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Grazing warm-season grass pastures with stocker cattle {Bos taurus) is an important economic activity in the southern Great Plains, and substantial increases in the price of Ν fertilizer have negatively affected profitability of forage producers. The goal of the study was to determine if bermudagrass [Cynodon dactylon (L.) Pers.] pastures interseeded with either annual or perennial legumes are more profitable than the conventional method of fertilizing with 112 kg Ν ha-1 commercial fertilizer. A completely randomized design grazing study was conducted in south-central Oklahoma during the spring and summer months of 2008, 2009, and 2010. Preconditioned stocker cattle (260 ± 47 kg head-1) were randomly assigned to pastures (1.42 ± 0.10 ha; three replicates per system) at 2.32 ± 0.40 animals ha-1, beginning when measured standing forage reached 2000 kg ha-1 and grazing continuously until forage mass declined to 1000 kg ha-1. Results of the 3-yr grazing study show that under continuous stocking for the growing conditions common to the south-central Great Plains, the legume systems could not compete economically with the common practice of fertilizing bermudagrass pastures with synthetic inorganic Ν fertilizer. Results are most sensitive to number of grazing days, price of N, and prices of legume seed. [ABSTRACT FROM AUTHOR]

Ruminant livestock provides meat and dairy products that sustain health and livelihood for much of the world's population. Grazing lands that support ruminant livestock provide numerous ecosystem services, including provision of food, water, and genetic resources; climate and water regulation; support of soil formation; nutrient cycling; and cultural services. In the U.S. southern Great Plains, beef production on pastures, rangelands, and hay is a major economic activity. The region's climate is characterized by extremes of heat and cold and extremes of drought and flooding. Grazing lands occupy a large portion of the region's land, significantly affecting carbon, nitrogen, and water budgets. To understand vulnerabilities and enhance resilience of beef production, a multi-institutional Coordinated Agricultural Project (CAP), the 'grazing CAP,' was established. Integrative research and extension spanning biophysical, socioeconomic, and agricultural disciplines address management effects on productivity and environmental footprints of production systems. Knowledge and tools being developed will allow farmers and ranchers to evaluate risks and increase resilience to dynamic conditions. The knowledge and tools developed will also have relevance to grazing lands in semiarid and subhumid regions of the world. [ABSTRACT FROM AUTHOR]