Recovery of Steppe Ecosystems on Abandoned Fields
Bill Lauenroth, Dept of Forest, Range, and Watershed Stewardship, Colorado State University, Ft. Collins, CO 80523
970-491-7581 billl@cnr.colostate.edu
Indy Burke, Dept of Forest, Range, and Watershed Stewardship, Colorado State University, Ft. Collins, CO 80523
970-491-1620 indy@cnr.colostate.edu
Objective: To evaluate recovery of plants and soils on abandoned agricultural fields, and the effects of grazing or protection from grazing on recovery. Vegetation and soils were sampled in 1990 and 1991 on two fields abandoned in the 1930's and on adjacent, unplowed areas. Both of these fields were located in section 26 (see previous summary form). Plant sampling was nondestructive: cover and density by species were obtained using 20 X 50-cm quadrats located on six 105-m transects placed perpendicular to the west edge of each field. Soils were sampled by collecting soil cores at three depths (0-5, 5-10, 0-30 cm) on two of the transects. Soils were analyzed for texture, nutrients, and biological activity. These sites at the CPER are part of an east-west transect of sites in the Pawnee National Grasslands that were established under LTER and Earthwatch funding, and will be part of a larger transect of north-south sites to be established under EPA funding.
Methods: We are proposing to continue and extend this project in 1992 by sampling all old fields and adjacent unplowed areas, including adjacent grazed and ungrazed areas on abandoned fields at the CPER (See color map for location of old fields). Sampling will be similar to that used previously for vegetation and soils. Four old fields that contain grazing exclosures will also be sampled (sections 6, 8, 10, 18; seee site description). We will sample both inside and outside exclosures on abandoned fields, and in an adjacent location within the sections on native rangeland. Sampling will be similar to that used previously: plant cover and density by species will be obtained at each of the three locations within each section: (1) old field, exclosed; (2) old field, grazed; (3) adjacent, unplowed rangeland. Soils will be sampled at each of the three locations within each section by collecting 10 30-cm depth cores, 10 15-cm depth cores, and by locating 10 15-cm depth cores for in situ incubations.
01/21/2008