抛秧稻田节肢动物及杂草群落结构研究

STUDY ON THE COMMUNITY STRUCTURE OF ARTHROPOD ANIMALS AND WEEDS IN BROAD CASTING SEEDLING FIELDS OF RICE

抛秧稻田节肢动物在水稻生育前期以刺吸类物种为主,相对多度为67.96%～75.79%,其中以稻蓟马优势度指数最高,幅度为0.6004～0.7333;至拔节以后,以食叶类和刺吸类为主,相对多度分别为6.93%～41.87%和3.25%～33.20%;水稻各生长期,钻蛀类物种相对多度为0.35%～3.66%,相对多度很低.天敌主要为隐翅虫类和蜘蛛类捕食性类群.整个生长季节,禾本科杂草和阔叶类杂草为主要类群,禾本科杂草相对多度为24.49%～62.04%,阔叶类杂草相对多度为27.74%～69.39%,稗草和慈菇为其中的优势种群,优势度指数分别为0.187 3～0.615 6和0.082 5～0.171 5.

In the earlier growth periods of rice plants, the dominant pests in broad casting seedling fields were found to be sucking insects, their relative abundance varying between 67.96% and 75.79%. The index of richness of rice thripid （ Thrips oryxae J was the highest [0. 600 4 - 0. 733 3 ） in the sucking group. After the jointing stage of the plants, the dominant pests were leaf -eating and sucking groups, their relative abundance being 6.93% - 41.87% and 3.25% -33.20%, respectively. Throughout the whole growth period of rice, the relative abundance of the borer group was low, varying from 0.35% to 3.66%. The main natural enemies of the pests were such predators as damselfly, Staphylinidae and spiders. Broad - leaf plants and grasses were the main weeds throughout the growing season, their relative abundance being 27.74% - 69.39% and 27.74% - 69.39% , respectively. Barnyard grass （ Echinochloa crusgalli Beauv. ） and Sagittifolia L. were the dominant weed species, their richness index bein 0. 187 3 -0. 615 6 and 0. 082 5 -0. 163 3. respectively.