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ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #250658
Title: Switchgrass and intermediate wheatgrass aboveground and belowground response to nitrogen and calcium

Author
item Schmer, Marty
item Hanson, Jonathan
item Johnson, Holly

Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2010
Publication Date: 5/11/2012
Citation: Schmer, M.R., Hanson, J.D., Johnson, H.A. 2012. Switchgrass and intermediate wheatgrass aboveground and belowground response to nitrogen and calcium. Journal of Plant Nutrition. 35:1065-1079.

Interpretive Summary: Switchgrass and intermediate wheatgrass are widely used in conservation plantings and forage production in the Northern Great Plains, U.S.A. Both perennial grasses are currently being evaluated as bioenergy feedstocks. Switchgrass is being developed as a bioenergy crop in the Great Plains because of favorable feedstock costs, soil carbon sequestration, and significant net energy benefits when grown on marginal lands. Intermediate wheatgrass is being evaluated as a potential bioenergy feedstock based on wide-adaptability and stable yields in semi-arid conditions. Optimal nutrient management will be critical in developing sustainable perennial biofeedstocks. Calcium (Ca) and nitrogen (N) treatments effects on aboveground and belowground biomass of switchgrass and intermediate wheatgrass was investigated. Switchgrass and intermediate wheatgrass aboveground and belowground biomass were harvested and analyzed to determine total biomass, macronutrient concentrations (N, Ca, P, K, Mg, S), and forage quality. Intermediate wheatgrass biomass followed a positive response to increasing N and Ca while switchgrass response to N and Ca treatments varied by cultivar. Aboveground Ca concentrations were higher for switchgrass than intermediate wheatgrass under all treatments but intermediate wheatgrass had higher belowground Ca concentrations. A 16-fold increase in Ca supplementation rates resulted in a 2-fold and 3-fold increase in aboveground Ca concentration for switchgrass and intermediate wheatgrass, respectively. Calcium treatments had little impact on measured cell wall characteristics with the exception of hemicellulose content in intermediate wheatgrass. Further investigation on Ca fertilization effects for intermediate wheatgrass yield is warranted.

Technical Abstract: Optimal nutrient management will be critical in developing sustainable perennial biofeedstocks. Calcium (Ca) and nitrogen (N) treatments (2, 8, and 32 mg L-1) were investigated on aboveground and belowground growth of switchgrass (Panicum virgatum L.) and intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] in a greenhouse experiment. Switchgrass (cv. ‘Sunburst’ and ‘Dacotah’), and intermediate wheatgrass (cv. ‘Reliant’) aboveground and belowground biomass were harvested and analyzed to determine total biomass, macronutrient concentrations (N, Ca, P, K, Mg, S), and forage quality. A positive, linear relationship was found between total aboveground and belowground biomass for switchgrass cultivar Sunburst (r2 = 0.92), Dacotah (r2 = 0.95), and intermediate wheatgrass (r2 =0.78). Intermediate wheatgrass biomass followed a positive response to increasing N and Ca while switchgrass response to N and Ca treatments varied by cultivar. Aboveground Ca concentrations were higher for switchgrass than intermediate wheatgrass under all treatments but intermediate wheatgrass had higher belowground Ca concentrations. Increased Ca supplementation rates from 2 mg L to 32 mg L-1 increased aboveground Ca concentrations of 113% and 257% for switchgrass and intermediate wheatgrass, respectively. Calcium treatments had little impact on measured cell wall characteristics with the exception of hemicellulose content in intermediate wheatgrass. Further investigation on Ca fertilization effects for intermediate wheatgrass yield is warranted.