Biotic and Abiotic Drivers of Topsoil Organic Carbon Concentration in Drylands Have Similar Effects at Regional and Global Scales

Drylands contain 25% of the world’s soil organic carbon (SOC), which is controlled by many factors, both abiotic and biotic. Thus, understanding how these factors control SOC concentration can help to design more sustainable land-use practices in drylands aiming to foster and preserve SOC storage, something particularly important to fight ongoing global warming. We use two independent, largescale databases with contrasting geographic coverage (236 sites in global drylands and 185 sites in Patagonia, Argentina) to evaluate the relative importance of abiotic (precipitation, temperature and soil texture) and biotic (primary productivity) factors as drivers of SOC concentration in drylands at global and regional scales. We found that biotic and abiotic factors had similar effects on SOC concentration across regional and global scales: Maximum temperature and sand content had negative effects, while precipitation and plant productivity exerted positive effects. Our findings provide empirical evidence that increases in temperature and reductions in rainfall, as forecasted by climatic models in many drylands worldwide, promote declines in SOC both directly and indirectly via the reduction in plant productivity. This has important implications for the conservation of drylands under climate change; land management should seek to enhance plant productivity as a tool to offset the negative impact of climate change on SOC storage and on associated ecosystem services.

Estación Experimental Agropecuaria Bariloche

Fil: Gaitan, Juan Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; Argentina. Universidad Nacional de Luján. Departamento de Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Maestre, Fernando T. Universidad Rey Juan Carlos. Escuela Superior de Ciencias Experimentales y Tecnología. Departamento de Biología y Geología, Física y Química Inorgánica; España

Fil: Bran, Donaldo Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; Argentina

Fil: Buono, Gustavo Gabriel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Chubut; Argentina

Fil: Dougill, Andrew J. University of Leeds. School of Earth and Environment; Reino Unido

Fil: Garcia Martinez, Guillermo Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Esquel; Argentina

Fil: Ferrante, Daniela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina

Fil: Guuroh, Reginald Tang. CSIR-Forestry Research Institute of Ghana; Ghana

Fil: Linstadter, Anja. University of Cologne. Botanical Institute; Alemania

Fil: Massara Paletto, Virginia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Chubut; Argentina

Fil: Thomas, Andrew David. Aberystwyth University. Department of Geography and Earth Sciences; Reino Unido

Fil: Oliva, Gabriel Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina