Legume crops exhibited high P-acquisition capacity under low soil phosphorus conditions

Phosphorus (P) acquisition in plants involves a range of strategies, with differences between legume and non-legume crop species. We studied 11 legume and 11 non-legume crop species under two P levels for P acquisition strategies related to root morphological and physiological traits and their roles in biomass accumulation and P content. We hypothesise that the legume crops species used a P-mining strategy related to carboxylates and non-legume crop species used a P-scavenging strategy related to root morphological trait, contributing to differences in P-acquisition strategies between legume and non-legume crop species. Legume crop species demonstrated higher P concentrations and greater biomass than non-legume under both P conditions. Legume crop species relied on root morphological traits and carboxylate release, while non-legume crop species relied on arbuscular mycorrhizal (AM) colonisation and acid phosphatase activity. Legume crop species exhibited a lower response ratio for AM colonisation and acid phosphatase activity but a higher response ratio for rhizosheath carboxylate release than non-legume crop species. Legume crop species utilised a P-scavenging strategy, characterised by enhanced root length and a P-mining strategy through carboxylate release; legume crop species exhibited greater plasticity in carboxylate release but lower plasticity in AM colonisation and acid phosphatase activity than non-legume crop species did, indicating a trade-off between different P-acquisition strategies. These results provide insights into the P-acquisition strategies of crop species adapted to low soil P conditions, offering valuable ecological insights for sustainable intercropping systems and strategies to enhance P-use efficiency in low-input agricultural system.