Competition for resources between crops and weeds hinders the increase of production in agroecosystems. The trait-based plant species selection of cover crops can be a useful tool to suppress competing plants in addition to providing environmental services. Here, we assessed the growth and macronutrient accumulation metrics in Diodia saponariifolia (Rubiaceae) plants, a native cover crop found in family farming systems in southeastern Brazil. Under greenhouse conditions, three viable D. saponariifolia cuttings were planted per tray. The experimental design was entirely randomized, with treatments consisting of plant sampling times, at regular intervals of 7 days between 16 and 93 days after transplanting (DAT) and 15 days between 93 and 138 DAT. Based on dry mass and chemical analysis of leaves, stems, and roots; we fitted the logistic model to explore the metrics of growth and macronutrient accumulation. Overall, the increment in plant dry mass was slow about halfway through the experimental period, being subsequently replaced by a phase of rapid growth. The stem was the plant fraction with the highest relative biomass accumulation. The total macronutrient concentration followed the descending order of K > N > Ca > Mg > P, varying along the plant ontogeny. Considering the nutrient content, the estimated 200 g m⁻² of aboveground dry mass, and 0.3 m² of leaf area, it is suggested to perform the first mechanical weeding along the third month of growth. Our results suggest that D. saponariifolia has satisfactory agronomical features for its establishment as a cover crop in different agricultural contexts.

中文翻译：

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巴西东南部作为潜在原生覆盖作物的皂角植物的生长和养分积累指标

作物和杂草之间对资源的竞争阻碍了农业生态系统产量的增加。除了提供环境服务外，覆盖作物的基于性状的植物物种选择可以成为抑制竞争植物的有用工具。在这里，我们评估了皂角（茜草科）植物的生长和常量营养素积累指标，这是一种在巴西东南部的家庭农业系统中发现的原生覆盖作物。在温室条件下，三种有活力的皂角每个托盘种植插条。实验设计完全随机化，处理包括植物采样时间，移植后 16 至 93 天 (DAT) 间隔 7 天，93 至 138 DAT 间隔 15 天。基于叶、茎和根的干质量和化学分析；我们拟合了逻辑模型来探索生长和常量营养素积累的指标。总体而言，植物干重的增加在实验期的一半左右是缓慢的，随后被快速生长阶段所取代。茎是具有最高相对生物量积累的植物部分。总常量营养素浓度按照K > N > Ca > Mg > P的降序排列，随植物个体发育而变化。考虑到营养成分，地上部干重，叶面积0.3 m ²，建议在生长的第三个月进行第一次机械除草。我们的研究结果表明D. saponariifolia具有令人满意的农艺特征，可以在不同的农业环境中作为覆盖作物。