Southern High Plains Of Texas Research Articles

Seasonal Abundance and Habitat Associations of American Kestrels on the Southern High Plains of Texas

ABSTRACT American Kestrel (Falco sparverius) populations are generally declining across the species' North American distribution but the population in the Southern High Plains region currently appears to be stable. Historical evidence suggests the region formerly had a low abundance of kestrels, and that their current numbers are due to landscape changes associated with European settlement. We conducted monthly surveys for American Kestrels across 2 yr to estimate seasonal densities and identify land cover associations in the Southern High Plains of Texas. We found an overall estimated density of 0.99 birds/km2 (95% CI = 0.406, 1.582) across the 2-yr period, with seasonal estimated densities highest in autumn and winter (0.92–2.53/km2), and lowest in spring (0.49–0.67/km2). Whereas other studies have found that temperature influenced detection of wintering kestrels, we found an interaction of drought conditions and snow most strongly influenced the number of kestrels in our study area. Kestrels largely used land cover types in proportion to availability but there was some evidence of seasonal shifts. Generally, they tended to avoid cotton fields and sometimes selected for areas with woodlots, abandoned or occupied houses, and barns, all of which likely provided nesting and roosting opportunities. Our study provides the first contemporary assessment of seasonal abundance and habitat associations of American Kestrels in the Southern High Plains, where their presence and abundance has been unintentionally facilitated by landscape changes following settlement. We provide a baseline for population monitoring and studies assessing response to additional landscape changes (e.g., development of wind energy facilities) and a changing climate.

Trends in Lesser Prairie-Chicken Habitat Extent and Distribution on the Southern High Plains

The lesser prairie-chicken (Tympanuchus pallidicinctus) is a species of prairie grouse that occupies grassland ecosystems in the Southern and Central High Plains of the Great Plains. Reduced abundance and occupied ranges have led to increased conservation efforts throughout the species’ range. Habitat loss is considered the predominant cause of these declines. In the Southern High Plains of Texas and New Mexico, lesser prairie-chicken habitat corresponds to the Sand Shinnery Oak Prairie Ecoregion, which is comprised of a mixture of sand shinnery oak (Quercus havardii)-dominated grasslands, sand sagebrush (Artemisia filifolia)-dominated grasslands, and mixed grasslands. In sand shinnery oak–grassland communities, conversion to row-crop agriculture, continuous unmanaged livestock grazing, restriction of natural fire, invasive plant species (e.g., mesquite (Prosopis spp.)), extensive use of herbicides, energy development, and a variety of other factors have also negatively affected ecosystem extent and function. We integrated historical maps and remote sensing-derived information to measure trends in the extent and geographical distribution of sand shinnery oak prairies in eastern New Mexico and northwest Texas. Potential lesser prairie-chicken habitat was reduced by 56% from a potential of 43,258 km2 to 18,908 km2 in ~115 years (since pre-settlement). Our assessment indicated both mixed grasslands and sand shinnery oak-dominated grasslands were transformed from large parcels of existing vegetation communities to urban settlements, row crops, roads, and industrial land uses by the 1970s. Currently, potential habitat is highly fragmented and restricted to isolated locations in Texas and New Mexico, with an increasing dominance in mixed grasslands, especially in the southeastern portion of the lesser prairie-chicken range. Sand shinnery oak-dominated grasslands have been declining rapidly, from 69% of its potential extent in 1985, 65% in 1995, 54% in 2005, to 42% in 2015. Mixed grasslands drastically declined to 50% of its potential distribution by 1985. Since then, it has been stable until the 2005–2015 period when it declined to 45% of its potential extent. Based on the 2015 assessment, the current potential habitat for lesser prairie-chicken is estimated at 18,908 km2 (1,890,800 ha or 4.6 million acres), where 13,126 km2 corresponds to mixed grasslands and 5782 km2 corresponds to sand shinnery oak-dominated grasslands.

Particle size distribution and particulate matter concentrations during synoptic and convective dust events in West Texas

Abstract. Dust events are an important and complex constituent of the atmospheric system that can impact Earth's climate, the environment, and human health. The frequency of dust events in the Southern High Plains of West Texas has increased over the past 2 decades, yet their impact on air quality in this region is still unclear. This is due to the fact that there is only one air quality monitoring station that measures only PM2.5 concentrations (particulate matter with an aerodynamic diameter < 2.5 µm), and there is no information on other PM sizes or the particle size distribution. The Aerosol Research Observation Station (AEROS) unit provides insight into the local variation in particle concentration during different dust events and allows for a better understanding of the impact of dust events on air quality. As this area is prone to dust events, we were wondering if dust events generated by different meteorological causes (synoptic vs. convective) would present similar particle concentrations or particle size distributions. Thus, in this project, three different dust events were measured by AEROS and compared. Each dust event originated from a different direction and lasted a different duration. One of the dust events was synoptic (10 April 2019) and two were convective (5 and 21 June 2019). Measurements of particle mass and number concentration, size distribution, and meteorological conditions for each dust event were compared. The synoptic dust event (on 10 April) was longer (12 h) and had stronger wind speed conditions (up to 22.1 m s−1), whereas the two respective convective dust events on 5 and 21 June lasted only 20 and 30 min and had lower wind speeds (up to 16.5 and 13.4 m s−1). Observation of PM based on daily and hourly values showed an impact on air quality, yet measurements based on daily and hourly values underestimate the impact of the convective dust events. Observations based on a shorter timescale (10 min) reveal the true impact of the two convective dust events. A comparison of the particle size distribution showed that all three dust events presented an increase in particles in the 0.3–10 µm size range. Comparisons of the particle concentration for particles > 5 and > 10 µm show very high values during the dust events. Some particle sizes even increase in concentration by ∼ 2 orders of magnitude compared with the time before the dust event. This leads us to speculate that the impact of convective dust events on air quality in this region is underestimated with the current (hourly basis) method.

The Aerosol Research Observation Station (AEROS)

Abstract. Information on atmospheric particles' concentration and sizes is important for environmental and human health reasons. Air quality monitoring stations (AQMSs) for measuring particulate matter (PM) concentrations are found across the United States, but only three AQMSs measure PM2.5 concentrations (mass of particles with an aerodynamic diameter of < 2.5 µm) in the Southern High Plains of West Texas (area ≥ 1.8 × 105 km2). This area is prone to many dust events (∼ 21 yr−1), yet no information is available on other PM sizes, total particle number concentration, or size distribution during these events. The Aerosol Research Observation Station (AEROS) was designed to continuously measure these particles' mass concentrations (PM1, PM2.5, PM4, and PM10) and number concentrations (0.25–35.15 µm) using three optical particle sensors (Grimm 11-D, OPS, and DustTrak) to better understand the impact of dust events on local air quality. The AEROS aerosol measurement unit features a temperature-controlled shed with a dedicated inlet and custom-built dryer for each of the three aerosol instruments used. This article provides a description of AEROS as well as an intercomparison of the different instruments using laboratory and atmospheric particles. Instruments used in AEROS measured a similar number concentration with an average difference of 2 ± 3 cm−1 (OPS and Grimm 11-D using similar particle size ranges) and a similar mass concentration, with an average difference of 8 ± 3.6 µg m−3 for different PM sizes between the three instruments. Grimm 11-D and OPS had a similar number concentration and size distribution, using a similar particle size range and similar PM10 concentrations (mass of particles with an aerodynamic diameter of < 10 µm). Overall, Grimm 11-D and DustTrak had good agreement in mass concentration, and comparison using laboratory particles was better than that with atmospheric particles. Overall, DustTrak measured lower mass concentrations compared to Grimm 11-D for larger particle sizes and higher mass concentrations for lower PM sizes. Measurement with AEROS can distinguish between various pollution events (natural vs. anthropogenic) based on their mass concentration and size distribution, which will help to improve knowledge of the air quality in this region.

Major land use and vegetation influences on potential pollinator communities in the High Plains of Texas

In 2016, the annual value of all global crops dependent upon pollination was valued at $ 235–$ 577 billion (US$). Pollination service is threatened by habitat loss, pesticides, and climate change. We collected potential pollinators with blue vane traps in native grasslands, Conservation Reserve Program (CRP) lands, and cropland (land use), and their embedded playa wetlands (land type) in the Southern High Plains of Texas (SHP). We collected vegetation data that included floral cover, floral diversity, native grass cover, introduced grass cover, canopy gap, and duff cover. Our objective was to determine if individual vegetation characteristics influenced potential pollinator abundance and richness in addition to land use or land type as a whole. The top model explaining abundance was land use, land type, and floral cover. Floral cover had a positive influence on all land uses. The top model that explained insect richness was land use x floral cover, land type, canopy gap, and duff cover. Floral cover positively influenced insect richness in native grasslands but negatively influenced cropland and CRP richness. Percent of canopy gap had a slight negative influence on insect richness, and duff cover positively influenced richness. Our recommendations to land managers are to protect playas to preserve undisturbed areas and native floral resources and seed all future CRP contracts with floral rich plantings to provide for pollinators over the entire growing season.Implications for insect conservationOur results show that vegetation characteristics shared by all land uses such as floral cover, canopy gap and duff cover influence pollinator abundance and richness. Therefore, conserving playa wetlands and programs such as the CRP have the potential for enhancing pollinator habitat in working landscapes of the SHP of Texas.

Structural and functional landscape connectivity for lesser prairie‐chickens in the Sand Shinnery Oak Prairie Ecoregion

AbstractThe lesser prairie‐chicken (Tympanuchus pallidicinctus) is a species of conservation concern on the Southern High Plains of Texas and New Mexico, USA. Because fragmentation and isolation have increased since pre‐settlement, dispersal through this heterogeneous landscape may be constrained, with serious implications for conservation and management of this species. Our objectives were to quantify landscape connectivity for lesser prairie‐chickens within a patch network of potentially isolated leks (breeding display grounds), and examine effects of land use change on modeled lesser prairie‐chicken movements through the landscape. We used graph theory to quantify structural landscape connectivity and circuit theory to quantify functional landscape connectivity for lesser prairie‐chickens in the Sand Shinnery Oak Prairie Ecoregion of the Southern High Plains. There was a high degree of clustering among leks (n = 1,023 leks), with a 41.9‐km coalescence distance of the network. We identified 3 leks as cutpoints within the network, meaning if the habitat patches containing these leks were fragmented, the remaining leks would become isolated from each other. We also identified several leks that were important for maintaining overall population connectivity for lesser prairie‐chickens on the Southern High Plains. Conservation Reserve Program land was important for maintaining connectivity among leks to the north and west of the main lek core area located in New Mexico, but wind energy development constrained pathways to the north and south of this main lek core area. Our results suggest that landscape connectivity was reduced by row‐crop agriculture and energy production and facilitated by the Conservation Reserve Program within the Sand Shinnery Oak Prairie Ecoregion.

Annual Rainfall and Dryland Cotton Lint Yield—Southern High Plains of Texas

Agriculture in the Texas High Plains (THP) is in a transition phase of producing crops with a diminishing supply of irrigation-water from the Ogallala aquifer to dryland production systems. This shift is driven by the fact that the depth to the water table of the Ogallala aquifer continues to increase. Dryland cotton production systems are prevalent in the southern counties of the THP and our purpose was to use the long-term dryland cotton lint yields from these counties as precursors of the future cotton production patterns that will emerge in this region. For this purpose, from 1972 to 2018, we calculated the ratio of dryland cotton lint yield per unit of annual rainfall at the county level. This ratio is called crop water productivity (CWP) and has units of mass per unit volume (g/m3). In our analysis, we used cotton lint yield data provided by the National Agricultural Statistics and rainfall data provided by the National Oceanic and Atmospheric Administration. Our results indicated that the three datasets used in our analysis, i.e., cotton lint yield, rainfall and CWP were all normally distributed. In this time period, 1972 to 2018, only one year 2011—a year with a record drought of 179 mm of rain failed to produce a dryland cotton crop in all the counties used in our analysis. The mean cotton lint yield ± standard deviation ranged from a high of 400 ± 175 kg/ha in Lubbock County to a low of 252 ± 144 kg/ha in Andrews County. However, the counties with the largest CWP > 90 g/m3 were Glasscock, Midland and Martin County. The importance of this result is that these counties are in the southern region of the THP and are subject to extreme environmental conditions and yet cotton producers manage to produce a cotton crop in most years. We conclude that management production methods used by these dryland producers represent the future schemes that will need to be adopted in other counties to sustain the emerging dryland cropping systems across the THP.

Food Habits of American Kestrels in the Southern High Plains of Texas

ABSTRACT The American Kestrel (Falco sparverius) is in general decline across its North American distribution. In contrast to widespread patterns of decline, kestrel populations appear stable in the southern Great Plains region. Historically, this region had a very low occurrence of kestrels, and their current abundance is highly likely due to vegetation and structures associated with settlement by people of European descent. To determine prey use by breeding kestrels, we placed motion-activated video cameras at preexisting kestrel nest boxes located in the Southern High Plains in 2017. We recorded over 4200 prey deliveries during 1748 hr of observation at five nests over the 4-wk brood-rearing period. On basis of frequency, these deliveries were dominated by reptiles (74.8%), with invertebrates (18.2%), mammals (4.4%), birds (2.9%), and unidentified (1.2%) prey used to lesser extents. Prey delivery rates were high relative to other studies; across the brood-rearing period we recorded an average of 2.3 deliveries/hr, equating to an average of 0.49 deliveries and 3.85 g of prey/nestling/hr. Because invertebrates dominate the diet reported in most kestrel food habit studies, the volume of reptiles captured as prey was unexpected. Even more unanticipated was the number of large prey captured, including juvenile eastern cottontails (Sylvilagus floridanus) and ground squirrels (Ictidomys tridecemlineatus, Xerospermophilus spilosoma). We suspect the proportion of vertebrate prey captured during the nesting season may explain the local high rates of nesting success and number of young fledged.

Field-scale spatial variability of soil calcium in a semi-arid region: Implications for soil erosion and site-specific management

Excess calcium (Ca) in soils of semi-arid and arid regions has negative effects on soil structure and chemical properties, which limits the crop root growth as well as the availability of soil water and nutrients. Quantifying the spatial variability of soil Ca contents may reveal factors influencing soil erosion and provide a basis for site-specific soil and crop management in semi-arid regions. This study sought to assess the spatial variability of soil Ca in relation to topography, hydraulic attributes, and soil types for precision soil and crop management in a 194-ha production field in the Southern High Plains of Texas, USA. Soils at four depth increments (0–2, 0–15, 15–30, and 30–60 cm) were sampled at 232 points in the spring of 2017. The Ca content of each sample was determined with a DP-6000 Delta Premium portable X-ray fluorescence (PXRF) spectrometer. Elevation data was obtained using a real-time kinematic GPS receiver with centimeter-level accuracy. A digital elevation model (DEM) was derived from the elevation data, and topographic and hydraulic attributes were generated from this DEM. A generalized least-squares model was then developed to assess the relationship between soil Ca contents of the four layers and the topographic and hydraulic attributes. Results showed that topographic attributes, especially slope and elevation, had a significant effect on soil Ca content at different depths (P < 0.01). In addition, hydraulic attributes, especially flow length and sediment transport index (STI), had a significant effect on the spatial distribution of soil Ca. Spatial variability of soil Ca and its relationships with topographic and hydraulic attributes and soil types indicated that surface soil loss may occur due to water or wind erosion, especially on susceptible soils with high slopes. Therefore, this study suggests that the application of PXRF in assessing soil Ca content can potentially facilitate a new method for soil erosion evaluation in semi-arid lands. The results of this study provide valuable information for site-specific soil conservation and crop management.

Late Quaternary Stratigraphy and Geochronology of the Spring Creek Drainage along the Southern High Plains Eastern Escarpment, Northwest Texas

The eastern escarpment breaks of the Southern High Plains of Texas are both a geomorphic and ecotonal transition zone from the high plains surface to the Rolling Plains below. The geoarchaeological record on the Southern High Plains surface is well documented, but few studies have investigated the sediments, soils, and geochronology of the eastern escarpment. The current investigation has targeted the discontinuous remnants of Late Quaternary deposits within Spring Creek, a tributary within the upper Brazos River basin. A total of 19 profiles, core, and isolated exposure locations placed along a transect from Macy Fork through upper Spring Creek and 40 radiocarbon ages provide a composite sequence and geochronology that also documents the Late Pleistocene to Late Holocene paleoenvironments of this drainage. The resulting record illustrates a series of major changes in sediments and local habitats over the past ~11,550 radiocarbon years (13,469–13,390 calendar years), characterized primarily by reductions in available water and increasing aridity that peaked during the middle Holocene. This sequence provides significant context to an expanding record of Late Pleistocene to middle Holocene biota and cultures. Subsequent downcutting of the drainage post-6000 14C yr B.P. (6988–6744 calendar years) removed large sections of the depositional sequence. Local topography within Spring Creek drainage greatly impacted the preservation of these deposits. The remaining record provides some different insights than those available from the Southern High Plains record.

Compost and legume management differently alter soil microbial abundance and soil carbon in semiarid pastures

AbstractEstablishment of improved perennial pasture systems for livestock production has been demonstrated to improve soil health in the semiarid Texas Southern High Plains (SHP). Use of waste products from other components of the animal production chain, such as applying composted manure from feedlot operations to grazed pastures, may provide an additional means of improving soil health and sustainability of these systems. However, few studies have examined the impact of composted animal manure on the changes in soil microbial communities, although they are important indicators of soil health. We investigated the effects of a one‐time composted cattle manure application at 3.36 Mg ha−1 on soil microbial community size and structure, soil organic C (SOC), total N (TN), and soil organic matter (SOM) up to 1.5 yr after application. We compared pastures consisting of either WW‐B. Dahl Old World bluestem grass [Bothriochloa bladhii (Retz.) S.T. Blake] alone or in mix with alfalfa (Medicago sativa L.). Results showed that compost application significantly increased SOC by about 4.4 g kg−1 soil within 1.5 yr after application. In N‐fertilized grass‐only pastures, compost addition increased microbial phospholipid fatty acid abundance, SOC, TN, and SOM, but no significant differences were observed between compost treatments in unfertilized pastures containing legumes. Our results show that even a one‐time compost addition at a relatively low rate can augment SOC in this semiarid pasture system after 1.5 yr, and that stimulation of soil microbial abundance and soil C and N from compost is more pronounced in fertilized grass‐only pastures compared with those with legume establishment.

A tiered stochastic framework for assessing crop yield loss risks due to water scarcity under different uncertainty levels

Agricultural production in arid and semi-arid regions is threatened by increased droughts (climate change) and groundwater depletion. Farmers increasingly must weigh the short-term economic gains from irrigation against the long-term aquifer longevity needs. Risk-based deficit irrigation is proposed to tackle this trade-off. A tiered risk assessment approach is developed to evaluate crop yield loss risks as a function of crop water supply (CWS) from irrigation and precipitation. Risk is defined as the probability of obtaining a crop yield below a pre-specified threshold. Logistic regression is used to quantify risks as a function of CWS, if the producer can specify a fixed minimum yield threshold. Distribution regression is used to develop the cumulative distribution function of the crop yield assuming heterogeneous model parameter and is useful when the producer can estimate CWS but cannot specify a minimum yield threshold. Finally, the CWS is also modeled as a stochastic variable and the crop yield risk conditioned on CWS risk is computed using the Kolmogorov axiom. The methodology is illustrated using a cotton production case-study in the Southern High Plains of Texas. Logistic regression indicated that crop yield risk was a nonlinear function of CWS. CWS corresponding to ∼80 % of the total crop water demand was enough to reach negligible crop yield risks. Heterogeneous cotton yield distribution was modeled using Box-Cox-Cole-Green function with location and scale parameters being nonlinear and linear functions of CWS respectively and a stationary shape parameter. Irrigation at lower CWS reduced the risks substantially but the risk reductions were marginal at higher CWS. The conditional distribution of crop yield risk indicated that CWS corresponding to ∼80 %–85 % of crop water demand was enough to bring down risks. The tiered risk assessment provides a rational risk-based approach to evaluate the impacts of crop water supply reductions and promote deficit irrigation practices.

Evaluation of Cotton Establishment Strategies Using Subsurface Drip Irrigation (SDI) in the Southern High Plains of Texas

Abstract.HighlightsPlanting date and crop row distance from SDI laterals affect final cotton plant population, lint yield and water use.Cotton rows directly above 2.03-m spaced SDI laterals should only be used late within the cotton planting window.Positioning pairs of rows nearer to 2.03-m spaced SDI laterals increased yield compared to evenly spaced rows.SDI laterals spaced 1.02 m versus 2.03 m apart increased cotton yield by 5% and water use efficiency by 7%. In the Texas High Plains (THP), water table declines in the Ogallala Aquifer and the high evaporative environment have helped motivate the transition from surface and center pivot irrigation to subsurface drip irrigation (SDI). A major challenge to wider adoption of SDI in the region is inconsistent cotton seed germination and plant establishment due to dry overwinter conditions, the difficulty of “pushing” irrigation water upward into the seed germination zone, and the high evaporative environment during the optimum cotton planting period. To evaluate strategies for improving cotton establishment using SDI in the Southern High Plains (SHP) of Texas, a field experiment having five crop row/ SDI lateral configurations, each with two planting dates, was conducted from 2013 to 2018 at the Texas A&amp;amp;M AgriLife Research Center in Halfway, Texas. Differences in final plant stands, cotton yields, cotton fiber qualities, and water productivities were determined. Averaged over planting dates and years, planting directly over 1.02-m spaced SDI laterals (Every-Row configuration) increased final plant stand by 9.5%, cotton yield by 5.1%, irrigation water use efficiencies (IWUE) by 6.7%, and irrigation value (IValue) by 6.1% over planting pairs of 1.02-m spaced rows equidistant and parallel to 2.03-m spaced laterals (Traditional configuration). Compared to the Traditional configuration, planting pairs of cotton rows 0.76 m apart with both rows closer to 2.03-m spaced SDI laterals (30-50 configuration) increased final plant stand by 9.5% and yield by 3.0%. Considering additional treatments with 2.03-m spaced cotton rows planted directly over 2.03-m spaced SDI laterals (Skip-Row configuration) and 1.02-m spaced cotton rows having one row directly over 2.03-m spaced laterals and one row “not irrigated” (Skip-Row Plus configuration), early plantings resulted in five-year yields of 1400 and 1600 kg ha-1, respectively. However, these yields were less than those from the late planted, Traditional treatment at 1620 kg ha-1. Also, IValues and IWUEs of both Skip-Row treatments were significantly lower (p&amp;lt;0.05) than those of the Traditional treatment. Based on these results, the Skip-Row or Skip-Row Plus configurations should only be used late in the cotton planting period when soil water is not available for plant establishment using the Traditional or 30-50 configurations. Advantages of Every-Row and 30-50 over the Traditional configuration must be weighed against their increased costs. Keywords: Cotton, Germination, Irrigation, Southern High Plains, Subsurface drip irrigation (SDI).

A Survey of the Insects of the Southern High Plains (Llano Estacado) of Texas, with Particular Reference to Pollinators and Other Anthophiles

The economic value of insect pollination to the world economy is tremendous, and pollination service is critical for our food supply and persistence of native plants. Little data are currently available on pollinator occurrence in the Southern High Plains (SHP) of Texas. Past studies on hybrid cottonseed production in the region documented high abundance of six species of Agapostemon and lower abundance of Diadasia spp., Melissodes spp., and Perdita spp. Historical records indicated the presence of Bombus fraternus and B. pensylvanicus which now have Endangered and Vulnerable IUCN status respectively. In 2013 and 2014, we used blue vane traps and targeted netting to collect insect pollinators and anthophiles on the three dominant land uses in the region; cropland, Conservation Reserve Program (CRP), and native grasslands. With capture methods combined, we collected 74,215 insect specimens; 63% of the specimens were Hymenoptera (289 taxa), 28.61% were Coleoptera (150 taxa), 4.48% were Diptera (115 taxa), 2.34% were Lepidoptera (60 taxa), and 1.61% were of other orders (15 taxa). Our capture included all previously documented bee genera, but we did not detect B. fraternus. Studies support that blue vane traps are an effective method of trapping bees and our results demonstrated that they are also effective in attracting some families of anthophilous Coleoptera and Diptera. However, we captured several species of Hymenoptera, Diptera, and Lepidoptera with aerial nets that we did not capture in blue vane traps. This study documents pollinator and anthophile species present in a highly altered landscape and is the most comprehensive list of pollinators and anthophiles in this region to date.

Multiscale Habitat Selection of Lesser Prairie-Chickens in a Row-Crop and Conservation Reserve Program Land Matrix

Abstract The lesser prairie-chicken Tympanuchus pallidicinctus has received considerable attention in recent years, as a result of population decline and the uncertainty of its status under the 1973 U.S. Endangered Species Act. Substantial effort has been exerted studying the life history of the species and effects of some management practices on its ecology. However, information is lacking regarding lesser prairie-chicken use and selection of Conservation Reserve Program fields in the Southern High Plains of Texas. To fill in this knowledge gap, we assessed habitat selection by lesser prairie-chickens within Conservation Reserve Program fields, native grassland, and row-crop agriculture in Texas, 2015–2017. We assessed habitat selection using a Type II design at the second order of selection (home range placement within the landscape) and a Type III design at the third order (Global Positioning System locations within the home range). At the second order of selection, lesser prairie-chickens selected Conservation Reserve Program fields seeded in nonnative grasses (wi = 3.99, 95% CI = 1.60–6.39) and native grasses and forbs (wi = 3.25, 95% CI = 1.99–4.52) year-round. Row-crop agriculture (wi = 0.17, 95% CI = 0.06–0.28) and native grassland (wi = 0.30, 95% CI = 0.06–0.55) were avoided. Native grass Conservation Reserve Program fields were used in proportion to their availability (wi = 1.33, 95% CI = 0.81–1.85) year-round. Only Conservation Reserve Program fields seeded in native grasses and forbs were selected at the third order of selection (wi = 1.32, 95% CI = 1.16–1.47). Based on our results, Conservation Reserve Program fields provide habitat for lesser prairie-chickens, and as such, may be beneficial to persistence of the species on the High Plains of Texas.

Comparative geochemistry of urban and rural playas in the Southern High Plains

Playas are common natural occurrences in the Southern High Plains of Texas and act as sources of runoff in rural and urban settings and provide habitat for migratory waterfowl. Rural and urban playas in Lubbock County, TX were geochemically compared in order to optimize management for ecological functionality. Soil texture, specifically sand and clay, and organic matter concentration influenced geochemical properties such as trace element concentration, pH, and electrical conductivity. Rural playas contained more clay, organic matter, trace elements, and electrical conductivity than urban playas. Urban playas had a higher pH and roughly twice the sand content of rural playas. The prevalence of sand in urban playas likely influences groundwater recharge dynamics and potentially disqualifies these lakes as Vertisols owing to their sandy nature. The soil mineralogy between urban and rural playas were also different. Quartz and muscovite were the dominant minerals in urban and rural playas, respectively. The differing soil properties between rural and urban playas signify the necessity of unique management strategies.

Using rare earth elements to trace wind-driven dispersion of sediments from a point source

Abstract The entrainment and movement of aeolian sediments is determined by the direction and intensity of erosive winds. Although erosive winds may blow from all directions, in most regions there is a predominant direction. Dust emission causes the removal preferentially of soil nutrients and contaminants which may be transported tens to even thousands of kilometers from the source and deposited into other ecosystems. It would be beneficial to understand spatially and temporally how the soil source may be degraded and depositional zones enriched. A stable chemical tracer not found in the soil but applied to the surface of all particles in the surface soil would facilitate this endeavor. This study examined whether solution-applied rare earth elements (REEs) could be used to trace aeolian sediment movement from a point source through space and time at the field scale. We applied erbium nitrate solution to a 5 m2 area in the center of a 100 m diameter field 7854 m2 on the Southern High Plains of Texas. The solution application resulted in a soil-borne concentration three orders of magnitude greater than natively found in the field soil. We installed BSNE sampler masts in circular configurations and collected the trapped sediment weekly. We found that REE-tagged sediment was blown into every sampler mast during the course of the study but that there was a predominant direction of transport during the spring. This preliminary investigation suggests that the REEs provide a viable and incisive technique to study spatial and temporal variation of aeolian sediment movement from specific sources to identifiable locations of deposition or locations through which the sediments were transported as horizontal mass flux and the relative contribution of the specific source to the total mass flux.

CPPU (N-(2-chloro-4-pyridinyl)-N’-phenylurea) Enhancement of Cotton Yields

The gradual depletion of the Ogallala Aquifer under the Southern High Plains of Texas during the past fifty years has resulted in reduced well capacities for cotton irrigation. Water table declines have already led some to shift from irrigated to dryland farming, and many of the remaining wells cannot provide enough water for full irrigation. The present study evaluated the effectiveness of the synthetic cytokinin CPPU (N-(2-chloro-4-pyridinyl)-N’-phenylurea) on the stimulation of lateral root production and enhancement of cotton yields under dryland conditions. Seed treatments of 250 µmol/mol or seedling sprays of 5 µmol/mol at the cotyledon stage, increased lateral root production. Cotton yield increases associated with the increased rooting ranged from 8 to 20% in three years of field studies under dryland conditions. The greatest yield increases were associated with dry shallow soils. Evaluation of water-deficit stress levels in untreated and CPPU-treated cotton showed reduced water-deficit stress levels throughout the growing season in the CPPU-treated cotton. This study showed that application of CPPU to cotton, early in development, has the potential to reduce water stress and increase yields.

An Agrocentric Analysis of Regional Rain Patterns as They Relate to a Rained Cotton Cropping System on the Southern High Plains of Texas

Rain is the major limiter of cotton yields on the Southern High Plains of Texas. Rain can be analyzed in terms of its effect on the crop. An “agro-centric rain” analysis assesses the amounts and timing of rain events within a defined management system. Cotton on the Southern High Plains of Texas at Lubbock, TX, USA was analyzed in terms of the crop water environment associated with 70 potential cotton crop seasons over the period from 2006 to 2015. For the 10-year period, the 238-day cotton growing season was divided into seven potential cotton crop seasons of 154-days each. Rain and crop water status (as reference and crop evapotranspiration) were calculated for each of the 70 potential cotton crop seasons. The highest rain amounts were associated with earlier plantings. Maximum values of reference evapotranspiration were associated with the mid-season plantings and minimum values with the earliest and latest plantings. Crop stress (rain-reference evapotranspiration) showed a pattern with maximum stress associated with the earliest plantings. Crop water status across potential cotton crop seasons can vary with planting date across years and it may be possible to exploit the variation to improve yield in terms of germplasm and management practices.

Food‐energy‐water nexus to mitigate sustainability challenges in a groundwater reliant agriculturally dominant environment (GRADE)

Groundwater reliant and agriculturally dominant environments (GRADEs) utilize exhaustible aquifer resources to supply food and fiber demands. The sustainability of these GRADES is threatened by over‐exploitation of fresher groundwater resources. There is an interest in exploring deeper brackish groundwater resources to sustain agricultural based economies in these regions. Using the southern high plains of Texas (SHP) as a test‐bed, the interlinkages between food‐energy‐water on improving water resiliency through brackish groundwater development is explored. Three scenarios—(1) direct use of deeper formations; (2) blending deeper and shallower groundwaters and 3) desalination of blended resources were evaluated in a spatially explicit manner. The results indicate that direct reuse of deeper water is possible over 30% of the study area, but it is not available in areas of critical need. The parameters limiting the suitability of deeper groundwater for agriculture in the order of decreasing importance are EC &gt; TDS &gt; SAR &gt; B &gt; Na &gt; Cl. Simple blending of water from deeper and shallower aquifers improve water quality over roughly 900,000 acres. While blending greatly reduces the specific ion toxicities caused by sodium absorption ratio (SAR) and boron (B), the limitations of total dissolved solids (TDS) cannot be overcome. The over‐burden pressures in the deeper confined aquifer somewhat alleviate the blending energy requirements, especially in the southern portions of SHP. Desalination increases the energy requirements by several fold and is not suitable to sustain current agricultural practices which are focused mostly on lower valued staple crops. Using desalinated water for municipal and industrial uses can help ameliorate the stresses on the Ogallala Aquifer and enhance its longevity. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 21–36, 2018Novelty or Significance: The study is focused on the linkages between food, energy and water in groundwater dependent agricultural economies. Using the Southern High Plains of Texas as a test‐bed, the work evaluates whether a deeper brackish groundwater resource (Dockum geological unit) can be used to augment water supplies to sustain intensive agricultural production. The study identifies various factors that limit the use of this deeper resource and quantifies the energy footprint associated with three progressively complex approaches to improve water resiliency in the region and prolong the life of the Ogallala Aquifer.