Intercropping, i.e., growing several species in the same field for a major part of their growing periods, often improves yield and weed control, but their performance greatly varies across situations. The aim of this study was to evaluate the effects of bi-species legume–cereal intercrops on weed dynamics and their impact on crop production, in the absence of nitrogen or water stress, via simulations with FS. This individual-based 3D model simulates daily crop–weed seed and plant dynamics over the years, from cropping system and pedoclimate, focusing on competition for light. The study tested seven species proportions in two species mixtures (wheat–faba bean and barley–pea) and nine spatial sowing patterns in three species mixtures (triticale–faba bean, wheat–faba bean, wheat–pea), in both cases comparing the intercrops with the corresponding sole crops (controls). Intercrops and controls were inserted into rotations and simulated over 30 years and repeated with 10 climate scenarios from South-Western France, either with or without weeds. The simulations showed that: (1) the intercrops that best controlled weeds were barley–pea and triticale–faba bean, (2) the spatial pattern alternating one cereal row with one legume row as well as the 67 %-cereal–33 %-legume and 100 %-cereal–50 %-legume species proportions were those that maximised yields and minimised losses due to weeds, (3) the weed biomass in intercrop was greater than or equal to that of the sole cereal, and less than that of the sole legume, and (4) legumes benefitted more from intercropping than cereals because cereals are more competitive against weeds. Intercrop yield was best when combining species with contrasting shading responses (etiolated with stockier plants, leafy with stemmier plants) but early and good plant emergence was essential, particularly for weed suppression.

中文翻译：

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豆类-谷物间作农业生态杂草管理的最佳物种比例、性状和播种方式


间作，即在同一田地中种植多个物种的大部分生长期，通常可以提高产量和杂草控制，但其表现因情况而异。本研究的目的是通过 FS 模拟，在没有氮或水胁迫的情况下，评估双种豆类-谷物间作对杂草动态的影响及其对作物生产的影响。这种基于个体的 3D 模型从种植系统和土壤气候方面模拟了多年来的日常作物-杂草种子和植物动态，重点关注光的竞争。该研究测试了两种物种混合物（小麦-蚕豆和大麦-豌豆）中的七种物种比例以及三种物种混合物（小黑麦-蚕豆、小麦-蚕豆、小麦-豌豆）中的九种空间播种模式，在这两种情况下都比较了与相应的单一作物间作（对照）。间作作物和对照被插入轮作中，并模拟了 30 多年，并在法国西南部的 10 种气候情景中重复，无论有或没有杂草。模拟结果表明：(1) 控制杂草效果最好的间作作物是大麦-豌豆和小黑麦-蚕豆，(2) 一排谷物与一排豆类交替的空间格局以及 67%-谷物-33%-豆科植物和 100%-谷物-50%-豆科植物的物种比例是使产量最大化和杂草损失最小化的比例，(3) 间作作物中的杂草生物量大于或等于单一谷物的生物量，并且小于单一谷物的生物量。 (4) 豆类比谷物更能从间作中获益，因为谷物对杂草更具竞争力。 当将具有对比遮荫反应的物种（较矮壮的植物黄化，较茎的植物多叶）组合时，间作作物产量最高，但早期和良好的植物出苗至关重要，特别是对于杂草抑制而言。