title: Dinitrogen-fixing Acacia species from phosphorus-impoverished soils resorb leaf phosphorus efficiently.
abstract: Nitrogen (N) and phosphorus (P) resorption from senescing leaves were studied, and the contribution of N and P cycling through litterfall to soil nutrient patchiness was investigated for four Acacia species in the Great Sandy Desert in north-western Australia. N and P concentrations of mature and recently shed leaves were analysed and compared; soils under the canopies of the shrubs and soils in gaps (open areas) between the shrubs were also analysed and compared for N and P concentrations. Mature leaf P concentrations of the plants were considerably lower than the global average values, and N : P ratios of mature leaves were high. Plants derived 0-75% of their leaf N from symbiotic N(2)-fixation. N-resorption efficiency was between 0 and 43%, and P-resorption efficiency was between 32 and 79%; all plants were more efficient at P resorption than at N resorption, and litter N : P ratios were significantly higher than mature leaf N : P ratios. Soils of the study sites were P-impoverished. Total soil N and P concentrations were higher under the canopy than in gaps, but bicarbonate-extractable P concentration was higher in gaps. Nutrient cycling through litterfall results in soil nutrient patchiness and forms 'islands of fertility' under the canopies of the shrubs.
authors.affiliation: School of Plant Biology, The University of Western Australia, Crawley, WA 6009, Australia. heh01@student.uwa.edu.au
authors.forename: Honghua
authors.initials: H
authors.lastname: He
authors.forename: Tim M
authors.initials: TM
authors.lastname: Bleby
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Veneklaas
authors.forename: Hans
authors.initials: H
authors.lastname: Lambers
mesh_terms: D000045:Acacia / Q000378:metabolism* / Q000502:physiology; D017753:Ecosystem; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation; D010758:Phosphorus / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D014904:Western Australia
chemical_list: D012987:Soil; D010758:Phosphorus; D009584:Nitrogen