| Maja Krzic, Klaas Broersma, Don J. Thompson, and Arthur A. Bomke |
| Authors Krzic and Bomke are research associate and associate professor, Faculty of Agricultural Sciences, University of British Columbia, Vancouver, BC, Canada V6T 1Z4; Broersma and Thompson are soil scientist and range ecologist, Agriculture and Agri-Food Canada, Range Research Unit, 3015 Ord Road, Kamloops, BC, Canada V2B 8A9. |
Abstract |
| Crested wheatgrass (Agropyron cristatum (L.) Gaertn.) is an introduced grass used extensively for rangeland revegetation in the semiarid and arid regions of western North America. The long-term effects of crested wheatgrass on soil properties and plant community were evaluated on 5 grazed sites in the southern interior of British Columbia, Canada. Each site included plant communities of native bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) Scribn. & Smith) and 14- to 60-year-old stands of crested wheatgrass. Soil samples and plant data were collected in June 1997. Species numbers were similar for native and crested wheatgrass rangelands, while the diversity index of crested wheatgrass rangeland was lower due to lower evenness. Crested wheatgrass and native grasses were observed to produce similar amounts of root biomass. Most soil properties were similar under the 2 rangelands. One of the exceptions was soil carbon at 0–7.5 and 7.5–15 cm depths, which was higher on crested wheatgrass than native rangeland. Soil nitrogen at 15–30 cm depth was also higher on crested wheatgrass rangeland. Greater soil penetration resistance was observed at 7.5 and 9 cm depths on crested wheatgrass than native rangeland. Higher soil compaction was caused by grazing of crested wheatgrass earlier in the season when soils are wetter relative to the native rangeland. The results of this study indicate that seeding of crested wheatgrass combined with the long-term grazing by cattle did not result in the degradation of soil properties, but plant diversity was reduced relative to grazed native, bluebunch wheatgrass rangeland. |
| Key Words: Soil C, soil N, penetration resistance, aggregate stability, root biomass, bluebunch wheatgrass |