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United States Department of Agriculture

Agricultural Research Service

Title: Growth and Photosynthesis Rate in Upland and Lowland Ecotypes of Switchgrass

Authors
item Stroup, J. - TEXAS A&M UNIVERSITY
item SANDERSON, MATT
item Mcfarland, M. - TEXAS A&M UNIVERSITY
item Reed, R. - TEXAS A&M UNIVERSITY

Submitted to: American Forage and Grassland Council Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 13, 1997
Publication Date: N/A

Interpretive Summary: Switchgrass is a warm-season perennial forage species that can be classified into two strains. Upland strains have been used mainly for hay and grazing and may be more tolerant of drier conditions. Lowland strains are taller growing, more robust plants than upland strains and do well in wetter environments. Limited evidence suggests that upland and lowland strains may differ in their response to nitrogen fertilizer and water inputs. We conducted a pot study outdoors to examine responses of both strains to low and high nitrogen levels. The lowland strains yielded more dry matter and had a greater leaf area than did the upland strains. Nitrogen at 90 lb per acre increased individual plant yields by sixfold and upland strains had a proportionately greater response to nitrogen fertilizer than did lowland strains. These data indicate that upland strains may be more sensitive to low soil nitrogen fertility than lowland strains. Continued research will focus on responses of each strain to drought.

Technical Abstract: Research is being conducted on the management and productivity of switchgrass (Panicum virgatum L) as a bioenergy crop. Our objective was to examine lowland ('Alamo' and 'Kanlow') and upland ecotypes ('Blackwell' and 'Caddo') of switchgrass for differences in response to water deficits and N fertilizer. Ecotypes were grown in pots with fritted clay at two water levels and two N levels (9 and 90 lb/acre). Due to environmental conditions, water stress was not realized during the experiment. Nitrogen at 90 lb/acre increased individual plant yields by sixfold and upland ecotypes had a proportionately greater response to fertilizer N than did lowland ecotypes. Biomass yields of lowland ecotypes were twice that of upland ecotypes at both N levels.

Last Modified: 9/10/2014
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