Acclimation to phosphorus supply of annual pasture legumes

I examined root acclimation to phosphorus (P) supply by annual pasture legumes in three glasshouse experiments, and factors that could affect field-relevance of results. Six Trifolium subterraneumcultivars had similar acclimation, but intrinsically different average root diameter. Increased rhizosheath carboxylates in microswards with canopy spread constrained, as opposed to unconstrained, likely compensated for decreased root growth and allowed maintenance of shoot P content. External critical
P requirements were higher for T. subterraneum than two Ornithopus species,and differed with contrasting communities
of arbuscule-forming root endophytes. The implications of these findings for the methodology used in future glasshouse experiments are discussed.