The biochemical drivers of phosphorus (P) availability and cycling are sensitive to changes in soil pH. However, reports of lime-induced pH modification effects on P availability are (1) inconsistent, (2) focused mainly on chemical changes, and (3) often limited to the bulk soil. Using lupin as an indicator species, we aimed to evaluate the effects of lime-induced soil pH change, from 5.3 to 6.0, on biochemical processes responsible for P mobilization and dynamics in the rhizosphere of two different lupin species. Indicator species, blue lupin (Lupinus angustifolius) and Russell lupin (Lupinus polyphyllus), were grown in a P-deficient acid grassland soil without P inputs for 11 weeks in a glasshouse. The rhizosphere soils were analyzed for enzyme activity, microbial P, and carboxylates. Both bulk and rhizosphere soils were analyzed for P fractions, exchangeable aluminum (Al), and pH. Plant yields and shoot P uptake were measured. Labile inorganic P (P_i) increased in the rhizospheres of both lupin species, likely due to P_i desorption combined with labile organic P (P_o) mineralization, induced by rhizosphere pH elevation after liming. Soil pH increase promoted microbial P immobilization and reduced phosphomonoesterase activity in the rhizosphere, leading to an accumulation of P_o mainly as moderately labile and stable P_o forms. Total carboxylate concentration (TCC) increased with soil pH increase. Variation in shoot P uptake was mostly explained by TCC. These results indicate that (1) lime application strongly affects P biochemical processes and dynamics in the rhizosphere of lupins. (2) Russell lupin utilizes less P than blue lupin and is unresponsive to liming.

磷（P）的有效性和循环的生化驱动因素对土壤pH值的变化很敏感。但是，关于石灰引起的pH调节对磷有效性的影响的报道（1）不一致，（2）主要集中在化学变化上，（3）通常限于整块土壤。我们以羽扇豆为指示物种，旨在评估石灰诱导的土壤pH值从5.3到6.0的变化对负责两种不同羽扇豆物种的磷动员和根际动态的生化过程的影响。指示种，蓝色羽扇豆（羽扇豆）和罗素羽扇豆（羽扇豆））在没有磷输入的磷缺乏的酸性草原土壤中于温室中生长11周。分析了根际土壤的酶活性，微生物P和羧酸盐。分析了块状土壤和根际土壤的P含量，可交换铝（Al）和pH。测量了植物的产量和芽磷的吸收。两种羽扇豆物种的根际中不稳定的无机P（P _i）均增加，这可能是由于石灰在石灰形成后根际pH升高引起的P _i解吸和不稳定的有机P（P _o）矿化。土壤pH的升高促进了根际微生物固定化P，降低了根际的磷酸单酯酶活性，导致了P _o的积累，主要是中度不稳定和稳定的P _o。形式。随着土壤pH值的增加，总羧酸盐浓度（TCC）也增加。TCC可以解释芽P摄取量的变化。这些结果表明（1）施用石灰强烈影响羽扇豆根际中磷的生化过程和动力学。（2）罗素羽扇豆的磷含量低于蓝羽扇豆，对石灰无反应。