Effects of grazing management on spatio-temporal heterogeneity of soil carbon and greenhouse gas emissions of grasslands and rangelands: Monitoring, assessment and scaling-up

Grazing lands provide many goods and ecosystem services, such as forage, livestock, soil carbon (C) storage, biodiversity, and recreational opportunities. Ensuring the long-term sustainability of grazing lands requires optimal management to simultaneously balance livestock productivity for sustaining human food and nutritional demands while reducing environmental impacts, such as greenhouse gases (GHG) emissions and soil degradation. In this paper, we revisit grazing management in grazing lands exposed to different grazing systems. In Section 2, we briefly review parameterization and multi-faceted goals for sustainability of grazing systems considering broader sustainability from economic to environmental aspects. We also discuss the inconsistencies between grazing researchers and ranchers' practices. In Section 3, we review the separate experimental data to examine the impacts of multipaddock rotational grazing on soil carbon, nutrient and GHGs. In Section 4, we present status and upcoming challenges in monitoring and upscaling of grazing ecosystem research and management. In Section 5, new concepts of multiple source monitoring networks are presented that enable the analysis of scale-dependent processes. Finally, we point out future directions for monitoring and assessment of managing soil C and GHG emissions from grazing lands. The results show that the inconsistences are essentially due to (1) effects of spatiotemporal scales on both economic and ecological outcomes, and (2) simplistic representations of multi-faceted grazing systems and sustainability. The development of multi-faceted monitoring systems needs to be further parametrized and standardized to make consistent for meaningful and comparable assessment of grazing management impacts on SOC and GHGs. (C) 2020 Elsevier Ltd. All rights reserved.