INTEGRATED LANDSCAPE MANAGEMENT FOR IMPROVING WATER QUALITY IN THE MIDWEST

Nutrient loss due fertilizer runoff and leaching in agricultural regions impacts surface water and groundwater quality, resulting in problems that include toxic algal blooms, increased costs for water treatment facilities, and the hypoxic zone in the Gulf of Mexico. We are pursuing the approach of integrated landscape management (ILM) to reduce this effect through the installation of perennial bioenergy crops in marginal land. Such land is underproductive for commodity crops due to a high leaching rate for fertilizer, and may result in increased costs for additional fertilizer application. This six-year study introduced shrub willows (Salix miyabeana SX64) as a bioenergy crop in marginal (low-yielding and environmentally susceptible) areas within a 6.5-ha cornfield in east-central Illinois to quantify their effect on ecosystem services (ES). The focus has been the evaluation of nutrient interception from an upland cornfield as well as the overall influence of energy crop placement on the agricultural landscape. Nutrient cycling at the field scale is measured by sampling soil, soil water, groundwater, and vegetation to evaluate nutrient loss and uptake. Additional field measurements include soil moisture, groundwater elevation, greenhouse gas flux, transpiration, invertebrate biodiversity, and plant biomass. Results show that since willow establishment in 2013, the trees have significantly reduced concentrations of nitrate leachate compared to the adjacent corn crop. Additionally, willows were comparable to corn in terms of rates of water use and soil nitrogen reserve utilization. Our research has shown that ILM can be cost-competitive, when compared on a nitrogen removal basis, to mainstream conservation practices, because the value of the biomass generated compensates for part of the cost of implementation. Converting marginal land to perennial crops to intercept nitrate in the subsurface allows the willows to self-serve for their nutrient requirements, while providing biomass feedstock and substantial benefits for water quality and other ES.