Assessment of soil carbon stocks in integrated agricultural systems in Brazil: a geoinformatics approach

Abstract

Soils and plants are indispensable components of the terrestrial ecosystem that have important contributions in the fluxes of Greenhouse Gases (GHG) and mitigation of climate change. A large percentage of atmospheric CO2 are captured and stored in soils and plants. But in the recent decades larger amount of CO2 is released daily into the atmosphere due to rise in population and increase in anthropogenic activities. Presently, government and experts in different fields are seeking for sustainable measures. Having realized the important of Integrated Agricultural Systems (IASs), the Brazilian government pledged to fight the challenges of low soil carbon stocks by incorporating IASs in the Nationally Determined Contributions (NDCs) contained in the Paris Agreement. Integrated agricultural systems have become the promising and sustainable measures to enhance soil carbon pools. The IASs improve land productivity by combining annual crops, forage crops, livestock and agroforestry practices in the same area under different management. In addition to serving as a sustainable-based formula for improving carbon sequestration, IASs will become a panacea to hunger and climate change because more food will be produced as soil quality is restored and more GHG especially CO2 will be sunk by plants and soil. To achieve accurate estimation of soil carbon stocks, geospatial technologies such as Remote sensing (RS) and GIS are necessary because soil has a high spatial variability. Soil is better understood if analyzed spatially since it is a component that has spatio-temporal attributes inherent from many natural and human drivers including climate, topography, vegetation, and land use. Therefore, for more accuracy and good understanding of the soil carbon stock dynamics vis-à-vis GHG fluxes in the agricultural soils, RS and GIS are needed as effective spatial analytical and mapping tools. On this background, the main aim of this project is to quantify and map the soil carbon stocks of IASs performed in different bioclimatic, edaphic and agricultural management scenarios. Data from the long-term experiments, new experiments, satellite images, aerial photos, and digital maps will be collected, processed and integrated within the GIS environment. Geographically Weighted Regression (GWR), kriging, Inverse Distance Weight (IDW), Markov chain, Land use Change Model (LCM), Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) and other spatial analytic extensions and tools of GIS will be used for spatial analysis, modelling and mapping. Integrating all relevant data using geospatial techniques with the associated models and statistics will provide accurate estimate of the soil carbon stocks in IASs. It will also help in knowing the costs and benefits attached to carbon sequestration for adopting the IASs. This information will support decision makers with a strong scientific knowledge base required for achieving human and environmental sustainability in Brazil specifically, and probably world-wide. (AU)