|BONNER, IAN - Idaho National Laboratory|
|CAFFERTY, KARA - Idaho National Laboratory|
|MUTH JR., DAVID - Agsolver|
Submitted to: Energies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2014
Publication Date: 10/13/2014
Citation: Bonner, I.J., Cafferty, K.G., Muth Jr., D.J., Tomer, M.D., James, D.E., Porter, S.A., Karlen, D.L. 2014. Opportunities for energy crop production based on subfield scale distribution of profitability. Energies. 7:6509-6526.
Interpretive Summary: Incorporation of perennial crops into agricultural landscapes could expand feedstock supplies for the biofuels industry, while benefiting soil and water quality, and increasing biodiversity. Despite these advantages, concerns over their practicality and cost of implementation hinder adoption of dedicated bioenergy crops. A case study was conducted to model crop yields and profitability in Hardin County, Iowa, to demonstrate how the decision to manage part of a field differently can open new possibilities for energy crop production and increased agricultural profitability. If switchgrass (Panicum virgatum L.) could be placed in subfield landscape positions where corn (Zea mays L.) grain is expected to operate at a net economic loss, there is the potential to increase sustainable biomass production by 48 to 99%, compared to corn stover collection and depending on the level of soil conservation that limits stover harvest. Field-level profitability can also be improved, but the amount of land that can be profitably converted is highly sensitive to grain price, and depends on whether a break-even or a net loss (ranging to minus $400 per acre) provides a decision point to shift from corn to switchgrass production. Switchgrass can be profitably integrated into landscapes under row crop production if management decisions can be made at a subfield scale and the areas targeted for conversion are those operating at a negative net profit. This information will be of interest to agricultural producers, the bioenergy industry, and conservation advocates seeking to diversify agricultural landscapes dominated by annual row crops.
Technical Abstract: Incorporation of dedicated herbaceous energy crops into row crop landscapes is a promising means to supply an expanding biofuel industry while increasing biomass yields, benefiting soil and water quality, and increasing biodiversity. Despite these positive traits energy crops remain largely unaccepted due to concerns over their practicality and cost of implementation. This paper presents a case study on Hardin County, Iowa, to demonstrate how subfield decision making can be used to target candidate areas for conversion to energy crop production. The strategy presented integrates switchgrass (Panicum virgatum L.) into subfield landscape positions where corn (Zea mays L.) grain is modeled to operate at a net economic loss. The results of this analysis show that switchgrass integration has the potential to increase sustainable biomass production from 48 to 99% (depending on the rigor of conservation practices applied to corn stover collection) while also improving field level profitability. Candidate land area is highly sensitive to grain price (0.18 to 0.26 US$ kg-1) and dependent on the acceptable net profit for corn production (ranging from 0 to -1,000 US$ ha-1). This work presents the case that switchgrass can be economically implemented into row crop production landscapes when management decisions are applied at a subfield scale and compete against areas of the field operating at a negative net profit.