Comparison of Interseeding Lespedeza with Additional Nitrogen Fertilization on Forage Production and Steer Performance in a Wheat-Crabgrass Grazing System

Abstract

Grazing and subsequent finishing performance of steers (Bos taurus) grazed on a wheat (Triticum aestivum L.)-crabgrass [Digitaria ciliaris (Retz) Koel.] system were evaluated in 1999, 2000, and 2001 to compare interseeding lespedeza (Lespedeza stipulacea Maxim.) with an additional application of N fertilizer. Hard red winter wheat was no-till seeded in fall 1998, 1999, and 2000 in pastures previously seeded to ‘Red River’ crabgrass. In early spring 1999, 2000, and 2001, additional crabgrass seed was broadcast over all pastures, and Korean lespedeza was no-till seeded in 4 pastures. All pastures received similar applications of fertilizer; however, 3 pastures not seeded with lespedeza received an additional 56kg of N/ha in mid July. Wheat grazing was initiated in mid to late March of each year. Following wheat graze-out, cattle remained on the pastures and grazed crabgrass from mid May until early September. Legume cover, forage DM production, grazing steer performance, and subsequent finishing performance were measured. Available forage DM and grazing BW gains were similar (P > 0.05) between pastures fertilized with additional N and those interseeded with lespedeza. Although there were no treatment differences (P > 0.05), there were significant (P < 0.05) year effects on BW gains. Overall grazing ADG for the wheat-crabgrass system were 0.74, 1.02, and 0.99 kg/d during 1999, 2000, and 2001, respectively. Forage production, BW grazing gains, and subsequent finishing gains were similar (P > 0.05) when pastures in a wheat-crab-grass grazing system were interseeded with lespedeza or fertilized with additional N. However, there were significant (P < 0.05) treatment x year interactions during the finishing phase.