Abstract Extensive grain crop production systems in the Flat inland Pampas mainly include soybean, double-crop wheat-soybean and maize in rotation. Due to difficult-to-control weed problems, farmers are tending to intensify the rotations in their fields by increasing the number of double crops or by including cover crops before the main crop. Land use intensification may be characterized using the intensification sequence index (ISI), which is the number of crops per year considering all crops sown in a particular period; i.e. the average number of crops sown in a time unit. To determine how agricultural intensification and crop sequences may modify weed communities, 31 soybean fields of commercial farms located in the Flat Pampa of Argentina were surveyed from 2012 to 2014. Frequency of individual weeds within the fields was determined and various statistical methods were used to evaluate changes in weed community composition or function due to intensification (ISI level). A total of fifty-three species, mostly therophytes (28 species), were recorded in soybean crop fields at harvest. Three weed communities were identified, which were related to the ISI level of the fields, and also to the number of years continuously sown with grain crops (i.e. number of years since the last pasture). Weed community under intensified fields was characterized by low species richness (p

中文翻译：

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轮作对平原内陆潘帕草原大豆（Glycine max L. Merr.）农田杂草群落的影响

摘要 平原内陆潘帕斯草原粗放型粮食作物生产系统主要有大豆、麦豆双季和玉米轮作。由于难以控制的杂草问题，农民倾向于通过增加双季作物的数量或在主要作物之前加入覆盖作物来加强田间轮作。土地利用集约化可以使用集约化序列指数 (ISI) 来表征，该指数是考虑特定时期播种的所有作物后每年的作物数量；即在一个时间单位内播种的作物的平均数量。为了确定农业集约化和作物序列如何改变杂草群落，2012 年至 2014 年对位于阿根廷平地潘帕的 31 个商业农场的大豆田进行了调查。确定田间杂草的频率，并使用各种统计方法来评估由于集约化（ISI 水平）引起的杂草群落组成或功能的变化。收获时在大豆作物田中记录了总共 53 种植物，主要​​是雄性植物（28 种）。确定了三个杂草群落，它们与田地的 ISI 水平有关，也与粮食作物的连续播种年数（即自上次牧场以来的年数）有关。集约化田下杂草群落的特点是物种丰富度低（p 确定了三个杂草群落，它们与田地的 ISI 水平有关，也与粮食作物的连续播种年数（即自上次牧场以来的年数）有关。集约化田下杂草群落的特点是物种丰富度低（p 确定了三个杂草群落，它们与田地的 ISI 水平有关，也与粮食作物的连续播种年数（即自上次牧场以来的年数）有关。集约化田下杂草群落的特点是物种丰富度低（p