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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGING FORAGE AND GRAZING LANDS FOR MULTIPLE ECOSYSTEM SERVICES Title: Evaluation of Native Warm-Season Grass Cultivars for Riparian Zones

Authors
item Skinner, Robert
item Zobel, Richard
item Van Der Grinten, Martin - USDA-NRCS
item Skaradek, William - USDA-NRCS

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 18, 2009
Publication Date: December 1, 2009
Citation: Skinner, R.H., Zobel, R.W., van der Grinten, M., Skaradek, W. 2009. Evaluation of native warm-season grass cultivars for riparian zones. Journal of Soil and Water Conservation. 64:413-422.

Interpretive Summary: Due to periodic flooding of their habitat, plants growing in riparian areas are subjected to a variety of stresses including reduced nutrient uptake and reduced oxygen availability. In response to waterlogged conditions, many plant species develop large air spaces in their roots called aerenchyma. These air spaces allow oxygen from shoots to move into submerged root tissues, thus allowing continued root growth and nutrient uptake. We examined aerenchyma development, root growth, plant survival, and aboveground growth of several native warm-season grass species and cultivars. In a greenhouse study, all cultivars exhibited extensive aerenchyma formation but the presence of aerenchyma did not guarantee good root growth under waterlogged conditions. Suitable plant materials for inclusion in riparian areas were found among four of the six warm-season species examined. Nine cultivars representing a range of tolerance to waterlogged soils were further evaluated at four field locations subjected to flooding. Red River prairie cordgrass provided superior performance at all locations. The worst performing cultivars in the greenhouse study also performed poorly in the field. However, not all cultivars that performed well in the greenhouse also performed well in the field. Osage indiangrass was the third ranked cultivar for flooding tolerance in the greenhouse but had acceptable performance at only one of the four field sites. Conversely, Meadowcrest eastern gamagrass exhibited only moderate flooding tolerance in the pot study but was among the best performing cultivars at three of the four locations. Controlled environment studies were useful for eliminating unacceptable cultivars, but field studies were necessary to identify the best cultivars for riparian areas.

Technical Abstract: We examined the suitability of native warm-season grass species and cultivars for use in riparian areas. In a greenhouse study, all cultivars exhibited extensive aerenchyma formation in well-drained soil, and percent aerenchyma was significantly greater in the well-drained control than in the saturated treatment (89 vs. 71%, respectively, P is less than 0.01). However, the presence of extensive aerenchyma development did not guarantee good root growth under anaerobic conditions. Suitable plant materials for inclusion in riparian areas were found among four of the six warm-season species examined, although a wide range in suitability was observed within species where multiple cultivars were tested. Cultivars representing a range of responses were further evaluated at four field locations subjected to flooding and soil saturation. Red River prairie cordgrass (Spartina pectinata L.) provided superior performance at all locations. The worst performing cultivars in the greenhouse study also performed poorly in the field. However, not all cultivars that performed well in the greenhouse also performed well in the field. Osage indiangrass (Sorghastrum nutans L.) was the third ranked cultivar for flooding tolerance in the greenhouse but had acceptable performance at only one of the four field sites. Conversely, Meadowcrest eastern gamagrass (Tripsacum dactyloides L.) exhibited only moderate flooding tolerance in the pot study but had among the lowest mortality, highest vigor, and highest biomass at three of the four locations. Controlled environment studies were useful for eliminating unacceptable cultivars but field studies were necessary to identify suitable material for riparian areas.

Last Modified: 12/20/2014