频次少,树龄较大,郁闭度高,田间多年生杂草多,杂草种类多,田间杂草密度低;类群Ⅱ为马唐、小旱稗、小飞蓬、野老鹳草、狗尾草杂草群落,该类群以化学除草为主,田间一年生禾本科恶性杂草和抗除草剂杂草多,杂草优势种突出;类群Ⅲ为马唐、小旱稗、牛筋草、野老鹳草、酢浆草、虮子草杂草群落,该类群茶园管理较为精细,田间优势杂草种类少,杂草密度低。对外来入侵杂草与环境因子关系的数量分析发现,化学除草剂的使用和翻耕频率显著影响外来入侵杂草在江苏茶园的发生和分布。研究表明,不同管理措施,如化学除草剂和翻耕频率,对杂草群落的形成起决定性作用。
To investigate the effects of herbicide use, tillage, tree age, slope, and canopy density on the weed species composition and community structure in autumn tea gardens in Jiangsu Province, 90 representative sampling sites of Yizheng, Jintan, and Yixing were selected, and weed surveys were conducted in October 2013. The 90 sampling sites were classified into three groups based on the dominant weed species and weed abundance according to canonical correspondence analysis (CCA) and principal component analysis (PCA). The Group Ⅰ consisted of Arthraxon hispidus, Geranium carolinianum, Oxalis corniculata, Setaria viridis, Rubus hirsutus, and Ophitopogon japonicum, and these species were present in all sample sites from the tea gardens with lower frequencies of tillage and herbicide application, older trees, and higher canopy densities. This community had more perennial weeds and weed species and a lower weed density. The Group Ⅱ consisted of Digitaria sanguinalis, Echinochloa crus-galli var. austro-japonensis, Conyza canadensis, G. carolinianum, and S. viridis. All the sample sites in this group relied primarily on chemical control of weeds, and therefore more annual grassy malignant weeds, herbicide-tolerant weeds, and prominent dominant weed species were present. The Group Ⅲ contained D. sanguinalis, E. crus-galli, Eleusine indica, G. carolinianum, O. corniculata, and Leptochloa panacea. Because the tea gardens of this group were intensively managed, fewer dominant weed species were present, and weed density was lower. Moreover, analyses of alien invasive weed species and environmental factors indicated that herbicide application and tillage highly significantly affected the occurrence and distribution of alien invasive weeds in autumn tea gardens in Jiangsu Province. The results indicated that different management practices, e.g., herbicide application and tillage practice, play decisive roles in the formation of weed communities.