Surveys were made for weed species and their damages in rice fields in Jiaxing, Hangzhou, Jinhua, and Wenzhou, Zhejiang Province in 1986- 2000 by a collaborative team of scientists. It involved early rice, late rice, one season rice, rice nursery or direct seeding rice, transplanted rice by seedling-broadcasting, arid rice nursery. The result showed that there are 131 species and 2 varieties belonging to 77 genus and 41 families of weeds appearing in rice fields in Zhejiang, among which 41 species and 1 variety belonging to 35 genus and 21 families are dominant. They are Echinochloa crusgalli, Leptochloa chinensis, Paspalum distichum, Cyperus difformis, Alternanthera philoxeroides, Monochoria vaginalis, Sagittaria sagittifolia, Rotala indica, Eleocharis yokoscensis, Ludwigia prostrata, et al. Weeds have the heaviest damage to one season rice, heavier to late rice, and the least to early rice. In simple weed community in early rice fields, E. crusgalliis only one main weed, whereas weed community in late rice fields is complex and consists of E. crusgalli, broad leaf weeds and sedge weeds. The damage of weeds is heavier in fields of direct seeding rice and transplanted rice by seedling-broadcastng than in conventional cultivation fields, and there are more weed species in arid rice nursery than in paddy rice nursery. Since long application of herbicides, annual weeds have decreased, perennial weeds increased, while E. crusgalli keeps its main place in rice fields. A list of weed species in rice fields was appended at the end.%1986～2000年由科研、推广及管理8家单位组成的浙江省农田杂草研究协作组在浙江省嘉兴、杭州、金华和温州4个农区，对水稻田杂草发生种类和危害程度开展全面系统调查，涉及早稻、晚稻、单季稻、秧田等各种耕作稻制和直播、抛秧、旱育秧等不同轻型栽培方式。调查结果，浙江省水稻田共有杂草41科77属131种和2变种，其中主要杂草21科35属41种和1变种，如稗草、千金子、双穗雀稗、异型莎草、空心莲子草、鸭舌草、矮慈菇、节节菜、牛毛毡、丁香蓼等。杂草危害以单季稻田最重，晚稻田次之，早稻田最轻；早稻田杂草群落简单，以稗草占绝对优势，而晚稻田群落较为复杂，由稗草和阔叶草及莎草共同构成群落。一些杂草在局部地区造成严重危害。同时，直播田和抛秧田杂草危害重于常规移栽田，早育秧田杂草种类多于常规水育秧田。长期使用除草剂，使常规栽培稻田一年生杂草发生减轻，而多年生杂草危害上升，但稗草仍为主要恶性杂草。最后，附有浙江省水稻田杂草名录。
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