Soil organic carbon temperature sensitivity of different soil types and land use systems in the Brazilian semi‐arid region

Abstract

Quantifying the sensitivity of soil organic matter decomposition (SOM) to global warming is critical for predict future impacts of climate change on soil organic carbon stocks (SOC) and soil respiration, especially in semi‐arid regions such as north‐eastern Brazil, where SOC stocks are naturally small. In this study, the responses of the labile and recalcitrant carbon components and soil respiration dynamics were evaluated in three different soil types and land use systems (native vegetation, cropland and pasture) of the Brazilian semi‐arid region, when submitted to temperature increase. After 169 days of incubation, the results showed that an increase of 5°C generated an average increase in CO2 emission of 12.0%, but which could reach 28.1%. Overall, the labile carbon (LC) in areas of native vegetation showed greater sensitivity to temperature than in cropland areas. It was also observed that recalcitrant carbon (RC) was more sensitive to warming than LC. Our results indicate that Brazil's semi‐arid region presents a substantial vulnerability to global warming, and that the sensitivity of RC and of LC in areas of native vegetation to warming can enhance SOC losses, contributing to positive feedback on climate change, and compromising the productive systems of the region. However, further studies evaluating other types of soil and texture and management systems should be carried out to consolidate the results obtained and to improve the understanding about SOM decomposition in the Brazilian semi‐arid region.

Sustainable soil use and management: An interdisciplinary and systematic approach

“…Moreover, different soil types and land use systems are unevenly sensitive to temperature changes. Soil carbon that is normally recalcitrant in semi-arid regions is vulnerable to rising temperature (Maia et al, 2019). Therefore, soil management practice in these areas may have a tremendous effect on carbon cycling.…”

Climate Change Dominated Long‐Term Soil Carbon Losses of Inner Mongolian Grasslands

“…Minor changes in SOC may alter or even tip the carbon balance of grassland ecosystems (Davidson & Janssens, 2006; Trumbore & Czimczik, 2008). Additionally, the spatiotemporal changes of SOC, as well as the underlying mechanisms and feedbacks to climate, are jointly affected by the changing climate (Maia et al, 2019; Schimel et al, 1994; Scurlock & Hall, 1998) and human activities (Chen et al, 2018; Derner et al, 2018; Larreguy et al, 2014; McSherry & Ritchie, 2013)—a research frontier in global climate change (Booker et al, 2013). Accurate estimation of SOC in grassland soils thus far is mostly based on modeling and experimental approaches that carry extremely high uncertainties at regional scale and over long‐term periods (Groisman et al, 2018).…”

Losses and gains of soil organic carbon in grasslands in the Brazilian semi-arid region

“…Several physico-chemical processes provide high stability to SOC stored at deeper layers, which prevents its mineralization by microorganisms (Jobbágy and Jackson, 2000;Schmidt et al, 2011). However, the effects of environmental changes on SOC dynamics at depth have been little studied, since most research on SOC concentrates on the 0-50 cm layer of soil (Ogle et al, 2004;Numata et al, 2007;Corrêa et al, 2009;Maia et al, 2009;Giongo et al, 2011;Sousa et al, 2012;Oliveira et al, 2015;Maia et al, 2019).…”