soil properties

Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Temperature, Moisture, and Carbon Dioxide Data from the Sevilleta National Wildlife Refuge, New Mexico (2011 - present)

Abstract: 

Humans are creating significant global environmental change, including shifts in climate, increased nitrogen (N) deposition, and the facilitation of species invasions. A multi-factorial field experiment is being performed in an arid grassland within the Sevilleta National Wildlife Refuge (NWR) to simulate increased nighttime temperature, higher N deposition, and heightened El Niño frequency (which increases winter precipitation by an average of 50%). The purpose of the experiment is to better understand the potential effects of environmental drivers on grassland community composition, aboveground net primary production and soil respiration. The focus is on the response of two dominant grasses (Bouteloua gracilis and B eriopoda), in an ecotone near their range margins and thus these species may be particularly susceptible to global environmental change.

It is hypothesized that warmer summer temperatures and increased evaporation will favor growth of black grama (Bouteloua eriopoda), a desert grass, but that increased winter precipitation and/or available nitrogen will favor the growth of blue grama (Bouteloua gracilis), a shortgrass prairie species. Treatment effects on limiting resources (soil moisture, nitrogen availability, species abundance, and net primary production (NPP) are all being measured to determine the interactive effects of key global change drivers on arid grassland plant community dynamics and ecosystem processes. This dataset shows values of soil moisture, soil temperature, and the CO2 flux of the amount of CO2 that has moved from soil to air.

On 4 August 2009 lightning ignited a ~3300 ha wildfire that burned through the experiment and its surroundings. Because desert grassland fires are patchy, not all of the replicate plots burned in the wildfire. Therefore, seven days after the wildfire was extinguished, the Sevilleta NWR Fire Crew thoroughly burned the remaining plots allowing us to assess experimentally the effects of interactions among multiple global change presses and a pulse disturbance on post-fire grassland dynamics.

Core Areas: 

Data set ID: 

305

Keywords: 

Methods: 

Experimental Design

Our experimental design consists of three fully crossed factors (warming, increased winter precipitation, and N addition) in a completely randomized design, for a total of eight treatment combinations, with five replicates of each treatment combination, for a total of 40 plots. Each plot is 3 x 3.5 m. All plots contain B. eriopoda, B. gracilis and G. sarothrae. Our nighttime warming treatment is imposed using lightweight aluminum fabric shelters (mounted on rollers similar to a window shade) that are drawn across the warming plots each night to trap outgoing longwave radiation. The dataloggers controlling shelter movements are programmed to retract the shelters on nights when wind speeds exceed a threshold value (to prevent damage to shelters) and when rain is detected by a rain gauge or snow is detected by a leaf wetness sensor (to prevent an unintended rainout effect).

Each winter we impose an El Nino-like rainfall regime (50% increase over long-term average for non-El Nino years) using an irrigation system and RO water. El Nino rains are added in 6 experimental storm events that mimic actual El Nino winter-storm event size and frequency. During El Nino years we use ambient rainfall and do not impose experimental rainfall events. For N deposition, we add 2.0 g m-2 y-1 of N in the form of NH4NO3 because NH4 and NO3 contribute approximately equally to N deposition at SNWR (57% NH4 and 43% NO3; Bez et al., 2007). The NH4NO3 is dissolved in 12 liters of deionized water, equivalent to a 1 mm rainfall event, and applied with a backpack sprayer prior to the summer monsoon. Control plots receive the same amount of deionized water.

Soil Measurements

Soil temperature is measured with Campbell Scientific CS107 temperature probes buried at 2 and 8 cm In the soil. Soil volume water content, measured with Campbell Scientific CS616 TDR probes is an integrated measure of soil water availability from 0-15 cm deep in the soil. Soil CO2 is measured with Vaisala GM222 solid state CO2 sensors. For each plot, soil sensors are placed under the canopy of B. eriopoda at three depths: 2, 8, and 16 cm. Measurements are recorded every 15 minutes.

CO2 fluxes are calculated using the CO2, temperature, and moisture data, along with ancillary variables following the methods of Vargas et al (2012) Global Change Biology

Values of CO2 concentration are corrected for temperature and pressure using the ideal gas law according to the manufacturer (Vaisala). We calculate soil respiration using the flux-gradient method (Vargas et al. 2010) based on Fick’s law of diffusion where the diffusivity of CO2 is corrected for temperature and pressure (Jones 1992) and calculated as a function of soil moisture, porosity and texture (Moldrup et al. 1999).

Data sources: 

sev305_wenndex_soiltemp_moisture_co2_2011
sev305_wenndex_soiltemp_moisture_co2_2012
sev305_wenndex_soiltemp_moisture_co2_2013
sev305_wenndex_soiltemp_moisture_co2_2014
sev305_wenndex_soiltemp_moisture_co2_2015

Instrumentation: 

Instrument Name: Solid State Soil CO2 sensor
Manufacturer: Vaisala
Model Number: GM222

Instrument Name: Temperature Probe
Manufacturer: Campbell Scientific
Model Number: CS107

Instrument Name: Water Content Reflectometer Probe
Manufacturer: Campbell Scientific
Model Number: CS616

Monsoon Rainfall Manipulation Experiment (MRME) Soil Temperature, Moisture and Carbon Dioxide Data from the Sevilleta National Wildlife Refuge, New Mexico (2012- present)

Abstract: 

The Monsoon Rainfall Manipulation Experiment (MRME) is designed to understand changes in ecosystem structure and function of a semiarid grassland caused by increased precipitation variability, by altering rainfall pulses, and thus soil moisture, that drive primary productivity, community composition, and ecosystem functioning. The overarching hypothesis being tested is that changes in event size and frequency will alter grassland productivity, ecosystem processes, and plant community dynamics. Treatments include (1) a monthly addition of 20 mm of rain in addition to ambient, and a weekly addition of 5 mm of rain in addition to ambient during the months of July, August and September. It is predicted that changes in event size and variability will alter grassland productivity, ecosystem processes, and plant community dynamics. In particular, we predict that many small events will increase soil CO2 effluxes by stimulating microbial processes but not plant growth, whereas a small number of large events will increase aboveground NPP and soil respiration by providing sufficient deep soil moisture to sustain plant growth for longer periods of time during the summer monsoon.

Core Areas: 

Data set ID: 

304

Keywords: 

Methods: 

Experimental Design

MRME contains three ambient precipitation plots and five replicates of the following treatments: 1) ambient plus a weekly addition of 5 mm rainfall, 2) ambient plus a monthly addition of 20 mm rainfall. Rainfall is added during the monsoon season (July-Sept) by an overhead (7 m) system fitted with sprinkler heads that deliver rainfall quality droplets. At the end of the summer, each treatment has received the same total amount of added precipitation, delivered in different sized events. Each plot (9x14 m) includes subplots (2x2 m) that receive 50 kg N ha-1 y-1. Each year we measure: (1) seasonal (July, August, September, and October) soil N, (2) plant species composition and ANPP, (3) annual belowground production in permanently located root ingrowth cores, and (4) soil temperature, moisture and CO2 fluxes (using in situ solid state CO2 sensors).

Soil Measurements

Soil temperature is measured with Campbell Scientific CS107 temperature probes buried at 2 and 8 cm In the soil. Soil volume water content, measured with Campbell Scientific CS616 TDR probes is an integrated measure of soil water availability from 0-15 cm deep in the soil. Soil CO2 is measured with Vaisala GM222 solid state CO2 sensors. For each plot, soil sensors are placed under the canopy of B. eriopoda at three depths: 2, 8, and 16 cm. Measurements are recorded every 15 minutes.

CO2 fluxes are calculated using the CO2, temperature, and moisture data, along with ancillary variables following the methods of Vargas et al (2012) Global Change Biology

Values of CO2 concentration are corrected for temperature and pressure using the ideal gas law according to the manufacturer (Vaisala). We calculate soil respiration using the flux-gradient method (Vargas et al. 2010) based on Fick’s law of diffusion where the diffusivity of CO2 is corrected for temperature and pressure (Jones 1992) and calculated as a function of soil moisture, porosity and texture (Moldrup et al. 1999).

Data sources: 

sev304_mrme_soiltemp_moisture_co2_2012
sev304_mrme_soiltemp_moisture_co2_2013
sev304_mrme_soiltemp_moisture_co2_2014
sev304_mrme_soiltemp_moisture_co2_2015

Instrumentation: 

Instrument Name: Solid State Soil CO2 sensor
Manufacturer: Vaisala
Model Number: GM222

Instrument Name: Temperature Probe
Manufacturer: Campbell Scientific
Model Number: CS107

Instrument Name: Water Content Reflectometer Probe
Manufacturer: Campbell Scientific
Model Number: CS616

Additional information: 

Additional Study Area Information

Study Area Name: Monsoon site

Study Area Location: Monsoon site is located just North of the grassland Drought plots

Vegetation: dominated by black grama (Bouteloua eriopoda), and other highly prevalent grasses include Sporabolus contractus, S.cryptandrus, S. lexuosus, Muhlenbergia aernicola and Bouteloua gracilis.

North Coordinate:34.20143
South Coordinate:34.20143
East Coordinate:106.41489
West Coordinate:106.41489

Fungal Thermophile Survey at the Sevilleta National Wildlife Refuge, New Mexico

Abstract: 

Biological soil crusts (BSCs) are complex assemblages of fungi, lichens, bacteria, mosses and green algae that stabilize surface soils and manage and traffic photosynthate, nutrients and water to diverse microbial and producer communities in arid environments worldwide.  In Sevilleta grasslands, BSCs occupy much of the open space between clumps of vegetation and vary substantially in terms of structure. 

BSCs have important biological and physical roles.  They have been termed ‘mantles of fertility’ because of their general importance in biogeochemical cycling and net primary production in arid ecosystems.  It has been proposed that BSCs play a role in the rapid movement of N, C and water from open areas to plants (see below).  BSCs stabilize soils, and physical and chemical disturbances of BSCs lead to topsoil loss and dust storms.  BSCs are therefore critical components in efforts to understand implications of both climate change and physical disturbance.  Related to this, it has been suggested that BSC diversity can be used to inform conservation policies.

BSCs have been the subject of several previous Sevilleta LTER studies.  Green et al. showed that stable-isotope carbon and nitrogen could be transferred bi-directionally between BSCs and adjacent plants.  This led Collins et al. to propose that fungal hyphae provide connections between plant roots and BSCs that allow for transport between the two, a proposal known as the “fungal loop hypothesis.”  Porras-Alfaro et al. have surveyed the diversity of fungi in BSCs from Sevilleta grasslands using molecular methods.  We have also shown that thermophilic fungi are common in BSCs (unpublished results), a result that is not unexpected given the high summer temperatures attained in Sevilleta surface soils.  Yet, many questions remain regarding the organisms present in BSCs, their biological roles and how long it takes for BSCs to re-establish after disturbance.  Long-term, we are interested in the types of fungi present in BSCs and in how fungi function in transporting nutrients between BSCs and adjacent plants.  We are also interested in the extent to which specific fungi provide structure to BSCs and in how they help protect from stress agents such as desiccation.  We are interested in the extent to which fungi might help BSCs tolerate high summer soil temperatures, which often reach ≥ 60C.  We therefore have a special interest in thermophilic fungi present in the BSCs.  To date, little has been done to actually culture fungi from Sevilleta BSCs, hence the need for the current study.  

In summary, BSCs are one of the most important features of aridland ecosystems and form a critical interface between physical and biological domains.  Understanding the roles of BSCs in protecting soil structure, and in the cycling of carbon, water and nitrogen, is fundamental to aridland ecology.  The work proposed here continues efforts to characterize the specific fungi associated with Sevilleta BSCs.  It is a modest but important step toward addressing the long-term goals mentioned above.

Core Areas: 

Additional Project roles: 

31

Data set ID: 

281

Keywords: 

Methods: 

For each sampling site and sampling period a small amount of surface crust (approx. one teaspoon per sample) was taken from each of 10 locations at approximately 1 meter intervals across a transect.  Samples were transported back to the laboratory in plastic bags.

On rare occasions, a larger sample of 0.5 liter volume or less may have been removed at one or two sampling stations.

Additional information: 

Data was collected at: LTER PJ site (N 34 23’ 08.7” W 106 31’ 27.0”), a sand dune above the railroad tracks near the Sevilleta wetlands (N34 18' 06.5"  W106 51' 14.1"), gypsum outcroppings (N34 12' 40.5"  W106 45' 35.5"), grasslands near the Sev LTER warming and monsoon sites (N34 21' 34.3" W106 41' 29.4" and N34 20' 38.1"  W106 43' 34.5"), and the Rio Grande Bosque (N34 19'45" W106 51'40").

 

The varied topography and large elevation gradients that characterize the arid and semi-arid Southwest create a wide range of climatic conditions - and associated biomes - within relatively short distances. This creates an ideal experimental system in which to study the effects of climate on ecosystems. Such studies are critical givien that the Southwestern U.S. has already experienced changes in climate that have altered precipitation patterns (Mote et al. 2005), and stands to experience dramatic climate change in the coming decades (Seager et al. 2007; Ting et al. 2007).

Influence of Pedogenic Carbonate on the Physical and Hydrologic Properties of a Semi-Arid Soil at the Sevilleta National Wildlife Refuge, New Mexico

Abstract: 

The goal of this project is to determine the nature and magnitude of changes in the hydrologic properties of arid soils with increasing amounts of pedogenic calcium carbonate. The amount and morphology of the calcium carbonate in arid soils varies laterally and vertically with changes in the age of the soils, thus the hydrologic properties also vary systematically The calcium carbonate cements soil particles changing the apparent texture of the soil horizon and thus other soil properties such as structure, porosity, moisture retention, and unsaturated and saturated hydraulic conductivity also change significantly. There has been no systematic study of the impact of increasing amounts of calcium carbonate on the hydrologic properties of semi-arid soils. The ultimate goal of this study is to provide a basis for developing more accurate pedotransfer functions, which are the main methods for obtaining soil hydrologic properties of rangeland soils. 

Core Areas: 

Additional Project roles: 

42
43
44

Data set ID: 

240

Keywords: 

Methods: 

Selection of Surfaces: Three terraces of different ages were chosen at the outlet of a small watershed basin at the base of Sierra Ladrones  in North West Sevilleta National Wildlife Refuge. These surfaces have shown varying stages of calcic horizons.

Digging Pits: 3 Pits up to a meter deep were dug on each surface. 

Describing the Soils: the soil profile in each pit was described using USDA soil survey guidelines.

Soil Sampling: From every pit, soil samples were collected every 10 cm. Also soil peds were collected from every horizon for bulk density analysis.

Infiltration Experiment: In order to check the soil hydraulic conductivity, a tension disk infiltrometer was used on every soil horizon in each pit.

Laboratory Analysis: The soil samples were split and sieved for laboratory analysis

CaCO3 Content: The total inorganic carbonate content was calculated using Chittick’s apparatus

Bulk Density: The bulk density of the soil peds was calculated using the Clod’s apparatus.

PSDA: Particle size distribution analysis was carried out with the presence of carbonate on the 2mm sample.

Carbonate Digestion: The carbonate was digested to remove the amount of carbonate from the sample. PSDA was performed again on the soil samples without the carbonate.

Additional information: 

Information on Collection Sites:

Study Area 1:  

Study Area Name: Surface 1(Pit 1)(Young Surface)

Study Area Location: Outlet of the small watershed basin at the base of Sierra Ladrones

Study Area Description:  

Elevation: 1623 m

Landform: Terrace

Geology: Quaternary Sierra Ladrones Formation

Soils: Laborcita-Pilabo-Lemitar complex

Vegetation: Shrubland

Climate: Semi arid, Rainfall ~ 250 mm

Single Point:  

North Coordinate:  34° 24.5’

West Coordinate: 106°  58.1'

Study Area 2: 

Study Area Name: Surface 2 (Pit 2)(Intermediate Surface)

Study Area Location: Outlet of the small watershed basin at the base of Sierra Ladrones

Study Area Description:  

Elevation: 1615 m

Landform: Terrace

Geology: Quaternary Sierra Ladrones Formation  

Soils: Laborcita-Pilabo-Lemitar complex

Vegetation: Shrubland

Climate: Semi-arid, Rainfall ~250 mm

Single Point:  

North Coordinate: 34°   24.491' 

West Coordinate: 106°  58.046' 

Study Area 3:  

Study Area Name: Surface 3 (Pit 3) (Oldest Surface)

Study Area Location: Outlet of the small watershed basin at the base of Sierra Ladrones

Study Area Description:  

Elevation: 1633 m 

Landform: Terrace

Geology: Quaternary Sierra Ladrones Formation  

Soils: Laborcita-Pilabo-Lemitar complex

Vegetation: Pinon-Juniper/Shrubland

Climate: Semi-arid, Rainfall~250 mm

Single Point:  

North Coordinate: 34° 24.405' 

West Coordinate: 106° 58.020'

Other Field Crew Members: Ritchie Andre and Ramirez Carlos

Temporal Dynamics of Soil Carbon and Nitrogen Resources Within a Grassland-Creosote Ecotone at the Sevilleta National Wildlife Refuge, New Mexico (1992-1994)

Abstract: 

Plant communities across large portions of the southwestern United States have shifted from grassland to desert shrubland. Studies have demonstrated that soil nutrient resources become spatially more heterogeneous and are redistributed into islands of fertility with this shift in vegetation. This research addressed the additional question of whether soil resources become more temporally heterogeneous along a grassland-shrubland ecotome. Within adjacent grassland and creosotebush sites, soil profiles were described at 3 pits and samples collected for description of nutrient resources within the profile. Relative cover of plant species and bare soil were determined within each site by line transects. The top 20-cm of bare soil or soil beneath the canopy of grasses/creosotebush were collected 17 times during 1992-1994. Soil samples were analyzed for soil moisture, extractable ammonium and nitrate, nitrogen mineralization potential, microbial biomass carbon, total organic carbon, microbial respiration, dehydrogenase activity, ratio of microbial C to total C (C[mic]-to-C[org]), and microbial respiration to biomass carbon (metabolic quotient).

The major differences in the structure of soils between sites were the apparent loss of a 3 to 5-cm depth of sandy surface soil at the creosotebush site and an associated increase in calcium carbonate content at a more shallow depth. Soils under plants at both sites had greater total and available nutrient resources with higher concentrations under creosotebush than under grasses. Greatest temporal variation in available soil resources was shown in soils under creosotebush. When expressed on an area basis, greater temporal variation in the total amount of available soil resources was shown in the grassland site, primarily due to greater plant cover (45% in grassland vs. 8% in creosote).

Core Areas: 

Data set ID: 

52

Additional Project roles: 

192
193
194
195

Keywords: 

Data sources: 

sev052_soilnutrient_11102003.txt

Methods: 

Study Area - The study area was located on the Sevilleta National Wildlife Refuge (NWR) in Central New Mexico, a 93,000 ha wildlife refuge managed by the U.S. Fish and Wildlife Service established in 1973. Prior to establishment of the refuge, the area was grazed by livestock, but domesticated livestock are now totally excluded.  An area within the Sevilleta NWR locally known as "5-Points" has been the focus of intense study as part of the Sevilleta Long-Term Ecological Research (LTER) project. Our study area is located approximately 2.5 km west of 5-Points, 13 km east of the Rio Grande, and 1 km north of Palo Duro Canyon, an ephemeral drainage. The study area was selected in 1989 for intensive study because it appeared "typical" of the grassland-creosote bush ecotone in the northern Chihuahuan Desert, with creosotebush extending from the area closest to the rim of Palo Duro Canyon into the grasslands to the north.

Sampling Webs - Within the study area, experimental plots used to quantify arthropod and rodent populations were established in 1989. These circular plots, or "webs" (Anderson et al. 1983), have a 100-m radius. Five webs were in a site dominated by creosotebush and five other webs were in a site within the grassland to the northeast. Each web was at least 200 m from other webs. Each web comprised a sample unit for this study.

Meteorological collections - Meteorological conditions were measured at a permanent station (Deep Well) approximately 3 km to the northeast of the study area. This station continuously measures meteorological conditions including precipitation, air temperature, relative humidity, mean wind speed, mean vectored wind speed, mean vectored wind direction, maximum and minimum wind speeds, precipitation, 1- and 10-cm depth soil temperature, 10- and 30-cm depth soil moisture, and solar flux. All variables are recorded on an hourly basis, except for precipitation which is recorded on a 1-minute basis during periods of precipitation. The data are downloaded at the Sevilleta Field Research Station every 8 hours through radio links.

Soil characterization - Soil pits were excavated to characterize the soil's morphological properties and to collect representative samples from individual horizons for laboratory analyses of physical and chemical properties. Three pits were dug in each vegetative community near the grassland and creosotebush webs. Genetic horizons were identified and their mean depth and thickness, color, and root score were determined. Samples were analyzed at New Mexico State University's Soil, Water and Air Testing Laboratory for the following: organic matter; exchangeable Ca, Mg, Na, and K; pH; electrical conductivity; extractable phosphorus; total phosphorus; KCl-extractable ammonium and nitrate; and % CaCO3 equivalents. Water content was measured gravimetrically after 24 h desiccation at 105 degrees C. Soil pH was measured using a pH meter on a 1:1 wt/wt slurry of soil and 0.01 M CaCl2. Soil texture was measured by the hydrometer method (Day 1965).

Vegetative community structure - Aboveground cover of individual plant species, as well as non-vegetative ground cover by categories (bare soil, litter, gravel and rock), were measured in the grassland and creosotebush communities using the Community Structure Analysis (CSA) technique of Pase (1981) (Wolters et al. 1996).

Soil sampling for C and N dynamics - For each soil collection, a randomly located point on the circumference of each web was selected. A different point was used for each of the 10 webs, and this point was removed from the pool of possible points for future collections. Soil samples consisted of 4-cm diameter by 20-cm long cores collected from the perimeters of the webs (5 webs for each site). Samples were collected from beneath the canopies of the two closest individual plants (within the grass clumps or a single core at 1/3 the canopy radius from the base of the closest two creosotebushes in their respective webs) and two from open soils approximately mid-point between the closest plants. Comparable samples from diametrically opposite points on the circle were collected and pooled in the field, resulting in one pooled sample consisting of 4 cores each of canopy soil and open soil from each of the ten sample webs.

Sample webs were collected 17 times during 1992-1994, beginning in April 1992 and ending in August 1994. Samples were placed in an ice chest and transported on ice to the Sevilleta Field Station or the University of New Mexico, where they were sieved (2 mm), mixed, split into two portions and stored at 5 degrees C. Total carbon was measured on all soils by a wet oxidation technique (Nelson and Sommers 1982).

Microbial biomass and respiration analyses - Microbial measurements were made within 3 weeks of sample collection. Basal respiration was measured as the change in CO2 concentration in the headspace gas in 60-ml serum vials containing soil samples as they were incubated (Anderson 1982). CO2 was measured using gas chromatography as described by Kieft et al. (1991). Soil samples (10 g wet wt.) were placed into serum vials, moistened to approximately field capacity with deionized water, and the vials were sealed with rubber septa. Respiration was measured in triplicate subsamples of each sample during 24-h incubation at 22oC, beginning 24 h after the vials were sealed. Microbial biomass carbon was measured using the substrate induced respiration method (Anderson and Domsch 1978) as modified by West and Sparling (1987). Soil samples (10 g wet wt.) were placed into 60 ml serum vials along with 5 mg glucose and were then wetted to field capacity. Vials were sealed with rubber septa and incubated at 22oC. Headspace gas was sampled at intervals during a period beginning 0.5 h after sealing the vials and extending for 2 h. Respiration rates were converted to Cmic by the equation of Anderson and Domsch (1978): y = 40.04x + 0.37; where y = Cmic (mg 100 g-1 dry wt. soil) and x = respiration rate (ml CO2 100 g-1 dry wt. sediment h-1). Four replicates of each sample were tested.

Dehydrogenase activity - Soil dehydrogenase activity was measured using the substrate iodonitrotetrazolium (INT). The method was a slight modification of Griffiths' (1989) method. Tetrazolium salts are colorless in solution and are reduced by cellular dehydrogenases to colored tetrazolium formazans. Soil (1.0 g wet wt) was added to a screw-cap test tube, and then 2.0 ml of a 0.5% (W/V) INT and 1.5 ml deionized water (W/V) were added. The soil suspensions were vortex-mixed and the tubes incubated in the dark at 40oC. After 2 h incubation, enzymatic activity was halted and INT-formazan was extracted by adding a 10.0 ml of a 1:1 mixture of dimethylformamide and ethanol. Extraction was carried out in the dark for 1 h with vortex mixing every 20 min. The soil was then removed by centrifugation. INT- formazan concentrations of the supernatants were determined spectrophotometrically at 460 nm using the extracting solution as a blank. Triplicate tubes were set up for each soil sample along with an autoclaved control of each sample. Absorbance in the control extract was subtracted from the average of the extracts in the live soils.

N mineralization potentials- After determining water-holding capacity (WHC)(White and McDonnell 1988), a portion of each sample was adjusted to 500f determined WHC and up to 11 subsamples were apportioned into plastic cups. Each cup contained approximately 30 g dry-weight (DW) mineral soil. One subsample of each sample was immediately extracted with 100 ml 2 N KCl for NO3--N and NH4+-N analyses. The remainder of the cups were covered with plastic wrap, sealed with a rubber band, and incubated in the dark at 20oC. The plastic wrap minimized water loss during incubation, yet exchange of CO2 and O2 was sufficient to keep the subsamples aerobic during incubation. Moisture content was monitored by mass loss and replenished as needed. At weekly intervals, one subsample of each sample was removed and extracted with KCl for 18-24 h. The clarified KCl was filtered through a Kimwipe and analyzed for NH4+-N and NO3--N+NO2--N on a Technicon AutoAnalyzer as described in White (1986).

LITERATURE CITED

Anderson, D. R., K. P. Burnham, G. C. White, and D. L. Otis. 1983. Density estimation of small-mammal populations using a trapping web and distance sampling methods. Ecology 64:674-680.

Anderson, J. P. E. 1982. Soil respiration. Pages 831-871 in A. L. Page, editor. Methods of soil analysis, Part 2, Chemical and microbiological properties. American Society of Agronomy, Madison, Wisconsin.

Anderson, J. P. E., and K. H. Domsch. 1978. A physiological method for the quantitative measurement of microbial biomass in soils. Soil Biology and Biochemistry 14:273-279.

Day, P. R. 1965. Particle fractionation and particle-size analysis. Pages 562-566 in C. A. Black, editor. Methods of soil analysis Part I: Physical and mineralogical properties including statistics of measurement and sampling. American Society of Agronomy, Madison, Wisconsin.

Griffiths, B. S. 1989. Improved extraction of iodonitrotrazolium-formazan from soil with dimethylformamide. Soil Biology and Biochemistry 21:179-180.

Nelson, D. W., and L. E. Sommers. 1982. Total carbon, organic carbon, and organic matter. Pages 539-579 in A. L. Page, editor. Methods of soil analysis, Part 2, Chemical and microbiological properties. American Society of Agronomy, Madison, Wisconsin.

Pace, C. P. 1981. Community structure analysis - a rapid, effective range condition estimator for semi-arid lands. Pages 425-430 in H. G. Lund, et al. (tech. coord.). Arid land resources inventories: developing cost-efficient methods. USDA Forest Service General Technical Report WO-28, Washington, D.C.

West, A. W., and G. P. Sparling. 1986. Modification to the substrate induced respiration method to permit measurement of microbial biomass in soils of differing water contents. Journal of Microbiological Methods 5:177-189.

White, C. S. 1986. Effects of prescribed fire on rates of decomposition and nitrogen mineralization in a Ponderosa pine ecosystem. Biology and Fertility of Soils 2:87-95.

White, C. S., and M. McDonnell. 1988. Nitrogen cycling processes and soil characteristics in an urban versus rural forest. Biogeochemistry 5:243-262.

Wolters, G. L., S. R. Loftin, and R. Aguilar. 1996. Changes in plant species composition along a Chihuahuan desertscrub/desert grassland transition. Pages 614-615 in N. West (ed.) Fifth International Rangeland Congress Proceedings. July 23-38, 1995. Salt Lake City, Utah.

Maintenance: 

10-09-96 added keywords, methods, and persons involved with the data (JAC)10-10-96 reformatted document to fit an 80 column screen (JAC)10-10-96 added abstract (JAC)10-11-96 appended formated data and began variable descriptions (JAC)12-09-96 appended water data (JAC)12-10-96 completed variable descriptions (JAC)02-24-99 linked /db/archive/nutrient/soils/FPCN-data.dbf to the web site. GM

Snakeweed (Gutierrezia sarothrae) Habitat Soils Data from the Sevilleta National Wildlife Refuge, New Mexico (1984)

Abstract: 

In 1984, a research project was initiated on a relatively small disturbance patch just south of Deep Well. This disturbance was thought to be the result of an old praire dog town, probably dating back to when a nearby ranch was active, and a lot of old mammal mounds remained in the disturbed area. One of the things that made the disturbance patch particularily noticeable was the lush growth of snakeweed (Gutierrezia sarothrae) within the patch. This prompted the designation of the disturbance patch as the "snakeweed patch" or "Gutierrezia patch." In addition, there was an obvious increase in bare ground and a shift in vegetation composition across the patch boundary. The dominant vegetation was not consistent around the boundary, with a marked dominance of black grama on the west side of the plot and a blue/black grama mix on the other three sides. To obtain information on the cause and/or effect of this disturbance, a survey of the soil and vegetation was performed.

Core Areas: 

Data set ID: 

150

Additional Project roles: 

103
104
105

Keywords: 

Data sources: 

sev150_snakeweedsoil_03302009

Methods: 

Sample collection - The soil samples were collected using a hammer-driven soil corer. The barrel of the corer was fitted with a plastic sleeve that allowed extraction of the soil core generally intact. The  soil corer was driven to a depth of 50 cm and soils split ito 10 cm fractions. This data set contains data for only the top 30 cm.

Samples were taken along six 100 m transects. Four of these transects crossed the patch boundary on the four cardinal points. On these four transects the 0m sample was taken starting 50 m outside the boundary, the 50 m sample was taken at the patch boundary and the 100 m sample was taken 50 m into the patch. The other two transects formed a cross near the center of the patch.

Twenty-one cores were collected along each transect, with increased sampling intensity near the boundary. However, this data set contains data from only the 10 m intervals for a total of 11 samples.

Sample processing - Soil samples were kept in a refrigerator prior to analysis. Each sample was weighed and samples were well-mixed before analysis. Samples were sieved through 2mm screens to remove pebbles and roots. A sample of 25 g was added to a preweighed soil can. Samples were dried for 24 hours at 105 degrees C then cooled and then reweighed. This dry/wet moisture correction was used to calibrate weights for other samples. A 1 g sample was taken from the oven-dried samples and ashed at 500 degrees C for 2 hours and re-weighed after cooling. This provided a measure of organic content. A 12 g sample was weighed into a 125 ml plastic bottle and 100 ml of 2 N KCL added before the bottles were well-shaken. After standing for 24 hours, the KCL was decanted and the samples analyzed for NO3-N and NH4-N on a Technicon Autoanalyzer. Another 5 g sample was weighed into a centrifuge tube and extracted repeatedly with pH 7 ammonium acetate. These samples were brought up to 250 ml and analyzed for Ca, Mg and K using atomic absorption. Fifty g samples of soil were mixed and texture determined using the hydrometer method. Samples were mixed 2:1 with 0.001N CaCl2 and pH measured. From the oven-dried samples 1 g samples were digested using sulfuric acid using the Kjeldahl method. Samples were then brought up to 250 ml and analyzed on a Technicon Autoanalyzer for total nitrogen and phosphorous.

Coordinates (NAD27): 

End of

Transect Transect Latitude Longitude

North 0 34 21' 1.2" 106 41' 8.3"W

100 34 20' 57.9"N 106 41' 8.6"W

East 0 34 20' 47.0"N 106 41' 1.6"W

100 34 20' 46.5"N 106 41' 5.4"W

West 0 34 20' 53.7"N 106 41' 16.3"W

100 34 20' 53.7"N 106 41' 12.4"W

GCSA 0 34 20' 49.1"N 106 41' 9.2"W

100 34 20' 45.6"N 106 41' 9.2"W

GCSB 0 34 20' 47.1"N 106 41' 8.9"W

100 34 20' 47.4"N 106 41' 5.1"W

Maintenance: 

12/10/00 (DM) File created.2/10/2009. (DM) Metadata was updated and compiled.

Time Domain Reflectometry at the Sevilleta National Wildlife Refuge, New Mexico (1996-2005)

Abstract: 

This file contains hourly time-domain reflectometry (TDR) soil moisture data for 1996-2005. A key factor in a spatially explicit water-balance model is a measure of moisture in the soils over time. This metric is crucial for both calibration and validation of such a model. One of the best methods of measuring soil moisture on a continuous basis is TDR. Therefore, a network of TDR soil moisture sensors was installed at all meteorological stations on the Sevilleta National Wildlife Refuge. At two of the sites the sensors were measured on an hourly basis in conjunction with the meteorological variables. At the four other sites the sensors were measured on a much less frequent basis - about every two weeks. Sensors were installed in pits in sets of five. One sensor was installed vertically adjacent to the pit to measure the top 30 cm of soil. The other four were installed horizontally in the face of the pit at 5, 10, 20, and 40 cm. Pits were then backfilled.

Core Areas: 

Additional Project roles: 

86

Data set ID: 

78

Keywords: 

Purpose: 

To measure moisture in soils at the field site over time.

Data sources: 

sev078_tdr_12092011.txt

Methods: 

Analytical Procedures:

Probes were measured every hour and collected propogating velocities were converted to soil moisture values using the Ledieu calibration. Each probe was run in sequence and the 15 probes could take 4 or 5 minutes to read.

Sampling Design:

Three sites were designated as water-balance monitoring sites: 1.) Deep Well - Met 40, 2.) Rio Salado - Met 44 and 3.) Field Station Sta1. At these sites replicate TDR probes were installed at specific depths while other probes were installed vertically to get an average soil moisture for the top 30 cm of soil.

Measurement Techniques: Time Domain Reflectometry:

TDR measures the reflectance of an electromagnetic pulse down a probe. This reflectance is affected by the amount of moisture in the soil surrounding the probe. Algorithms have been developed relating reflectance to volumetric soil moisture that work for most soils. The Campbell system has a built in program which reads the inflection points of the wave-form and automatically outputs soil moisture.

Locations where measurements were taken by year:

1996:1, 40, 41, 42, 43, 44, 45

1997:1, 40, 41, 42, 43, 44, 45

1998:1, 40, 41, 42, 43, 44, 45

1999:40,44,1

2000:40,42

2001:40,42

2002:40

2003:40

2004:40

2005:40

Instrumentation: 

Instrumentation: CR10 Datalogger; Tecktronx 1502B Cable Tester; Multiplexer SDMX50; TDR probe 30 cm

Instrument Name: Soil Moisture Potential Probe Manufacturer: Campbell Scientific Model Number: 227

Maintenance: 

2/19/1996 - Douglas Moore:

Jan 12, 1996 Sta 40 Installed probes in two more pits. Reprogrammed so data is being collected from all 15 probes.

Jan 19, 1996 Sta 01 Installed probes in two more pits.

Jan 19, 1996 Sta 44 Replaced probe w3_30 which had been chewed off by rodent.

Jan 30, 1996 Sta 41 Installed probes in Pit 1.

Feb 07, 1996 Sta 45 Installed probes in two more pits.

Feb 09, 1996 Sta 01 Installed datalogger, TDR enclosure and multiplexer. Installed program to collect data.

Feb 14, 1996 Sta 01 Replaced w1_10 probe. Changed program so battery voltage is collected.

Feb 23, 1996 Sta 42 Installed probes in two more pits.

Feb 28, 1996 Sta 40 Began having problems with data - missing hours or getting -699 due to dying internal battery in reflectometer.

Mar 08, 1996 Sta 40 Pulled reflectometer out to send back to Campbell.

Mar 12, 1996 Sta 01 Pulled reflectometer out to put in at Sta 40.

Mar 12, 1996 Sta 40 Put reflectometer from Sta 1 into Sta 40.

Mar 20, 1996 Sta 43 Installed probes in two pits (except w2_30).

Mar 27, 1996 Sta 41 Installed probes in a second pit.

Apr 01, 1996 Sta 41 Replaced faulty w2_30 probe.

Apr 08, 1996 Sta 43 Installed w2_30 probe.

12/15/1998: Douglas Moore:

 Jan 22, 1997 Sta 44 Replaced TDR meter with one from field station.

Jan 22-April 04, 1997 Sta 40 W1_5 bad data replaced with- 999.

Apr 16, 1997 Sta 40 New w2_5 - 5 cm probe in pit B.

Apr 30-May 07, 1997 Sta 01 Missing data - Lost power to datalogger.

May 14-May 21, 1997 Sta 01 Missing data - Forgot to turn reflectometer on after returning to shelter.

Aug 01-Aug 20, 1997-Sta 40 w2_30 data bad changed to -999.

Aug 20, 1997 Sta 40 Replaced w2_30 sensor.

Quality Assurance: 

This data was QA'd/QC'd.

Additional information: 

Personnel associated with the Data Collection / Data Processing: Karen Wetherill, Yang Xia, Terri Koontz, Amaris Swann, Michell Thomey, Jay McLeod, Jim Elliott, Chelsea Crenshaw

Soil Characteristics Following a Lightning-Initiated Fire at MacKenzie Flats, Sevilleta National Wildlife Refuge, New Mexico (1998)

Abstract: 

We evaluated soil characteristics after a lightning-initiated fire. Following the fire in July 1998, 25 experimental plots were established on the eastern edge of MacKenzie Flats at the Sevilleta National Wildlife Refuge. Ten of these plots were located in a Bouteloua gracilis (blue grama)-dominated site, while 15 were established in another area dominated by Bouteloua eriopoda (black grama). All plots were oriented along a topographic gradient that ran in an east-west direction. At three topographic locations within each plot, soil samples were taken at two depths from an area covered by perennial grass as well as an area devoid of vegetation. Soil samples were collected in July 1998 and analyzed for moisture content and soil texture.

Data set ID: 

170

Additional Project roles: 

236
237
238
239
240
241
242
244
245
246

Core Areas: 

Keywords: 

Methods: 

Experimental Design - Following a lightning-initiated fire in July 1998, 25 experimental plots were established on the eastern edge of the MacKenzie Flats area of the Sevilleta National Wildlife Refuge. Ten of these plots were located in a Bouteloua gracilis (blue grama)-dominated site, while 15 were established in another study area, where B. eriopoda (black grama) was more abundant. In the former site, five of the 10 plots were established in burned areas, and the others were positioned in unburned grassland vegetation. In the latter study area, five plots were placed in burned areas, five were positioned in unburned grasslands, and the five remaining plots were located in an area that contained a mix of burned and unburned patches of grassland vegetation.

Sampling Design - All of the plots in the Bouteloua gracilis-dominated site were 4 m x 16 m in dimension. Of the 25 plots where B. eriopoda was more abundant, nine were 4 m x 16 m, and 16 were 4 m x 25 m. Regardless of site, all plots were oriented such that the long axis of each was parallel to a topographic gradient that ran in an east-west direction.

We established three 1.5 m x 1.5 m quadrats at the two corners and midpoint along the south side of each plot. Each quadrat was divided into four square cells of equal area. Within a southeastern cell (northeastern cell if a shrub was present in a southeastern cell), we selected three grass clumps and three interspace areas between plants. At the center of each plant and interspace, one sample was removed at each of two depths (0 - 2.5 cm and 2.5 - 10cm). The three "grass" samples at each depth were pooled to create one composite sample; similarly, the three interspace samples at each depth were also pooled into one sample (4 composite samples in total).

Field Methods - For the 0 - 2.5 cm samples, a 2.5-cm corer (6.7 cm diameter) was driven into the ground with a mallet. Over grass clumps, the corer was inserted such that the average original soil surface was flush with the top of the corer, generally at about one-half the height of the tussock. A sharpened trowel was hammered beneath the corer to cut the roots, and the core was removed. Any soil which fell onto the new surface was scraped away.

For the 2.5 - 10 cm samples, a 25-cm corer (4.5 cm diameter) was driven to a depth of 7.5 cm below the surface created by the previous sample. The corer was then twisted and gently pulled up. The average point of break for any individual core was estimated to be within 1 - 2 mm for at least 90% of the cores.  The soil was resampled if this error exceeded 3 mm.

Samples were placed into pre-labeled paper lunch bags and transferred to a cooler (without ice). They were transported to a drying shed with ambient temperature and humidity and placed on shelves within 36 hours.

Laboratory Procedures - Soil moisture was determined by the gravimetric method (Gardner 1986). Soil texture was determined by the hydrometer method (Sheldrick and Wang 1993).

Gardner, W. H. 1986. Water content. Pages 493-544 in A. Kluite (editor), Methods of soil analysis, Part 1. Physical and minerological methods, agronomy monograph no. 9, 2nd edition. American Society of Agronomy and Soil Science Society of America, Madison, WI.

Sheldrick, B.H. and C. Wang. 1993. Particle size distribution. Pages 499-557 in M.R. Carter (editor), Soil sampling and methods of analysis. Canadian Society of Soil Science, Lewis Publishers, Ann Arbor, MI.

Data sources: 

sev170_bootleg_soils_20140121.txt
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