Western Kansas Research Articles

Evaluation of Novel Deficit Irrigation Techniques in Western Kansas

Evaluation of Novel Deficit Irrigation Techniques in Western Kansas

Western Kansas Field Station Weather Report: 2022 Growing Season

Western Kansas Field Station Weather Report: 2022 Growing Season

Strategic grassland conservation for swift foxes in multi-use landscapes

Grasslands are among the most widely distributed, but most imperiled, biomes on Earth. North American grasslands once covered ~162 million ha prior to European colonization, but only ~30 % of this landcover currently remains due to continued human-modified landscape changes. Strategic conservation of remaining grassland landcover, which considers species-specific habitat requirements, is critical for the persistence of grassland species and has become a global priority. Intact grassland landcover is critical for swift fox (Vulpes velox), a facultative prairie carnivore, and we sought to strategically identify areas where grassland conservation would most impact population persistence in an agro-prairie ecosystem. We modeled site (n = 381) occupancy by swift foxes using three years of camera-trap data (2018–2020) from western Kansas, USA, and integrated known-fate survival information to identify priority native grassland conservation areas. Additionally, we evaluated ownership of our identified priority conservation lands to determine strategies for conservation delivery. Our grassland assessment of two thresholds of predicted swift fox occupancy (≥0.09 [priority] and ≥0.18 [high priority]) identified 2,377,193 ha and 84,420 ha for conservation in Kansas, respectively. Identified conservation areas were overwhelmingly located on privately owned working lands (98 % [priority and high priority]), rather than federal, state, or non-governmental organization owned lands (2 % [priority and high priority]), and highlight the need for using conservation easements and incentive-based programs to promote grassland conservation to private landowners.

Reconstructing late Miocene depositional environments in the central High Plains, USA: Lithofacies and architectural elements of the Ogallala Formation

The late Miocene Ogallala Formation hosts much of the High Plains aquifer of North America, though it is poorly studied in the central High Plains region where only a small fraction of its total thickness is exposed. One exception is in western Kansas, where up to 40 m of the Ogallala Formation crop out along the bluffs of Ladder Creek Canyon. These deposits consist of stacked and laterally extensive, multistory channel bodies dominated by sandy bedforms with little or no intervening floodplain mudstone. We interpret each ~2–4 m-thick story as a sandstone bed that formed during a single depositional episode and infilled a broad and relatively shallow braided river channel. Each story preserves elements suggesting high discharge conditions, followed by low discharge or the complete abandonment of the river channel after active streamflow either migrated away from the study area or ceased regionally for a relatively long period of time. High discharge conditions are characterized by channel-filling, current-formed transverse bars, gravel-rich longitudinal bars, and sand sheets deposited while the channel was largely flooded and nearly the entire riverbed mobilized. Low discharge conditions are indicated by lens-shaped, trough cross-stratified channels scoured into previously deposited bars. Channel-fill deposits were formed when the remaining flow was confined to one or more narrow streams that braided across the exposed channel belt. Persistent low discharge conditions are suggested by channel-belt-wide subaerial exposure of bar surfaces for a period of time sufficient to promote colonization by soil-burrowing organisms and moderate soil development. Abandonment of the broader channel belt is indicated by advanced calcretization within a story and the presence of aerially restricted and fossiliferous mud-filled channel pools where the final repositories of surface water attracted local paleofauna before infilling or drying completely. The depositional environment of the Ogallala Formation in the study area is most similar to “Platte type” fluvial systems characterized as shallow, perennial, and sand-dominated braided rivers. Comparisons with previously studied localities in the northern and southern High Plains reveal differences in fluvial style, sediment source areas, cut-and-fill geometries, and eolian input.

Analysis of the protohistoric period fauna from the Scott County Pueblo site in western Kansas

The Scott County Pueblo (14SC1) is a seven-room masonry pueblo situated on the High Plains in western Kansas. Recent analyses identify at least two occupations prior to the Pueblo Revolt of 1680: an earlier Dismal River Complex (ancestral Apache, Ndee) occupation dating between AD 1470 and 1640, and a later multiethnic occupation of ancestral Apache (Ndee) and Rio Grande Puebloan peoples dating around AD 1630–1690. This paper reports the results of the zooarchaeological analysis of a faunal collection excavated by James H. Gunnerson in 1965. Our results indicate Scott County hunters preyed upon an array of species, although bison, canids, and turtles were the most common taxa procured. Based on bison skeletal part representation, we hypothesize small groups of hunters traveled to procure bison, and the differential transport of high utility body parts reflects a subsistence strategy to accommodate for the limited labor available for carcass transport.

Net Inflow: An Important Target on the Path to Aquifer Sustainability.

Aquifers supporting irrigated agriculture are a resource of global importance. Many of these systems, however, are experiencing significant pumping-induced stress that threatens their continued viability as a water source for irrigation. Reductions in pumping are often the only option to extend the lifespans of these aquifers and the agricultural production they support. The impact of reductions depends on a quantity known as "net inflow" or "capture." We use data from a network of wells in the western Kansas portions of the High Plains aquifer in the central United States to demonstrate the importance of net inflow, how it can be estimated in the field, how it might vary in response to pumping reductions, and why use of "net inflow" may be preferred over "capture" in certain contexts. Net inflow has remained approximately constant over much of western Kansas for at least the last 15 to 25 years, thereby allowing it to serve as a target for sustainability efforts. The percent pumping reduction required to reach net inflow (i.e., stabilize water levels for the near term [years to a few decades]) can vary greatly over this region, which has important implications for groundwater management. However, the reduction does appear practically achievable (less than 30%) in many areas. The field-determined net inflow can play an important role in calibration of regional groundwater models; failure to reproduce its magnitude and temporal variations should prompt further calibration. Although net inflow is a universally applicable concept, the reliability of field estimates is greatest in seasonally pumped aquifers.

Spring‐planted cover crop effects on weed suppression, crop yield, and net returns in no‐tillage dryland crop production

AbstractIntegrating cover crops (CCs) into dryland crop rotations could provide options for herbicide‐resistant (HR) weed control in no‐tillage (NT) systems. Field experiments investigated weed suppression potential of spring‐planted CCs and their effects on plant available water, crop yields, and net returns. The CC treatments were implemented during the fallow phase of NT wheat (Triticum aestivum L)–sorghum (Sorghum bicolor Moench)–fallow rotation at two locations: Brownell and Colby, over 3 yr in western Kansas. Treatments were oat–triticale (OT), oat–triticale–pea (Pisum sativum; OTP), spring pea, and fallow. Spring pea aboveground biomass was 3,290 kg ha−1, whereas OT produced 5,640 kg ha−1 and OTP produced 5,260 kg ha−1. Regardless of location, weed biomass was reduced between 86 and 99% with CCs relative to weedy fallow. Cover crops reduced plant available water at winter wheat planting in three out of the six site‐years. Averaged across years, CCs reduced winter wheat yields by 18% compared with fallow at Brownell but not at Colby. Replacing fallow with spring pea increased gross revenue but generated negative net returns because of high cost of herbicide and pea seed. Net return with OT or OTP CCs were negative in four out of six site‐years when used strictly for weed suppression. However, net returns were mostly positive when OT ($110–876) or OTP (−$110–832) CCs were used as forage. Our results showed replacing fallow with spring‐planted CCs for weed suppression in dryland cropping system is profitable only when the CCs are used for forage.

Hydrology of a hydroperiod: Assessing recharge to the High Plains aquifer through a playa in western Kansas

Playa lakes have been promoted as potential point sources of recharge to the High Plains aquifer, but information about recharge rates is only available for the Southern High Plains, where soils and substrate differ significantly from the Central High Plains. The goal of this study is to determine the degree to which functioning playas contribute to recharge of the aquifer in the Central High Plains. This is accomplished through a multifaceted study across a single 34–43 day-long playa hydroperiod, combining physical and geochemical evidence to measure fluid flux through the playa and geochemical evidence of fluid flux through the nearby interplaya. The hydroperiod resulted in increased matric potential and decreases in chloride and other anion concentrations in the vadose zone beneath the playa, and increases in groundwater levels downgradient, likely indicating recharge to the aquifer over the course of the short event. Anion concentrations are significantly higher in the interplaya compared with the playa, while fluid flux estimates are significantly higher beneath the playa. The fluid fluxes determined in this study are consistent with estimates from elsewhere in the High Plains region. The combination of physical and geochemical data decreased the uncertainty and improved the overall conclusion that recharge rates are higher beneath the playa than the interplaya, providing evidence that playas in the Central High Plains function similarly to those in the Southern High Plains.

The herbicide well runs dry

Since the 1980s, crop protection companies have introduced only one herbicide with a new weed-killing mechanism. During this period, many weeds have evolved to survive the modes of action used by existing herbicides, creating huge problems for farmers. In response, crop protection companies are increasing R&D efforts to discover new modes of action. They’re using new tools, often borrowed from the pharmaceutical industry, to speed up that process. But even if new products do emerge, many experts warn that farmers should moderate their use of herbicides to avoid the evolution of resistance going forward. The first herbicide-resistant weeds started showing up on Keith Miller’s farm about 18 years ago. He grows sorghum, wheat, alfalfa, and soybeans on 4,000 hectares in western Kansas. Amaranthus , often called pigweed, is his biggest problem. Spraying weeds with the workhorse herbicide glyphosate does virtually nothing these days, Miller says. A combination of dicamba, 2,4-D,

Remote sensing of field-scale irrigation withdrawals in the central Ogallala aquifer region

For agricultural areas facing water scarcity, sustainable water use policy relies on irrigation information that is timely and at a high resolution, but existing publicly available water use data are often insufficient for monitoring compliance or understanding the influence of policy on individual farmer decisions. This study attempts to fill this data gap by using remote sensing to map annual irrigation quantity at the field-scale within the central Ogallala aquifer region of the United States. We compiled in situ annual irrigation volume data at the field scale in the Republican River Basin of Colorado for 2015–2018 and at the Public Land Survey System (PLSS) section scale in western Kansas for 2000–2016, which served as reference data in random forest models that relied on Landsat-based actual evapotranspiration from the Operational Simplified Surface Energy Balance model (SSEBop) along with maps of irrigated area, Landsat spectral indices, climate, soils, and derived hydrologic variables. The models explained 87% of the variability in irrigation volume in Colorado and 75% in Kansas, but accuracy declined when transferring the models in spatial cross-validation (Colorado R2 =0.81; Kansas R2 =0.51) and temporal cross-validation (Colorado R2 =0.82; Kansas R2 =0.68). Predicted annual totals of irrigation volume in western Kansas had a mean absolute error of 11.9%, which was slightly higher than the average annual change of 11%. Use of predicted irrigation maps also lead to an underestimated effect size for a water use restriction policy in Kansas. These results indicate that field- and section-scale irrigation can be mapped with reasonable accuracy within a region and time period that has adequate sample data, but that methods may need to be improved for applying the models more broadly in areas that lack extensive in situ irrigation data to support further research on water use and aid in structuring policy.

Comparing CO2 and Variable-TDS Waste-Fluid Injection Into Deep Saline Geologic Formations

There is a renewed interest in carbon capture, utilization, and storage technology due to recently expanded US Internal Revenue Service 45Q credits as well as to reduce anthropogenic carbon emissions to the atmosphere. Deep carbonate reservoirs in western Kansas have the potential for CO2 storage because they have experienced low waste-fluid injection volumes to date. Waste-fluid injection in Kansas has not caused felt seismicity for more than seven decades. However, beginning in 2013, the state has experienced increased seismicity due to increased subsurface pressure associated with the injection of large volumes of variable-TDS (total dissolved solids) waste-fluid in US EPA Class I and Class II wells. This work compares CO2, low-TDS, and high-TDS injection practices and quantifies the induced spatial and temporal patterns in overpressure in the caprock, reservoir, and its hydraulically connected crystalline basement, where the majority of induced seismicity in Kansas has been observed. Our results show that pressure buildup is higher in the caprock and lower in the crystalline basement when injecting CO2 as compared to variable-TDS waste-fluid injection. The CO2 plume tends to expand at the top of the reservoir, primarily due to its lower density and viscosity than reservoir brines, creating an overpressure plume that moves the resident brine across the caprock. In contrast, waste-fluid injection moves more resident brine down into the basement, particularly when high-TDS waste-fluid is injected. This result is particularly valid for high-permeability carbonate reservoirs, in which gravity forces dominate over viscous forces and move the CO2 and overpressure plume toward the top of the reservoir. Our study may explain the lack of human-perceivable induced seismicity at operating CO2 injection projects globally.

The gap between experts, farmers and non-farmers on perceived environmental vulnerability and the influence of values and beliefs

Science has played a mixed role in guiding conservation and sustainability-oriented decision-making by individuals, policymakers, institutions, and governments. Not all science-based conservation and sustainability initiatives that address issues facing humanity and ecosystems and global problems have gained public support. Conservation decisions and policy prescriptions are and may be based on perceptions about and experiences with the environment, local land use, and ecosystems that may not align with or be grounded in science or evidence from experts in the field. Values, beliefs, and perceptions associated with nature play a critical role in how individuals view biodiversity conservation, sustainability, and natural resource management. This study first examines the gap between experts (scientists and other field experts) and the public (farmers and non-farmers) about the state of water and land resources, wildlife and associated habitats, and aquatic biodiversity in the Smoky Hill River Watershed in western Kansas. Second, the study examines the role that values and beliefs play in shaping environmental perceptions for farmers and non-farmers. Analysis confirms that a gap between experts and farmers/non-farmers does exist, especially with respect to the state of the Ogallala Aquifer, playas, rivers and streams, lakes and reservoirs, native grasslands, wildlife habitats, farmland, native fish populations, and wildlife species. Ordered-logistic regression analyses, meanwhile, indicate that farmer and non-farmer perceptions about the state of the local environment are influenced by traditional and self-interested values, as well as environmental values and beliefs, but less so by religiosity and political ideology. Despite broad takeaways, results exhibited heterogeneity across the farmer and non-farmer subpopulations. If environmental professionals cannot align ecological data, stakeholders’ values/perceptions, and policies, then the existing body of technical research and management on sustainability in natural and social sciences may be of little value.

Bacterial but Not Fungal Rhizosphere Community Composition Differ among Perennial Grass Ecotypes under Abiotic Environmental Stress.

ABSTRACTEnvironmental change, especially frequent droughts, is predicted to detrimentally impact the North American perennial grasslands. Consistent dry spells will affect plant communities as well as their associated rhizobiomes, possibly altering the plant host performance under environmental stress. Therefore, there is a need to understand the impact of drought on the rhizobiome, and how the rhizobiome may modulate host performance and ameliorate its response to drought stress. In this study, we analyzed bacterial and fungal communities in the rhizospheres of three ecotypes (dry, mesic, and wet) of dominant prairie grass, Andropogon gerardii. The ecotypes were established in 2010 in a common garden design and grown for a decade under persistent dry conditions at the arid margin of the species’ range in Colby, Kansas. The experiment aimed to answer whether and to what extent do the different ecotypes maintain or recruit distinct rhizobiomes after 10 years in an arid climate. In order to answer this question, we screened the bacterial and fungal rhizobiome profiles of the ecotypes under the arid conditions of western Kansas as a surrogate for future climate environmental stress using 16S rRNA and ITS2 metabarcoding sequencing. Under these conditions, bacterial communities differed compositionally among the A. gerardii ecotypes, whereas the fungal communities did not. The ecotypes were instrumental in driving the differences among bacterial rhizobiomes, as the ecotypes maintained distinct bacterial rhizobiomes even after 10 years at the edge of the host species range. This study will aid us to optimize plant productivity through the use of different ecotypes under future abiotic environmental stress, especially drought.IMPORTANCE In this study, we used a 10-year long reciprocal garden system, and reports that different ecotypes (dry, mesic, and wet) of dominant prairie grass, Andropogon gerardii can maintain or recruit distinct bacterial but not fungal rhizobiomes after 10 years in an arid environment. We used both 16S rRNA and ITS2 amplicons to analyze the bacterial and fungal communities in the rhizospheres of the respective ecotypes. We showed that A. gerardii might regulate the bacterial community to adapt to the arid environment, in which some ecotypes were not adapted to. Our study also suggested a possible tradeoff between the generalist and the specialist bacterial communities in specific environments, which could benefit the plant host. Our study will provide insights into the plant host regulation of the rhizosphere bacterial and fungal communities, especially during frequent drought conditions anticipated in the future.

36 Kansas State University Feedlot Boot Camp and Teaching Program: Growing Student Interest and Engagement in the Feedlot Industry

Abstract The Kansas State University Collegiate Feedlot Boot Camp and Teaching Program was initiated in January 2019 with the goal to develop student knowledge, skills, and professional relationships in feedlot management to help meet critical need for trained professionals in the feedlot industry. Allied industry supporters including feedlot nutrition and veterinary consultants, pharmaceutical companies, and lenders, as well as feedlot owners/managers and the Kansas State University Department of Animal Sciences and Industry collaborated to develop, sponsor, and offer the program, which is offered at no cost to students who are selected. Specific objectives are to train students in aspects of feedlot management through a 4-d comprehensive “Boot Camp” at Western Kansas feedlots, enhance students’ likelihood of participating in feedlot internships, and cultivate students’ vision of potential career paths within the industry. Boot Camp topics include cattle health, feeding and nutrition, feedlot design and maintenance, and the business of cattle feeding. A networking dinner brings students and feedlot managers together to facilitate students gaining internship and full-time employment with feedlots. Following the January Boot Camp, students share individual presentations on relevant industry topics. Presentations are recorded and shared with feedlot managers to further engagement between students and feedlot managers. Later in the spring semester students also participate in a half-day cattle processing experience at a feedlot near Kansas State to provide additional insight and experience with feedlot health management. Limited to 20 participants per year, 59 undergraduate students have completed the program. When surveyed, over 98% (58/59) of student participants agreed with the statement “My interest in pursuing an internship and (or) career in the feedlot industry grew as a result of this Boot Camp.” Approximately 50% of students participated in feedlot internships or earned full-time jobs working in feedlots. Ranging from students with little to no experience with feedlots to being raised on beef cow-calf or feedlot operations, progress is being made in growing student interest and awareness of career opportunities in the feedlot industry.

Public narrative and sustained civic engagement: The Wichita County Water Conservation Area in Rural Kansas

ABSTRACT Sustained civic engagement is important to the success of social movements, which contribute to community development outcomes. Our qualitative case study of the Wichita County Water Conservation Area (WCA) suggests that sustained civic engagement among producers in Western Kansas can be understood as a positive feedback loop whereby organizers use public narrative to increase social, cultural, and political capitals in their community. The Wichita County WCA team uses public narrative to increase interpersonal solidarity (social capital) and develop a shared sense of meaning and purpose (cultural capital), while taking a diffuse and relational approach to leadership (political capital). They manage emotions such as fear, grief, despair, and frustration in a manner consistent with the Public Narrative model of social action. Our findings suggest that organizers should consider using a public narrative approach to sustain civic engagement in rural communities.

Designing monitoring networks for local earthquakes

Abstract Seismic networks are essential for monitoring local earthquakes in connection to industrial activities, including wastewater injection and CO2 sequestration. Because these networks are typically deployed for short periods of time at specific sites, it is beneficial to develop best practices for efficient and effective installation and monitoring. Such standards are available for regional earthquake and microseismic monitoring, but not readily available for local scale (tens of kilometer scale) monitoring. Once the region of interest has been determined, the key parameters for establishing a network are available monitoring station locations, site noise, and site utility. Networks should be designed based on the project monitoring goals for earthquake magnitude and density. Herein, a network was established at the Patterson and Hartland Oil Fields in western Kansas in association with a US Department of Energy CarbonSAFE carbon capture and sequestration research project. We employed observations from an analog local network, the Wellington Earthquake Monitoring Network in south-central Kansas, to assess site noise and estimate earthquake detection thresholds for the Patterson and Hartland fields. Noise from oil production facilities was evaluated, concluding that oil lease sites are suitable for monitoring small local earthquakes (M1-M3). The network was designed to have a magnitude of completeness of M1 while using station locations on existing field operator leases. Fifteen months of continuous network operation demonstrates reliable and efficient local earthquake monitoring and provides best practices recommendations for similar operations.

Cattle grazing in CRP grasslands during the nesting season: effects on avian abundance and diversity

AbstractThe Conservation Reserve Program (CRP) is a primary tool for restoring grassland in the United States, in part as wildlife habitat, which has benefited declining grassland bird populations. Among potential mid‐contract management practices used to maintain early‐successional CRP grasslands, cattle grazing had been prohibited and is currently disincentivized during the primary nesting season for birds (much of the growing season), despite the important role that large herbivores historically played in structuring grassland ecosystems. Conservative grazing of CRP grasslands could increase spatial heterogeneity in vegetation structure and plant diversity, potentially supporting higher densities of some grassland bird species and higher bird diversity. Our objective was to determine the effect of experimental cattle grazing on species‐specific relative abundance and occupancy, species diversity, and community dissimilarity of grassland birds on CRP grasslands across the longitudinal extent of Kansas, USA (a 63.5‐cm precipitation gradient) during the 2017–2019 avian breeding seasons. Fifty‐three of 108 fields were grazed by cattle during the growing seasons of 2017 and 2018 and all fields were rested from grazing in 2019. For all analyses, we examined separate model sets for semiarid western versus more mesic eastern Kansas. Using data from line transect surveys, we modeled relative abundances of 5 songbird species: grasshopper sparrow (Ammodramus savannarum), dickcissel (Spiza americana), eastern meadowlark (Sturnella magna), western meadowlark (Sturnella neglecta), and brown‐headed cowbird (Molothrus ater). Grazing had delayed yet positive effects on abundances of grasshopper sparrow in western Kansas, and eastern meadowlark in eastern Kansas, but negative effects on dickcissel abundance in western Kansas and especially on burned fields in eastern Kansas. Somewhat counterintuitively, brown‐headed cowbirds in western Kansas were more abundant on ungrazed versus grazed fields in the years after grazing began. In addition, we modeled multi‐season occupancy of 3 gamebird species (ring‐necked pheasant [Phasianus colcicus], northern bobwhite [Colinus virginianus], mourning dove [Zenaida macroura]) and Henslow's sparrow (Centronyx henslowii); grazing did not affect occupancy of these species. In eastern Kansas, species diversity was highest in grazed, unburned fields. In western Kansas, bird communities in grazed and ungrazed fields were dissimilar, as determined from multivariate analysis. Though regionally variable, conservative stocking of cattle on CRP grasslands during the nesting season as a mid‐contract management tool might increase bird species diversity by restructuring habitat that accommodates a greater variety of species and decreasing abundances of species associated with taller, denser stands of vegetation.

Fall-Planted Cover Crops for Weed Suppression in Western Kansas

The widespread evolution of herbicide-resistant (HR) kochia and Palmer amaranth warrants the use of alternative ecological-based strategies for weed management in no-tillage (NT) dryland cropping systems in western Kansas. A field study was established in the fall of 2020 at Kansas State University Agricultural Research Center near Hays, KS, to determine the impact of fall-planted cover crop (CC) mixture on 1) kochia and Palmer amaranth suppression (density and biomass reduction), and 2) Palmer amaranth emergence dynamics in subsequent grain sorghum. A CC mixture of winter triticale, winter pea, radish, and rapeseed was planted in wheat stubble in the fall of 2020. The CC mixture was terminated at triticale heading stage on May 26, 2021 by using 1) Roundup PowerMax (glyphosate) at 32 fl oz/a, and 2) Roundup PowerMax at 32 fl oz/a + Degree Xtra (premix of acetochlor + atrazine) at 2.2 quart/a. A chemical fallow treatment (without CC) was included for comparison. The study site was planted with grain sorghum hybrid ‘DKS 38-16’ on June 10, 2021. The CC mixture produced an average of 1360 lb/a aboveground biomass at the time of termination. The CC terminated with Roundup PowerMax + Degree Xtra had 98 and 95% less total weed density at 0 and 30 days after termination (DAT), respectively, compared to chemical fallow. No difference in weed density was observed at later evaluations. At grain sorghum harvest, CC terminated with Roundup PowerMax and Roundup PowerMax + Degree Xtra reduced total weed biomass by 61% and 73%, respectively, compared to chemical fallow. The time taken to reach 10, 50, and 90% cumulative emergence of Palmer amaranth was delayed by 9, 15, and 21 days, respectively, in CC terminated with Roundup PowerMax and 11, 39, and 128 days, respectively, in CC terminated with Roundup PowerMax + Degree Xtra when compared with chemical fallow. Grain sorghum yield did not differ between CC and chemical fallow treatments. These results suggest that a fall-planted CC mixture can play an important role for kochia and Palmer amaranth suppression in NT dryland crop production in western Kansas.

Spring and Summer Cover Crop Effects on Dryland Wheat and Grain Sorghum Yields in Western Kansas

Incorporating cover crops (CC) to replace fallow in traditional dryland cropping systems in the semi-arid conditions of western Kansas has the potential to enhance soil health, suppress weeds, and increase precipitation use efficiency. The returns from haying or grazing can help cover costs of CC establishment and any reduction in yield from the subsequent grain crop. Two studies were initiated in 2015 and 2016 near Brownell, KS, to investigate dual-purpose spring and summer CC management effects on subsequent grain yields in a three-year no-till (NT) dryland winter wheat-grain sorghum-fallow cropping system. Cover crops were planted in early spring between grain sorghum and winter wheat or in mid-summer soon after wheat harvest. Cover crops were grazed with yearling heifers, hayed at a six-inch stubble height, or left standing (no forage removal). All CC treatments were compared to NT fallow with no CC. Results showed spring CCs reduced wheat yields between 25 and 31% compared to fallow (59 bu/a) in two of three years, with no difference in the other year. Wheat yields were not different among CC management strategies. Summer CCs reduced grain sorghum yields at rates up to 39% compared to fallow (67 bu/a) in one of three years only when CCs were grazed or left standing but not when CCs were hayed. Sorghum yields were not different in the other two years. Yields of wheat or grain sorghum grown more than one year following CCs in the crop rotation were unaffected by CC treatments. These results showed CCs reduced subsequent crop yields compared to fallow. However, grazed or hayed CCs had no negative effects on dryland wheat and grain sorghum yields compared to standing CCs. Allowing grazing or haying of CCs on land enrolled in Natural Resources Conservation Service cost-share programs could increase producer adoption of CCs in semi-arid western Kansas to enhance regional soil health and increase dryland cropping system profitability.

Wheat Variety-Specific Response to Seeding Rate Under Intensive Management Conditions in Western Kansas in 2020–2021

Wheat response to seeding rate is variable and depends on resource availability during the growing season (e.g., fertility, moisture, and temperature). Our objective was to evaluate winter wheat population and grain yield responses to seeding rate and its interaction with variety in a highly-managed production system where manageable stresses were limited. This study was established to evaluate the response of the wheat varieties Joe, WB-Grainfield, Langin, and LCS Revere to five seeding rates ranging from 200,000 to 1,000,000 seeds per acre. The site was managed by growers that consistently win state and national wheat yield contests near Leoti, KS. The trial was established on September 25, 2020, after a long summer fallow in sorghum residue, approximately 10 days after a 0.3-in. rainfall event, ensuring good stand establishment. The fall was dry, but spring conditions were favorable for high yields with cool temperatures and about 11 inches of precipitation. There were significant effects of seeding rate and variety on stand count, but the interaction was weak (P = 0.12). Main effects suggested that the stand count increased with increases in the seeding rate (from 252,265 to 521,347 plants per acre), with the 800,000 and 1,000,000 seeds/a rates attaining the highest stands. However, we note that final populations were closer to the target population at lower seeding rates as compared to higher seeding rates. Grain yield also depended primarily on variety and on seeding rate, with no interaction between both effects. Grain yield ranged between 97 and 101.3 bushels per acre for the seeding rates ranging between 600,000 and 1,000,000, and from 89.9 to 93.3 bu/a for lower seeding rates. Langin was the highest yielding variety (102 bu/a), followed by LCS Revere and WB-Grainfield (94.7–97.5 bu/a), and lastly by Joe (90.3 bu/a). These results suggest that wheat grain yield responses to seeding rate were not dependent on variety, with optimum seeding rates as low as 600,000 seeds/a. We note that increasing seeding rates beyond 600,000 seeds/a led to numerical but not statistical increases in yield.