宁波地区抛秧晚稻生长前期主要杂草及生态位分析

为明确晚稻生长前期田间主要杂草群落组成及其生态位,预测除草剂作用下农田杂草群落的演变。采用对角线五点取样法对宁波晚稻田杂草群落开展调查。结果表明本地区晚稻田主要杂草种类有稗(Echinochloa crusgalli)、千金子(Leptochloa chinensis)、耳叶水苋(Ammannia arenaria)、异型莎草(Cyperus difformis)、矮慈姑(Sagittaria pygmaea)、李氏禾(Leersia hexandra Swartz)。计算这些杂草的生态位宽度和生态位重叠值,结果表明稗和千金子的时间、水平生态位宽度均在0.90以上,且二者时间和水平生态位重叠值最大(0.9088、0.8261),说明稗和千金子为晚稻生长前期杂草群落中的优势种群。耳叶水苋时间生态位宽度最低(0.4955),但与稗和千金子水平生态位重叠值较高,分别为0.7201和0.6990。说明耳叶水苋出草较迟,但有着较强竞争优势,忽视对耳叶水苋的防治,将使其成为水稻生长后期杂草群落的优势种群。

Analysis of the Composition and Eco-niches of Major Weeds During the Early Growth Period of Late Rice in Ningbo

The study aims to make clear the composition and eco-niches of the major weeds during the early growth period of late rice, and to predict the evolution of weed communities under the action of herbicides. Weed communities in late rice fields of Ningbo were studied by using diagonal five-point sampling method. The results showed that Echinochloa crusgalli, Leptochloa chinensis, Ammannia arenaria, Cyperus difformis, Sagittaria pygmaea, Leersiahexandra swartz were the main populations in this area. The niche breadth and niche overlap of the species were calculated. The results indicated that E. crusgalli and L. chinensis had time and horizontal niches breadth >0.90, their niches overlaps were the highest (0.9088, 0.8261), which indicated that they were the dominant species in the early growth stage of late rice. A. arenaria had minimum time niche breadth (0.4955), but had higher horizontal eco-niches overlaps together with E. crusgalli and L. chinensis, which were 0.7201 and 0.6990 respectively. This indicated that A. arenaria had a later germination, but with strong competitive advantage. Neglecting of prevention on A. Arenaria will lead it to be the dominant species in the late stage of rice growth.