**The objective of the present research was to determine whether there have been changes in the structure and function of the surface (0-20cm) soil system, the zone most affected by litter decomposition, which is associated with the rapid movement of mesquite from historical habitats (arroyo and playa fringe) into recent habitats (grassland and dunes). We hypothesized that the soil biotic communities would be poorly developed in the recent mesquite habitats because of lower soil C and nutrient concentrations. As a result of these differences we predicted lower rates of net N mineralization in the soils from recent mesquite habitats. Data set contains analyses for gravimetric soil moisture, pH, phosphate, total Kjeldahl nitrogen, total phosphorus, NO3-N nitrogen mineralization, total inorganic nitrogen, NH4-N nitrogen mineralization, organic carbon, inorganic carbon, total roots, tap roots, intermediate roots, and fine roots.
Mesquite litterfall collected monthly from mesquite fringe on south side of College Playa. Oven-dry weights of leave, stem, and seed fractions as well as total dry weight are recorded.
*Changes in microarthropod assemblages were monitored in six types of decomposing surface leaf-litter confined in mesh bags and set across a Chihuahuan Desert watershed for 17 months. The following hypotheses were tested: 1) microarthropod density and diversity are higher in soils with maximum surface litter accumulation, and 2) temporal patterns of density and diversity are more dependent on seasonal factors and physical disturbances than on the decompositional stage of the litter.
Soil nutrient distribution in NPP quads in the Mesquite, Grassland, Playa, Creosotebush, and Tarbush plant communities sampled at 3 spatial scales of grids. Soils were sampled from the NPP (biomass plots). Each of the five vegetation types (mesquite, grassland, playa, creosote, tarbush) had three sites (with low, medium, and high production levels). At 14 of 15 sites a grid of 70 by 70 meters was set out. Within this 49 plots of 10 by 10 meters were placed and labeled (numbered) in serpentine design. At the 15th site, Playa College, 48 plots of 10 by 10 meters were laid out in three long rows of 16 plots per row. At all sites the soil sample of 0-10 cm depth was taken 1 meter from the NE marker bar at a diagonal (heading toward the SW marker). 70m x 70m layout of NPP quads where 1 is in NE corner. 43 42 29 28 15 14 1 44 41 30 27 16 13 2 45 40 31 26 17 12 3 46 39 32 25 18 11 4 47 38 33 24 19 10 5 48 37 34 23 20 9 6 49 36 35 22 21 8 7 160m x 30m layout of P-COLL NPP quads where 1 is in NE corner. 33 32 1 34 31 2 35 30 3 36 29 4 37 28 5 38 27 6 39 26 7 40 25 8 41 24 9 42 23 10 43 22 11 44 21 12 45 20 13 46 19 14 47 18 15 48 17 16 At one of each of the five vegetation types another set of 49 soils (#101-149) was taken from within one of the 10 by 10 meter plots. Using a 7 by 7 meter grid (bounded by the southern east-west boundary line and the western north-south boundary line[#149 is in the SW corner]) soils were sampled 1 meter apart using a serpentine design. 7m x 7m layout within single 10m x 10m NPP plot. 143 142 129 128 115 114 101 144 141 130 127 116 113 102 145 140 131 126 117 112 103 146 139 132 125 118 111 104 147 138 133 124 119 110 105 148 137 134 123 120 109 106 149 136 135 122 121 108 107
Soil nutrient distribution beneath and between plant canopies in the Mesquite, Grassland, Playa, Creosotebush, and Tarbush plant communities. The LTER plant biomass plots was sampled in June 1989. A total of 750 soil samples were collected from 5 depths (0- 10, 10-20, 20-40, 40-60, 60-100 cm), 2 locations (under and between shrubs), within 5 vegetation zones (Mesquite, Grassland, Playa, Creosotebush, Tarbush), 3 sites per zone (site with low, medium, and high biomass, ranked based on FALL-89 biomass), and 5 directions per site (in buffer zone just outside of NPP plots N, S, E, W, and in the center of NPP plots C). Samples were analyzed for pH, CaCO3, NaHCO3- extractable P, KCl-extractable NH4 and NO3, total kjeldahl N, Saturation extrac cations, and DTPA-extractable micronutrients.
Soils were sampled under Prosopis at four sites and under Larrea at one site on the Jornada Desert Site on October 1, 1986. Samples were taken from two depths (0-15cm, 15-30cm) for three canopy positions and one interzone position for each tree or shrub. Four trees or shrubs were sampled at each site. The soils were analyzed for Total Kjeldahl Nitrogen (TKN), and inorganic N-- nitrate-N and ammonium-N.
Plant nutrient distribution beneath and between plant canopies in the Mesquite, Grassland, Playa, Creosotebush, and Tarbush plant communities. The LTER plant biomass plots were harvested during spring, fall, 1989 and winter 1990, in 5 vegetation zones (Mesquite, Grassland, Playa, Creosotebush, Tarbush), 3 sites per zone (site with low, medium, and high biomass, ranked based on fall-89 biomass). Samples were analyzed for total Kjeldahl N, and total phosphorus. Site ranking based on Fall 1989 biomass estimates: ZONE SITES BIOMASS (using FALL-89 rank of plant) M RABB low M NORT medium M WELL high G IBPE low G SUMM medium G BASN high P TABO low P COLL medium P SMAL high C CALI low C GRAV medium C SAND high T WEST low T TAYL medium T EAST high
**We addressed the question, are microarthropod assemblages present in soils throughout the rhizosphere of a deep-rooted desert plant? If microarthropods are present, what is the taxonomic and functional structure of that assemblage? The presence of a generalist microarthropod assemblage would suggest functional relationships among deep soil biota similar to the relationships documented in shallow soils. Data set consists of microarthropods and microarthropod numbers found at different soil depths associated with four mesquite ecosystems (playa, coppice dune, arroyo, and grassland).
Soil cores were collected under mesquite (Prosopis glandulosa) trees at playa, wash, sand dune, and grassland sites on the Jornada LTER site to depths of 15, 9, 7, and 4 m. Soil cores (to 4 m) were also taken under creosote bush (Larrea tridentata) near the wash site. Soils were extracted and analyzed for micronutrients, Zn, Cu, Fe, and Mn.
Soil cores collected under mesquite (Prosopis glandulosa) trees at several sites and under Larrea at one site at the Jornada LTER were incubated to determine the N-mineralization potential.