Submitted to: Global Change Biology Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2023
Publication Date: 7/15/2023
Citation: Adler, P.R. 2023. Life cycle greenhouse gas emissions from miscanthus production at farm scale. Global Change Biology Bioenergy. 14:1029141. https://https://.doi.org/10.3389/fpls.2023.1029141.
Interpretive Summary: Models for economic and environmental analysis of new biomass crops such as the perennial grass Miscanthus have been based on small plot trials which can dramatically over estimate yields. Therefore, we collected data from a commercial farm with over 4,000 acres of Miscanthus, recording all inputs and yield. We found that regional biomass yields were more than 50% lower than predicted by conventional models and were able to estimate yields from satellite imagery. This demonstrates the potential for farmers to estimate yields from satellite data prior to harvest, understands factors contributing to within field yield variability, and researchers to understand regional yield variability.
Technical Abstract: There has been considerable interest in use of Miscanthus (Miscanthus x giganteus) as a feedstock for bioenergy production due to its potential to reduce greenhouse gas emissions associated with cellulosic feedstock production. To date, data on Miscanthus production in the US has been based on small scale research plots due to the lack of commercial scale production fields. Research plot yields are often much higher than commercial fields for a variety of reasons including reduced spatial variability and location on better quality farm land. The objective of this study was to quantify the inputs for production of Miscanthus at the commercial farm scale. We logged energy use on agricultural machinery from Miscanthus production planted on more than 1000 ha of land and modeled N2O emissions and changes in soil carbon using DayCent. Although fuel use was higher for land preparation in fields with perennial vegetation, fuel to harvest Miscanthus dominated greenhouse gas (GHG) emissions from agriculture machinery for crop management. The N2O emissions and changes in soil carbon were the largest source and sink of GHG emissions associated with Miscanthus production, respectively. Data from field scale yield analysis shows a good relationship between field scale biomass yields and fuel use for Miscanthus harvest (R2= 0.7), Miscanthus coverage (R2= 0.6), and satellite based Enhanced Vegetation Index (EVI) (R2= 0.5). This demonstrates the potential to use this within field yield data to better understand factors driving subfield yield variability and use of satellite data to quantify early yield predictions.