Weed phytosociological in irrigated rice under different cultivation systems and crop rotation intensity

ABSTRACT: This research aimed to evaluate the phytosociology of weeds in irrigated rice in different soil management systems and crop rotation intensity. Therefore, two field studies were carried out. Study 1 was conducted in an area that has been cultivated since 1994 with three cultivation systems: direct, pre-germinated and conventional ones. Study 2 was carried out in an experimental area in five Integrated Farming Systems, with crop rotation. Phytosociological evaluations were conducted when rice was fully blooming, in the first study, and when grain filling was ending, in the second study. Pre-germinated system of rice cultivation has predominance of aquatic weeds. Conventional system when compared with direct sowing has lower weed densities. Integrated Agricultural Production Systems with higher intensity of crop rotation have been higher infested of perennial species.

摘要：本研究旨在评估不同土壤管理系统（soil management systems）与作物轮作（crop rotation）强度下，灌溉水稻（irrigated rice）田杂草的植物社会学（phytosociology）特征。为此，本研究开展了两项田间试验（field studies）。试验1设于1994年起开始耕作的地块，设置三种种植模式：直接播种、水稻催芽播种与常规种植系统。试验2设于某试验田，包含五种实施作物轮作的整合农作系统（integrated farming systems）。两项试验的植物社会学调查分别于水稻盛花期（试验1）与灌浆末期（试验2）开展。研究结果表明：水稻催芽播种种植模式下水生杂草占优势；相较于直接播种模式，常规种植模式的杂草密度更低；作物轮作强度更高的整合农作系统，受多年生杂草侵染更为严重。