Assessing Marginal Land Availability Based on Land Use Change Information in the Contiguous United States

Abstract

Utilization of marginal land for growing dedicated bioenergy crops for second-generation biofuels is appealing to avoid conflicts with food production. This study develops a novel framework to quantify marginal land for the Contiguous United States (CONUS) based on a history of satellite-observed land use change (LUC) over the 2008–2015 period. Frequent LUC between crop and noncrop is assumed to be an indicator of economically marginal land; this land is also likely to have a lower opportunity cost of conversion from food crop to bioenergy crop production. We first present an approach to identify cropland in transition using the time series of Cropland Data Layer (CDL) land cover product and determine the amount of land that can be considered marginal with a high degree of confidence vs with uncertainty across the CONUS. We find that the biophysical characteristics of this land and its productivity and environmental vulnerability vary across the land and lie in between that of permanent cropland and permanent natural vegetation/bare areas; this land also has relatively low intrinsic value and agricultural profit but a high financial burden and economic risk. We find that the total area of marginal land with confidence vs with uncertainty is 10.2 and 58.4 million hectares, respectively, and mainly located along the 100th meridian. Only a portion of this marginal land (1.4–2.2 million hectares with confidence and 14.8–19.4 million hectares with uncertainty) is in the rainfed region and not in crop production and, thus, suitable for producing energy crops without diverting land from food crops in 2016. These estimates are much smaller than the estimates obtained by previous studies, which consider all biophysically low-quality land to be marginal without considering economical marginality. The estimate of marginal land for bioenergy crops obtained in this study is an indicator of the availability of economically marginal land that is suitable for bioenergy crop production; whether this land is actually converted to bioenergy crops will depend on the market conditions. We note the inability to conduct field-level validation of cropland in transition and leave it to future advances in technology to ground-truth land use change and its relationship to economically marginal land.

Water Quality Effects of Economically Viable Land Use Change in the Mississippi River Basin under the Renewable Fuel Standard

“…BEPAM endogenously determined the economically optimal land allocation to major row crops and energy crops on active cropland and land that is considered idle 27 under three potential policy scenarios (RFS1 baseline, corn ethanol only, and corn + cellulosic ethanol). We generated the spatial allocation of land use and N application at the end of the modeling period, 2030, by simulating the potential policy scenarios using BEPAM (Table S1, described in Section S2, Supporting Information (SI)) over the 2016−2030 period.…”

“…12 We coupled an economic model (Biofuel and Environmental Policy Analysis Model (BEPAM)) with an agroecosystem model (Integrated BIosphere Simulator−Agricultural Version (Agro-IBIS)) and a nutrient transport and hydrologic model (Terrestrial Hydrologic Model with Biogeochemistry (THMB)) to simulate water quality effects from corn grain and cellulosic feedstocks under potential biofuel production scenarios (see Sections 2.1 and 2.2). Our objectives are to (1) assess the endogenously determined area needed to produce the feedstocks considered here and their spatial pattern of production across active and idle (i.e., cropland that earns relatively low net returns while under crop production 27 ) cropland in the MARB and (2) quantify the amount of N loss these land use scenarios could generate for each potential policy scenario relative to baseline levels before the RFS2. The intent of this research is to undertake a forward looking analysis of the water quality implications of biofuel targets that may be mandated by an extension of the RFS2.…”

Satellite Data Applications for Sustainable Energy Transitions

“…Data on land cover have been used to identify abandoned agricultural lands with potential to support bioenergy feedstock production (Zumkehr and Campbell, 2013;Baxter and Calvert, 2017;Goga et al, 2019;Naess et al, 2021) and to screen for land that may be deemed as marginal for food production (Nalepa and Bauer, 2012;Kang et al, 2013;Khanna et al, 2021) due to economic instability (Jiang et al, 2021), environmental sensitivity (Wang et al, 2020), and biophysical limitations in climate, soils, or topography (Gelfand et al, 2013;Gu and Wylie, 2016). For example, satellite-based productivity thresholds on low-yielding lands have been used to identify marginal areas for second generation bioenergy production (Longato et al, 2019).…”

Redefining marginal land for bioenergy crop production

“…In a recent study, Jiang et al (2021) identify economically marginal land as land that is frequently transitioning between crop and non-crop use using high-resolution land use data from the Cropland Data Layer from 2008 to 2016. They consider frequent land use change as an indicator of land that is at the borderline of profitability in crop production and likely to switch easily between crop and non-crop in response to changes in market conditions (i.e., farmers choose to cultivate only in years when they perceive it likely to be profitable).…”

“…This is an imperfect approach to identify economically marginal land because (a) land use change data from satellite images is subject to noisiness and (b) ex-ante assessments of profitability that guide crop planting decisions may differ from ex-post realizations of profits given weather, market, and policy conditions. Jiang et al (2021) use statistical algorithms to distinguish between land use changes that can be inferred as indicators of economic marginality with confidence from those that are in the statistical noise. They find that the area of land that can be confidently classified as economically marginal, and that is in the bioenergy-suitable rainfed region of the US, is substantially smaller than estimates from previous studies using biophysical criteria.…”