The potential of regenerative agriculture to improve soil health on Gotland, Sweden

Background Regenerative agriculture has gained attention in mainstream media, academic literature, and international politics in recent years. While many practices and outcomes relate to RA, there is no uniform definition of the term, and only a few comprehensive scientific studies exist of "real-life" farms and the complexity of what is considered regenerative management and its impact on soil health. Aims This study aimed to relate the impact of single and various combinations of regenerative management practices to soil health indicators on Gotland, Sweden. Methods Soil health of 17 farm fields and six gardens was assessed on 11 farms that had applied regenerative agricultural practices for zero to 30 years. We measured a variety of physical (bulk density , infiltration rate, wet aggregate stability, root depth and abundance, penetration resistance), chemical (pH, electric conductivity, C:N ratio, total organic carbon ) and biological (earthworm abundance, active carbon, microbial biomass carbon) soil indicators. These parameters were related to regenerative practices (reduced tillage, application of organic matter , livestock integration, crop diversity, and share of legumes and perennials) through a combination of hierarchical clustering, Analysis of Variance and Tukey's tests, principal component analysis, and multiple linear regressions. Results At our study sites, the application of organic matter had a positive impact on bulk density, carbon-related parameters, wet aggregate stability, and infiltration rate, while reduced tillage and increased share of perennials combined had a positive impact on vegetation density, root abundance and depth, and wet aggregate stability. The field plots were divided into four clusters according to their management, and we found significantly higher values of total organic carbon (*), C:N (*), infiltration rate (**), and earthworm abundance (*) for crop-high-org-input, the management cluster with highest values of organic matter application and no tillage. We found significantly higher values of vegetation density (***) and root abundance (**) for perm-cover-livestock, the cluster with no tillage, integration of livestocks, and permanent cover (*** p 0.1). Conclusions We support existing knowledge on positive impacts of regenerative practices, namely, the addition of an organic amendment that improved C-related parameters, as well as the positive effects on soil structure of reduced tillage in combination with an increased share of perennials. We argue for an outcome-based, and principle-led concept of RA as a context-dependent agricultural approach

THE AMOUNT AND SPECIATION OF TRACE ELEMENTS TRANSPORTED FROM RICE FIELD TO CANAL DURING A FLOODING EVENT

Trace element pollution of soils, sediments and surface water can pose a risk for the local population and the environment of Vietnam. Rice fields can be affected by storm events, which cause the release of trace elements into surface water and transport them into drinking wells. The aim of this study was to investigate if dissolved and suspended As, Pb and Zn concentrations in surface water of a paddy rice fields and an irrigation canals increased during a flooding event and exceed the Vietnamese Surface Water Quality Standards and WHO Guidelines for Drinking-water Quality. The study site is a rice field area in the Thanh Hoa province in Central Vietnam, which experiences an average of 2.4 storms every year causing overflow of streams and low-order canals. Concentrations of As increased during the flooding event with dissolved As being the prevailing fraction, which followed a late flush behavior. Lead showed no significant difference in concentration over time. Zn concentrations only increased significantly in the canal upstream the field in the morning of the first day. Suspended Zn dominated at that time, following the first flush behavior of TSS concentrations. Concentrations of As, Pb and Zn did not exceed the Vietnamese Surface Water Quality Standards or WHO Guidelines for Drinking-water Quality at any time and they are therefore of no concern for the health of the local populatio