Nitrogen Management in No-Till and Conventional-Till Dual-Use Wheat/Stocker Systems
Keywords:nitrogen fertility, dual-purpose wheat, grazing systems, conservation, tillage
Winter wheat in the Texas Rolling Plains is utilized both as forage and grain crop on more than 50% of the wheat sown, and employs conventional tillage in a semi-arid region prone to severe soil erosion by wind and water. The study compared forage and grain yield response to pre-plant and top-dress N application in no-till and conventional-till dual-use wheat production systems. Five pre-plant N levels, two tillage systems, and one top-dress N application were evaluated. There was a linear increase in forage production with increasing pre-plant N application, and no significance difference in forage yield between conventional- and no-till in 3 of 4 yr. Grain production increased with increased pre-plant N, while top-dressed N enhanced grain yield an additional 20 to 40%. In 2 of 4 yr, conventional-till resulted in increased grain yield over no-till by about 10 to 12 %. Top-dressed N resulted in significant yield increases in all pre-plant N treatments but with the greatest yield increases from the 0 and 34 kg ha-1 pre-plant N treatments. Soil analysis data indicate that following poor wheat production years, residual nitrate N can be substantial and could offset N fertilizer requirements for the following wheat crop.