Western Kansas Research Articles

156 Effect of shipping stress on complete blood counts of backgrounded beef steers

Abstract The objective of this study was to quantify the effect of shipping to feedyards in western Kansas from the Southeast on the immune response of beef steers using complete blood counts. Angus- and Hereford-sired steers (n = 24, BW = 266.3±24.9 kg) from E.V. Smith Research Center in Shorter, AL, were weaned on June 14, 2018. The following day, blood was collected for analysis. These calves were a subset from a larger project involving grazing. As such, calves were then maintained in drylots for 14 d until grazing was available. Once grazing was initiated, these calves were placed in drylot pens with a diet consisting of dry hay with supplemented with 1% of BW of dried distiller’s grains with solubles. After 80 d, half of the calves were shipped (n = 12, SC) to Hy-Plains Feedyard, LLC. in Montezuma, KS. Immediately prior to shipment, immediately post-shipment, and after 24-hr rest, blood was collected. Blood was also collected from the unshipped calves (UC) at similar time points. Whole blood collected at each time point was analyzed for complete blood counts. The data was analyzed using the Mixed Procedure in SAS. No significant differences (P > 0.05) were detected post-weaning or pre-shipping. Immediately post-shipment, white blood cell, and neutrophil counts were greater in SC while lymphocytes counts were less (P < 0.05) than UC; however, these were not different after 24-hr rest (P > 0.05). Hematocrit and monocyte count were elevated in SC both immediately post-shipping and after 24 hr of rest (P <0.05), while reticulocyte count was lower in SC at those same time points (P < 0.05). Basophil counts were lower in SC at the 24-hr rest time point (P = 0.03). Results of this study indicate that SC did not completely rehydrate after 24 hr of rest and complete blood counts show differences in immune response due to shipping

110 Effect of different backgrounding diets for weaning beef calves on complete blood counts pre and post shipping

Abstract The objective of this study was to evaluate if diet during the background phase has an effect on complete blood counts as an indicator of the stress response and immune function of calves shipped to feedyards in western Kansas from the Southeast. One hundred twenty (n = 120) Angus- and Hereford-sired steers (n = 60, 237.9±21.6 kg BW) and heifers (n = 60, 227.6±17.9 kg BW) from the E.V. Smith Research Center in Shorter, AL, were weaned on June 14, 2018. The following day, calves were weighed and blood was collected for analysis. Calves were then held in drylots for 14 d until forages reached an adequate height to begin grazing. Calves were then stratified by weight and randomly assigned to four dietary treatments, with three pens per treatment: Grazing (G), Grazing with supplement (GS), dry hay with supplement (HS), or baleage with supplement (BS). Dried distiller’s grains with solubles fed at 1% of BW was used in each diet including supplementation. After 80 d on treatment diets, calves were shipped to Hy-Plains Feedyard, LLC. in Montezuma, KS. Immediately prior to shipment, immediately post-shipment, and after 24 hr rest, blood was collected for analysis. Whole blood collected at each of the four times points was analyzed for complete blood counts using a ProCyte Dx Hematology Analyzer. The data were analyzed using the Mixed Procedure in SAS. While no significant differences (P > 0.05) were detected post-weaning and prior to initiation of dietary treatments, differences across diets were seen in red blood cell count, hemoglobin, hematocrit, reticulocyte count, platelet count, white blood cell count, neutrophil count, lymphocyte count, neutrophil to lymphocyte ratio, and basophil counts (P < 0.05). Results of this study show that post-weaning backgrounding diets can have an effect on immune response to shipping stress

Sediment accumulation and sedimentation rates in playas on the High Plains of western Kansas, USA

Grassland ecosystems are some of the most modified ecosystems in the world, largely due to conversion to cropland, and the High Plains of the central United States is no exception. Playa wetlands are ubiquitous features of the High Plains and have experienced increased sediment accumulation, which is the primary cause of reduced playa ecosystem function. Seven playas on the High Plains of western Kansas, five with cropland-dominated watersheds and two with grassland-dominated watersheds, were examined to quantify the amount of recent (past ~100–175 yr) sediment accumulated within playas and to establish chronologies of playa filling. Thicknesses of recent sediment were determined in the field, and soil cores were extracted from study playas. Four playa cores were analyzed for 210Pb to establish the chronology of recent sediment accumulation and sedimentation rates. Chronologies of pre-agricultural sediments and sedimentation rates were calculated by 14C dating of buried soils preserved within playa cores. Radiocarbon ages indicate playa stratigraphic records span the Holocene and that these playas have persisted on the landscape since at least the Late Pleistocene. Long-term, natural sedimentation rates were highest during the Pleistocene-Holocene transition and early Holocene, at ~2–4 cm/century. During the middle and late Holocene, sedimentation rates averaged ~1 cm/century. Cropland playas accumulated ~10–15 cm of recent sediment at average rates of ~6.5–10 cm/century, while grassland playas accumulated only ~2 cm of recent sediment. Conversion of watersheds to cropland has greatly accelerated sediment accumulation within playas, which is generally resulting in a decline in critical playa ecosystem functions.

Conceptualizing Groundwater-Surface Water Interactions within the Ogallala Aquifer Region using Electrical Resistivity Imaging

Dynamic interactions between rivers and aquifers are controlled by the underlying hydrogeologic environment, as well as the type of hydrologic connection between the riverbed and saturated zone. The Arkansas River supplies groundwater to a heavily exploited region of the Ogallala Aquifer across Western Kansas. Site characterizations of this region using existing well and borehole data reveal large scale geologic features that significantly impact recharge processes, such as the Bear Creek fault. However, the existing hydrogeologic data do not provide the level of detail needed to fully understand the contribution of the losing river system to Arkansas Alluvial aquifer recharge. Knowledge about riverbed hydrogeology is acquirable using electrical resistivity imaging (ERI) surveys. ERI surveys and soil sample analysis were conducted at three sites along the Arkansas River to characterize the hydrogeologic environment within the Arkansas River Alluvial aquifer, which overlies the Ogallala aquifer. Temporal changes in electrical resistivity served as an indicator of the hydrologic response of the alluvial sediments to changes in river discharge as different patterns of water movement from the Arkansas River to Arkansas River Alluvial aquifer were observed. The ERI surveys revealed both fully connected and disconnected regions between the riverbed and groundwater table. The results supplement the existing geologic characterization of this region, and provide a more spatially detailed view of the hydrogeologic environment that has a direct causative effect on groundwater surface water interactions. Understanding the behavior of river-aquifer interactions is vital to the ability to predict the future holds of this important groundwater system.

The “perfect storm” for distributed wind markets

Over 1 GW of distributed wind has been installed across all 50 states, the District of Columbia, Puerto Rico, Guam, and the U.S. Virgin Islands. Yet the number of installations varies greatly by state, even when wind resources are similar. This article presents the results of a county-by-county study of markets for distributed wind in the contiguous United States that culminates with a figure that represents the relative strength of markets across the United States based on a composite assessment of 1) policy environments, including incentives, and interconnection, net metering, and permitting policies; 2) electricity prices, and 3) wind resources. The number of megawatts of installed distributed wind is superimposed on the combined figure, in most cases confirming the influence of these market factors. This analysis identified Indiana, Michigan, Pennsylvania, Maine, eastern Colorado, western Kansas, and northern New Mexico as areas that have untapped economic distributed wind potential. Specific policy, electricity price, and wind resource examples are provided from Iowa, New York, Washington, Oregon, and California.

Dicamba-resistant kochia (Bassia scoparia) in Kansas: characterization and management with fall- or spring-applied PRE herbicides

AbstractDicamba-resistant (DR) kochia is an increasing concern for growers in the US Great Plains, including Kansas. Greenhouse and field experiments (Garden City and Tribune, KS, in the 2014 to 2015 growing season) were conducted to characterize the dicamba resistance levels in two recently evolved DR kochia accessions collected from fallow fields (wheat–sorghum–fallow rotation) near Hays, KS, and to determine the effectiveness of various PRE herbicide tank mixtures applied in fall or spring prior to the fallow year. Dicamba dose–response studies indicated that the KS-110 and KS-113 accessions had 5- to 8-fold resistance to dicamba, respectively, relative to a dicamba-susceptible (DS) accession. In separate field studies, atrazine-based PRE herbicide tank mixtures, dicamba + pendimethalin + sulfentrazone, and metribuzin + sulfentrazone when applied in the spring had excellent kochia control (85% to 95%) for 3 to 4 mo at the Garden City and Tribune sites. In contrast, kochia control with those PRE herbicide tank mixtures when applied in the fall did not exceed 79% at the later evaluation dates. In conclusion, the tested kochia accessions from western Kansas had evolved moderate to high levels of resistance to dicamba. Growers should utilize these effective PRE herbicide tank mixtures (multiple sites of action) in early spring to manage kochia seed bank during the summer fallow phase of this 3-yr crop rotation (wheat–corn/sorghum–fallow) in the Central Great Plains.

Integrated modelling of the life cycle and aeroecology of wind-borne pests in temporally-variable spatially-heterogeneous environment

Integrating population ecology and aeroecology is important for understanding dispersal dynamics of pest insects that depend on aerial habitats. Sugarcane aphid (Melanaphis sacchari) is an economic pest of sorghum in Asia, Africa, Australia, and South America and recently invaded North America, affecting over 90% of the continent’s sorghum production. Long-distance, wind-aided dispersal together with the ability to overwinter in the southernmost sorghum-producing areas appear responsible for their geographic spread in North America. We developed a spatially-explicit, individual-based, stochastic model that integrates the life cycle and aeroecology of sugarcane aphids to forecast regional infestations of sorghum fields. We parameterized and calibrated the model to represent environmental conditions and sorghum phenologies of the southern to central Great Plains of the USA where sorghum is cultivated. We validated the model by comparing simulated spatial-temporal patterns of aphid infestations to georeferenced field data on infestations collected as part of an extensive field project. We assessed potential usefulness of the model by analysing regional patterns of aphid infestations on sorghum simulated under climatic conditions recorded in the southern to central Great Plains in 2017.On a regional scale, the simulated northward advance of aphid infestations generally followed the seasonal development of sorghum, with the main invasion front moving northward from southern to central Texas, then northwest towards the panhandles of Texas and Oklahoma (northernmost and westernmost regions, respectively, of these states), and then northward again into central and western Kansas. Within this general regional trend, the stochastic nature of simulated infestations resulted in wide variation within each region with regard to time lags between the appearance of sorghum and initial infestation, which led to wide variation in infestation levels. The geographical distribution of simulated aphid infestation probabilities approximately mirrored the proportion of land cover in sorghum production, with a prominent infestation “hot spot” covering west-central Kansas and the panhandles of Texas and Oklahoma. Models capable of simulating both local population dynamics as well as long-range, multi-generational dispersal of wind-borne pests show promise as a component of adaptive areawide pest management programs.

First Report of Kochia (Bassia scoparia) with Cross-Resistance to Dicamba and Fluroxypyr in Western Kansas

AbstractEvolution and rapid spread of herbicide-resistant (HR) kochia has become a significant challenge for growers in the U.S. Great Plains. The main objectives of this research were to confirm and characterize the response of putative auxinic HR (Aux-HR) kochia accessions (designated as KS-4A, KS-4D, KS-4H, KS-10A, KS-10-G, and KS-10H) collected from two different corn fields near Garden City, KS, to dicamba and fluroxypyr and to determine the EPSPS gene copy number to detect whether those accessions were also resistant to glyphosate. Single-dose experiments indicated that putative Aux-HR kochia accessions had 78% to 100% and 85% to 100% survivors when treated with dicamba (560 g ae ha−1) and fluroxypyr (235 g ae ha−1), respectively. Whole-plant dicamba dose–response studies revealed that the selected Aux-HR accessions had 2.9- to 15.1- and 3.1- to 9.4-fold resistance to dicamba relative to two susceptible accessions (MT-SUS and KS-SUS). In a separate fluroxypyr dose–response experiment, the selected Aux-HR accessions also exhibited 3.8- to 7.3- and 3.0- to 8.6-fold resistance to fluroxypyr on the basis of shoot fresh and dry weight responses, respectively. The confirmed Aux-HR kochia accessions also had 3 to 13 EPSPS gene copies relative to MT-SUS and KS-SUS accessions (each with 1 EPSPS gene copy). These results suggest that the putative Aux-HR kochia accessions from Kansas had developed moderate to high levels of cross-resistance to dicamba and fluroxypyr and low to high levels of resistance to glyphosate. This is the first confirmation of kochia accessions with cross-resistance to dicamba and fluroxypyr in Kansas. Growers should use diverse kochia control programs, including the proper use of dicamba and fluroxypyr stewardship, use of cover crops, occasional tillage, diversified crop rotations, and alternative effective herbicides to prevent further evolution and spread of Aux-HR kochia on their fields.

Seed yield and oil quality as affected by Camelina cultivar and planting date

ABSTRACTCamelina [Camelina sativa (L.) Crantz] has been identified as a potential oilseed crop for fallow replacement in cropping systems in the semiarid US Great Plains. However, camelina production is limited to the northern Great Plains region. We investigated the effects of three planting dates [mid-March, early-April, and mid-April] and three cultivars (Blaine Creek, Pronghorn, and Shoshone) on spring camelina seed yield and oil quality under non-irrigated conditions in western Kansas. Results showed planting in April increased seed yield by 34% compared with mid-March planting date. Blaine Creek produced greatest seed yield among the cultivars. Planting in mid-March increased oil, polyunsaturated fatty acids (PUFA), and linolenic acid concentrations compared with April planting dates. Saturated fatty acid (SFA) concentration increased with an April planting date. Heat stress in the growing season reduced seed yield, oil, PUFA, linoleic, and linolenic acid concentrations. However, increase in precipitation amounts improved seed yield, oil, PUFA, and linolenic acid concentrations. Our findings showed early- to mid-April is the best-planting window for optimum spring camelina stands and seed yield in this environment.

Effects of Spring-Planted Cover Crops on Weed Suppression and Winter Wheat Grain Yield in Western Kansas

Effects of Spring-Planted Cover Crops on Weed Suppression and Winter Wheat Grain Yield in Western Kansas

No Impact of Increased EPSPS Gene Copy Number on Growth and Fecundity of Glyphosate-Resistant Kochia (Bassia scoparia)

AbstractThe level of glyphosate resistance in kochia [Bassia scoparia(L.) A. J. Scott] was reported to be due to an increase in 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene copy number. A field study was conducted near Manhattan, KS, in 2014 and 2015 to evaluate the relationship between EPSPS gene copy number and growth and fecundity variables ofB. scopariaindividuals within suspected glyphosate-resistant (GR) populations from western Kansas. Initial assays of EPSPS gene copy and in vivo shikimate accumulation showed thatB. scopariapopulations from Finney (FN-R), Scott (SC-R), and Thomas (TH-R) counties were segregating for glyphosate resistance, with some individuals still being glyphosate susceptible (GS). A target-neighborhood competition approach was used to evaluate the competitive response of individual target plants with relatively low (classified as GS) and high (classified as GR) EPSPS gene copy number within the populations. There was no relationship observed between EPSPS gene copy number and vegetative or fecundity variables. There was no differential competitive response of target plant biomass to increasing neighbor density between individuals with low and high EPSPS gene copy number within each population. Lack of associated vegetative growth and fecundity cost to the increased EPSPS gene copy in the GRB. scopariaplants suggests that the plants are likely to persist in field populations, except when effective weed management strategies are adopted that would prevent their growth and seed production.

Factors influencing nesting ecology of lesser prairie‐chickens

ABSTRACTLesser prairie‐chicken (Tympanuchus pallidicinctus) populations have declined since the 1980s. Understanding factors influencing nest‐site selection and nest survival are important for conservation and management of lesser prairie‐chicken populations. However, >75% of the extant population is in the northern extent of the range where data on breeding season ecology are lacking. We tested factors influencing fine‐scale and regional nest‐site selection and nest survival across the northern portion of the lesser prairie‐chicken range. We trapped and affixed satellite global positioning system and very high frequency transmitters to female lesser prairie‐chickens (n = 307) in south‐central and western Kansas and eastern Colorado, USA. We located and monitored 257 lesser prairie‐chicken nests from 2013 to 2016. We evaluated nest‐site selection and nest survival in comparison to vegetation composition and structure. Overall, nest‐site selection in relation to vegetation characteristics was similar across our study area. Lesser prairie‐chickens selected nest microsites with 75% visual obstruction 2.0–3.5 dm tall and 95.7% of all nests were in habitat with ≥1 dm and ≤4 dm visual obstruction. Nests were located in areas with 6–8% bare ground, on average, avoiding areas with greater percent cover of bare ground. The type of vegetation present was less important than cover of adequate height. Nest survival was maximized when 75% visual obstruction was 2.0–4.0 dm. Nest survival did not vary spatially or among years and generally increased as intensity of drought decreased throughout the study although not significantly. To provide nesting cover considering yearly variation in drought conditions, it is important to maintain residual cover by managing for structural heterogeneity of vegetation. Managing for structural heterogeneity could be accomplished by maintaining or strategically applying practices of the Conservation Reserve Program, using appropriate fire and grazing disturbances in native working grasslands, and establishing site‐specific monitoring of vegetation composition and structure. © 2018 The Wildlife Society.

Assessment of climate change for extreme precipitation indices: A case study from the central United States

Five extreme precipitation indicators were calculated on an annual basis for 1890 through 2013 and analysed to determine spatial patterns and temporal trends in the frequency and magnitude of observed extreme precipitation events in Kansas located in the central United States. Indicators were selected from the list of the World Meteorological Organization–Commission for Climatology (WMO–CCL) and the Research Programme on Climate Variability and Predictability (CLIVAR). The indicators included the number of days with precipitation greater than or equal to 10 mm/day (R10), maximum number of consecutive dry days (CDD; days with precipitation lower that 1 mm), maximum 5‐day precipitation total (R5D), and simple daily intensity index (SDII) which is the annual precipitation total divided by number of days with precipitation greater than or equal to 1 mm, and the fraction of annual total precipitation due to events exceeding the 95th percentile (R95T) based on the period 1961–1990. Positive trends in the results were found for a majority of stations for R10, R5D, SDII, and R95T. Consecutive dry days was the only index that had a negative trend at a majority of stations. Spatial pattern analysis indicates greater changes in frequencies and magnitudes for eastern Kansas. Results from this study highlight observed climate shifts in precipitation patterns with a tendency towards greater and more frequent extreme precipitation in eastern Kansas and a tendency towards drier conditions in western Kansas. These hydroclimatic adjustments can produce costly impacts in areas that include flood management, hydraulic structures, water availability throughout the year, agricultural production, ecosystems, and human health.

The Mystery of Elasmosaurus platyurus Cope 1868 – Where is the Rest of the Type Specimen?

As originally described by Cope (1868), the type specimen of Elasmosaurus platyurus from western Kansas included more than 100 vertebrae, portions of the skull, and the reasonably complete pectoral and pelvic girdles of what was then the largest known plesiosaur. Within four years of its discovery, however, both of the limb girdles had disappeared with no official explanation. Here we document the events leading up to the loss of important portions of this unique specimen.

Using the GOES-16 Split Window Difference to Detect a Boundary prior to Cloud Formation

AbstractGeostationary Operational Environmental Satellite-16 (GOES-16) was launched into geostationary orbit in late 2016 and began providing unprecedented spatial and temporal resolution imagery early in 2017. Its Advanced Baseline Imager has additional spectral bands including two in the “clear” window and “dirty window” portion of the infrared spectrum, and the difference of these two bands, sometimes called the split window difference, provides unique information about low-level water vapor. Under certain conditions, low-level convergence along a boundary can cause local water vapor pooling, and the signal of this pooling can sometimes be detected by GOES-16 prior to any cloud formation. This case study from 15 June 2017 illustrates how the technique might be used in an operational forecast setting. A boundary in western Kansas was detected using the split window difference more than 2 h before the first cloud formed.

Genetic and environmental influences on stomates of big bluestem (Andropogon gerardii)

Big bluestem (Andropogon gerardii) is a dominant C4 prairie grass that has wide distribution and several genetically distinct ecotypes. Many of the ecotypic adaptations are related to water availability in the native environment. Stomates facilitate photosynthetic gas exchange and regulate water loss from the plant. As such, stomatal size and density represent possible adaptations to conserve water. We hypothesized drought-tolerant ecotypes of big bluestem would have fewer or smaller stomates compared to more mesic ecotypes. Five ecotypes of big bluestem were planted in four common gardens from western Kansas to southern Illinois, USA to determine genetic and environmental influences on stomates. Leaves of all ecotypes of A. gerardii were largely hypostomatous and genetics was a greater influence than environment for stomatal size and density. The drought-tolerant Sand bluestem had larger stomates on abaxial surfaces of leaves, but a lower density compared to most other ecotypes. The most mesic Illinois ecotype and the Kaw cultivar had the greatest density of stomates on abaxial surfaces of leaves. Sand Bluestem had a greater density of stomates on adaxial surfaces of leaves compared to all other ecotypes. Gas exchange measures followed patterns of stomate distribution, where abaxial CO2 uptake rates were greater than adaxial CO2 uptake rates, although differences between leaf surfaces was more pronounced in stomatal density than in CO2 uptake. There were minor differences in size and density of stomates among sites that corresponded with precipitation, although these differences were minor, illustrating the genetic underpinnings of stomates in big bluestem. There is a genetic predisposition for drought-tolerant ecotypes to have fewer stomates, illustrating an evolutionary adaptation to drought tolerance in an important prairie species.

Optimal blending management of biomass resources used for biochemical conversion

AbstractThis research develops an optimization model to describe the tradeoff among blend components in the least‐cost biomass blend, based on resource availability, quality requirements, and logistics cost for a biochemical conversion. A mixed‐integer linear programming model is developed to determine the least‐cost blend from a set of candidate feedstocks. A case study – based on a biorefinery located in western Kansas that uses three‐pass corn stover, two‐pass corn stover, switchgrass, miscanthus, and municipal solid waste fractions to meet biochemical conversion specifications and feedstock demand – shows that the delivered cost of an optimal blend that meets carbohydrate and ash specifications is 12.12% higher than the delivered cost of optimal blend that meets a carbohydrate specification only. The results indicate that a least‐cost blend that meets both carbohydrate and ash specifications consists of miscanthus (48.2%) and switchgrass (29.4%) whereas the least‐cost blend meeting carbohydrate specification only comprises three‐pass corn stover (55.4%) and two‐pass corn stover (20.4%). An optimal blend uses a low‐cost municipal solid waste fraction in all cases, implying that blending could be a potential strategy to reduce delivered feedstock cost. Published 2018. This article is a U.S. Government work and is in the public domain in the USA. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

Grain sorghum production functions under different irrigation capacities

Water is the major factor limiting crop production in semi-arid regions of the southern and central US High Plains. The Ogallala Aquifer is the major source of irrigation water in the region. The water levels in the aquifer have been declining due to water withdrawals for irrigation exceeding mean annual recharge. As a result, some of the wells in the region are not able to meet the crop water requirements due to lower irrigation capacity (IC). Grain sorghum, one of the major crops grown in western Kansas is considered drought tolerant. There is limited literature on the effect of IC on grain sorghum yield under erratic rainfall patterns of the semi-arid High Plains. Study objectives were to: (1) evaluate the Decision Support System for Agrotechnology Transfer – Cropping System Model (DSSAT-CSM) for assessing grain sorghum yield and water productivity; (2) develop grain sorghum water production functions under five different IC, two cultivars and three irrigation scheduling strategies; and (3) evaluate response of grain sorghum under various IC in western Kansas based on long term historical weather; 4) to determine the minimum irrigation capacity required for irrigating grain sorghum in western Kansas. A calibrated and validated late maturing cultivar in prior study was used, while measured yield and phenology data of an early maturing cultivar was used to evaluate an existing cultivar in DSSAT model. Results showed that the cultivar in DSSAT were representative of the cultivars in the field with Normalized Root Mean Square of Error (NRMSE) 18%, index of agreement (I) of 0.97 and percent of deviation (d) −19 to 29%. The corresponding statistical goodness of fit values for days to flowering was 12%, 0.99 and 0–17%, respectively. Overall, the simulated yield and phenology values agreed with the measured indicating the satisfactory simulation performance of the model. Highest yield, crop water productivity and irrigation water use efficiencies were obtained from IC of 2.5–3.6 mm/day under the irrigation scheduling strategies from panicle initiation to grain filling. However, long term simulation showed that the minimum IC for growing grain sorghum varied depending on the minimum yield goal to be met based on long term perspective. In some wet years, lower IC up to 1.7 mm/day or even in some of the wettest years no irrigation was suitable. Our findings indicate that it might not be necessary to irrigate grain sorghum from planting to maturity but if producers are forced to do so by climatic conditions, an IC of 1.7–2.5 mm/day was found to produce a yield of at least 5 t/ha similar to that of 5 mm/day IC in 75% of the long-term growing seasons. If producers have to irrigate grain sorghum from panicle initiation to maturity, the 2.5 mm/day IC was found to be adequate to meet a minimum yield goal of 5 t/ha in 3 out of 4 years based on soils and long-term average climate around western Kansas. IC of 3.6 mm/day was found to be adequate if producers wish to irrigate only from panicle initiation to grain filling to meet a minimum yield goal of 6 t/ha in 75–90% of the long-term seasons.

Registration of Two Wheat Germplasm Lines Fixed for Pm58

Powdery mildew is a persistent threat to global wheat (Triticum aestivum L.) production. To broaden the genetic base for resistance to powdery mildew in wheat, germplasm lines U6714‐A‐011 (Reg. No. GP‐1023, PI 682090) and U6714‐B‐056 (Reg. No. GP‐1022, PI 682089) were developed at Michigan State University and are fixed for the novel powdery mildew resistance gene Pm58. This gene was identified in Aegilops tauschii Coss. accession TA1662, introgressed, and mapped to wheat chromosome 2DS. The two germplasm lines described are BC2F4–derived inbred backcrossed lines from a direct cross between TA1662 and the recurrent wheat parent KS05HW14, a hard white winter wheat line adapted to western Kansas. In addition to exhibiting resistant reactions to multiple Bgt isolates with broad virulence profiles, both lines have moderate yield potential and good agronomic characteristics, making them suitable as breeding germplasm. The availability of these lines will enable the incorporation of Pm58 into wheat breeding programs, providing additional genetic variation for resistance to powdery mildew.

Long-Term Nitrogen and Phosphorus Fertilization of Irrigated Grain Sorghum

Long-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be applied to optimize production of irrigated grain sorghum in western Kansas. In 2015, N applied alone increased yields 66 bu/a, whereas N and P applied together increased yields up to 92 bu/a. Averaged across the past 10 years, N and P fertilization increased sorghum yields up to 76 bu/a. Application of 40 lb/a N (with P) was sufficient to produce 88% of maximum yield in 2015 which is slightly above the 10-year average. Application of potassium (K) has had no effect on sorghum yield throughout the study period. Average grain N content reached a maximum of ~0.7 lb/bu while grain P content reached a maximum of 0.15 lb/bu (0.34 lb P2O5/bu) and grain K content reached a maximum of 0.19 lb/bu (0.23 lb K2O/bu).