The Science
Planting bioenergy crops such as switchgrass and prairie along with crops like corn and soybeans can limit erosion, rebuild soil carbon, and promote natural pest control. Deciding where and how to plant these crops involves tradeoffs between environmental benefits and profit. A new computer model balances economic, biodiversity, greenhouse gas, and water quality objectives to determine the best possible layout based on the chosen goals.
The Impact
Industrial farming has made it possible to feed the world’s growing population, but it has negative impacts on the environment. Production increases have led to loss of species and contributed to increases in greenhouse gases, water pollution, and erosion. Bioenergy crops can restore some of these lost ecosystem services and provide additional income for farmers. Models like this one could help show the best layout depending on the desired outcome.
Summary
Scientists with the Great Lakes Bioenergy Research Center developed a mixed-integer quadratically constrained program to optimize the layout of cropland considering economic, biodiversity, greenhouse gas emissions, and water quality objectives as well as edge effects. Decision variables include spatially varying fertilization and crop establishment location.
To demonstrate the applicability, researchers applied it to an example field, showing how the optimal cropland design changes as a decision-maker prioritizes different objectives and as edges have different impacts on biodiversity. The case study demonstrated tradeoffs between maximizing profit and environmental objectives. Planting switchgrass or prairie in place of corn increases biodiversity, GHG sequestration, and water quality simultaneously, though by different amounts and with potentially large negative impacts on profit. However, there are solutions where switchgrass is planted in areas with low corn yield that are better than planting and fertilizing corn throughout the entire cropland (the status quo) for each of the four objectives.