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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #308319
Title: Maize stover and cob cell wall composition and ethanol potential as affected by nitrogen fertilization

Author
item Sindelar, Aaron
item SHEAFFER, CRAIG - University Of Minnesota
item LAMB, JOHN - University Of Minnesota
item Jung, Hans Joachim
item ROSEN, CARL - University Of Minnesota

Submitted to: BioEnergy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2015
Publication Date: 3/8/2015
Citation: Sindelar, A.J., Sheaffer, C.C., Lamb, J.A., Jung, H.G., Rosen, C.J. 2015. Maize stover and cob cell wall composition and ethanol potential as affected by nitrogen fertilization. BioEnergy Research. 8(3):1352-1361. DOI: 10.1007/S12155-015-9595-0.

Interpretive Summary: Corn residues that remain after grain harvest can serve as a feedstock for cellulosic ethanol production in attempt to increase renewable fuel production. The amount of nitrogen fertilizer applied to corn has been shown to affect its cellulosic production on an area basis, but its effects on production on a mass basis or its plant cell wall composition are not known. Field trials were conducted over a 2-yr period across multiple locations to answer these questions. Corn cobs and stover (all aboveground corn material minus grain and cobs) were individually examined. This research found that the ethanol yield of stover on a mass basis decreased as the amount of N fertilizer increased. In comparison, ethanol yield of cobs was not affected by N fertilizer amount. These findings are important because the amount of N fertilizer needed to maximize grain yields is dependent upon a range of factors, meaning ethanol potential of stover can vary from field to field. This study also found that lignin, a key component in plant structure and an inhibitor in the cellulosic ethanol production process, increased as N fertilizer increased at four of eight sites for stover, but only at one of eight for cobs. These responses of corn cobs in this study further add to its reported advantages of its limited effects on erosion and runoff nutrient loss and lesser effects on nutrient removal and replacement costs when compared to removing all aboveground cellulosic material.

Technical Abstract: Maize (Zea mays L.) stover and cobs are potential feedstock sources for cellulosic ethanol production. Nitrogen (N) fertilization is an important management decision that influences cellulosic biomass and grain production, but its effect on cell wall composition and subsequent cellulosic ethanol production is not known. The objectives of this study were to quantify the responses of maize stover (leaves, stalks, husks, and tassel) and cob cell wall composition and theoretical ethanol yield potential to N fertilization across a range of sites. Field experiments were conducted at rainfed and irrigated sites in Minnesota, USA, over a 2-year period. Stover cell wall polysaccharides, pentose sugar concentration, and theoretical ethanol yield decreased as N fertilization increased. Stover Klason lignin increased with N fertilization at all sites. Cob cell wall composition was less sensitive to N fertilization, as only pentose and Klason lignin decreased with N fertilization at two and one site(s), respectively, and hexose increased with N fertilization at one of eight sites. Cob theoretical ethanol yield was not affected by N fertilization at any site. These results indicate variation in stover cellulosic ethanol production is possible as a result of N management. This study also demonstrated that cell wall composition and subsequent theoretical ethanol yield of maize cobs are generally more stable than those with stover because of overall less sensitivity to N management.