Correction of leaf nutrient resorption efficiency on the mass basis

Abstract

Nutrient resorption is a crucial mechanism for plant nutrient conservation, but most previous studies didn’t consider the leaf-mass loss during senescence for lack of measured data, leading to an underestimation of nutrient resorption efficiency (NuRE), or had to calculate NuRE of various species based on the average mass loss at plant-functional-group level in the literature, which affected its accuracy. We here measured the leaf-mass loss to correct NuRE with the species-specific mass loss correction factor (MLCF), so as to foster a more accurate calculation of the nutrient fluxes within and between plants and the soil. Green leaves and senesced leaves were collected from 35 dominant woody plants in northern China. Mass of green and senesced leaves were measured to calculate the MLCF at species level. The MLCF was reported for each of the 35 dominant woody plants in northern China. These species averagely lost 17% of the green-leaf mass during leaf senescence, but varied greatly from 1.3%~36.8% mass loss across the 35 species, or 11.7%~19.6% loss across the functional types. Accordingly, the MLCF varied from 0.632~0.987 across the 35 species with an average value 0.832. The NuRE corrected with MLCF was remarkably increased on the whole (e.g., both the average nitrogen and phosphorus NuRE became about 9% higher, or more accurate), compared with the uncorrected ones, especially in the case of low resorption efficiencies. Our field data provides reliable references for the MLCF of plants in related regions at both species and functional-type levels, and is expected to promote more accurate calculations of NuRE.