江苏省主棉区棉田杂草草害发生规律的研究

江苏省主棉区棉田杂草有 1 2 4种 (含变种 ) ,隶属于 37科、 93属 ,其中恶性杂草有马唐、铁苋菜、稗、鳢肠、狗尾草、马齿苋、牛筋草、千金子和刺儿菜等 9种 ,区域性恶性杂草 1 3种 ,常见杂草 2 0种 ,一般杂草 82种。发生优势度最大的为马唐、铁苋菜、稗、鳢肠 ,是江苏各棉区杂草群落的优势种。由于棉花耕作栽培方式的不同 ,导致杂草的发生有差异 ,在水旱轮作棉田 ,稗、千金子、牛繁缕等喜湿性杂草的发生优势度较大 ;而在旱连作棉田 ,狗尾草、牛筋草、刺儿菜、波斯婆婆纳、香附子、苣荬菜等旱生性杂草种群发生较多。江苏棉田的杂草危害基本上以 1～ 2级为主 ,3～ 5级出现的田块相对较少。各棉区发生的杂草种类亦有差异 ,沿江棉区的杂草危害最严重 ,沿海棉区和淮北棉区次之 ,里下河棉区又次之。就江苏各棉区棉田总体情况来看 ,旱 旱连作棉田杂草的危害程度比水 旱轮作棉田略高

Study on weed infestation in main cotton regions of Jiangsu Province

The survey results showed that 124 weed species(including varieties)belonging to 37 families and 93 genera were found in the cotton fields in Jiangsu Province.Of them,9 species were considered as malignant weeds,including Digitaria sanguinalis,Acalypha australis,Echinochloa crusgalli,Eclipta prostrata,Setaria viridis,Portulaca oleracea,Leptochloa chinensis and Cephalanoplos segetum ;13 species were regional malignant weeds;20 species common weeds and the other 82 species general weeds. Digitaria sanguinalis,Acalypha australis,Echinochloa crusgalli and Eclipta prostrata were dominant weeds of the weed communities at different cotton growing regions in the province.One of the main factors resulting in the difference of weed occurrence was the cropping system.In the cotton fields of rotation with rice,hydrophilous weeds such as Echinochloa crusgalli,Leptochloa chinensis and Myosolon aquaticum occurred abundantly,but in dry land cotton fields,xerophilous weeds Setaria viridis,Eleusine indica,Cephalanoplos segetum,Veronica persica,Cyperus rotundus and Sonchus brachyotus were popularly found.The degree of weed infestation in cotton fields in Jiangsu was primarily 1 or 2,while the degree of 3 5 was relatively fewer.There was some different weed distribution among the four cotton growing regions.Of the four cotton growing regions in Jiangsu,the weed infestation on Yanjiang region was the most serious,then followed by Yanhai region and Huaibei region,but Lixiahe region was the slightest.In overall,the weed infestation in the cotton fields with dry cropping system was more serious than that of rotation with rice.