Data set ID:
Twenty 6 x 6 m plots were established with a 3 m buffer between plots. Five plots were randomly assigned to one of four treatments: (1) chlordane amendment 100ml AI (active ingredients) per 10,000 ml) to exclude microarthropods, (2) sprinkler irrigation (6 mm per week), (3) sprinkler irrigation (6 mm/week) plus chlordate amendment (as above), (4) control (no treatment). Measurements are taken on Erioneuron pulchellum at monthly intervals. Three randomly located subsamples are collected from each plot. Data set contains plant diameters, mites soil weight, root weight, nematode soil weight, root total nitrogen, and nematode number.
field data sheets, instrumental
For each sample a plant was measured (two diameters and one height) then clipped at ground level, collected in a paper bag and transported the lab. After a plant was collected, a rhizosphere soil sample was taken using a soil core (10 cm diameter, 15 cm depth). The soil sample was placed in a plastic bag, stored in a cooler and immediately transported to the lab. Roots were separated from the soil using a 2 mm sieve, picked up from debris with forceps and cleaned up by hand. Roots were stored in envelopes, oven-dried for 96 hours at 50 C, weighed and ground in a Wiley Mill for total nitrogen analysis. The ground roots were prepared for N analysis by a micro Kjeldahl digestion using an aluminum block digestor (Keeney and Nelson 1982). Nitrogen analyses were performed on the digest using automated procedures on a Scientific Instruments Continuous Flow Analyzer. For each soil sample, subsamples were taken for extraction of microarthropods and nematodes. Microarthropods were extracted in modified Tullgren funnels into water (Santos et al. 1978), then counted and identified to species (Krantz 1978). After microarthropod extraction the soil was sieved through a 2-mm screen mesh and roots were collected. On subsamples for nematode extraction, roots were carefully separated by hand, then nematodes were extracted by a modified sugar flotation technique (Freckman et al. 1977). Remaining soil was sieved through 2-mm screen mesh, then roots were collected and added to roots collected from other subsamples.
This study was conducted in the Jornada del Muerto Basin on the NSF Long-Term Ecological Research (LTER) site, located on the New Mexico State University College Ranch 40 km NNE of Las Cruces, Dona Ana County, New Mexico. The site lies on an alluvial piedmont (bajada) sloping from west to the east and north. The non-arroyo areas of the upper bajada where this study was conducted have an essentially monospecific shrub cover of creosotebush and support a veriety of annuals and the small perennial grass Erioneuron pulchellum (fluff grass). Study plots were established in an area that is downslope from the LTER Upper Trailer and immediately downslope from the road running from the NMSU College Ranch headquarters SSE past the LTER Weather Station and exiting the College Ranch at the south boundary on the same powerline road that runs on along the north side of Mt. Summerford in the Dona Ana Mountains.