ABSTRACT:

In dryland soils, spatiotemporal variation in surface soils (0-10 cm) plays an important role in the function of the “critical zone” that extends from canopy to groundwater. Understanding connections between soil microbes and biogeochemical cycling in surface soils requires repeated multivariate measurements of nutrients, microbial abundance, and microbial function. We examined these processes in resource islands and interspaces over a two-month period at a Chihuahuan Desert bajada shrubland site. We collected soil in Prosopis glandulosa (honey mesquite), Larrea tridentata (creosote bush), and unvegetated (interspace) areas to measure soil nutrient concentrations, microbial biomass, and potential exoenzyme activity. We monitored the dynamics of these belowground processes as soil conditions dried and then rewetted due to rainfall. Most measured variables, including inorganic nutrients, microbial biomass, and soil enzyme activities were greater under shrubs during both wet and dry periods, with the highest magnitudes under mesquite followed by creosote and then interspace. Two exceptions were soil organic carbon, which was slightly higher in interspace areas, and nitrate, which was highly variable and did not show resource island patterns. Temporally, rainfall pulses were associated with substantial changes in soil nutrient concentrations, though resource island patterns remained consistent during all phases of the soil moisture pulse. Microbial biomass was more consistent, decreasing only when soils were driest. Potential enzyme activities were even more consistent, and did not decline in dry periods, potentially helping to stimulate observed pulses in CO2 efflux following rain events observed at a co-located eddy flux tower. These results indicate a critical zone with organic matter cycling patterns consistently elevated in shrub resource islands, high decomposition potential that limits soil organic carbon accumulation across the landscape, and nitrate fluxes that are decoupled from the organic matter pathways.

ABSTRACT:

Spatial variability in soil CO2 efflux across landscapes is an important feature of the "Critical Zone" within dryland ecosystems. In dryland critical zones, resources are often distributed in patches or resource islands. Although this is particularly true in natural settings, the significance of spatial variability in CO2 efflux and its patterns also extends to dryland agriculture. In both irrigated and unirrigated systems, human management practices can significantly impact both organic and inorganic carbon cycling processes, highlighting the importance of studying CO2 efflux in these systems. We examined the spatial patterns of soil CO2 efflux and quantified the magnitude and scale of spatial autocorrelation using geostatistical techniques in a flood-irrigated pecan orchard and a creosote bush shrubland. Moreover, we explored some of the associated factors that may drive spatial variability in soil CO2 efflux. Our results indicated that while CO2 efflux was autocorrelated at short distances, it was quite variable and difficult to predict at larger scales across the study sites. Furthermore, the level of spatial autocorrelation varied depending on water availability, with weaker patterns at intermediate water levels at the flood-irrigated site. We also found that CO2 efflux had shorter ranges of autocorrelation compared to tree diameter and electrical conductivity. Tree diameter, proximity to the nearest tree and electrical conductivity did show some association with soil CO2 efflux, but the correlations were weak. Overall, this research provides evidence that electrical conductivity, tree diameter and proximity to the nearest tree are weak predictors of spatial variability in soil CO2 efflux and that there are likely other unmeasured factors that control spatial variation in soil CO2 efflux at these sites.

ABSTRACT:

In natural drylands, the formation of pedogenic carbonate (secondary calcite, CaCO3) is critical in impacting the soil properties hydrologically and biogeochemically, and modifying the global carbon cycle over geological time. When dryland ecosystems are converted to managed agricultural sites, irrigation water supplies HCO3- and Ca2+, accelerating the rates of CaCO3 formation and releasing abiotic CO2. We investigated the abiotic and biotic processes that have produced soil CO2 in dryland soils at an irrigated pecan orchard in Tornillo, Texas. Two sites within the pecan orchard, Pecan_Coarse, and Pecan_Fine, have contrasting soil textures resulting in different soil salinity, pedogenic carbonate accumulation rates, and tree sizes. A range of methods was employed including soil CO2, soil O2, and soil moisture sensors at two different soil depths (30 cm and 60 cm below ground surface), as well as soil CO2 efflux at ground surface. The overall objective of this study is to quantify the release of abiotic CO2 during the precipitation of irrigation-induced calcite, as a function of spatial variability due to soil texture, and as a function of growing season and irrigation events at a high temporal scale (5-minute). The data were collected as part of the Dryland Critical Zone project (NSF Award #2012475) and as part of a Low-temperature Geochemistry and Geobiology project (NSF Award # 1853680).

ABSTRACT:

These data were collected as part of the Critical Zone Network REU and the UTEP Chihuahuan Desert Biodiversity REU programs in the Summer of 2023.
Soil samples were collected from two depths (0-10cm and 10-20cm) at four sites of varying soil age along a desert soil chronosequence in the Jornada Basin Long Term Ecological Research Range to measure a suite of phosphorus pools and pedogenic carbonate abundance. Our sampling locations mirrored those of Lajtha and Schlesinger (1988), which also measured phosphorus cycling and availability. Our study expanded on this work by considering biologically accessible P fractions and their relationships to calcium carbonate. We measured available P using the Olsen-P method, and biologically accessible pools were measured using the Biologically Based Phosphorus method from DeLuca et al. 2015. This method emulates strategies employed by plants and microbes to access different fractions of P in the soil.

ABSTRACT:

Playas are ephemeral wetlands in localized depressional areas of closed catchments in arid and semi-arid regions. They have critical ecological benefits, including habitat for biota and groundwater recharge. However, the US Southwest has been facing one of the most prolonged droughts in hundreds of years, affecting the source of water for these ecosystems. This study assessed the patterns and drivers of primary production and plant community structure in desert playas of the northern Chihuahuan Desert (New Mexico, USA). We combined NDVI times series (Sentinel-2 images from 2019 to 2024) with field surveys to classify five groups of playas based on vegetation biomass and community structure, as well as soil characteristics and other factors related to geology and landscape position. Marked differences in vegetation biomass and structure were associated with distinct environmental conditions and topographical characteristics. The most productive playas were those with connectivity to ephemeral arroyos, particularly those located in basin depression landforms. Vegetation in these sites appeared more resistant to drought than those in less connected playas. On the other hand, less productive sites were located in isolated lake basins and often underlain by gypsiferous sediments. The least productive playa received water from a large drain area, was dominated by gypsiferous sediments, and contained saline soils, which may have limited plant growth. These results highlight how vegetation in playas within proximity to each are structured by differing environmental factors and how hydrologic connectivity can play an essential role in maintaining the productivity of playas even during dry periods.

ABSTRACT:

Water availability is crucial for organismal survival and growth in dryland environments, affecting both ecological interactions and carbon dynamics. The goal of this thesis is to develop soil water release curves (SWRCs) that link soil water potentials (Ψ) to soil water content (θ). Using the SWRCs, temporal soil water sufficiency curves are developed, which quantify the amount of time that dryland critical zones have enough water to sustain the physiology of organisms. These curves allow for effectively indicating water availability across different species, coverage types, and soil conditions, enhancing our understanding of water dynamics in drylands and contributing important parameters for a variety of studies. I examine the interaction between water, soil, and plant dynamics at two sites: the Ivey pecan farm in Tornillo, Texas and the Jornada Experimental Range in Las Cruces, New Mexico. I assess physical soil properties, including depth, texture, and ground cover types such as bare ground, creosote, mesquite, and grass. At the Ivey Pecan Orchard, fine and coarse sites were sampled to analyze variations in soil texture. Data from moisture sensors for the period of 2011-2021 were cross-verified with direct soil gravimetric measurements and SWRCs at corresponding depths. A corresponding adjustment in data allowed for accurate quantifications of soil moisture and subsequently conversions of these measurements into water potentials using the Fredlund-Xing (1994) model, thus providing a detailed view of moisture trends across different soil coverages and textures. At the Jornada Experimental Range, it was found that shallow soils at depths of 5 and 10 cm experienced significant increases in water loss (retained water less well), whereas deeper soils exhibited more water retention stability. Our
refined data showed that the upper 30 cm of soils under creosote and mesquite shrubs typically maintained water availability above the wilting point of creosote (-6 MPa) only slightly more than 50% of the time. Thus, we conclude that shallow (0-30 cm) soils in the shrubland has insufficient water availability for sustained plant health year-round, which is consistent with seasonal grass
dieback at the site. Shrub species, such as creosote and mesquite, likely compensate with access to deeper water sources via their rooting structures. Preliminary correlations of soil moisture data with carbon exchange measured via eddy flux tower were inconclusive, but further modeling could reveal important connections between water sufficiency and net carbon balance. The development
of temporal soil water sufficiency curves and their ability to predict water availability for organisms contribute to a broader understanding of organism water availability in drylands. This tool provides a solid foundation for future studies in drylands and works to advance the understanding of soil-plant-atmosphere relations in dryland critical zones.

ABSTRACT:

This dataset has Optically Stimulated Luminescence ages of the loess sediments from one less-managed soil profile and one irrigated soil profile in Kimberly/Twin Falls, Idaho.

ABSTRACT:

Drylands store a highly significant proportion of recalcitrant soil carbon, the SIC, primarily controlled by parent material and low aridity index (from 0.05 to 0.65) that favors more precipitation and lesser salt dissolution. Even though the annual net ecosystem carbon exchange (NEE) of these ecosystems is small compared to the grasslands and forests, their NEE is substantial and dominates with rapid climatic and land use change response of global land carbon sink. For instance, the agricultural practices such as saline water irrigation, fertilizer addition, tillage and mowing induced soil salinization, carbonate dissolution, nutrient loss, and organic matter decomposition as a response to land use change, can evidently play substantial role in affecting the unusually large soil C sink. Such a considerable response of soil C to the land use change arises the question about the relative contribution of possible factors altering the recalcitrant soil carbon pool (SIC) and affecting the development of soil organic carbon pool (SOC), with major implications for predicting and understanding the possible direction and magnitude of global carbon budget. Addressing these, we have collected in total one hundred, a meter deep soil cores from a flood irrigated Pecan orchard and analyzed the three depth ranges (surface: 0 to 10 cm, middle: 50 to 60 cm and bottom: 90 to 100 cm) for soil pH, EC, particle size, root biomass, soil organic (SOC) and soil inorganic carbon (SIC). Sampling points with prefixes 1 to 40 (1-0-10 to 40-90-100) were allocated to intensive sampling area, which were not randomized, while the sampling points with prefixes 41 to 90 (41-0-10 to 90-90-100) were allocated to non-intensive random sampling area. Sampling points with prefixes 91 to 100 (91-0-10 to 100-90-100) were ten random sampling points chosen at less than 1 m distance from ten other sampling points (chosen from intensive and non-intensive area), so, that a fine scale spatial variability across the study site can be estimated. Our results indicated soil texture as a master component of overall spatial variability, having good associations with SOC, SIC, root biomass and soil EC. A clear depth wise variation was recorded for the total root biomass, exhibiting an overall parabolic trend with maxima in middle depth range. However, the fine root biomass was found constant across different depth ranges. Soil EC showed mixed depth wise variation, with clear separations between the qualitative soil textural classes (sand and clay), exhibiting higher salt deposition in clay compared to sand. SOC exhibited a decreasing trend with depth ranges while SIC showed an overall constant trend across different depth ranges. Surface layer exhibited statistically similar SOC and SIC in different textural classes (i.e. sand and clay) while these differences become clear with middle and bottom depth range. CN ratio exhibited constant trend with depth range and textural variations, with overall similar mean CN ratio across different depth ranges and texture classes. Overall, this research indicates qualitative soil texture and depth ranges as strong predictors for variations in belowground carbon stocks (in soils and plant roots). However, there will be more to learn from the quantitative soil particle size analysis, soil carbon and EC analysis of the remaining sampling points.

ABSTRACT:

Radiocarbon ages of soil inorganic carbon and soil organic carbon

ABSTRACT:

Falling head double ring infiltrometer test data for sites on the Jornada I and Organ surfaces from the Dryland Critical Zone's Piedmont site and from the Red Lake Playa, both in Jornada Experimental Range, New Mexico. Data were collected between September, 2021 and August, 2022 using a portable double ring infiltrometer (6" & 12" X 4" Double Infiltration Ring from AMS, Inc.). Infiltration patterns exhibited near-linear behavior almost immediately after tests began, so linear rates in units of centimeter per second are reported.

ABSTRACT:

The data set includes auger hole depth to refusal notes from the Jornada Experimental Range in southern New Mexico. Depth to refusal is described to be the maximum depth at which an aguger can penetrate the surface before hitting impenetrable material. Data recording was in tandem with various sample collections and occured between February 2021 - September 2022. The two sedimentary surfaces that were noted during the data collection include Jornada and Organ.

ABSTRACT:

Compared to all other terrestrial components, soil comprises the largest organic C stocks such that knowing the controlling factors and underlying processes can help to utilize its potential. Owing to the substantial spatio-temporal interplay at soil-plant-microbial interface, we have insufficient information to answer how different soil types and tree biomass interactions influence the surface layer soil microbial dynamics. Recognizing the uneven distribution of different soil fractions and temporal dynamics in moisture, soils of dryland agroecosystems are expected to have unknown trends in microbial biomass C. To understand how spatially variable tree biomass and temporal soil moisture trends affect soil microbial biomass, we performed periodic sampling runs in a flood irrigated Pecan orchard, located in Tornillo, Texas. The concerned study site has some unique spatial contrast developed by fluvial deposits on the regionally coarse soil fractions. The intriguing mosaic of contrasting soil textures has resulted in pecan trees with substantially variable tree biomass and created a spatial pattern of large and small trees adjoining the contrasting soil textures. In the present investigation, we have taken advantage of these features and chosen two pecan trees of contrasting biomass and collected four samples each on the north and south side of trees at a distance less than 5m from the tree base. The campaign involved surface soil sampling (0-10 cm) at every four-days interval for a period of 36 days and covering two irrigation events. Analysis of soil samples involved gravimetric soil moisture content, microbial biomass C and N. We found that soils associated with lower tree biomass (addressed as Pecan-fine) recorded significantly higher microbial biomass over the larger trees (addressed as Pecan-coarse). Furthermore, the regression analysis of soil microbial biomass versus gravimetric soil moisture content exhibited weak dependency of soil microbial biomass on the soil moisture variations. Overall, these results conclude that Tree size have substantial influence on the soil microbial biomass whereas the moisture dynamics have weakly affected the microbial biomass C.

ABSTRACT:

In the middle Rio Grande, valuable wetlands and riparian areas have been lost due to the expansion of urban and agricultural
land. Additionally, the channelization of the river along the US–Mexico border has altered hydrological dynamics,
contributing to the degradation of these ecosystems. The Rio Bosque wetlands were constructed in El Paso, Texas, USA,
to mitigate the loss of these habitats. Unfortunately, these wetlands faced issues with water availability until 2016, when
they began to receive the resource more frequently. Vegetation was allowed to establish naturally over time in response to
winter water deliveries (2005–2014) and summer water deliveries (2016–2017). This study investigated how changes in
water delivery influenced the plant community development over more than a decade of restoration activities. We observed
that water depth was an important predictor of increasing the relative frequency and cover of wetland plants, as well as
macrophyte diversity. A non-metric multidimensional scaling (NMDS) ordination showed a transition of the vegetation
community from limited water years to more regular water availability. The plant community changed from one dominated
by upland plants, including invasive tumbleweed (Salsola tragus), to one dominated by flood-tolerant, competitive
wetland plants (Lemna spp. and Polygonum lapathifolium). Deeper areas had a greater proportion of wetland plants, while
facultative wetland plants occurred on the edges of ponds. In general, this 12-year study has helped to understand how the
Rio Bosque ecosystem has changed after more regular water availability and will assist managers in tracking the future
recovery and restoration of this valuable desert wetland.

Garcia, E., Lee, L., & Lougheed, V. (2025). The Long-term Development of Wetland Plant Communities with Water Deliveries in a Created Wetland in the Desert Southwest. Wetlands, 45. https://doi.org/10.1007/s13157-025-02000-z

ABSTRACT:

This dataset covers soil inorganic carbon (SIC), radiocarbon dates (14C) for a pecan orchard near Tornillo, TX, an alfalfa field formerly within El Paso/Socorro, TX, and a natural site near Fabens, TX. This data also includes optically stimulated luminescence dates (OSL) for the pecan orchard. These dates and SIC contents are then used to calculate pedogenic carbonate accumulation rates. Additionally, data is provided on soil amendments at the pecan orchard to understand the potential contributors of pedogenic carbonate.

ABSTRACT:

This dataset documents time-lapse Electrical Resistivity Tomography (ERT) measurements conducted as part of a controlled rainfall simulation experiment at the Jornada Experimental Range in the Chihuahuan Desert. A total of 6,000 liters of water were applied over a 20x10 m experimental plot using two sprinklers to simulate a 60 mm rainfall event. To monitor subsurface water redistribution, a 72-electrode array (8x9 grid) was installed, and 26 ERT surveys were conducted using a dipole–gradient configuration. One baseline survey was performed prior to irrigation, followed by 25 monitoring surveys over a two-month period. Early measurements were taken every 2 hours and gradually spaced out over time to capture longer-term changes.

The resulting dataset includes raw resistivity files, inverted resistivity models for each survey, and time-lapse visualizations highlighting temporal changes in soil resistivity at the same location. These data allow for detailed analysis of infiltration patterns, water retention, and redistribution in arid soils, and contribute to a better understanding of how rainfall pulses affect water availability in desert ecosystems. The ERT method provides a valuable non-invasive tool to observe and quantify soil moisture dynamics in three dimensions under real-world field conditions.

ABSTRACT:

This study explores the dynamics of water fluxes and carbon exchange in the Chihuahuan Desert using high-frequency data collected at the Jornada Experimental Range from October 2019 to December 2024. Measurements were recorded every 10seconds using a Licor 7500i system paired with a Vaisala sensor for atmospheric humidity and temperature, as well as radiation sensors and soil moisture and temperature probes. These instruments were installed on a 2.4-meter tower located at the piedmont zone of the ranch. Motivated by recent shifts in rainfall intensity, frequency, and increasing drought conditions, this research aims to better understand how desert ecosystems respond to rainfall pulses—particularly how much water is lost through evaporation versus how much is used by vegetation. To address this, we applied the underlying Water Use Efficiency (uWUE) method to partition evapotranspiration after rainfall events. Complementarily, an artificial rainfall experiment was conducted on a 20x10m plot at the same site to monitor soil water movement using TDR sensors and 3D Electrical Resistivity surveys up to 3 meters deep. These combined approaches help shed light on the role of shallow calcium carbonate layers in water storage and accessibility, and how desert plants adapt their water use strategies following precipitation pulses.

ABSTRACT:

CZ core obtained by sonic drilling, 100 m deep core beneath a playa in Jornada Basin, New Mexico. This collection includes core images providing visual documentation of its geochemical features. These images are saved for future use, showing soil structure and lithological features of the core. Along with the core images, a word document is attached containing a detailed walk-through for opening and navigating images in corelyzer. The actual corelyzer file which includes XRF element distribution data and other relevant metadata, is also included.

ABSTRACT:

CZ core obtained by sonic drilling, 50 m deep core beneath an irrigated pecan farm in Rio Grande alluvial deposits in Fabens, TX. This collection includes core images providing visual documentation of its geochemical features. These images are saved for future use, showing soil structure and lithological features of the core. Along with the core images, a word document is attached containing a detailed walk-through for opening and navigating images in corelyzer. The actual corelyzer file which includes XRF element distribution data and other relevant metadata, is also included.

ABSTRACT:

We present a dataset that contains raw data for different physiological variables (exopolysaccharide production, chlorophyll a, photosynthetic activity) measured for biocrust cyanobacteria under optimal growth and phosphorus limitation treatments in laboratory conditions. These cyanobacteria were collected from biocrusts in the Chihuahuan and Mojave Deserts. The data values were collected for six biocrust cyanobacteria each five days during 20 days. We also provide the data used to create a calibration curve and quantify the concentration of exopolysaccharides. The purpose of this datase is to evaluate the effect of phosphorus limitation on growth, photosynthetic activity and exopolysaccharides production in biocrust cyanobacteria.

ABSTRACT:

This dataset contains data from the Ivey Pecan Orchard soil monitoring sensor array. These sensors are installed at two sites with contrasting soil textures - Pecan_Fine and Pecan_Coarse. At each of these sites, there are the following sensors: VWC, EC, T, O2, CO2 at 30cm and 60cm depths, and CO2 efflux at the soil-air interface. At Pecan_Coarse, there is also a differential pressure sensor measuring the difference between ambient pressure and soil pressure, in order to better capture changes in pressure. These changes in pressure may contribute to changes in CO2 efflux as advection dominates over diffusive CO2 transport.

ABSTRACT:

This dataset contains data from two soil sensor monitoring arrays installed at Ivey Pecan Orchard. There are two sites installed in contrasting soil textures, Pecan_Fine and Pecan_Coarse. At each of these two sites, there are the following sensors: barometric pressure from Apogee SB-100 sensors, VWC, EC, T from Campbell CS-650 sensors, O2 and T from Apogee SO-110 sensors, at 30cm and 60cm, CO2 concentration from Vaisala GMP343 (at 30cm) and Vaisala GM251 (at 60cm), and CO2 efflux at the soil-air interface from Eosense eosFD chambers. At Pecan_Coarse there is also a differential pressure sensor from Dwyer Digimag DM-003 Differential Pressure Gauge.

ABSTRACT:

This data contains major anion and cation analyses for shallow groundwater samples and irrigation water samples, taken following 1 irrigation event in July 2022 and 1 irrigation event in July 2024. Data is also plotted on Piper Diagrams for visualization as water chemistry evolves following an irrigation event. Preliminary results show that water becomes more Na Cl rich, from Ca-Mg-CaCO3. The irrigation water applied is much more dilute than any groundwater samples, suggesting that the change in chemistry comes from processes happening within the vadose zone as water percolates following irrigation - dissolving existing soluble salts (NaCl) and precipitating less soluble salts (CaCO3).

ABSTRACT:

Borehole geophysical data (natural gamma, induced electrical conductivity, magnetic susceptibility, fluid temperature, fluid conductivity) from depths of 154.700 to 0.600 feet below top of well casing of dryland critical zone well DCZN-1A, into the Rio Grande Alluvium Aquifer and the Hueco Bolson Aquifer. Borehole logging performed by Bill Smith (Granite Geophysical) and Christian Leach (University of Texas at El Paso). Data is in standard LAS file format. Water level present at a depth of 6.5-7.0 feet below top of casing during measurement.

ABSTRACT:

Borehole geophysical data (natural gamma, induced electrical conductivity, magnetic susceptibility, fluid temperature, fluid conductivity) from depths of 301.450 to 2.30 feet below top of casing of dryland critical zone well DCZN-2A, into the vadaose zone and Mesilla Bolson aquifer, below the Red Lake Playa and the Jornada Experimental Range, New Mexico. Borehole logging performed by Bill Smith (Granite Geophysical) and Christian Leach (University of Texas at El Paso). Data is in standard LAS file format. Water level present at a depth of ~70m below top of casing during measurement.