Southwest Kansas Research Articles

AGE-SPECIFIC VARIATION IN APPARENT SURVIVAL RATES OF MALE LESSER PRAIRIE-CHICKENS

Abstract We used mark-recapture methods to estimate age-specific apparent survival rates for male Lesser Prairie-Chickens (Tympanuchus pallidicinctus), a gamebird of conservation concern. A total of 311 male prairie-chickens (135 yearlings, 176 adults) were captured and banded during a 5-year study in southwest Kansas. Time-since-marking models were used to estimate apparent survival after first capture (ϕ1), apparent survival among returning birds (ϕ2+), and probability of capture (p) for yearling and adult prairie-chickens. Apparent survival is the product of true survival and site fidelity, and our model-averaged estimates of this parameter were ranked: yearlings after first capture (ϕ1yr = 0.60 ± 0.12) > adults after first capture (ϕ1ad = 0.44 ± 0.10) > returning birds (ϕ2+ = 0.36 ± 0.10). In contrast, movement data showed that site fidelity to communal display sites (or leks) increased with male age; yearlings returned to leks at lower rates (80%, n = 60) than adults (92%, n = 65). Thus, true surv...

Reservoir geology of Nicholas and Liverpool Cemetery fields (lower Pennsylvanian), Stanton County, Kansas, and their significance to the regional interpretation of the Morrow Formation incised-valley-fill systems in eastern Colorado and western Kansas

Reservoirs in the lower Pennsylvanian Morrow Formation of eastern Colorado, southwestern Kansas, and northwestern Oklahoma have produced greater than 8 tcf of gas and 200 million bbl of oil. This prolific depositional system produces from reservoirs representing a range of depositional environments from updip, fluvial-dominated, incised-valley fills to deep-water basin-floor systems. The valley fills of the Morrow Formation are of particular significance because they can be mapped in great detail from subsurface control over very long distances. Facies distributions in the valleys change systematically downdip. As a result, reservoir characteristics and trapping mechanisms vary with these changes in internal valley stratigraphy.This paper focuses on the reservoir geology of Nicholas and Liverpool Cemetery fields. These fields produce gas from the extreme downdip region of an incised-valley-fill system in the lower Morrow Formation. The valley systems in this downdip region are deeper and wider and demonstrate greater marine influence than the updip regions of the valley systems farther north and into the hinterland.Compartmentalization in these downdip reservoirs differs significantly from updip valley-fill reservoirs. The reservoirs in this downdip region are more highly compartmentalized because the dominant reservoir facies in these fields is a series of bayfill delta deposits. These deposits are isolated by shale deposits in the valley. This depositional setting contrasts markedly with predominantly fluvial reservoirs in updip regions of the valleys. Understanding the scale, geometry, and internal complexity of this depositional system is important because the associated sandstones are important gas reservoirs in southwest Kansas. Cores, wire-line logs, pressure data, and production data collected from the Morrow Formation at Nicholas and Liverpool Cemetery fields provide valuable information from which to describe and interpret this downdip valley fill. This paper describes the downdip incised-valley-fill reservoirs in this producing complex and documents the trapping relationships of these reservoirs and their production characteristics.

The Value of Bt Corn in Southwest Kansas: A Monte Carlo Simulation Approach

While most Corn Belt farmers consider planting Bt corn to control European corn borer, southwestern Kansas farmers must also take into account an array of other insect pests, including corn rootworm, spider mites, and southwestern corn borer. This research uses a decision analysis framework to estimate the expected economic value of Bt corn in southwest Kansas. Mean per acre Bt values ranged from $12.49 to $34.60, well above the technology fee assumed to be $14 per unit, or $5.25 per acre at a seeding rate of 30,000 seeds per acre. The minimum value over all scenarios was $8.69 per acre. Using Monte Carlo simulation, it was shown that European and southwestern corn borer infestation probabilities, expected corn price, and expected pest-free yields are important determinants of the value of Bt corn.

Vegetation of Prairie Dog Colonies and Non-Colonized Shortgrass Prairie

Black-tailed prairie dogs have declined by 98% in the past century. Due to continued declines, the U. S. Fish and Wildlife Service designated the species as a candidate for listing in 2000. Prairie dogs foster both plant and animal diversity, and their continued presence is a concern in the Great Plains. We compared vegetation structure and composition of black-tailed prairie dog (Cynomys ludovicianus Ord) colonies in southwest Kansas and southeast Colorado to non-colonized grassland in 1996, and 1997. Dominant species on prairie dog colonies were Bouteloua gracilis (H. B. K.) Lag. ex Griffiths (14% cover in 1996, 15% in 1997), Buchloe dactyloides (Nutt.) Engelm. (7% cover in 1996, 17% in 1997) and Aristida purpurea Nutt. (9% cover in 1996, 16% in 1997). Dominant vegetation at randomly selected non-colonized sites were Bouteloua curtipendula (Michx.) Torr. (16% cover in 1996, 18% in 1997), Bouteloua gracilis (13% cover in 1996, 17% in 1997) and Buchloe dactyloides (5% cover in 1996, 5% in 1997). Non-colonized shortgrass sites were dominated by Bouteloua gracilis (23% cover in 1996, 41% in 1997) and Buchloe dactyloides (8% cover in 1996, 12% in 1997). Cover of grass was higher (P 0.05) among treatments either year. While components of the vegetation on prairie dog colonies differed from that found on non-colonized sites, the vegetation of prairie dog colonies was, nonetheless, characteristic of a shortgrass region. Prairie dogs undoubtably alter vegetation structure and composition in shortgrass prairie, and likely have a great influence on landscape heterogeneity, but our results suggest that shortgrass prairie is well adapted to the herbivory and soil disturbing activities of prairie dogs.

Land Cover Change and Associated Trends in Surface Reflectivity and Vegetation Index in Southwest Kansas: 1972-1992

Land cover is an important component of the earth system. Human induced surface alteration can affect earth systems directly, through loss or degradation of ecosystems, or indirectly through impact on the climate and biogeochemical cycles necessary to sustain life on earth. The significance of the earth's surface has made land use/land cover change an important issue in global change research. Alteration of land cover occurs at a variety of spatial scales, but as with many environmental change issues, the impacts of surface changes are often conceptualized at the global scale. In this study, we investigate the effects of land cover change on total reflected radiation and the Normalized Difference Vegetation Index (NDVI) in a 10,000 km2 local area in the High Plains of southwestern Kansas. Landsat MSS data from five years of record within the twenty‐year period 1973 to 1992 were classified into cool season crop, warm season crop, and pasture/prairie. Mean values of summer reflectance and NDVI from each cover type and for the study area as a whole were then analyzed for systematic change over the study period. Both reflectivity and vegetation index increased during the study period, although causes for the increase appear to be different. Results suggest that changes in mean surface reflectance in the study site are strongly influenced by land cover change, whereas changes in NDVI are more closely linked to 50‐day antecedent precipitation.

Sequence stratigraphic and sedimentologic significance of biogenic structures from a late Paleozoic marginal- to open-marine reservoir, Morrow Sandstone, subsurface of southwest Kansas, USA

Integrated ichnologic, sedimentologic, and stratigraphic studies of cores and well logs from Lower Pennsylvanian oil and gas reservoirs (lower Morrow Sandstone, southwest Kansas) allow distinction between fluvio-estuarine and open marine deposits in the Gentzler and Arroyo fields. The fluvio-estuarine facies assemblage is composed of both interfluve and valley-fill deposits, encompassing a variety of depositional environments such as fluvial channel, interfluve paleosol, bay head delta, estuary bay, restricted tidal flat, intertidal channel, and estuary mouth. Deposition in a brackish-water estuarine valley is supported by the presence of a low diversity, opportunistic, impoverished marine ichnofaunal assemblage dominated by infaunal structures, representing an example of a mixed, depauperate Cruziana and Skolithos ichnofacies. Overall distribution of ichnofossils along the estuarine valley was mainly controlled by the salinity gradient, with other parameters, such as oxygenation, substrate and energy, acting at a more local scale. The lower Morrow estuarine system displays the classical tripartite division of wave-dominated estuaries (i.e. seaward-marine sand plug, fine-grained central bay, and sandy landward zone), but tidal action is also recorded. The estuarine valley displays a northwest–southeast trend, draining to the open sea in the southeast. Recognition of valley-fill sandstones in the lower Morrow has implications for reservoir characterization. While the open marine model predicts a “layer-cake” style of facies distribution as a consequence of strandline shoreline progradation, identification of valley-fill sequences points to more compartmentalized reservoirs, due to the heterogeneity created by valley incision and subsequent infill. The open-marine facies assemblage comprises upper, middle, and lower shoreface; offshore transition; offshore; and shelf deposits. In contrast to the estuarine assemblage, open marine ichnofaunas are characterized by a high diversity of biogenic structures representing the activity of a benthic fauna developed under normal salinity conditions. Trace fossil and facies analyses allow environmental subdivision of the shoreface-offshore successions and suggest deposition in a weakly storm-affected nearshore area. An onshore–offshore replacement of the Skolithos ichnofacies by the Cruziana ichnofacies is clearly displayed. The lower Morrow fluvio-estuarine valley was incised during a drop of sea level coincident with the Mississippian–Pennsylvanian transition, but was mostly filled during a subsequent transgression. The transgressive nature of the estuarine infill is further indicated by the upward replacement of depauperate brackish-water trace fossil assemblages by the open-marine Cruziana ichnofacies. Additional stratal surfaces of allostratigraphic significance identified within the estuary include the bayline surface, the tidal ravinement surface, the wave ravinement surface, and a basinwide flooding surface recording inundation of the valley interfluves. A younger sequence boundary within the lower Morrow is also recorded in the Gentzler field at the base of a forced regression shoreface, demarcated by the firmground Glossifungites ichnofacies, indicating a rapid basinward facies migration during a sea-level drop. Trace fossil models derived from the analysis of Mesozoic and Cenozoic reservoirs are generally applicable to the study of these late Paleozoic reservoirs. Pennsylvanian brackish-water facies differ ichnologically from their post-Paleozoic counterparts, however, in that they have: (1) lower trace fossil diversity, (2) lower degree of bioturbation, (3) scarcity of crustacean burrows, (4) absence of firmground suites, and (5) absence of ichnotaxa displaying specific architectures designed to protect the tracemaker from salinity fluctuations. Morrow open-marine ichnofaunas closely resemble their post-Paleozoic equivalents.

Vegetation of prairie dog colonies and non-colonized shortgrass prairie

Black-tailed prairie dogs have declined by 98% in the past century. Due to continued declines, the U. S. Fish and Wildlife Service designated the species as a candidate for listing in 2000. Prairie dogs foster both plant and animal diversity, and their continued presence is a concern in the Great Plains. We compared vegetation structure and composition of black-tailed prairie dog (Cynomys ludovicianus Ord) colonies in southwest Kansas and southeast Colorado to non-colonized grassland in 1996, and 1997. Dominant species on prairie dog colonies were Bouteloua gracilis (H. B. K.) Lag. ex Griffiths (14% cover in 1996, 15% in 1997), Buchloe dactyloides (Nutt.) Engelm. (7% cover in 1996, 17% in 1997) and Aristida purpurea Nutt. (9% cover in 1996, 16% in 1997). Dominant vegetation at randomly selected non-colonized sites were Bouteloua curtipendula (Michx.) Torr. (16% cover in 1996, 18% in 1997), Bouteloua gracilis (13% cover in 1996, 17% in 1997) and Buchloe dactyloides (5% cover in 1996, 5% in 1997). Non-colonized shortgrass sites were dominated by Bouteloua gracilis (23% cover in 1996, 41% in 1997) and Buchloe dactyloides (8% cover in 1996, 12% in 1997). Cover of grass was higher (P < 0.01) on random sites (44%) than on prairie dog colonies (31%) or shortgrass sites (33%) in 1996, whereas cover of forbs was higher (P < 0.01) on prairie dog colonies (18%) than on random sites (7%) or shortgrass sites (8%) that year. Vegetation height was greater (Q = 3.66) and visual obstruction was greater (Q = 3.39) on random sites (33.6 and 6.4 cm, respectively) than on prairie dog colonies (9.5 and 2.5 cm, respectively) in 1997, the only year these variables were measured. Percent bare ground did not differ (P > 0.05) among treatments either year. While components of the vegetation on prairie dog colonies differed from that found on non-colonized sites, the vegetation of prairie dog colonies was, nonetheless, characteristic of a shortgrass region. Prairie dogs undoubtably alter vegetation structure and composition in shortgrass prairie, and likely have a great influence on landscape heterogeneity, but our results suggest that shortgrass prairie is well adapted to the herbivory and soil disturbing activities of prairie dogs.

The Circle Dot Cowboys at Dodge City: History and Imagination in Andy Adams's the Log of a Cowboy

IN THE THIRD WEEK OF JUNE 1882, seven Texas cowboys from an outfit grazing cattle on Duck Creek in southwest Kansas set out for nearby Dodge City. Like hundreds of cowhands and cattlemen before them, these Circle Dot men intended to see the elephant. Originally referring to the main attraction of any mid-nineteenth-century circus, the elephant reference was strictly metaphorical, meaning a unique sight or spectacle.1 Here it specifically alluded to the gaudy entertainments of one of the most notorious towns in America. Famous from coast to coast as a major western livestock market, Dodge City was equally celebrated and widely condemned for its all-night bars, gaming tables, dance halls, brothels, and general civic irregularity-all seasoned by the town's highly overblown reputation for gun violence.2 In the 1870s and 1880s, seemingly every cowboy ascending the Western Trail felt obliged to stop and ogle the excitement, if not actually participate in it.3

Prevalence, antibiotic susceptibility, and diversity of Escherichia coli O157:H7 isolates from a longitudinal study of beef cattle feedlots.

Prevalence, antibiotic susceptibility, and genetic diversity were determined for Escherichia coli O157:H7 isolated over 11 months from four beef cattle feedlots in southwest Kansas. From the fecal pat (17,050) and environmental (7,134) samples collected, 57 isolates of E. coli O157:H7 were identified by use of bacterial culture and latex agglutination (C/LA). PCR showed that 26 isolates were eaeA gene positive. Escherichia coli O157:H7 was identified in at least one of the four feedlots in 14 of the 16 collections by C/LA and in 9 of 16 collections by PCR, but consecutive positive collections at a single feedlot were rare. Overall prevalence in fecal pat samples was low (0.26% by C/LA, and 0.08% by PCR). No detectable differences in prevalence or antibiotic resistance were found between isolates collected from home pens and those from hospital pens, where antibiotic use is high. Resistant isolates were found for six of the eight antibiotics that could be used to treat E. coli infections in food animals, but few isolates were multidrug resistant. The high diversity of isolates as measured by random amplification of polymorphic DNA and other characteristics indicates that the majority of isolates were unique and did not persist at a feedlot, but probably originated from incoming cattle. The most surprising finding was the low frequency of virulence markers among E. coli isolates identified initially by C/LA as E. coli O157:H7. These results demonstrate that better ways of screening and confirming E. coli O157:H7 isolates are required for accurate determination of prevalence.

ABSTRACT: Western Tight Gas Carbonates: Comparison of Council Grove Group, Panoma Field, Southwest Kansas and Western Low Permeability Sandstones

ABSTRACT: Western Tight Gas Carbonates: Comparison of Council Grove Group, Panoma Field, Southwest Kansas and Western Low Permeability Sandstones

Sedimentology and Ichnology of Paleozoic Estuarine and Shoreface Reservoirs, Morrow Sandstone, Lower Pennsylvanian of Southwest Kansas, USA

Integration of facies and trace-fossil evidence tests and refines depositional models constructed solely on the basis of physical sedimentology. In recent years, the petroleum industry has increasingly used trace-fossil analysis of cores as an aid in reservoir characterization. In particular, ichnologic data have been instrumental in the recognition of estuarine deposits and their distinction from open-marine facies (e.g., MacEachern and Pemberton, 1994). Previous ichnologic analyses of cores, however, have concentrated on post-Paleozoic reservoirs (e.g., Bockelie, 1991; Pemberton, 1992; Taylor and Gawthorpe, 1993; Howell et al., 1996; Martin and Pollard, 1996; MacEachern and Pemberton, 1997). The present study represents one of the first attempts to apply trace-fossil analysis to cores from Paleozoic reservoirs.
 The Lower Pennsylvanian Morrow Sandstone contains oil and gas reservoirs in a wide variety of shallow and marginal-marine depositional environments. Delta-front, shoreface, and estuarine valley-fill reservoir sandstones are encased in offshore and estuarine mudstones (Sonnenberg, 1985; Krystinik and Blakeney, 1990; Sonnenberg et al., 1990; Wheeler et al., 1990). An integrated stratigraphic, sedimentologic, and ichnologic study provides a more accurate characterization of reservoir facies and geometry. This study allows distinction between marine-shoreface and estuarine valley-fill sandstones from four cores of the lower Morrow in southwestern Kansas. Core analysis subsequently was integrated with well-log information. Previous studies have emphasized the presence of estuarine valley-fills in the upper Morrow (Wheeler et al., 1990). Our integrated approach extends the estuarine valley interpretation into the lower Morrow. Within the midcontinent, trace fossils are useful in distinguishing different facies in estuarine incised valleys and marine shorefaces. Detailed study of biogenic structures provides high-resolution information to solve problems in facies, stratigraphic, and reservoir modeling. In some cases, they represent the only evidence available to develop a reasonable picture of depositional conditions and to estimate reservoir heterogeneity. The present study provides a detailed analysis of the sedimentary facies, documents the associated trace fossils, and illustrates how trace fossils are used to refine environmental interpretations of the lower Morrow sandstone reservoirs.

Replanting strategies for grain sorghum under risk

Risk analysis of replanting strategies for grain sorghum at three Kansas locations was conducted using stochastic dominance techniques. Yield data were simulated for seven planting dates, six seeding rates or target plant populations, and three maturity classes over a 33-year period using weather data for each year at each location. The results showed that optimal planting dates, seeding rates, and maturity classes vary by location and risk preference. In northeast and southcentral Kansas, planting at later rather than earlier dates was preferred as risk aversion increased. In southwest Kansas, generally no change occurred in the preferred strategy as the level of risk aversion increased. Early- and medium-maturing hybrids and low-to-moderate seeding rates often were selected. Late-maturing hybrids never were selected by risk-averse managers. The degree of risk aversion did not significantly affect the selection of a replanting strategy for southcentral and southwest Kansas, but did for northeast Kansas. However, whether managers replanted immediately or delayed, replanting varied with the replanting decision date and degree of risk aversion. Replanting on the first replanting decision date in southwest Kansas rather than delaying 2 weeks or more was preferred by all risk-averse managers. More strongly risk-averse managers in the northeast and all risk-averse producers in southcentral Kansas preferred to delay replanting of damaged stands, in some cases by 2–4 weeks after the decision date. Results also showed that when a stand was damaged late in the season, the expected yield from the damaged stand had to be lower than that from a stand damaged early in the season in order for replanting to occur. Price changes had only minor impacts on the preferred replanting strategies. A higher crop price caused replanting to occur more often, because the yield reduction of a damaged stand required for replanting to be economically feasible grew smaller as the price increased.

Heritability and stability of resistance to Bacillus thuringiensis in Ostrinia nubilalis (Lepidoptera: Pyralidae)

AbstractRealized heritability, h2, of resistance in European corn borer, Ostrinia nubilalis (Hübner), to Bacillus thuringiensisBerliner ssp. kurstaki endotoxins was examined in five resistant laboratory colonies. These colonies were reared on a meridic diet that incorporated a commercial formulation of B. thuringiensis, Dipel ES. Resistance in these colonies reached 42–67× by the seventh to twentieth selected generations and then plateaued. The realized heritability of resistance averaged 0.17–0.31 over all selected generations for the five colonies. In the three Iowa colonies, the highest realized heritability, 0.18–0.33, occurred during the second period of selection (seventh to thirteenth selected generations). In the two Kansas colonies, the highest realized heritability, 0.36 and 0.46, occurred during the first period of selection (first to sixth selected generations). In the absence of selection pressure, resistance in the southwest Kansas colony decreased from 62× to 42× after two generations, and remained at about that level for the next five generations.

Risk Analysis of Planting Date, Seeding Rate, and Grain Sorghum Hybrid Maturity in Kansas Using Simulated Yields

Many variables influence yields of grain sorghum [Sorghum bicolor (L.) Moench] and make it difficult to provide appropriate recommendations to managers concerning planting dates, seeding rates, and hybrid maturity classes. General recommendations in extension publications provide a wide range of possible planting dates and seeding rates and usually suggest planting the latest maturing hybrid within the limitations of projected moisture availability and average length of growing season. Most research related to these issues focuses on just one variable, while holding others constant. This study used simulated grain sorghum yields to provide an economic risk analysis of planting date, seeding rate, and hybrid maturity for grain sorghum production in Kansas. The results showed that optimal planting dates, seeding rates, and maturity classes vary by location and risk preference. In general, the results indicate that extremely risk-averse managers would choose somewhat later planting dates, earlier maturing hybrids, and lower seeding rates than less risk-averse or risk-preferring managers.

Transformation of Landownership and Land Use in the Sandhills of Southwest Kansas

The adoption and diffusion of center pivot irrigation systems transformed the traditional landscape of the High Plains. While Finney County in southwest Kansas has been known as one of the most advanced irrigation districts of the High Plains, vast sandhills on the right bank of the Arkansas River remained extensive cattle pasture until center pivot irrigation systems had completely changed the farming landscape during the 1970s. The new irrigation technology and feed crop cultivation combined to develop the feedlot and beef packing industries in the region. This paper examines the transformation process of landownership and land use in the sandhills of Finney County with special reference to the diffusion of center pivot irrigation systems.Cattle industry began in the Garden City area in the late nineteenth century, and large landholdings and extensive cattle raising continued to dominate the sandhills up to the 1960s. Large landholdings with over 10, 000 acres included Brown, Cowgill, Burnside, Douglas, and Jones ranches. They purchased calves from ranchers of the western states, raised them on the natural pasture, and shipped them to the corn belt for finishing. Some ranchers specialized in breeding high quality beef cattle, and others took care of the calves born in the local farms from spring through fall. The region, blessed with ground water and natural pasture, was also known as winter refuge for animals.Land register maps and aerial photos reveal substantial changes which took place in the sandhills during the 1970s. Large feedlot companies and agribusinesses came to own large tracts of land by purchasing traditional cattle ranches, while descendants of homesteaders also participated in the irrigation development. Gigot Irrigation Co. first demonstrated the effectiveness of center pivot irrigation systems in developing additional sandhills land which they purchased, while acting as a sales agent of the Valley brand irrigation systems. The company sold 600 sets of center pivot irrigation systems annually in two boom years of 1972 and 1973, while the company's average annual sales amounted to around 200 sets in the following years. Thus, the rich ground water resources of Ogalalla aquifer were exploited. The rapid process of adopting the new technology transformed the traditional barrens into the fertile farming regions irrigated by big circles.Large land holders are typically found in the sandhills. Circle Land and Cattle Inc. owned by Gigot families manage more than 20, 000 acres. Brookover Feedyards, which started cattle feeding in the early 1950s just northwest of Garden City, expanded their business in the sandhills by introducing center pivot irrigation systems, developing subdivisions, and managing golf courses. IBP, a beef packing company operating the world's largest packing plant just west of Garden City, and Tim Dewey Farms and Cattle Co. also started irrigation farming by purchasing land in the sandhills. Corn and alfalfa are the two major irrigation crops, which are consumed locally at large feedlots. Because of these developments since the 1970s, lowering the water table of the Ogalalla aquifer is considered a serious problem in order to sustain the highly water consuming farming of the sandhills.

アメリカ合衆国ハイプレーンズにおける潅がい化と農業地域の変化 カンザス州南西部の事例

In the High Plains regions of the United States, once called the Great American Desert, productive farming regions were formed due to the introduction of center pivot irrigation systems since the 1960s. Finney county of Southwest Kansas, our study area, is one of the most productive farming regions in the High Plains, where irrigation has a long history. While windmills were built to take advantage of shallow ground water in the late nineteenth century, surface water became diverted from the Arkansas River by constructing irrigtion ditches beginning in the 1880s. Ditch irrigation was further promoted by the construction of sugar factory in Garden City in 1906 and the subsequent sugar beet cultivation mainly on the High Plains tablelands of the left bank of the Arkansas. On the other hand, introduction of turbine pumps and the use of inexpensive natural gas pumped from the underlying Hugoton gas field combined to promote the development of ground water irrigation from the 1940s.The most striking in the history of the High Plains is the invention and introduction of the center pivot irrigation system. The Gigots introduced a valley brand system of center pivot irrigation in 1963 in order to improve their farmland in the sandhill, and their success triggered the application of the new irrigation technology. The early 1970s were boom years in Garden City and its vicinity when the Gigot Irrigation soled 600 systems annually. The sandhills on the right bank of the Arkansas, where rolling topography, infertile soils, and excessive drainage defied intensive use of land and therefore remained the barrens, were most efectively transformed into the landscape dominated by big circles. On the left bank, center pivot systems were introduced in the dry land farming districts on the talbelands, while they are gradually replacing traditional ditch and groundwater irrigation. Such a transformation process is well documented by the distribution of wells and the aerial photo analyses. Due to these irrigation developments, production of feed crops expanded such as maize, alfalfa, sorghum, and soy beans.The development of irrigation and feed crop production is key to understand the subsequent phases of regional changes, including feedlot and beef packing industries, population composition and dynamics, and undergroud water management. It is necessary to closely examine these geographic features in order to understand the sustainability of the High Plains regions.

Abstract: Sequence Stratigraphic Model for the Upper St. Loius Limestone Reservoirs of Southwest Kansas

Abstract: Sequence Stratigraphic Model for the Upper St. Loius Limestone Reservoirs of Southwest Kansas

An Agronomic and Economic Comparison of the Wheat-Corn-Fallow and Wheat-Sorghum-Fallow Rotations

Winter wheat (Triticum aestivum L.) and grain sorghum [Sorghum bicolor (L.) Moench] in the central and southern Great Plains are often grown in a 3-yr wheat-sorghum-fallow (WSF) rotation. Corn (Zea mays L.) can be substituted for sorghum in northern areas but is believed to lack sufficient drought and heat tolerance for southwest Kansas and areas further south. However, interest in dryland corn is increasing. We conducted a study from 1992 through 1995 near Garden City, KS, to compare wheat-corn-fallow (WCF) and WSF. Four tillage systems were compared: all conventional tillage (CT); all reduced tillage (RT); all no-tillage (NT); and a CT wheat, NT corn or sorghum combination (CNT). Wheat yields were unaffected by rotation and tillage. Corn yielded more than sorghum in 12 of 16 tillage x year combinations, primarily due to above average precipitation. Corn yields were increased by RT and NT in 3 of 4 yr whereas they increased sorghum yields in only 1 yr. Average returns from WCF were $31.22/acre per yr, whereas those from WSF were $19.79/acre per yr. Returns of WCF exceeded WSF returns in 10 of 16 tillage × year combinations. Average income for CNT in WCF exceeded incomes from CT, RT, and NT by $6, $7.16, and $11.90/acre per yr, respectively. The CNT system in WSF produced $3.79/acre per yr more than RT and $6.14/acre per yr more than NT, but $5.84/acre per yr less than CT. Under the conditions of this study, WCF was superior to WSF in terms of yield and return. The CNT system- usually produced more return, particularly in WCF.

Airborne Doppler Radar Analysis of Supercells during COPS-91

Abstract On 26 May 1991, NOAA P-3 airborne Doppler radar data were collected near two tornadic supercells in the southern Plains during the Cooperative Oklahoma Profiler Studies (COPS-91) field program. The 3-cm radar mounted in the tail of the aircraft was operated using the fore–aft scanning technique (FAST). Both storms were sampled just minutes after each had produced a tornado. The COPS-91 storms are the first tornadic supercells to be sampled extensively by airborne Doppler radar using the FAST methodology. Pseudo-dual-Doppler analyses of a dissipating storm in southwest Kansas show no remaining low-level circulation, even though the storm had just produced a tornado. The analyses of a storm in northwest Oklahoma reveal better-defined features in the wind field near the surface. In contrast to what has been previously observed in post-tornadic supercells, the cyclonic vorticity in both storms was greater aloft than at low levels. The 26 May 1991 storms provide further evidence that supercells often ...

Dryland Corn vs. Grain Sorghum in Western Kansas

Dryland crop yields in the U.S. Great Plains are limited by low precipitation and high potential evapotranspiration. In western Kansas wheat (Triticum aestivum L.) and grain sorghum [Sorghum bicolor (L.) Moench] are grown commonly, whereas corn (Zea mays L.) is believed to lack sufficient drought and heat tolerance for dryland production. A study was conducted near Garden City, KS, from 1991 through 1995 to determine whether corn could be grown successfully. No-till (NT) and conventional-till (CT) corn and grain sorghum were compared. In the driest year, sorghum yielded 137% more than corn with CT and 85% more with NT, but in 3 of 5 yr, NT corn yielded from 34% to 112% more than NT sorghum. In the remaining year, CT sorghum yielded more than CT corn, but NT yields did not differ. Overall, NT increased corn yields by 28% and net return by 69%, but increased sorghum yields by only 11% and had no effect on net return. No-till corn yielded 28% more than NT sorghum and produced 169% more net return, whereas CT corn yielded 11% more than CT sorghum and produced 48% more net return. Dryland corn can be grown in western Kansas if lower yields and returns are accepted in dry years in exchange for yields and returns considerably higher than those of sorghum in favorable years. No tillage will substantially increase yields in most years and is essential to assure adequate corn yields in dry years.