How do environmental and management factors affect ecosystem services from corn-soybean-based agricultural systems?

Abha Bhattarai
Category: 
Graduate (MS)
Advisor: 
Sami Khanal
Department: 
Food, Agricultural and Biological Engineering
Abstract: 

Ecosystem services from agricultural production systems can be influenced by weather and management practices such as type of tillage, fertilizer source, timing and application rate, presence of cover crops, and residue incorporation. Knowing the long-term impacts of different management practices can be crucial for designing and implementing sustainable agricultural systems. Process-based biogeochemical models such as the DeNitrification and DeComposition (DNDC) model have been widely used to simulate the impact of various management practices on agricultural ecosystem services such as crop yield, soil organic carbon (SOC) content, greenhouse gases (GHGs) emissions, and nutrient leaching. The focus of this study was to simulate and assess the effects of various management practices on ecosystem services for agricultural sites. The DNDC model was used to simulate GHGs and SOC content for an agricultural site with corn-winter wheat – alfalfa rotation in the Maumee River Watershed in Northwestern Ohio for 20 years. Effects of several alternative management practices such as no-till, cover crops, and manure were assessed and compared to the baseline scenario of corn-soybean rotation with mixed tillage and synthetic fertilizer application (the dominant cropping system in the Midwest). Results show an overall reduction of nitrous oxide (N₂O) emissions (ranging from -26% to -2.7%), an increase of SOC (ranging from 1% to 8.6%), and mixed results for carbon dioxide (CO₂) emissions (ranging from -4% to 34%) compared to the baseline scenario. Cover crops increased CO₂ emissions but also increased SOC sequestration, so trade-offs between these practices should be considered. As ecosystem services can be regulated by soil and weather conditions, the future work will involve simulation of ecosystem services for several agricultural sites with unique soil types under corn-soybean rotation systems and assess the effects of management practices.