Resprouting ability differs among plant functional groups along a soil acidification gradient in a meadow: A rhizosphere perspective

Abstract

Soil acidification as a global change factor can devastatingly affect plant growth and productivity. In frequently disturbed ecosystems, plant resprouting ability strongly determines biomass reconstruction and resilience after above-ground damage. However, how plant regrowth responds to soil acidification remains largely unknown for, especially regarding the role of rhizosphere in mediating this response. We manipulated a soil-acidification gradient via adding purified elemental sulphur powder at various rates (0–50 g S m−2 year−1) in a frequently mown meadow. Shoot regrowth of functional groups were measured after clipping and supporting roles of rhizosphere versus bulk soils were disentangled using isotope labelling along the acidification gradient. Regrowth of grasses and sedges increased while forbs decreased along the acidification gradient. The results suggest that grasses were competitors capable of taking up nutrients from both rhizosphere and bulk soils, while sedges were acid-tolerators with lower sensitivity to decreased nitrogen-mineralization rates. Forbs, as typical ruderals, were vulnerable to N competition with microbes, particularly in the rhizosphere soil. Therefore, biomass regrowth of forbs was explained more by physicochemical and biological parameters from the rhizosphere than bulk soil. Synthesis. Divergent interplay between plant functional groups and rhizosphere soils was the prominent driver for biomass regrowth responding to soil acidification.