Measurements and Models to Identify Agroecosystem Practices That Enhance Soil Organic Carbon under Changing Climate

Adapting to the anticipated impacts of climate change is a pressing issue facing agriculture, as precipitation and temperature changes are expected to have major effects on agricultural production in many regions of the world. These changes will also affect soil organic matter decomposition and associated stocks of soil organic C (SOC), which have the potential to feed back to climate change and affect agroecosystem resiliency. This special section brings together multiple efforts to assess effects of climate change on SOC stocks around the globe in grassland, pasture, and crop agroecosystems under varying management practices. The overall goal of these efforts is to identify optimum practices to enhance SOC accumulation. In this article, we summarize the highlights of these papers and assess their broader implications for future research to enhance agroecosystem SOC accumulation and resiliency to climate change. Fourteen of the twenty contributions apply dynamic process‐based models to assess climate and/or long‐term management impacts on SOC stocks, and four papers use statistical SOC models across landscapes or regions. Also included are one meta‐analysis and one long‐term study. The models applied in this collection performed well when reliable input data were available, underlining the usefulness of modeling efforts to inform management decisions that enhance SOC stocks. Overall, the findings confirm that most agroecosystems have the potential to store SOC through improved management. However, this will be challenging, particularly for dryland agriculture, unless crop yield and crop biomass increase under projected climate change. CORE IDEAS: Maintaining crop yields and increasing cropping intensity will be required to sustain SOC. Improving yields and reducing tillage is required to sustain SOC under dryland cropping. CQESTR is an effective tool for simulating SOC dynamics to a depth of 1 m. Grasslands are likely to sequester more SOC than annual cropping systems. Rotational grazing increases SOC vs. continuous grazing in semihumid and humid climates.