Estimation of the Carbon Sequestration Potential of Conservation Tillage Systems in Soils of Nayarit, Mexico

Abstract

Greenhouse gas emissions have unequivocally caused global warming and climate change, as documented in recent decades. The implementation of conservation tillage (CT) practices has been promoted to reduce soil degradation and as a climate change mitigation strategy through soil recarbonization. The objective of this study was to estimate the potential for soil organic carbon (SOC) sequestration under CT with 35% soil cover (2 Mg crop residues ha–¹) or 100% soil cover (4.66 or 5.64 Mg crop residues ha–¹), compared with traditional tillage (TT). In the state of Nayarit, Mexico, three study sites managed under a mixed crop–livestock system were located in soil units most suitable for agricultural production (Fluvisol, Luvisol, and Cambisol). The RothC-26.3 model was used to simulate SOC dynamics over a twenty-year period. The c factor of this model was determined through multitemporal analysis of satellite images from the Landsat platform. The results showed that, at the three sites/soils, TT would lead to an average SOC loss rate ranging from 0.119 to 0.341 Mg ha–¹ year–¹, whereas under CT, the model predicted average SOC accumulation rates ranging from 0.084 to 0.650 Mg ha–¹ year–¹, except in the Fluvisol under CT with 35% cover, where simulations indicated an average SOC loss of 0.129 Mg ha–¹ year–¹. The study concluded that SOC sequestration depended mainly on clay content and the amount of residues used as soil cover, particularly in Fluvisols, where residue cover must exceed 35% (> 2 Mg crop residues ha–¹ year–¹) to achieve positive SOC sequestration rates.