Halogeton (Halogeton glomeratus) is a halophytic, invasive species that displaces Gardner’s saltbush (Atriplex gardneri) on saline rangelands. Forage kochia (Bassia prostrata) is a potential species to rehabilitate these ecosystems. This study compared the salinity tolerance of these species and tall wheatgrass (Thinopyrum ponticum) and alfalfa (Medicago sativa). Plants were evaluated for 28 days in hydroponics where they were maintained at 0, 150, 200, 300, 400, 600, and 800 mM NaCl. Shoot growth and ion accumulation were determined. Alfalfa and tall wheatgrass were severely affected by salt with both species’ shoot mass just 32% of control at 150 mM NaCl. Alfalfa did not survive above 300 mM NaCl, while, tall wheatgrass did not survive at salt levels above 400 mM NaCl. In contrast, forage kochia survived to 600 mM, but produced little shoot mass at that level. Halogeton exhibited ‘halophytic’ shoot growth, reaching maximum mass at 141 mM, and not less mass than the control until salinity reached 400 mM. Gardner’s saltbush did not show a dramatic decrease in dry mass produced until it reached salt levels of 600 and 800 mM NaCl. Forage kochia yielded high amounts of dry mass in the absence of salt, but also managed to survive up to 600 mM NaCl. Salt tolerance ranking (GR50 = 50% reduction in shoot mass) was Gardner’s saltbush=halogeton>forage kochia> alfalfa>tall wheatgrass. Both halogeton and Gardner’s saltbush actively accumulated sodium in shoots, indicating that Na+ was the principle ion in osmotic adjustment. In contrast, forage kochia exhibited a linear increase (e.g. passive uptake) in Na+ accumulation as salinity increased. This study confirmed that halogeton is a halophytic species and thus well adapted to salt-desert shrubland ecosystems. Gardner’s saltbush, also a halophyte, was equally salt tolerant, suggesting other factors are responsible for halogeton displacement of Gardner’s saltbush. Forage kochia is a halophytic species that can survive salinity equal to seawater, but is not as salt tolerant as Gardner’s saltbush and halogeton.

Master of Science / Department of Agronomy / Johanna A. Dille / No-till producers can manage weeds by including cover crops during the fallow phase as part of an integrated weed management plan. Field experiments were conducted between 2007 and 2009 to quantify the influence of cover crops on weed emergence, biomass accumulation, and seed production. Field experiments were established near Garden City, KS with winter wheat or fallow as main plots and cover crop treatments as subplots including five spring- and five fall-sown individual or mixtures of crop species and a no-cover chemical fallow. Separate1-m2 quadrats were seeded with kochia or downy brome at 500 seed/m2. Kochia density was reduced by 75% and biomass reduced by 88% in fall-sown cover crops compared to chemical fallow across growing seasons. Spring-sown cover crop mixtures reduced kochia biomass in 2009 when kochia emergence was delayed. Downy brome biomass decreased exponentially as cover crop biomass increased. A second field experiment was established near Manhattan, KS with soybean, winter wheat, or grain sorghum phases of the rotation as main plots and six cover crop treatments as subplots sown after winter wheat harvest. Paired Palmer amaranth 1-m2 quadrats were seeded with 500 seed/m2 in each cover crop subplot. One quadrat was protected from any herbicide application made to the cover crop or to the grain sorghum. Combining burndown application with high biomass-producing cover crops reduced Palmer amaranth emergence and biomass. Influence of cover crop presence reduced early season Palmer amaranth emergence in the subsequent grain sorghum phase. Optimal seeding rate of forage soybean sown in winter wheat stubble and its impact on Palmer amaranth and downy brome emergence and growth were evaluated in field studies established near Manhattan and Hesston, KS in 2008 and 2009. Soybean was no-till drilled after wheat harvest at five rates ranging from 100,000 to 600,000 seeds/ha. A no-cover chemical fallow treatment was included. Separate 0.5-m2 quadrats were seeded with Palmer amaranth at 100 seed/0.5 m2 or with downy brome at 250 seed/0.5 m2. Three termination methods evaluated were killing frost, glyphosate application, or crop rolling. Palmer amaranth density was not affected by treatments but biomass decreased as soybean seeding rate and crop biomass increased. Downy brome emergence was less with rolled or sprayed termination methods in one site year as timing of termination was optimal. High biomass producing cover crops sown during the fallow phase of a crop rotation reduced weed emergence, density, and biomass accumulation. Cover crops can be part of an integrated weed management plan in Kansas.

Master of Science / Department of Agronomy / Anita Dille / A better understanding of kochia (Kochia scoparia) seed characteristics is necessary for long term management of this increasingly troublesome weed. The objectives were to evaluate maternal environmental factors influencing kochia seed produced in the field and to document variability in dormancy and seed viability produced within a single kochia plant grown in the greenhouse or field. Field experiments were conducted in 2012 and 2013 at the Kansas State Agricultural Research Center in Hays. Two different kochia biotypes from Hays were planted with and without five canopy types, namely corn, soybean, grain sorghum, wheat stubble, and kochia plants. A greenhouse experiment with two generations (F1 and F2) of self-pollination was conducted with the same kochia biotypes. Date of initial flowering and final plant heights were recorded. Plants were harvested when seed was mature and divided into three equal parts (top, middle, and bottom). Seeds were cold treated or not, and approximately 50 seeds were placed in petri dishes with water for germination counts taken over six weeks. Viability of remaining seeds were then tested. For field-grown kochia, plants were taller in corn, sorghum and weedy canopies compared to the absence of a canopy. Seed germination from field grown kochia ranged between 77 and 100% for both treatments. There was reduced germination in the presence of a weedy canopy for both treatments and biotypes (77 to 82%) compared to the absence (93 to 99%), with an increase in hard viable seed in the presence of weedy canopy (5 to 14%). In the greenhouse, the F2 generation produced more immediately germinable seed compared to the F1 generation which had more seed with delayed germinability. Seed from bottom third of F1 and F2 plants had greater total germination (73 and 70%, respectively) compared to the middle (61 and 65%) and top (50 and 59%) thirds of the plant. There was a maternal environmental effect on kochia seed characteristics with implications on generating persistent seed for the future seedbank.

Doctor of Philosophy / Department of Agronomy / Johanna A. Dille / Kochia (Kochia scoparia L. Schrad.), one of the most problematic weeds in the Great Plains of United States, has evolved resistance to some herbicides including glyphosate (5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor) which was first reported in western Kansas in 2007. The objectives of this research were to (1) characterize six kochia populations from western Kansas on the basis of glyphosate resistance or multiple herbicide resistance, (2) determine germination characteristics of the populations and evaluate their growth and fecundity in the field, and (3) determine if EPSPS gene amplification responsible for glyphosate resistance in kochia was associated with growth and fecundity cost in the plants. Six kochia populations were from Scott, Finney, Thomas, Phillips, Wallace, and Wichita counties. Based on shikimate assay for glyphosate and recommended field rates for four tested herbicides, three kochia populations (Scott (SC-R), Finney (FN-R), and Thomas (TH-R)) were grouped into glyphosate-resistant (GR) and three populations (Phillips (PH-S), Wallace (WA-S) and Wichita (WI-S)) were grouped into glyphosate-susceptible (GS). All populations were resistant to dicamba (synthetic auxin) and chlorsulfuron (acetolactate synthase inhibitor), however, atrazine (PS II inhibitor) resistance in FN-R was noted as exceptional among the GR populations. Across the three germination temperatures (5, 10 and 15 C), the GR populations consistently had less total cumulative germination and at 15 C, they consistently required more time to attain 50% of maximum cumulative germination than the GS populations. Both the field study and evaluation of relationship between EPSPS gene amplification and plant performance showed that differences in plant height, biomass accumulation and fecundity among populations were not in respect to glyphosate resistance but rather, differences in their inherent ability to grow and produce seeds in the presence or absence of neighbors. This research suggests that fitness differences between GR and GS kochia populations could be identified in germination characteristics but not in their growth or fecundity.

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) currently occupy an estimated 56% of the potential range-wide pre-European settlement habitat. Population declines have been largely attributed to direct habitat loss and fragmentation related to anthropogenic activities that promote wildfires and the subsequent spread of invasive plants. Vegetation manipulations, including the seeding of plant species, such as forage kochia (Bassia prostrata), have been identified as potential strategies to mitigate the risk of wildfire and enhance sage-grouse habitat in areas at risk to wildfires. I evaluated the composition changes that occurred in a lower elevation sagebrush (Artemisia spp.) plant community within the Grouse Creek Watershed in western Box Elder County, Utah, USA, in response to prescribed vegetation manipulations (green-stripping through chain harrowing, juniper mastication, seeding forage kochia, applying Plateau® herbicide) and studied the effect of these changes on sage-grouse habitat-use patterns and vital rates. I monitored 53 radio-collared sage-grouse throughout the Grouse Creek watershed from 2010-2012. Seasonal movements suggested local individual bird adaptations to annual variations in weather and habitat fragmentation. Sage-grouse selected for untreated areas; however, treated areas were used to expand the size of the lek. Untreated areas exhibited a higher percent composition of shrubs compared to areas that were chain harrowed to prepare a seedbed. Sage-grouse nest success and adult male survival rates during this study were relatively low compared to range-wide population estimates. Nest predation was higher for nests located closer to roads. The forage kochia seeded in the firebreaks emerged the season after seeding (2011). Using microhistological techniques, I detected small quantities of forage kochia in sage-grouse fecal pellets. Nutrient analysis confirmed that forage kochia samples collected from the sites exhibited a high protein content and low secondary metabolite content, similar to black sagebrush (Artemisia nova). Although greenstripping with forage kochia in lower elevation sagebrush communities may prove to be a beneficial technique for protecting rangelands from wildfire and provide a dietary source for wildlife, site preparation should be conducted to minimize the impact on existing sagebrush canopy cover habitats. Long-term monitoring should be implemented to determine extended effects of greenstripping treatments on sagebrush habitat and sage-grouse vital rates. Although individual sage-grouse demonstrated local adaptations to fragmentation and seasonal variations in weather, increased fragmentation and climate change in this part of the Great Basin may increase meta-population extirpation risks inhabiting lower elevation sagebrush areas in the Grouse Creek Watershed.

Gardner saltbush ecosystems are increasingly being invaded by halogeton, a competitive annual weed that increases soil surface salinity and reduces plant biodiversity. This study was established on the Flaming Gorge National Recreation Area, in the Ashley National Forest near Manila, UT to evaluate the ability of forage kochia, Russian wildrye, tall wheatgrass, Indian ricegrass and Gardner saltbush, in monocultures and binary mixtures with Gardner saltbush, to establish and compete in ecosystems dominated by halogeton. A dormant seeding, with and without prior disking, was conducted to determine the ability of plant materials to establish. A spaced-plant evaluation was used to determine the competitive ability of fully established plants by measuring halogeton densities at four 10 cm intervals (10-20, 20-30, 30-40, and 40-50 cm) distal from transplants. Gardner saltbush, tall wheatgrass, and Indian ricegrass did not establish or persist beyond the first year in either study. Conversely, Russian wildrye and forage kochia established and persisted, with Russian wildrye establishment higher (P ≤ 0.05) in the disked treatment (4.5 and 1.7 plants m-2, respectively) and no-till favoring (P ≤ 0.05) forage kochia establishment (2.0 and 0.8 plants m-2, respectively). Spaced-plants of these species reduced halogeton by 52% relative to the control. Furthermore, by the second year of evaluation, the competitive ability of Russian wildrye and forage kochia had extended to 50 cm distal from transplant. Transplant survival and halogeton frequency were highly correlated (r = -0.67, P = 0.0001), indicating the important of persistence. These results suggest that Russian wildrye and forage kochia can establish, persist, and compete with halogeton, thereby providing an opportunity for reclamation of halogeton-invaded areas. Conversely, direct restoration to Gardner saltbush and Indian ricegrass does not appear likely

Several experimental lines of forage kochia [Kochia prostrata (L. Shrad.)] have potential to provide taller forage on fall and winter rangelands than the only released variety of forage kochia, Immigrant. This study was conducted to determine differences in cattle utilization among experimental lines of forage kochia and relate them to forage quality and morphological attributes. The utilization of forage kochia was also compared to 'Ladak ' alfalfa [Medicago saliva (L.)] and two entries of winterfat [Krashnennikovia species (Guldenstaedt)]. Cattle utilization was determined by calculating a biomass consumed value and a percent biomass consumed value. Dry weights for each plant were taken after grazing and subtracted from a pre-grazing dry weight (predicted using a quadratic regression equation) that produced the biomass consumed value. The percent consumed value was calculated by dividing biomass consumed by pre-grazing dry weight. Ocularly estimated utilization scores (OU) were also used to measure utilization. Forage quality traits were analyzed on each entry using near infrared reflectance spectroscopy. Morphologic and phenological characteristics potentially related to utilization were made by physical measurements and visual evaluations. There were significant differences among forage kochia accessions for all traits evaluated. Four entries, including Immigrant and Ladak alfalfa, were significantly higher in percent herbage consumed than the other entries . These same entries were consistently high in OU ratings , forage quality analyses , and most morphological characteristics. Pre-grazing dry weight (r = -0.96 , P < 0.0001) , stem length (r = 0.67, P < 0.0001), and branch density (r = 0.63, P < 0.0001) were all highly correlated with utilization. Crude protein (partial R2 = 0.253 , P ≤ 0.0001) was the only forage quality trait associated with utilization using a stepwise regression to predict utilization. From this study we conclude that some forage kochia accessions are very palatable. They are comparable to Ladak alfalfa, and utilized more than Krashnikova spp., a desirable forage on western rangelands.

Kochia scoparia (L.) Schrad. has had limited use as a forage crop during the past fifteen. years in parts of the western United States, Canada, and Argentina. Erickson and Moxon (1947) reported kochia* to be a good emergency feed for sheep and cattle during dry years in South Dakota. Salguero (1946) said that this species could be utilized in Argentina as silage or pasturage if harvested before flowering. Bell, et al. (1952) in Saskatoon, Canada studied this species in a comparison with other introduced plants and reported that it seemed to have desirable nutrient characteristics for livestock roughage. Plummer (1949) reported beef cattle in Ephraim, Utah had eaten and gained normally on kochia hay.