Epsilon Archive for Student Projects

Abstract

Conservation agriculture practices, such as reduced tillage or residue retention, have gained attention for their potential to enhance agricultural system resilience to climate change and combat soil degradation. However, conventional soil-crop models often neglect the dynamics of soil properties, limiting their ability to predict changes in soil quality on large timescales relevant for sustainable management.
This study therefore applies and expands the recently developed Uppsala model of Soil Structure and Function to investigate the long-term impacts of conservation agriculture on soil organic matter (SOM) stocks, the water balance and winter wheat yields under current and future climate in temperate Europe.
The model was calibrated for a site in Switzerland and used to simulate a baseline period (1985-2015) as well as 6 future climate change scenarios (2020-2090) under two contrasting soil managements. Conventional intensive tillage with residue incorporation (CIT) was compared to no-till practices with residue retention (CNT).
Under current climate conditions, the CNT treatment was able to conserve soil moisture by reducing surface runoff (-97 %) and evaporation (-65 %), as compared to CIT. Though yields remained similar, as under the wet climate, crop growth was not limited by water availability. After 30 years, SOM stocks were 2.8 % higher under CIT, due to larger amounts of above-ground biomass being incorporated through tillage. In future climate projections, significant yield declines were simulated under hotter conditions, driven by much shorter growing periods, potentially linked to limitations of the employed phenology model. Despite declining SOM levels in both systems, CNT maintained 14% higher SOM on average.
Although no-till practices did not enhance yields, they showed strong potential to mitigate climate change impacts on SOM and soil function. This suggests that no-till practices, together with adequate residue management, could be a promising strategy for sustaining soil quality in the face of climate change. Further model development and improvement is necessary to predict the long-term effects on grain yields.