Background and aims Calcium uptake by plants and the ratio of calcium to phosphorus (Ca/P) in the uptake have been recently identified as important drivers of P acquisition in neutral to alkaline soils. However, this has rarely been studied under field conditions and no data are available for the effects of intercropping. Methods Durum wheat and faba beans were cultivated, both as sole crops and as intercrops, in a P-deficient, calcareous soil over three consecutive growing seasons. We measured a range of plant, soil, and rhizosphere properties at the flowering stage and grain yield at harvest. Results Root dry weight, N fixation, rhizosphere acidification, the ratio of Ca/P in the uptake, and available P in the soil were all higher for faba beans intercropped with durum wheat. However, its growth was limited by other factors, probably including water availability. However, durum wheat growth and nutrient acquisition were markedly facilitated by intercropping with faba beans. The facilitation of P acquisition by durum wheat was caused by the acidification of its rhizosphere, the subsequently higher solubility of Ca-P minerals, and the lack of competition by faba beans for P. Conclusions The results confirm the importance of Ca uptake and the ratio of Ca/P in the uptake for P acquisition by plants in calcareous soils and, more specifically, for a cereal intercropped with faba beans.

中文翻译：

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间作对钙质土壤田间磷吸收过程的影响

背景和目的 植物对钙的吸收以及吸收中的钙磷比 (Ca/P) 最近已被确定为中性至碱性土壤中磷获取的重要驱动因素。然而，这很少在田间条件下进行研究，也没有关于间作影响的数据。方法 在缺磷、钙质土壤中连续三个生长季节种植硬粒小麦和蚕豆，作为唯一作物和间作作物。我们测量了开花期的一系列植物、土壤和根际特性以及收获时的谷物产量。结果蚕豆与硬粒小麦间作的根干重、固氮、根际酸化、吸收钙磷比和土壤有效磷均较高。然而，它的增长受到其他因素的限制，可能包括水的可用性。然而，与蚕豆间作显着促进了硬粒小麦的生长和养分获取。硬粒小麦促进 P 吸收是由于其根际酸化、Ca-P 矿物质随后更高的溶解度以及蚕豆对​​ P 缺乏竞争。 结论 结果证实了 Ca 吸收和比例的重要性Ca/P 在钙质土壤中植物获取磷的吸收中的含量，更具体地说，对于与蚕豆间作的谷物。