|SINDELAR, AARON - University Of Minnesota|
|LAMB, JOHN - University Of Minnesota|
|SHEAFFER, CRAIG - University Of Minnesota|
|Jung, Hans Joachim|
|ROSEN, CARL - University Of Minnesota|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/4/2011
Publication Date: 3/1/2012
Citation: Sindelar, A.J., Lamb, J.A., Sheaffer, C.C., Jung, H.G., Rosen, C.J. 2012. Response of corn grain, cellulosic biomass, and ethanol yields to nitrogen fertilization. Agronomy Journal. 104(2):363-370.
Interpretive Summary: Congressional legislation has mandated 16 billion gallons of biofuel production from cellulosic biomass by the year 2022. Corn stover, the residue left after grain harvest, has been projected to supply the largest share of available biomass to meet this near-term goal. It is known that grain yield is increased with nitrogen fertilization, but the stover yield response of modern corn hybrids to nitrogen fertilizer is unknown. A series of studies were conducted around the State of Minnesota to determine the response profiles of corn grain and stover yields to increasing levels of nitrogen fertilization. Both grain and stover yields increased with higher levels of nitrogen fertilizer use, but increasing stover yields usually leveled off before grain yield increases in responding to more nitrogen. This result suggests that optimizing nitrogen fertilizer additions to maximize corn grain yield will generally ensure maximal stover yields also. These results will be of interest to farmers, agricultural consultants, and bioenergy developers.
Technical Abstract: Corn (Zea mays L.) stover will likely play an integral role in near-term attempts to produce renewable cellulosic transportation fuels. However, little is known regarding the influence of nitrogen (N) fertilization on biomass and ethanol yields of stover and cobs. The objectives were to evaluate the effect of N fertilization on stover and cob biomass and ethanol yields across a range of environments, and to determine if these biomass and ethanol yields can be maximized within N fertilization rates for grain yield optimization. Field experiments were conducted over eight environments across Minnesota to determine the effects of N fertilization on cellulosic biomass and ethanol yields. In most environments, stover and cob biomass and ethanol yields increased with increasing N fertilization, and agronomically optimum N rates (AONR) were identified in nearly all responsive environments. Ethanol yields for stover ranged from 2,414 to 3,842 L per hectare, while ethanol yields for cobs ranged from 513 to 906 L per hectare. When AONRs for stover and cob ethanol yields were compared to the respective AONR for grain yield, stover ethanol yield was maximized at N fertilization rates below the AONR for grain yield in five of the seven responsive environments and cob ethanol yield was maximized at N fertilization rates below the AONR for grain yield in five of the six responsive environments. This suggests that stover and cob ethanol yields will often be maximized when grain yield optimization is the primary goal.