Master of Science / Department of Agronomy / Walter H. Fick / Kevin Price / Caucasian bluestem [Bothriochloa bladhii (Retz) S.T. Blake] is a perennial, C4 warm-season bunchgrass that was first introduced in 1929 from Russia as a potential forage crop in the Great Plains. Due to its invasiveness and tolerance of drought and grazing pressure, Caucasian bluestem can out-compete native prairie species. Research has shown that this species, when compared to native tallgrass species in the Flint Hills of Kansas causes decreased cattle weight gains because of its poor forage quality relative to tallgrass prairie species. Traditional methods of plant data measurements and mapping are costly and time consuming. Use of remotely sensed data to map and monitor the distribution and spread of this plant would be most useful in the control of this aggressive invader. Spectroradiometer data were collected over the 2009 growing season to determine if and when Caucasian bluestem was spectrally unique from native tallgrass prairie species. Observations were made from June through September as the plants were going into a senescent state. Reflectance data were measured approximately every two weeks or when clear/near clear sky conditions prevailed. Statistical analyses for differences in spectral characteristics were conducted to determine the optimal spectral bands, indices and timing for discriminating Caucasian bluestem from native tallgrass species. Difference in reflectance for spectral reflectance of bands 760 nm, 940 nm, 1,070 nm, and 1,186 nm were found to be statistically significant on the June 17th and June 30th sampling dates. The following band ratios and indices were found to be significantly different between Caucasian bluestem and native range on the June 17th collection date: Simple Ratio, Modified Normalized Difference Index, Normalized Phaeophytinization Index, Plant Index 1, Normalized Water Difference Index, Water Band Index, Normalized Difference Nitrogen Index, and the Normalized Difference Lignin Index. Findings of this study suggest that Caucasian bluestem can be spectrally discriminated from native tallgrass prairies of the Flint Hills in Kansas if the measurements are collected in mid to late June. Statistical analyses also showed differences between treatments for percent litter, grass, and forb basal cover.

Master of Science / Department of Animal Sciences and Industry / Dale A. Blasi / An experiment was conducted to evaluate the effects of dry matter intake (DMI) restriction on early receiving performance by steers in a drylot and subsequent grazing performance, feedlot performance, and carcass characteristics. During the backgrounding period, crossbred, weanling steers (n = 329; initial BW = 191± 5.52 kg ) were randomly assigned to 1 of 4 DMI levels corresponding to ad libitum, 2.50% of BW (2.50%), 2.25% of BW (2.25%), and 2.00% of BW (2.00%) for 62 d. During the subsequent grazing period, the same steers were randomly assigned to 13 paddocks to graze for 90 d. Paddocks were stocked at 281 kg live weight per hectare. Initial steer BW were similar on each pasture and each backgrounding treatment was equally represented within a paddock. During the feedlot period, steers were finished at a commercial feedlot and were assigned to 1 of 4 pens according to their rank in BW. Entire pens were harvested when average steer BW reached 545 kg. During the backgrounding period, ad libitum-fed steers had greater (P < 0.001) ADG and final BW than other treatments; steers fed at 2.50 and 2.25% of BW had similar ADG and final BW and were greater (P < 0.001) than steers fed 2.00% of BW. During the grazing period, compensatory gain was observed in restricted DMI treatments. Steers fed at 2.00% of BW had greater (P = 0.006) ADG than ad libitum-fed steers but an ADG similar to that of the other restricted DMI treatments. Steers fed ad libitum, 2.50% of BW, and 2.25% of BW had similar final BW and steers fed 2.00% of BW had lesser (P < 0.001) final BW than other treatments. During the feedlot phase, steers fed 2.00% of BW were on feed longer (P < 0.05) than other treatments. Growth compensation during grazing illustrated that restricted feeding immediately prior to pasture grazing can reduce backgrounding costs.

Master of Science / Department of Civil Engineering / David R. Steward / Konza Prairie is one of the few areas in the United States were natural landscape of the area is still intact. Human action on changing the landscapes in this area is limited and much of the land remains as native grassland. In spite of its natural existence, this area is not completely isolated from the rest of the world. Changes that are taking place in climate will eventually have the same effect to this region as well as other human populated areas. Increase in carbon concentration in the air has resulted to increase in temperature, this increase in temperature increases the evaporation from the sea, oceans and the ice capes. As the atmospheric water vapor changes the precipitation pattern also change. Changes in precipitation due to climate change will result to change in hydrology and hydraulics of the streams and groundwater flow regime. Precipitation provides surface runoff and groundwater infiltration, which recharge the cracked limestone aquifer present in the Konza area. The infiltration water moves trough the cracked rocks and eventually reach the creeks such as Kings Creek and flow to the Kansas River. Increase in precipitation will result to increase in surface runoffs and more groundwater recharge. Decrease in precipitation will result to decrease in both surface and groundwater. To examine changes in groundwater elevation as recharge change in Konza, a groundwater model was developed based on erosion impact calculator (EPIC) ecological model and SLIT groundwater model. EPIC model estimates the deep percolation (recharge) as 12% and total runoff to about 24% of the annual average precipitation. The annual average recharge values from EPIC were used in SPLIT to simulate results for the groundwater elevation at Konza prairie. Field wells elevation were use to calibrate the SPLIT results. By estimating the hydraulic permeability value to 0.546m/d the field well measurements and SPLIT simulated groundwater elevation results provide a good match. After calibration max and min recharge together with a 5-years moving average were used to examine the changes in groundwater elevation as recharge changes. Future study intends to use the calibrated Konza groundwater model and the forecasted climate data to simulate result for groundwater elevation as climate changes.

Doctor of Philosophy / Department of Agronomy / Jay M. Ham / Land management practices such as burning and grazing may affect evapotranspiration (ET) and water balance of the tall grass prairie in the Flint Hills of eastern Kansas. Experiments were designed to estimate or measure the water balance of a stock-watering pond, and compare energy balance parameters and ET between grazed and ungrazed prairies. The hydrology of the native tallgrass prairie also was compared with mature stand of eastern red cedar (Juniperus virginiana), a site that was formerly prairie but converted to woodland when prescribed burning was discontinued. Data were collected to encompass the seasonal and yearly changes in weather variability. A host of micrometeorological sensors were used to measure surface atmosphere exchange and water losses, including: eddy covariance towers on prairie and woodland sites, specialized through fall and stem flow equipment at the woodland site, and an instrumentation raft at the stock watering pond. Results of the stock pond study showed that, on average, evaporation accounted for 64% of the water loss, followed by seepage at 31%, cattle use at 3% and transpiration at 2%. Comparisons of grazed and ungrazed areas showed that grazing caused only small, 3 to 6 %, reductions in seasonal ET compared with ungrazed pastures despite large differences in vegetative cover. In the woodland study, the 50-yr-old cedar canopy intercepted 54% of the precipitation received, thus decreasing the amount of precipitation reaching the soil. Evapotranspiration from woodland and prairie sites were similar, but net carbon exchange was greater on the prairie. Thus, the apparent water use efficiency during he summer months was 3 times greater on the prairie. Net radiation at the woodland site was 100 W m-2 higher compared with the prairie. This caused an increase in the woodland sensible heat flux and midday Bowen ratios, yet woodland latent heat flux and ET was similar to the prairie during the study, factors that could affect regional climate. Land management decisions regarding grazing, prescribed burning, and stock pond design will impact the watershed hydrology and productivity of the tallgrass prairie.

Doctor of Philosophy / Department of Animal Sciences and Industry / K C Olson / The objective of this series of studies was to examine select factors that affect behavior of beef cattle grazing native-tallgrass rangelands. Mineral supplements with divergent palatability characteristics were delivered to beef cows grazing native tallgrass range during various seasons of the year in order to measure mineral intake, frequency of supplement use, and duration of supplement use. We concluded that molasses-based mineral supplements influenced the activities of grazing cows more strongly than salt-based mineral supplements. These influences extended to the amount of supplement consumed as well as to the frequency, duration, and timing of use. Diet selection preferences of experienced, multiparous beef cows and naïve, primiparous beef cows grazing dormant, native tallgrass pastures were examined also during a short-term winter grazing bout. Naïve, primiparous cows selected more forbs and fewer grasses than experienced, multiparous cows. Previous research indicated that preference for broadleaf plants generally increased with grazing experience; however, these conclusions were based on research with greater-quality forages than those evaluated in our study. The differences in diet selection patterns between experienced, multiparous cows and naïve, primiparous cows during a short-term winter grazing period could be indicative of differences in long-term foraging strategies. In addition, the botanical composition of diets grazed by lactating beef cows with suckling calves and non-pregnant, non-lactating beef cows grazing either burned or unburned native tallgrass prairie during summer were evaluated. There were no differences in botanical diet composition between lactating cows suckling calves and non-lactating cows. In contrast, total graminoid selection was greater on burned (74.2%) than unburned pastures (71.8%) and total forb selection was greater on unburned (28.2%) than burned pastures (25.8%). We interpreted these data to suggest that forage selection preferences of beef cows can be altered with spring burning of native tallgrass pastures. Effects of large, round hay bale feeding method on intake of smooth bromegrass hay and eating behavior by beef cows were examined on dormant tallgrass prairie pastures during winter. Three large, round hay bale-feeding systems were evaluated: bales fed in a ring feeder, bales unrolled on the ground, and bales chopped with a flail-type hay processor (20-cm particle length) and deposited on the ground. Hay intake, hay refusal, frequency of use, and duration of use were not influenced by hay-feeding method. Foraging behaviors of beef cows in our studies were influenced by supplement type, cow age, and prescribed burning of rangeland. Conversely, foraging behaviors of beef cows were not influenced by lactation or by hay-feeding method.

Master of Science / Department of Agronomy / Walter H. Fick / Rough-leaved dogwood (Cornus Drummondii Meyer) is one of the most invasive woody plants in rangeland of Kansas. Reduced prescribed burning due to drought and urban encroachment probably has contributed to its spread. Herbicides are commonly recommended for control of rough-leaved dogwood, but minimal data exists for recommendation development. Ten herbicide treatments were applied in June during late flowering at two locations in northeast Kansas in 2005 and 2006. Each treatment was replicated three times in a randomized complete block design with individual plot sizes of 3 x 3 m. Herbicides were applied with hand sprayers in 1017 L/ha solution. Visual evaluations of defoliation were made about 1 and 12 months after treatment (MAT) and mortality was estimated about 1 year after treatment (YAT). Defoliation 1 MAT varied among herbicides with significant location by year and herbicide by year interactions. Treatments providing greater than 70% defoliation 12 MAT both years were triclopyr + 2,4-D (1.12 + 1.06 kg ae/ha), triclopyr + fluroxypyr (1.83 + 0.61 kg ae/ha), picloram + fluroxypyr (0.41 + 0.41 and 0.82 + 0.82 kg ae/ha), and picloram + 2,4-D + triclopyr (0.66 + 2.44 + 2.44 kg ae/ha). Rough-leaved dogwood is difficult to control with a single herbicide application, but treatments exist that will substantially reduce stands. Tebuthiuron pellets (Spike 20P) are another control measure recommended for rough-leaved dogwood. Treatments of 4.4 kg ai/ha (3/4 oz per 100 square feet) tebuthiuron pellets were applied in December 2004. A visual estimate of control indicated tebuthiuron reduced dogwood cover by 65% compared to a 3% decrease on untreated plots. Dogwood density was reduced by 2.2 stems/m2 (P<0.08). Total woody plant cover increased on untreated plots by 6.2 percentage units, but was decreased by 20.9 percentage units on tebuthiuron treated plots. Other woody plants decreased in both treated and untreated plots. Shading by a large elm tree likely caused variation between replications including increases in cover and density of rough-leaved dogwood on treated plots. Tebuthiuron is a photosynthetic inhibitor that often is not effective on shaded plants. Tebuthiuron pellets applied at 4.4 kg ai/ha was an effective control option for unshaded rough-leaved dogwood.

Master of Science / Department of Agronomy / Walter H. Fick / Patch-burn grazing is a relatively new concept in terms of rangeland management. While numerous benefits have been associated with this system, in the tallgrass prairie of Kansas, cattle production and sustainability of rangeland are critical. In 2006, 253 ha at the KSU Bressner Range Research Unit in Woodson County, Kansas were subjected to spring patch-burn grazing (using one-third portions) and traditional full-burn grazing. Each treatment within the split-block design was replicated four times for 3 years. The objectives were to evaluate whether livestock performance would be compromised under this grazing system, to monitor the health of the rangeland, and to observe the usefulness of this tool as a potential control of the invasive plant sericea lespedeza [Lespedeza cuneata (Dumont) G. Don]. In regards to cattle performance, burn treatments had no significant difference in average daily gain (p≥0.10) in any of the 3 years. On average, cattle utilized 61% of the current year’s forage production in patch-burned portions, which was higher (p≤0.10) than that of unburned (30%) and full-burn (41%) portions. Results of the botanical composition show forb and woody plant composition did not differ between treatments, however differences (p≤0.10) were present in grass composition. Total annual grasses increased 19.1 percentage units under patch-burn and 2.1 units under full-burn, while total perennial grasses decreased 18.4 and 1.1 units, respectively. When evaluated by treatment area (one-third portion), results indicated that the 3-year cycle did allow enough time for recovery. At 2 years after treatment (2-YAT), no significant difference in composition(p≥0.10) was present between initial patch-burn portions and the full-burn pastures. Finally, in only 1 year of the study did cattle statistically consume a greater percentage of sericea lespedeza plants (p≤0.10) in the patch-burned portions (92%) than in full-burned pastures (35%). Biomass utilization did not differ (p≥0.10) between burn treatments. Surprisingly, there was a trend for the number of plants in the sampled areas of the patch-burn portions to decrease throughout the cycle. However, at the conclusion of the 3-year cycle, sericea densities did not differ(p≥0.10) between treatments. Patch-burn grazing shows promise as a potential management tool for Kansas land managers.

Master of Science / Department of Agronomy / Walt Fick / Prescribed burning has been a common conservation practice on native prairie dating back to the days of pioneer settlement. Advantages include increased forage quality, reduction of undesirable plants, improved wildlife habitat, removal of accumulated dead plant litter and relatively low costs. While spring is the commonly accepted time to burn, little research has been conducted on late-summer and fall burning for specific objectives that include targeting undesirable plant species and measuring potential effects on soil physical properties. The first part of this study was to evaluate the effect that prescribed burning has on population dynamics of sericea lespedeza (Lespedeza cuneata [Dumont] G. Don), rough-leaf dogwood (Cornus drummondii Meyer), and additional woody species. Stem counts and cover estimates were taken from 20, 0.25-m[superscript]2 frames prior to and post-burn. Change in botanical composition, plant density, frequency, and Daubenmire canopy cover estimates were calculated. Sericea lespedeza plant frequency across all clay upland burns decreased 2.27% and increased 4.76% across all loamy/limy upland burns the first growing season post-burn. Dogwood densities increased 3.12 stems m[superscript]-[superscript]2 on spring burns compared to a decrease of 0.30 stems m[superscript]-[superscript]2 on unburned plots the first growing season post-burn. Changes in frequency of other woody species the first growing season post-burn showed significant interactions between burn treatment and ecological site, and between ecological site and year. A significant interaction between burn treatment and ecological site was found on total woody species plant composition changes two growing seasons post-burn for the first year of burn treatments. The secondary part of this study was to evaluate the effect of prescribed burning on soil bulk density and wet-aggregate stability. Soil samples were collected along the same line-transects used for vegetation sampling. Significant differences among mean weight diameters (MWD), percent water-stable aggregates (WSA), and WSA size fractions occurred between burned and unburned soils following burning in the fall of 2011. Monitoring plant and soil response to prescribed burning in different seasons may lead to adjustments being made in management of rangelands where sericea lespedeza, dogwood, and additional woody species occur.

Doctor of Philosophy / Department of Agronomy / Clenton E. Owensby / Most rangelands are harvested at some point during the year and removal of plant leaf area and biomass alters a host of ecosystem processes including gas exchange. An experiment was conducted in 2005 and 2006 to study the effects of clipping tallgrass prairie at different dates on water vapor and CO2 fluxes. A portable, non-steady-state chamber was designed to measure CO2 and water vapor fluxes from small plots in less than 40 s. A combination of sunlit and shaded readings allowed measurements of net carbon exchange (NCE) and ecosystem respiration (RE); by summing NCE and RE, gross canopy photosynthesis (GCP) was calculated. Throughout the two-year study, the chamber had a minimal effect on microclimate, i.e., average chamber temperature increased 2.9° C, while chamber pressure increased only 0.3 Pa during measurements, and photosynthetically active radiation attenuation was 10%. The immediate effect of all clipping treatments was a loss of leaf area that led to reductions in GCP, NCE, and RE and in most cases decreased water vapor flux. Further patterns of carbon flux were governed by the amount of water stress during canopy development, while water vapor flux rates varied with water availability. Canopies that developed during periods of low water stress quickly increased carbon flux rates following precipitation after a mid-season drought. However, flux rates of canopies, which developed during the mid-season drought, responded considerably slower to subsequent water availability. A separate experiment was conducted from June-October of 2006 to estimate GCP, leaf area index (LAI), and total aboveground biomass with a hyperspectral radiometer. Indices such as the Normalized Difference Vegetation Index and the Simple Ratio were used to estimate LAI and biomass had poor correlations with measured values. However, GCP was significantly correlated to all six indices derived in this study. While GCP measured from June-October was significantly correlated with all indices, removal of the senesced canopy scans recorded during October greatly increased the relationship.

Doctor of Philosophy / Department of Biology / Kimberly A. With / The loss, fragmentation, and degradation of grasslands have resulted in widespread declines in grassland birds. Nest predation is the leading cause of avian reproductive failure; therefore minimizing nest predation can lessen the severity of bird declines. Snakes are important predators of bird nests, but little is known about how snakes may enhance predation risk. To address this issue, I studied the habitat use, movement behavior, population genetic structure, and connectivity of snakes in the grasslands of northeastern Kansas. I addressed the connectivity of eastern yellowbelly racer (Coluber constrictor flaviventris) populations by using a landscape genetics approach at a broad scale (13,500 km2). I also radio-tracked the yellowbelly racer and Great Plains ratsnake (Pantherophis emoryi) at Konza Prairie Biological Station to understand their spatial ecology while simultaneously evaluating nest survival in grassland birds. Individual racers had limited dispersal (<3 km), but substantial admixture occurred within 30 km and populations were in migration-drift equilibrium and had high allelic diversity; therefore, racers must be abundant and continuously distributed for gene flow to be fluid throughout the region. Racers may be more likely to encounter bird nests, as they had more frequent movements and traversed greater distances on average than ratsnakes, which exhibited long periods of inactivity between directed movements. As for grassland birds, nest survival rates decreased with increasing shrubs and decreasing vegetation height. Discriminant function analysis revealed that successful nests were likely to occur in tall vegetation but reduced shrub cover, whereas higher shrub cover characterized snake habitats. Because snakes often use shrubs, nests in areas of increased shrubs may be at higher risk of predation by snakes. Targeted removal of shrubs may increase nest success by minimizing the activity of predators attracted to shrubs. Although predator removal is often a strategy for protecting bird populations, it may not be feasible in this instance, especially since snakes are a native component of the grassland community. Efforts to reduce snake predation on grassland bird nests should therefore focus on managing habitat within grasslands (i.e., shrubs) that influence snake activity, as no natural or anthropogenic habitat barriers currently limit snake movement across the landscape.