Multi-Scale Integrated Modeling of Sustainable Herbaceous Biomass Feedstock Production Potential in the Northeastern USA.

Developing a large bioenergy economy in the USA will require dramatically increasing sustainable feedstock production. We used geospatial modeling techniques to integrate data from remotely-sensed land cover, agricultural production, and field trials of dedicated feedstocks such as switchgrass. We analyzed land availability and suitability for 100 m pixels throughout the conterminous US and integrated county-scale data from surveys such as the 2007 Census of Agriculture. We are also conducting increasingly detailed analyses for the Northeastern Sun Grant region (Michigan to West Virginia to Maine), and New York.

In the conterminous USA, 47% of the land area is in farms, 21% in cropland, 16% in cultivated crops, and 21% in permanent pasture and rangeland, some of which could be used for perennial feedstock production. Of current pasture and rangeland, removing land with slopes steeper than 15% and Federal land leaves 18% of the total (henceforth “suitable grassland”). However the average productivity of  this land is less than current cropland. National Commodity Crop Productivity Indices (NCCPI) are being developed to indicate production potential based on detailed soils databases (SSURGO). These indices range from 0 to 1, with higher values representing greater production potential. For New York, we found that 71% of cropland has an overall NCCPI value above 0.4 compared to only 59% of the suitable grassland. For the conterminous USA, only 29% of suitable grassland has a value above 0.4, and only 11% greater than 0.6. Additionally, annual variability may be critical for feedstock production. For example, the minimum yield of corn during 10 years was only 71% of the average production. For grass hay, this figure was 68%, with much greater differences for individual counties. These results allow us begin to quantify the potential land base for expanded bioenergy feedstock production and the reduction in average production with such expansion.