Where can switchgrass production be more profitable than corn and soybean? An integrated subfield assessment in Iowa, USA

Abstract

Perennial bioenergy crops are considered an important feedstock for a growing bioeconomy. However, in the USA, production of biofuel from these dedicated, nonfood crops is lagging behind federal mandates and markets have yet to develop. Most studies on the economic potential of perennial biofuel crops have concluded that even high‐yielding bioenergy grasses are unprofitable compared to corn/soybeans, the prevailing crops in the United States Corn Belt. However, they did not account for opportunities precision agriculture presents to integrate perennials into agronomically and economically underperforming parts of corn/soybean fields. Using publicly available subfield data and market projections, we identified an upper bound to the areas in Iowa, United States, where the conversion from corn/soybean cropland to an herbaceous bioenergy crop, switchgrass, could be economically viable under different price, land tenancy, and yield scenarios. Assuming owned land, medium crop prices, and a biomass price of US$ 55 Mg−1, we showed that 4.3% of corn/soybean cropland could break even when converted to switchgrass yielding up to 10.08 Mg ha−1. The annualized change in net present value on each converted subfield patch ranged from just above US$ 0 ha−1 to 692 ha−1. In the three counties of highest economic opportunity, total annualized producer benefits from converting corn/soybean to switchgrass summed to US$ 2.6 million, 3.4 million, and 7.6 million, respectively. This is the first study to quantify an upper bound to the potential private economic benefits from targeted conversion of unfavorable corn/soybean cropland to switchgrass, leaving arable land already under perennial cover unchanged. Broadly, we conclude that areas with high within‐field yield variation provide highest economic opportunities for switchgrass conversion. Our results are relevant for policy design intended to improve the sustainability of agricultural production. While focused on Iowa, this approach is applicable to other intensively farmed regions globally with similar data availability.

Economic viability and carbon footprint of switchgrass for cellulosic biofuels: Insights from a spatial multi‐feedstock procurement landscape analysis

“…However, as noted earlier, this is also highly unlikely. Based on our other parameters, we find that switchgrass yield would have to be three times higher than our estimate for switchgrass to replace corn in highly productive land, which is in line with findings by Mitchel et al (2016) and Brandes et al (2018). Similarly, procurement patterns that consist of procuring switchgrass in a constrained market and stover in an unconstrained market do not emerge in equilibrium.…”

“…These findings are only reinforced by studies including dynamic considerations in farmers’ decision to switch from row crops to switchgrass (Song et al, 2011), as well as studies considering transaction costs associated with contracting for energy crops (Alexander et al, 2012; McCarty & Sesmero, 2021). However, we must keep in mind that new precision technologies may be able to exploit sub‐fields with lower crop productivity and plant switchgrass on those sub‐fields (Brandes et al, 2017, 2018).…”

Reviewing the interface of bioeconomy and ecosystem service research

“…Overall, there is a relatively strong business perspective, including considerations regarding environmental and social benefits, such as enterprise diversification, maintenance of local biodiversity and ecosystem services, and valorization of marginally productive land and maintenance of ecosystem services. Mitchell et al ( 2016 ), Brandes et al ( 2018 ), and French (2019) investigated profitability and crop suitability issues in bioenergy production. Ronzon and Piotrowski ( 2017 ) and Springer et al ( 2017 ) estimated biomass availability for bio-based material and bioenergy sectors, with a focus, respectively, on the European Union and the United States Midwest.…”

Optimizing pollinator conservation and crop yield among perennial bioenergy crops

“…As an alternative to annual grain crops, perennial cellulosic plants such as native grass species can be planted as a biofuel crop. With current production infrastructure, perennial cellulosic biofuels yield less ethanol per hectare than annual crops (Roozeboom et al, 2019), but potential exists to decrease this gap (Brandes et al, 2018). In addition to biomass production, perennial cellulosic biofuels increase ecosystem functions such as carbon sequestration and biodiversity (Hill et al, 2006; Landis et al, 2018; Werling et al, 2014), and ecosystem services, such as pollination, in the broader landscape (Bennett & Isaacs, 2014; Robertson et al, 2017).…”