Complementarity of two distinct phosphorus acquisition strategies in maize-white lupine intercropping system under limited phosphorus availability

Abstract

ABSTRACT Some P-mobilizing plants being non-mycorrhizal, their influence on mycorrhizal symbiosis of co-occurring species is poorly investigated and understood. Hence, the present study examined the effect of white lupine (Lupinus albus L.) on mycorrhizal symbiosis of neighboring maize (Zea mays L.) along with plant growth and rhizosphere P fractions. A pot experiment was conducted with Regosol soil for 42 days. Two P treatments used in the study were 0P (no P addition) and 100P (100 mg P kg−1 soil supplied by NaH2PO4•2H2O). Plant growth, rhizosphere P fractions, P acquisition, and mycorrhizal infection of maize roots were investigated. When maize was grown with white lupine, shoot P concentration and dry weight of maize in 0P were enhanced by 41% and 22%, respectively, compared with that in sole cropping. Application of the high dosage of soluble P (100P) eliminated those complementary effects with a substantial reduction in mycorrhizal infection of maize. Non-mycorrhizal white lupine did not strongly influence the mycorrhizal infection of maize root. Complementarity of two distinct P acquisition strategies (acquisition of mobilized P by root exudates and P uptake through mycorrhizal hyphae) promoted the growth and P uptake of maize plant during the early stage of growth in the intercropping system with P-efficient white lupine. Maize was able to get the additive P benefits from its own mycorrhizal colonization and P-mobilizing strategy of companion white lupine only under P-limited conditions. The results of this experiment could be useful in designing P-efficient cropping systems with compatible crop combinations for P-limited lands.