By 2050, elevated atmospheric CO₂ (eCO₂) could stimulate plant growth, but dwindling phosphorus (P) stocks in the soil could limit growth. However, little is known about how eCO₂ could affect soil P availability and dynamics in P-poor soils. Here, we conducted a 6-week pot experiment where three plant species were grown in a low-P soil under ambient (390 ppm) and eCO₂ (700 ppm) to investigate plant growth, rhizosphere properties, and changes in soil P fractions. Our results showed that under P deficiency, plant biomass, P uptake, and rhizosphere properties did not respond to eCO₂. Changes were noted by plant species. Compared to the control soil (unplanted pots), rhizosphere pH decreased the most under wheat, while microbial biomass P was higher under blue lupin. Among plant species, the blue lupin rhizosphere exhibited higher acid and alkaline phosphatase activity as well as organic anion release. Soil P fractions were impacted by plant species but similar across CO₂ treatments. Blue lupin accumulated labile organic P while depleted moderately labile organic P. Accumulation of labile organic P could be ascribed to microbial P immobilisation, whereas the mineralization of moderately labile organic P was associated with higher phosphatase activity. Wheat depleted acid extractable inorganic P the most, probably due to soil acidification and higher root biomass. These results suggest that plants can mobilise different P fractions irrespective of their chemical availability using morphological and/or physiological adaptations. However, these adaptations to acquire P from a low-P soil were not affected by eCO₂. This implies that current P fertiliser recommendations to boost or maintain crop production in low-P soils would remain unchanged under future eCO₂.

到2050年，升高的大气CO ₂（eCO ₂）可以刺激植物的生长，但是土壤中磷（P）的减少可能会限制植物的生长。然而，关于eCO ₂如何影响土壤贫磷的土壤中磷的有效利用和动态的知之甚少。在这里，我们进行了为期6周的盆栽实验，在低磷土壤中，在环境（390 ppm）和eCO ₂（700 ppm）的条件下，种植了三种植物，以研究植物的生长，根际特性和土壤P组分的变化。我们的结果表明，在磷缺乏的情况下，植物生物量，磷的吸收和根际特性对eCO ₂没有反应。植物种类表明变化。与对照土壤（未栽植的盆栽）相比，在小麦下，根际pH下降最多，而在蓝色羽扇豆下，微生物量P较高。在植物物种中，蓝色羽扇豆根际层显示出较高的酸和碱性磷酸酶活性以及有机阴离子的释放。土壤P分数受植物物种影响，但在CO _2中相似治疗。蓝羽扇豆积累了不稳定的有机磷，而消耗了中等程度的不稳定的有机磷。不稳定的有机磷的积累可归因于微生物磷的固定化，而中等不稳定的有机磷的矿化与较高的磷酸酶活性有关。小麦消耗的酸可提取的无机P最多，这可能是由于土壤酸化和较高的根系生物量所致。这些结果表明，植物可以利用形态和/或生理学适应性动员不同的P组分，而不论其化学有效性如何。但是，这些从低磷土壤中获取磷的适应措施不受eCO _2的影响。这意味着在未来的eCO ₂下，当前用于促进或维持低磷土壤中作物产量的磷肥建议将保持不变。。