Pasture Management Strategies to Optimize Forage Production in Semi-Arid Environments of the Texas Rolling Plains
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Since the early 2000's, the Southern Great Plains, including Texas, have been experiencing increasing frequency of severe droughts, floods, and heat waves that have negatively impacted almost all aspects of agricultural production. According to the recent report of the U.S. Global Change Research Program, climate models suggest that much of the southeast, south and southwest USA will experience further reductions in precipitation and increases in drought severity and duration. Native and improved grasslands in the USA have already been affected in various ways by the recent abrupt climatic patterns).Wheat is one of the most important cool-season forages in the Rolling Plains and High Plains. More than 70% of wheat acreage is grazed in Texas, and 40 to 45% is cultivated as a forage-only crop. The unpredictable autumn rain season often delays planting of dual-use wheat, resulting in a lack of forage for cattle to graze into the winter and early spring. Complementing wheat forage with improved cool-season perennial grasses has met with poor success because of their inability to adapt to prolonged heat waves and frequent, extended dry periods. Temperate (European continental) cool-season perennial forage grasses derive from germplasm originating from environments lacking extreme heat and prolonged droughts. One adaptation strategy to prolonged dry seasons may be adoption of grasses with a summer dormancy trait. Summer-dormant cool-season grasses originate from the Mediterranean Basin. They express an endogenous summer dormancy mechanism, that is, these grasses cease growth and often lose green leaves during summer even under irrigation. Our results suggest that in semi-arid environments of the Southern Great Plains, grasslands with summer-dormant cool-season grasses might be more persistent and resilient to recent climatic fluctuations than grasslands based on traditional, summer-active cultivars.The major objective of this research program is to optimize forage production based on dual-purpose wheat and other small grains, summer-dormant cool-season perennial grasses and accompanying annual and perennial legumes in semi-arid regions of the Texas Rolling Plains. This objective will be pursued by developing persistent and productive cultivars of summer-dormant cool-season greases, determining management practices of these new forages, and evaluating economic returns from complementary grazing systems based on dual-use wheat and summer-dormant cool-season grasses. Understanding mechanisms of plant responses to biotic and abiotic stresses will help select productive and persistent cultivars, minimize costs of forage production, and maximize return to the producers. Results will be reported to develop integrated forage management systems for semi-arid regions of the Texas Rolling Plains and Southern Great Plains.
