水稻免耕直播秸秆覆盖条件下稻田杂草的发生规律和防治策略

摘要

为探究免耕直播秸秆覆盖条件下稻田杂草发生规律及制定有效的防治策略,对湛江地区晚造免耕直播秸秆覆盖稻田杂草发生情况进行了调查分析.结果表明,稻田杂草共有8科15种,旱地杂草有向水田发展蔓延的趋势.秸秆覆盖对杂草萌发有一定的抑制作用,禾本科杂草呈单峰发生,莎草和阔叶草呈双峰发生.稻田杂草群落以莎草-禾本科杂草-阔叶草为主,以日照飘拂草相对多度最高;杂草空间分布上中下层分别为禾本科杂草、莎草-阔叶草、阔叶草;根据综合草害指数优势杂草为日照飘拂草、稗草和千金子,局部优势杂草为异型莎草和空心莲子草.还对稻田杂草发生的原因进行了探讨,并制定了相应的防治策略,以期最大限度减少杂草发生带来的产量损失.%Weed happen conditions were investigated in later no-tillage and direct seeding paddy with straw mulching of Zhanjiang City,in order to explore the happen regularity of weeds and develop effective prevention and control strategies.The results showed that there were 15 weeds species of 8 families,the dryland weeds showed a tendency to spread to the paddy fields.Straw mulching had certain effect to inhibit weed seed germination;gramineous weeds occurred with single peak,sedge and broadleaf weeds occurred with two peaks.The weeds community structure was dominated by sedge-gramineous weeds and broadleaf weeds.Fimbristylis miliacea had the highest relative abundant (RU) in weeds community.The spatial distributions of weeds were gramineous weeds,sedge-broadleaf weeds,and broadleaf weeds respectively at upper,middle and lower layers.The comprehensive infestation index (CⅡ) ranging of the dominant weed species were Fimbristylis miliacea,Echinochloa crusgalli,and Leptochloa chinensis.topical dominant weed species were Cyperus difformis,Alternanthera Philoxeroides.The cause of paddy weeds was discussed,and the prevention and control strategies were formulated,in order to minimize the yield loss by weeds.