Tuesday, November 3, 2009
Convention Center, Exhibit Hall BC, Second Floor
The effect of calcium and nitrogen on switchgrass and intermediate wheatgrass growth response was investigated in a greenhouse study. Switchgrass (cv. ‘Sunburst’ and ‘Dacotah’), and intermediate wheatgrass (cv. ‘Reliant’) were grown in hydroponic sand pots for six months. A factorial arrangement consisting of three calcium nutrient solution levels (2 mg L-1, 8 mg L-1, and 32 mg L-1) and three nitrogen nutrient solution levels (2 mg L-1, 8 mg L-1, and 32 mg L-1) were applied daily. Macro nutrients (P, K, Mg, S) and micro nutrients (B, Cu, Fe, Mn, Mo, Zn, Al, Br, I, Co, Li) were maintained at a constant level for the study duration. Greenhouse temperature was maintained at 29°C/18°C. Aboveground biomass was harvested eight times for the duration of the study at a clipped height of 15 cm. Belowground biomass (crown and roots) was harvested at the end the study. Aboveground and belowground samples were dried at 60°C until a constant temperature was reached and ground to pass a 1 mm screen. Cation and anion elements were analyzed using an ion chromatograph. Intermediate wheatgrass aboveground and belowground biomass followed a positive, polynomial response to increasing N and Ca treatments. High calcium rates (32 mg L-1) decreased switchgrass aboveground biomass under medium (8 mg L-1) to high nitrogen (32 mg L-1) treatments. Calcium concentrations in aboveground samples were higher for switchgrass than intermediate wheatgrass. Sulfur and magnesium concentrations in aboveground samples were higher for intermediate wheatgrass than switchgrass regardless of N or Ca treatments. Phosphorous and potassium concentrations increased for switchgrass and intermediate wheatgrass with higher N concentrations with intermediate wheatgrass having higher P and K concentrations than switchgrass. Overall, aboveground biomass response to Ca was positive for intermediate wheatgrass but resulted in lower yields for switchgrass.