Temperate grasslands are affected by nutrient deficiency and this deficiency is one of the main limiting factors for forage production, such as the grasslands of the Salado River Basin (Argentina), which exhibit low-P availability for plant growth. Alternatives to increase forage production include the selection of plant species adapted to grow under P deficiency, P fertilization, and arbuscular mycorrhizal (AM) fungi. In a pot experiment, we investigated the effect of low and high-P doses and AM fungi on the development of three forage species. The interaction of P addition and AM fungi increased L. tenuis (legume) biomass production and improve P nutrition, even with high-P dose, because of its higher P requirement to grow and lower ability for P uptake than grasses. High-P increased the biomass of S. arundinaceus (C3 grass) and P. coloratum (C4 grass), and AM fungi did not directly impact on plant growth of grasses, but did impact on P nutrition at either level of P fertilization. The specific P uptake of non-fertilized L. tenuis plants increased 97% due to AM inoculation and was the highest value among the three non-fertilized species. Furthermore, the specific P uptake of non-fertilized grasses was similar, despite the C metabolic pathway and AM fungi, but the specific root length was 70.88% lower for P. coloratum than for S. arundinaceus. Thus, the main strategy of L. tenuis was AM association, whereas that of S. arundinaceus was the highest ability of the root system to explore the soil. In P. coloratum, the strategy could not be explained by changes in specific root length or AM association. Our results would be an advantageous first step to promote better management of forage land sustainably while increasing forage production and preserve the beneficial effects of native AM communities in the Salado River Basin.

温带草原受到养分缺乏的影响，这种缺乏是牧草生产的主要限制因素之一，例如萨拉多河流域（阿根廷）的草原，其植物生长的磷素含量低。增加牧草产量的替代方法包括选择适合在缺磷，磷肥和丛枝菌根（AM）真菌下生长的植物。在盆栽实验中，我们研究了低磷和高磷剂量以及AM真菌对三种牧草物种发育的影响。磷的添加与AM真菌的相互作用增加了豆类L. tenuis（豆类）生物量的产生，并改善了P的营养，即使使用高磷剂量也是如此，这是因为与草相比，磷对植物的生长具有更高的磷需求，对磷的吸收能力也较低。高磷增加了S. arundinaceus（C3禾本科）和P. coloratum（C4禾本科），以及AM真菌不会直接影响草的植物生长，但是会在P施肥的任何一个水平上都影响P营养。由于AM接种，未受精的L. tenuis植物的特定P吸收增加了97％，在三个未受精的物种中是最高的。此外，未受精的草类的特定磷吸收相似，尽管与c代谢途径和AM真菌，但具体的根长度是70.88％下为P. coloratum比S.茅。因此，L。tenuis的主要策略是AM关联，而S. arundinaceus是根系探索土壤的最高能力。在P. coloratum中，无法通过特定根长或AM关联的变化来解释该策略。我们的结果将是有利的第一步，以促进可持续地更好地管理牧草土地，同时增加牧草产量，并保留萨拉多河流域原生AM群落的有益影响。