Expected Economic Potential of Substituting Legumes for Nitrogen in Bermudagrass Pastures

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 N 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 N 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 N fertilizer. Results are most sensitive to number of grazing days, price of N, and prices of legume seed.