Quantifying surface soil organic carbon distribution globally during the COVID-19 pandemic using satellite data

Abstract

Soil organic carbon (SOC) is an important soil parameter of agricultural soils, ensuring food security and agricultural sustainability. It plays a critical role in the global carbon budget and carbon sequestration. Spatial mapping of SOC can help develop sustainable management approaches to enhance soil carbon sequestration and mitigate greenhouse gas emissions and adverse environmental effects. However, quantifying Spatio-temporal distributions of SOC at the global level is complex because of high land heterogeneity and several climatic and hydrologic influential parameters. The main goal of this study was to quantify the annual global SOC change focusing on cropland using daily soil moisture active passive (SMAP) satellite SOC data. The specific objectives of this study were to assess annual SOC change globally, quantify the annual SOC distribution before and during the COVID-19 pandemic, and evaluate change in SOC on cropland during the study period. Results showed an increase of annual SOC on cropland in several countries in 2020 compared to 2019, which can be attributed to the direct and indirect impact of partial and complete lockdowns due to the COVID-19 pandemic. The change in SOC between 2015 and 2019 was considerably different from the SOC change between 2019 and 2020. For example, between 2019 and 2015, 45.6% of the global area showed a decrease in SOC 0 to 25 g C m−2 and 30.4% area showed an increase in SOC 0 to 25 g C m−2. However, between 2020 and 2019, 11.4% of the global area showed a decrease in SOC 0 to 25 g C m−2, and 55.4% area showed an increase in SOC 0 to 25 g C m−2. There is a good relationship between lockdown measures and improvement in SOC, as 48 out of 50 highly infected countries showed increased SOC in 2020 than in 2019. This study suggests better land use management practices can help enhance carbon sequestration and improve soil health.