ENHANCED MIDWESTERN CROPPING SYSTEMS FOR SUSTAINABILITY AND ENVIRONMENTAL QUALITY
Location: Agroecosystems Management Research Unit
Title: Nitrogen, phosphorus, and potassium requirements to support a multi-billion gallon biofuel industry
Submitted to: Soil and Water Conservation Society Proceedings
Publication Type: Book / Chapter
Publication Acceptance Date: August 22, 2011
Publication Date: September 27, 2011
Citation: Murrell, T., Fixen, P.E., Huang, W., Kovar, J.L., White Jr, P.M. 2011. Nitrogen, phosphorus, and potassium requirements to support a multi-billion gallon biofuel industry. In: Braun, R., Karlen, D., and Johnson D., (ed.). Sustainable Alternative Fuel Feedstock Opportunities, Challenges and Roadmaps for Six U.S. Regions. Ankeny, IA: Soil and Water Conservation Society. p. 160-176. Available: http://www.swcs.org/documents/resources/Chapter_10__Murrell__Billion_Ton_Re_8B308171BD289.pdf.
Interpretive Summary: The estimated one billion tons of feedstock material needed to reach biofuel and bioenergy production goals by 2030 will result in significant increases in the amounts of plant nutrients removed from arable land. Much of these projected increases come from harvests of corn stover and perennial forages. Although nutrient removal estimates could be much lower, if recently collected data for corn stover are a good indication, current data indicate that domestic demand for N, P, and K will increase significantly by 2030, making the U.S. more reliant on N and K imports and consuming significantly more domestic P production. In either case, greater U.S. consumption leaves less of the production capacity available for export to other countries. To help ease future demand and create a sustainable biofuel industry, nutrients will need to be recycled from production facilities back to the farmland from which the feedstock was removed. Until more is understood of cellulosic ethanol plants and their byproducts, it is not possible to estimate how much these secondary sources of nutrients will ease demand on the primary ones. Harvest management will need to minimize, to the extent possible, the removal of nutrients from farmland to ensure primary resources remain viable in the future. The information in this review will benefit the fertilizer and ethanol industries, as well as commercial growers, by providing estimates of fertilizer needs for sustainable feedstock production.
To accomplish the goals for biofuel and bioenergy production, 1 billion tons of biomass will need to be produced annually by the year 2030. Crop production data from a joint study by the U.S. Department of Energy (US DOE) and the U.S. Department of Agriculture (USDA) demonstrated how this goal could be met by changes in management and cropping strategies in the U.S. Based on this report, changes in nutrient removal were estimated from the baseline 2001 year to 2030. It was found that when published estimates of nutrient removal were used for the various crops, nitrogen (N), phosphorus (as P2O5), and potassium (as K2O) removal were projected to increase by 8.4, 8.8, and 11.6 times, respectively, when compared to 2001. Most of these increases were due to corn stover removal and perennial crop harvest. Disparities between published and observed nutrient removals were examined for corn stover. It was found that in at least one set of studies, N and K2O removal were about half of those typically published, while P2O5 removal was only a quarter of the published estimates. Consequently the estimated changes in nutrient removal may be much too high. Greater future nutrient removal by corn stover and perennials will consume a greater portion of fertilizer production capacity, leaving less fertilizer available for export to other countries, stressing the need to understand how to recycle, to the extent possible, nutrients and byproducts from biofuel production facilities back to the farmland that produces their feedstocks.