Long-term effects of mechanical renovation of a mixed-grass prairie: I. Plant production

摘要

In 1979, a study was initiated on the northern mixed-grass prairie of southeastern Wyoming to determine the effects of mechanical rangeland renovation ( ripping, double ripping, and contour furrowing) on forage production for livestock grazing. These mechanical treatments enhanced initial forage production and increased livestock carrying capacities. In 1999 and 2000, the original study plot was reevaluated to determine long-term ( 20 years) effects of ripping and double ripping on plant species composition and aboveground production. In 1999, plant production in the single ripped treatment was significantly ( p = 0.01) greater (1.7 Mg ha(-1)) compared to the control (1.3 Mg ha(-1)). Plant production in 2000 was also significantly ( p = 0.06) greater in the single ripped treatment (0.9 Mg ha(-1)) compared to the control (0.5 Mg ha(-1)). Plant production in the double ripped treatment and control were not significantly different in 1999 (2302 vs. 2180 kg ha(-1)) or 2000 (1372 vs. 1192 kg ha(-1)), respectively. Hesperostipa comata (Trin. x Rupr.) Barkworth (needle-and-thread) was the dominant plant species in both treatments in 1999 and 2000, comprising 50% of total forage production. Ripping provided long-term increased forage production on northern mixed-grass prairie by shifting the plant species composition from a plant community dominated by warm-season grasses to one dominated by cool-season grasses.