Multifunctional Agriculture: Conducting an Ecosystem Service Assessment for an Agricultural Watershed

To meet the food production demands on a finite area of land for an exponentially growing, global population, intensive agricultural management practices are being used. The implications of this these practices lead to soil degradation, loss of biodiversity, increased greenhouse gas emissions, and decreased water quality depending on the level of conservation practices implemented in a watershed. To offset these negative environmental effects, ecosystem services should be analyzed for possible economic valuation to provide incentives for good land stewardship. In this study a Multifunctional Agriculture (MFA) evaluation in a representative agricultural watershed in Iowa was performed by assessing the ecosystem services of water quality, crop/grain production, carbon sequestration, reduction in carbon dioxide emissions and biodiversity for representative land covers (e.g., corn-soybean rotation, alfalfa, oats, and Conservation Reserve Program, or CRP). The services were analyzed using a geo-spatial platform that simulated carbon dynamics with the biogeochemical model, CENTURY, as well as soil erosion/deposition and surface runoff with the Water Erosion Prediction Project (WEPP). Economic values given to the various services were based on current grain prices, water treatment costs, and hypothetical carbon storage credits. Results showed that crop/grain production for the corn-soybean rotations provided the largest service for the study site, followed by alfalfa. CRP provided the largest decrease in surface water runoff and CO2 emissions, while alfalfa provided the largest form of plant species diversity. The largest sequestration of carbon came from the corn-soybean rotation due to large amounts dead plant material being incorporated into the soil through tillage. Overall the MFA assessment can provide a framework for payment of ecosystem services supplied by agroecosystems which promote more sustainable land management practices.