直播早稻杂草发生规律研究

Analysis of Occurrence Regularity of Weeds in Direct Seeding Early Rice Fields

为明确直播早稻田间主要杂草群落组成及发生趋势,指导农民科学使用除草剂。采用"W"型五点取样法对象山县直播早稻田杂草群落开展调查。结果表明,直播早稻田杂草共有5科14种,以千金子、稗草为主要杂草,禾本科、莎草科及阔叶杂草分别占杂草出草总量的73.2%、13.6%和13.2%。播种后3~4天禾本科杂草开始萌发,特别是稗草出草较早,播后7~14天莎草科、阔叶杂草开始萌发。播后28天,出现第一个出草高峰,杂草总量达427株/m^2,主要为禾本科杂草,占总出草量的82.7%。播后42天时出现出草高峰趋势,达到364株/m^2,主要是阔叶杂草和莎草科杂草大量萌发。

In order to make clear the species and emergence trend of weeds in direct seeding early rice fields, and help farmers apply herbicide reasonably, weed communities in direct seeding early rice fields of Xiangshan were studied by using W type five-point sampling method. The results showed that there were 14 species belonging to 5 families of weeds appearing in rice fields, Leptochloa chinensis and Echinochloa crusgalli were the main species of weeds, total numbers of seedling emergence were 73.2%, 13.6%, 13.2% for grasses, sedges and broadleaf weeds, respectively. Grass weeds started to emerge in the fields 3 days to 4 days after rice was seeded, E. Crusgalli germinated especially earlier. Sedge weeds and broadleaf weeds started to emerge in the fields 7 days to 14 days after rice was seeded. Emergence peaks appeared 28 days after rice was seeded, numbers of weed were 427 plants/m2, grass weeds composed the majority of weeds and accounted for 82.7% of the total numbers of seedling emergence. Because of a mass germination of sedges and broadleaf weeds, emergence peaks appeared 42 days after rice was seeded, and the numbers of weed were 364 plants/m2.