PS 59-11
Targeted integration of perennials into Iowa farm fields: Win-win strategy for farm profit and ecosystem services
The USA has a large potential to reduce carbon emissions and increase community resilience by scaling up renewable energy production. A promising new energy source is lignocellulosic biomass from dedicated perennial crops, often referred to as second generation (2G) biomass. Despite well-established ecologic and long-term agronomic benefits of integrating perennial cover into the agricultural landscape, 2G biomass production and utilization lags behind mandates. Currently, farmers have little financial incentive to change management from grain crops to perennial energy feedstock. However, the underlying economy changes when subfield spatial variation of soil characteristics and associated corn yield variability is taken into account.
We applied a modeling framework that integrates agronomic computing tools, using the Water Quality Index for agricultural fields (WQIag) and Soil Conditioning Index (SCI) as indicators for conservation effects of integrated agricultural landscape management in Iowa. Current corn yields associated with soil properties were mapped to agricultural land. Crop budgets were used to assess subfield profitability for corn and identify unprofitable areas to target perennial grass production.
Results/Conclusions
We found that in a typical Iowa county, farmers lose more than $100 per acre with corn on 10% of land at a corn price of $5.00 per bushel. Converting these sub-field areas to perennial crops would mitigate economic loss, conserve soil, and reduce surface water loading of nitrogen and phosphorus from agricultural sources. Corn profitability correlates with both WQIag and SCI, two indicators used by the USDA for water nutrient runoff and soil organic matter loss estimates. Simulation of targeted integration of perennials resulted in a significant improvement in both indices. With an evolving demand for cellulosic feedstock, new high yielding switchgrass cultivars or Miscanthus × giganteus could serve as an additional income source to farmers. When corn is substituted with the establishment of highly diverse prairie, additional ecosystem services, such as attraction of pollinators and pest-controlling predatory arthropods, as well as aesthetic and recreational valorization, will be provided to the agricultural landscape.