Water balance in agricultural catchments amidst climate and land use changes in Sweden

• Crop production depends on water availability from precipitation and soil infiltration and storage. Historically, efforts to enhance soil moisture have focused on modifying agricultural landscapes and hydrological pathways. With climate change increasing water saturation and deficit risks, understanding the role of water diversion and storage in sustaining yields is crucial. This thesis explored how the water balance in agricultural landscapes can be affected by climate change, historical, current and potential future agricultural water management and anthropogenic interventions. Using the Soil and Water Assessment Tool (SWAT+), hydrological modeling was conducted in four Swedish agricultural catchments with varying temperature and precipitation regimes to assess historical and future water balance In Paper I, new datasets were developed for soil water, stream networks, open ditches and subsurface drainage. The results showed increased infiltration and water-holding capacity with the soil texture classification system used. Furthermore, the flow path length increased by 14% to 21 %, and two new maps over subsurface drainage were presented. In Paper II, modelling water balance in historic and current climate, land use, varying hydromorphology and water storage, resulted in marginal shifts in water partitioning, despite significant increase in subsurface and surface drainage and reduced wetland area over time. In Paper III, exploring effect on soil moisture and evapotranspiration under current and future climate in four contracting agricultural catchments showed increased drying of both soil moisture and evapotranspiration with increased warming. Hence partially opposing previous findings. In conclusion, representing historical landscape water balance across scales remains challenging due to variations in data resolution. Historical structures and stream delineation offer insights for enhancing catchment storage and infiltration capacity. However, Paper I highlights the necessity of high-resolution data for accurate landscape representation. Future climate change is expected to increase soil moisture drying, but responses at the catchment scale remain ambiguous, necessitating further investigation into soil moisture dynamics under climate impacts.

Ämnesord

LANTBRUKSVETENSKAPER  -- Jordbruk, skogsbruk och fiske -- Markvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Soil Science (hsv//eng)

Publikations- och innehållstyp

vet (ämneskategori)

dok (ämneskategori)