Decreased soil total phosphorus following artificial plantation in the Loess Plateau of China

Abstract

Artificial plantation, established on non-forest lands in recent decades in China’s Loess Plateau, play an important role in enhancing ecological restoration. However, soil phosphorus (P) dynamics following artificial plantation still remain unclear, especially at the regional scale. We aim to determine how do soil total P (TP) and available P (AP) change and how do drivers affect the dynamics of soil P following artificial plantation. Here we examined the effects of climate (precipitation and temperature), prior land use cover (cropland and barren land), current land use cover (forest, grassland, and shrubland), soil properties (soil organic carbon, bulk density, and pH), tree species, and plantation age on changes in soil TP and AP in top 100 cm following artificial plantation. Our examination was conducted based on a meta-analysis of 740 independent observations from 67 articles. The results showed that, across all the variations, TP concentrations significantly decreased by 17.5% in the top 100 cm soil layer following artificial plantation, with no significant change in AP. Concentration of TP in the 100 cm soil depth had a similar spatial pattern, characterized by a higher depletion in northwest area but lower depletion in southeast area. Climate, prior land use, tree species, and soil properties all played an important role on TP, while only tree species influenced AP response to artificial plantation. Our findings suggest that artificial plantation did not appear to directly induce P limitation because of the nearly unaltered AP in the regional scale. However, compared with lower TP depletion in southeast area, substantial declines in TP in northwest area may drive such region toward greater P limitation with the decrease of AP replenishment capacity in the future.