Interactive effects of rising temperature and lowering moisture on soil water chemistry: An experimental growth-chamber approach

Abstract

Climate change and its consequences has become a topical issue in recent years. In this context, while it is recognized the importance of soil-mediated responses to global climate change, the nature and magnitude of these responses are not well understood. Below-ground processes play a key role in the global carbon (C) cycle because they regulate storage of large quantities of C (Pendall et al., 2004; Ryan and Law, 2005). Soil organic matter is the second biggest carbon pool in the planet after the oceans, and below-ground processes regulate fluxes to the atmosphere that are approximately 10 times the current anthropogenic CO2 loading rate (Chapin et al., 2002). Soil processes include C allocation below-ground via roots; microbial and mycorrhizal processes; SOM pool sizes and turnover rates; and soil microbial and rhizosphere respiration rates (Pendall et al., 2008). All have distinct responses to environmental change drivers, although availability of C substrates will regulate all the responses (Pendall et al., 2004). Increasing evidence has shown that climate change components (e.g., elevated CO2, O3 and reactive N inputs) can significantly alter rhizosphere processes through modifying root and microbial growth and below-ground allocation of carbon (Paterson et al. 1997; Zhang et al. 2005). The resulting changes in rhizosphere physiochemical environments may affect the displacement, and/or bioavailability of nutrients. The magnitude, trend and long-term implications of climate change effects on soil cations are not well documented and neither the underlying mechanisms. We examined during a year period the dynamics of soil cations and anions of intact soil cores after experimental warming and decreased precipitation using growth chamber facilities.