Above- and below-ground biomass and its allometry of Salsola passerina
shrub in Alxa steppe desert in NW China
Abstract
Knowledge of the biomass allometry and partitioning is essential for
understanding shrub adaptive strategies to extreme arid environments as
well as for estimating organic carbon storage. We studied biomass
accumulation, allocation patterns, and allometric models of Salsola
passerina shrub in Alxa desert steppe, northwestern (NW) China. We
measured above- and below-ground biomass accumulation across different
ages (0-50 years) by destructive sampling. The biomass allocation
patterns between aboveground biomass (MA), leaves (ML), branches (MB)
and roots (MR) were studied by fitting allometric functions for both
pooled and age-classed data. Allometric biomass models were developed by
regressing on single-input variable of basal diameter (D), crown area
(C), height (H), and age (A) alone or on the pairwise variables of above
four parameters. Biomass accumulation increased with age, aboveground
components represented 86–89% of the total biomass, root to shoot
biomass ratios increased with shrub age. Allometry patterns of S.
passerina is relatively constant, the growth rate of root was faster
than that of aboveground components. Allometric models with two-input
variables were obviously better than single variable models. C and D
were the best predictors for biomass of S. passerina shrub.