Assessing the impacts of future climate scenarios on soil management practices and their hydraulic proprieties

Soil management practices influence soil physical parameters and crop productivity. No-till farming, which is a key component of conservation agriculture, is considered a sustainable alternative to conventional agriculture. The extent to which soil conservation management practices can mitigate the impacts of extreme events (heavy precipitation events and drought) remains unknown, and is examined as part of the SoilX project. This study focuses on two different tillage management practices and their effects on soil hydraulic properties, soil structure, and crop yields under current and future climate conditions. An experimental study site that is a Long-Term Field Experiment (LTE) since 2006 located in Hollabrunn, Lower Austria, was used for soil sampling and crop modelling. The site is located in a Pannonian climate, with average annual (1991-2020) precipitation of 493 mm and a mean air temperature of 9.8 °C. The soil is classified as a silt loam calcareous Chernozem under the WRB or as Typic Vermudoll under the US Soil Taxonomy. The experimental layout comprised two soil tillage treatments (conventional tillage (CT) and no-tillage (NT), both with annual crops and winter cover crops) arranged in a randomized block design. The crop model APEX (Agricultural Policy/Environmental eXtender) model was set up for both treatments to assess the impacts of CT and NT on soil physical properties and their respective hydrological properties. Field soil samples were taken from both treatments (up to 50 cm depth) and analyzed for soil bulk density, soil organic matter (SOC), water stable aggregates (WSA), unsaturated infiltration rates (determined with TDI), water retention curves, and oxygen isotopes in soil pore water. These field measurements were used to parameterize the APEX model. Field operations between 2009 and 2023 also provided model inputs on crop cultivation cycles, tillage, fertilization, sowing, crop protection, and harvesting. The yield (dry matter Mg ha^-1) per plot was used for model calibration. From the soil samples obtained in 2023 differences between CT and NT were determined with respect to bulk density and soil water content, i.e. at 10 cm, the unsaturated infiltration rates were higher in CT. The future climate simulations (2050-2100) derived from regional climate models (RCMs) with different representation pathways (RCPs) were input in APEX to assess the impacts of climate change on the soil physical and hydraulic properties (SOC, infiltration rates, soil water storage) under CT and NT. The research results quantify differences in soil physical and hydraulic properties in a future climate, particularly focusing on the extreme events. The findings provide information on soil management strategies to potentially mitigate the adverse impacts of heavy precipitation events and droughts in agricultural cropping systems.