ABSTRACT

The past 200 years have seen the US Midwest be transformed from natural prairie/wetlands to fertile croplands that currently produce about one third of the world?s corn and soybean. This landscape was transformed by human activities through extensive subsurface "tiling" (drainage piping) and intensified uses of fertilizer and other inputs. However, this transformation has also created important questions about environmental sustainability. With further stress from climate change, can the US Midwest remain as the global food basket for the next 100 years? How can food production and environmental quality both be sustained in this landscape? In the US Midwest agroecosystem, carbon (e.g. crop growth), hydrology (both water quantity and quality), and nutrient cycles are all closely intertwined across scales, from the field/headwater scale to the whole river (greater Mississippi river basin) network and continental scales. Any human activities and practices do not just affect one component, rather the complete set of interconnections. Thus, a "system" analysis of the complex feedbacks and interactions is required to assess potential adaptations in the US Midwest agroecosystem. This project adopts a system view to holistically model and quantify the coupled "food-water-nutrient nexus" for the US Midwest agroecosystem. These models will significantly advance the understanding of the processes and predict agroecosystem behavior under current and future climate conditions. Two promising management practices (i.e. controlled drainage, and nutrient management) to achieve co-sustainability of food production and environmental quality will be assessed

The ultimate goal of the research is to establish an advanced understanding of how crop growth, hydrology, and nutrient cycles interact under different human management and climate conditions in the setting of the US Midwest agroecosystem. The project will develop a coupled land-river model and a model-data fusion approach, and integrate field-level collected data and remote sensing measurements. Specifically, tile drainage extent and drainage strength will be estimated in a spatially explicit manner at the regional scale for the three key states in the US Midwest, by a new model-data fusion approach based on ecohydrological processes. This dataset of tile drainage will then be used to develop a coupled land-river network model (ecosys-THREW) to quantify feedbacks/interactions among the water cycle, nitrogen cycle, and crop production across spatial scales in this agroecosystem, as well as to assess the potential of promising human management practices to allow co-sustainability of food production and environment quality in the US Midwest. Simulation results from the coupled ecosys-THREW model are expected to be used by policy makers and farmer communities to assess the agroecosystem conditions and potential impacts of various conservation practices at the regional scale.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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