Data set ID:
Levels of basic cations (Ca, Mg, Na, K) extractable in 1N ammonium acetate (NH4Ac) from soils collected at stations C01 through C90 along the LTER-I Control transect.
Electronic date sheets
Samples are collected near each station on alternate sides of the transect. Distances from the station and from the control transect are designated prior to collection. Soil samples are collected from 0-10cm after removing surface litter. Samples were refrigerated in plastic bags for about 2 weeks and then taken to the NMSU soil and water test lab. Levels of basic cations (Ca, Mg, Na, K) were extracted in 1N ammonium acetate (NH4AC).
In the spring of 1982, as part of the establishment of the Jornada Long-Term Ecological Research site in southern New Mexico, a 135 ha portion of a 1500 ha, internally drained, watershed was exclosed from grazing by domestic livestock. Prior to exclosure the watershed, as well as the rest of the Jornada basin, had been moderately to heavily grazed for the past 100 years. Concurrent with grazing, the vegetation had undergone a dramatic change from desert grassland, with an almost continuous cover of C4 perennial grasses, to isolated patches of the original grassland in a mosaic with desert shrub dominated plant communities (Buffington and Herbel, 1965). The exclosure lies along a northeast facing piedmont slope at the base of a steep isolated mountain peak, and covers a variety of component landforms from the foot of the mountain to the basin floor. The northeast side of the exclosure is immediately upslope of the College Playa located near the NMSU College Ranch. Three parallel transects (2.7 km in length) run from the middle of the College Playa up into the foot of Mt. Summerford. The Control transect is to the west, the Treatment transect on the east side of the Control transect, and the Alternate Control to the east of the Treatment transect. Each transect is 30 meters wide with a 45 meter buffer zone between each transect. The Treatment transect was treated annually until 1987 with NHNO3 in a concentration equal to 10g N/m2. The station markers at 30 meter intervals along each transect. Only the control transect was used in this study.