Summer Dormancy Trait as a Strategy to Provide Perennial Cool-Season Grass Forage Alternatives in Southern Latitude Environments Affected by Climate Change
Additional Document Info
2015 by the American Society of Agronomy. Climate change and extreme weather events are affecting agriculture, water supplies, ecosystems, energy use, and the socioeconomic system in the southern Great Plains (SGP) of the United States and other semiarid regions of the world. Winter wheat (Triticum aestivum L.) is one of the crops with the ability to compensate for these weather extremes. Wheat is oft en managed as a dual-use crop in the SGP, providing winter forage for cattle and grain. In the 1970s and 1980s, introduced cool-season perennial grasses were an important source of high quality forage to complement dual-use wheat and perennial native and introduced warm-season grass pastures. Changing climatic conditions are considered one reason for declining persistence of traditional cool-season perennial grasses at the margin of their existence in C-4 dominated ecosystems of the SGP. A primary strategy to supply forage during the cool-season period will be adoption of new forage grasses with improved tolerance to heat and drought. Th is chapter presents current research on summer-dormant cool-season perennial grasses of Mediterranean origin. these grasses express a summer dormancy trait, for example, they cease growth during summer and actively grow during autumn to early spring. Th is growth pattern enables summer-dormant cool-season grasses to adapt to the bimodal springfall precipitation patterns in the SGP and makes them more persistent than traditional, summer-active cool-season perennial grass species. We discuss long-term data on forage productivity, persistence, and soil water dynamics of summer-dormant vs. summer-active cool-season perennial grasses and their potential implementation into grazing systems of the SGP.