Soil carbon in Norwegian outfield and infield grazing areas: Plant-soil-herbivory feedbacks on plant production and soil carbon dynamics

The main objective of this project is to quantify and predict grazing effects on soil organic carbon stocks and dynamics. Our goal is to come up with management recommendations that ensure nature-based solutions for reducing greenhouse gas emissions, mitigating climate change while promoting biodiversity. We aim to achieve this by studying the seasonal summer grazing by domestic animals both in outfield and infield areas, as well as whole year grazing by wild large herbivores in forest areas. We will build on existing and recently ended long-term experiments, where the effects of grazing sheep, cattle and wild ruminants have been studied. For outfield and forest grazing areas we will compare with existing fenced areas where grazing animals are excluded. For infield grazing areas, we will join forces with an ongoing project studying methane emissions from grazing dairy and beef cattle. The project will be organized in four work packages: Work package 1 and 2 will provide a comprehensive dataset on plant-soil properties. These data will enable us to test which plants herbivores impact and how herbivory changes plant biomass and chemical composition and how their input may drive changes in soil carbon and microbial communities. Furthermore, we will be able to compare domestic and wild herbivores and thereby synthesize the impacts of these two important herbivores. Our ambition is that our research will inform stakeholders on grazing practices optimal for soil carbon management in Norway’s outfield and infield areas. Through the empirical data collected in WP1 and WP2, we will provide input to both farm level carbon/climate models (WP3) and landscape scale grazing maps that also considers belowground carbon stocks (WP3). We also aim to provide advice on grazing practices for stakeholders, where all ecosystem services are considered. (WP4).

Two of the major environmental challenges facing humanity are mitigating climate change and reversing biodiversity decline. Measures intended to mitigate climate change may, however, not be measures that mitigate biodiversity loss. In this project we will focus on grazing aiming at quantifying and predicting grazing effects on soil organic carbon stocks and dynamics. Our aim is to establish efficient ways of preserving high SOC stocks, while also maintaining and promoting plant and soil microbial biodiversity. To achieve this, the project will build on long-term studies, ongoing and recently ended, where the effects of excluding grazing of sheep, cattle and wild ruminates in outfields and forest have been studied. Here we will use existing infrastructure in the form of long-time grazing exclosures, taking soil and vegetation samples inside and outside of these. We will also investigate the effect of dairy cows grazing in infield areas. In this way we will cover a broad set of ecosystems and grazing strategies, from low-land infields, forest, heathland, and alpine areas. We aim at advancing the state-of-the-art in our analysis of the plant-soil-herbivore interaction. The project will be organized in four work packages, WP1: Grazing effects on above and belowground biomass production, plant chemical composition and plant biodiversity. WP2: Grazing effects on soil carbon and dynamics. WP3: Soil carbon modelling and upscaling and WP 4: Ecosystem services framework; optimizing grazing and large herbivore management. Our results will also be integrated in an ecosystem services framework to synthesize data on how grazing impact a broad range of ecosystem services. The synthesis will be used as a basis for stakeholder discussions on the overall optimalisation of ecosystem services in outfield and infield grazing areas. Our industry partners will work together with us ensuring useful and targeted dissemination of our research.