Jornada Basin LTER Research

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Dataset: Transect Total Nitrogen in Soil


   Download data: File trantotn.dat
   File description including attribute definitions: data_JornadaStudy_400_transect_soil_total_nitrogen
   Original Investigator: Peter Wierenga
   Data contact: John Anderson
   Duration: 1985 - 1986
   Dataset ID: 210400004
   Abstract:

Total nitrogen in soil was determined on control and treatment (fertilized) transects by Kjeldahl digestion.


   Additional information:

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.

   Methods:

Lab data sheets

   Methods:

Total N determined by Kjeldahl digestion followed by digest NH4-N determination by an automated salicylate procedure. Two digests were performed for each sample; nitrogen expressed as mg-N/kg oven-dry (50C) soil ground to pass a 0.15 mm sieve

   Maintenance:

Twice