Agricultural management determines the size of the terrestrial carbon sink

Abstract

Agricultural management can significantly impact biogeochemical cycles. In this study, we estimate the effect of various agricultural management practices such as grazing management, manure application, residue management, tillage, and cover crops on land use change emissions using the LPJmL dynamic vegetation model. We follow the TRENDY protocol to perform model simulations and estimate land use change emissions. Our results show that these practices mitigate a large proportion of emissions from land conversion (such as deforestation) and thus substantially determine the size of the current terrestrial carbon sink. We argue that there is substantial potential to further enhance carbon sequestration by optimizing agricultural management practices. We demonstrate that changes in agricultural management practices typically have smaller effects on albedo, surface roughness, and evapotranspiration compared to dedicated CO2 removal techniques that entail land cover changes (such as afforestation). However, due to limited global data on agricultural management practices, the actual contribution of these practices to emissions and their potential to reduce emissions remain highly uncertain. Our study highlights the need for more research in this area and the importance of considering agricultural management practices in dynamic vegetation models to estimate land use change emissions accurately.