Relating the impacts of regenerative farming practices to soil health and carbon sequestration on Gotland, Sweden

Land degradation, greenhouse gas emissions and biodiversity loss through agriculture are some of the greatest challenges we are facing today. Fertile and productive soils are the basis of life on this planet and need to be protected and restored to support a growing population and lower negative impacts of climate change. Regenerative agriculture (RA) claims to improve environmental, social, and economic facets of food production. Its emphasis lies on carbon sequestration for climate change mitigation, biodiversity, and food security through the regeneration of degraded land. The concept of regenerative agriculture has gained attention both in mainstream media and in academic literature in recent years. However, there is no uniform definition of the term so far, and further there is a lack of comprehensive scientific studies on “real-life” farms that are changing their management from conventional to regenerative practices. This thesis investigates the contemporary and historical context of the emerging term regenerative agriculture and identifies the main themes, movements, and debates associated with it by a broad literature research. Further, we compare regenerative farms with conventional farms on Gotland, Sweden in order to draw first conclusions about the impact of certain farming practices on soil physical, chemical, and biological parameters. The soil health on 24 different plots is assessed by a variety of indicators, i.a. total, organic, active, and microbial biomass carbon, C:N ratio, wet aggregate stability, root depth and abundance, earthworm number, nutrient leaching, and soil texture. These parameters are related to four main management practices: application of organic matter, soil disturbance through tillage, crop diversity, and share of legumes through a principal component analysis and multiple linear regressions. We found that the amount of carbon added to the soil had a significant impact on several soil health indicators, mainly organic and active carbon, bulk density, number of earthworms, root abundance, water infiltration, and vegetation density. Reduced tillage was connected to higher wet aggregate stability, and vegetation density. These findings need to be confirmed in the coming years; however, they show that higher organic inputs and less soil disturbance generally had a positive impact on soil health on the investigated farms. Soil sampling will be continued on the same plots in the future to thoroughly investigate the impacts over a longer time period, as the thesis is part of the project Time Zero! Land surveys during farm conversion from abandoned land to regenerative agriculture performed at the Department of Soil and Environment at the Swedish University of Agriculture, Uppsala