Post-contract grassland management and winter wheat production on former CRP fields in the southern Great Plains

Integrated management guidelines for postcontract land use Conservation Res erve Program lands in semiarid regions are generally lacking. We determined the relative efficacy of four systems of transitional conservation practic es for producing 'Old World' bluestem (OWB) (Bothriochlora ischaemum L.) an d dryland wheat (Triticum aestivum L.) and cotton (Gossypium hirsutum L.) o n former CRP fields. The sites were located on Dalhart fine sandy loam (Ari dic Paleustalf) and La Casa-Aspermont clay loam (Typic Paleustoll) near For gan and Duke, OK, respectively. Removing old growth increased cumulative OW E yields between 1994 and 1997. Applications of 67 kg N and 16.5 kg P ha(-1 ) increased yields by 0, 70, and 180% at Forgan and 290, 70, and 280% at Du ke in 1995 to 1997, respectively. Removing the old dry matter and regrowth vigor also enhanced chemical suppression and killing of the grass, the perf ormance of conservation tillage, and achieving a uniform crop stand. Early OWE suppression conserved stored water that was vital to cool-season crop p roduction in the year the contract expired. First-year wheat yields average d 970, 490, and 1002 kg ha(-1) at Forgan and 1590, 600, and 830 kg ha(-1) a t Duke under unfavorable weather conditions (i.e., drought, late freeze) of 1995 through 1997, respectively. No-till generally produced higher yields, averaging 10 and 35% greater than conservation systems at Forgan and Duke, respectively. In variable semiarid environment, the chance of success for agronomic production decreased in the order of grass production, NT wheat, tilled wheat, and dryland cotton on former CRP lands.