Weed Science Commons^™

An Integrated Approach To Soil-Plat-Animal Interactions On Grazed Legume-Based Pastures On Tropical Acid Soils, M J. Fisher, C E. Lascano, R J. Thomas, M A. Ayarza, I M. Rao, G Rippstein, J.H M. Thornley

IGC Proceedings (1977-2023)

Legume-based pastures developed by the Tropical Pastures Program (TPP) of CIAT give spectacular increases in both stocking rates and animal live-weight gains on the savannas of Latin America, A team within the TPP is addressing the problems of their management for legume persistence and soil-plant-animal interactions, using as Its focus a grazing experiment on 2 oxisols of contrasting texture on the Colombian Llanos. The objective is to model the pastures to forecast the effect of management options on long-term persistence and nutrient cycling in grazed legume•grass associations in the Latin American savannas.

Persistence Of Roundleaf Cassia In Grazed Pastures - A Conceptual Model, R M. Jones, C K. Mcdonald, G A. Bunch

IGC Proceedings (1977-2023)

Roundleaf cassia (Cassia rotudifolla) cv. Wynn is a short-lived perennial that relies on seedling recruitment for long-term persistence. Its persistence is considered in terms of survival of plants from the initial sowing, seed set, seedling recruitment, run-down of reserves of soil seed, and survival of seedlings. The major factor controlling all these stages is soil moisture stress; grazing management 'is less important. A conceptual model of Wynn persistence is presented and progress in mathematical modeiling is reported.·

Variation In Hydrological Characteristics Of The Soils Associated With Grazed Patches In Granitic Landscapes In Northern Australia, M M. Sallaway, D Waters, B Bridge, F P. Wandera

IGC Proceedings (1977-2023)

Under medium to heavy grazing of black speargrass (Heteropogon contortus) landscapes of south-east Queensland, "patchiness" has developed with a change from H. contortus to Aristida spp., Cllrysopogo11 spp. or a,inual grasses. This grazed patch development is associated with changes in soil hydrological characteristics which in turn affect runoff and soil erosion. T!\e soil hydrologic properties were studied using a rainfall simulator and disc permeameter. The remnant H. contortus areas had higher infiltration characteristics mainly due to the maintenance of larger mncropores (1-3 mm). In the Arlstida patches, the contribution of those large macropores has been greatly reduced. Th is effect …

Evaluation Of Pastures For Sustained Beef Production In Subtropical New South Wales, P T. Mears, D L. Garden, R W. Dicker

IGC Proceedings (1977-2023)

Limitations of low-quality grass pastures, soil fertility, mechanisms of legume persistence and the long-term sustainability of pastures for beef production were studied in a humid subtropical environment of New South Wales, Australia. Sustainability of pastures and animal growth responses in 3 experiments (varying from 4 to 10 years' duration) al 2 sites have been analysed and described. Steers or heifers were used lo assess the effects of introducing subtropical or temperate legumes, level of superphosphate and stocking rate on natural grass pastures, Principal factors which improved the level of beef production from pasture were (i) introducing persistent legumes (ii) level …

Bothriochloa Pertusa- A Useful Grazing-Tolerant Grass For The Seasonally Dry Tropics?, R J. Jones, A Kerr

IGC Proceedings (1977-2023)

Data from 2 grazing experiments, small-plot studies, and a vegetation and soil survey showed that Bothriochloa pertusa increased relative to native tufted perennial grasses under heavy grazing pressure and was adapted to a wide range of soils in the 500-1000 mm zone of northern Australia. Ability to grow on low-P soils, lower relative palatability, strong stoloniferous development and good seed production, were features of its success. Annual steer gains on 8. pertusa pastures were similar to those on native pastures, with no species x stocking rate interaction. Steer gains on B. pertusa-Vernno stylo pastures were lower than on Urochloa …

Sustainability Of Sown Pastures In The Tropics And Subtropics, Jose M. Toledo, Daniel Formoso

IGC Proceedings (1977-2023)

Sown pastures in the tropics and subtropics are important components of production systems. Their role in and contribution to land productivity and economic development are well understood; however, their roles in sustainability and environmental protection are rather misunderstood and little known. The main constraints to sustainability of sown pastures fall into two categories: physical, biological and technical constraints include soil and climatic limitations, lack of adaptation of plants to physical and biotic stress and the limitations of farmers or ranchers to apply technology; socioeconomic factors include political instability, poorness of society and the market forces for land, inputs and products. …

Stability In Rangelands: Ecology And Economics, B H. Walker

IGC Proceedings (1977-2023)

Examples of changes in rangelands are presented relating to changes in livestock number, plant species. composition and soil changes (associated with changes in production), The mechanisms Involved are described, using examples, under the headings: event-driven change, threshold effects, non-linear and hysteresis effects, effects of spatial variation, significance of temporal variation, and interactive effects. The implications for management are presented in the form of a proposed optimal control model which maximises a complex function of welfnre based on long-term net economic benefit, in which stocking rate effects on the state of the rangeland feed back on to economic return.

Field Trials Report 2024: Wa Farming Systems Project (Daw2204-003rtx), Department Of Primary Industries And Regional Development, Western Australia

Farm Systems and Economics research reports

Within the Western Australian Faming Systems Project, a program of 11 field trials were conducted in 2024 from Ogilvie in the north to Wittenoom Hills in the south.

The season was a challenging one with a late break to the season at all sites and varying conditions from decile 3 to decile 10 growing season rainfall across the sites.

Rejuvra's Effect On Soil Seed Banks, Blake J. Roeslein, Bryan Endress, Abby Mcmurtry, Akasha Faist

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Invasive annual grasses are a major driver of grassland degradation globally. In perennial grasslands, invasion can heavily impact biodiversity, including potential changes to the soil seed banks. Seed banks, the living seeds stored in the upper soil column, play an important role in healthy systems, or can harbor invasive species. To reduce negative invasion outcomes, whether in the seed bank, or aboveground vegetation, pre-emergent herbicides are a commonly used tool for land managers. Pre-emergent herbicides work by targeting seeds as they germinate and begin emerging from the soil. Thus, our study asks 1) how does pre-emergent herbicide influence germination and …

Igc Oral Presentation Summary: Xxv Igc Congress, S. Ray Smith, Echo Elizabeth Gotsick, J. R. Weinert-Nelson, Alayna Jacobs, Christopher D. Teutsch, Will Fleming, D. R. Woodfield, James L. Klotz, Jeff Lehmkuhler, Greg S. Halich, Brittany Davis, Brittany Hendrix, Krista Lea

IGC Proceedings (1977-2023)

This paper will give an overview of the XXV International Grassland Congress thematic, keynote, and plenary sessions. The theme of the XXV IGC Congress meeting was “Grasslands for Soil, Animal, and Human Health.” We had many people attending, presenting, and participating in all these sessions. Within a month after the conclusion of the Congress, the proceeding’s papers presented at the meeting will be available on the IGC app. By the end of 2023 all papers will be available for download through any search engine at internationalgrasslands.org.

Screening Herbicides For Use In Newly Established Short Rotation Coppice Shrub Willow Plantations, Alex Thomas Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

A major setback for the establishment of short rotation coppice willow plantations is the control of competition from weeds. Weed competition has been found to cause increased mortality which lowers biomass yields when left uncontrolled. Mechanical weed control methods are the most used method of weed control, but their use can be complicated by cost, labor availability and site topography. Chemical weed control is also complicated by the fact that willow species are particularly sensitive to herbicides. Across three trials, we screen 11 herbicides for their potential to control weeds without significantly decreasing the vertical growth of willow trees. This …

Machine Learning And Uass For Managing Autumn Olive (Elaeagnus Umbellata) On Reclaimed Surface Mines, Sean Michael Keane

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research introduces an innovative approach for managing autumn olive (Elaeagnus umbellata) on reclaimed surface mines through the integration of machine learning algorithms and unmanned aerial systems. The proliferation of autumn olive presents significant ecological challenges on disturbed landscapes, necessitating more efficient detection and control methods. This study evaluated Random Forest classification and deep learning approaches using the U-Net architecture for identifying autumn olive across four phenological stages using high-resolution imagery. The RGB U-Net model achieved F1-scores of 0.927, 0.912, and 0.871 for autumn olive detection during peak, late, and senescence stages respectively, outperforming both multispectral and vegetation …

Effects Of Round-Up On The Environment, Sandra J. Marcu

Journal of Earth and Life Science

Many people around the world have used and still currently use Roundup but are unaware of the effects it has on the environment. Roundup is a spray on application weedkiller that is widely used around the world today both residentially and commercially. It enables its user to grow a garden or a field of crops with a no-tilling approach to eliminate weeds. It is a well-known and popular choice for killing weeds that has been around since the mid 1970’s (Oca, 2017). John Franz, a Monsanto scientist discovered that glyphosate (main ingredient in Roundup) was an herbicide or weedkiller, and …

Evaluation Of Poaceae Species And Suppression Application Methods For Perennial Groundcover In Corn, Hallie A. Sandeen

Theses and Dissertations--Plant and Soil Sciences

Intensive grain production aims to provide food security but has depleted once-perennialized land. Perennial groundcover (PGC) offers ecosystem services to intensive annual corn (Zea mays L.) production. In past research conducted in the U.S. Midwest, Kentucky bluegrass (Poa pratensis L.) has been the standard PGC species. However, it is slow growing and difficult to suppress. To characterize the PGC system in the midsouth, two separate field trials in Lexington, Kentucky, were conducted to (i) compare the first-year establishment of alternative cool-season species to Kentucky bluegrass, with and without a spring-applied broadleaf herbicide, and their impact on corn grain …

Zoysiagrass Tolerance To Selective Herbicides For The Removal Of Bermudagrass And The Distribution Of The Annual Bluegrass Weevil (Listronotus Maculicollis) In Kentucky, Kenneth D. Clayton

Theses and Dissertations--Plant and Soil Sciences

Bermudagrass (Cynodon dactylon) may be a problematic weed within zoysiagrass (Zoysia spp.) swards across its entire range. The objective of this study was to determine the efficacy of the herbicide safener metcamifen + trifloxysulfuron-sodium, in conjunction with fluazifop-P-butyl, at removing bermudagrass from zoysiagrass and how varying levels of treatment affected bermudagrass control and zoysiagrass tolerance. Field studies tested rates of metcamifen + trifloxysulfuron-sodium applied with fluazifop-P-butyl compared to treatments of fluazifop alone and fenoxaprop with triclopyr. All treatments controlled bermudagrass, and treatments with the herbicide safener remained under the 20% injury threshold for zoysiagrass for ≤ to 15 days compared …

Improving Reduced Tillage Vegetable Systems For The Northern Great Plains: How Does Early Season Soil Tarping (Solarization And Occultation) Reduce Weeds, Affect Soil Health, And Protect Yield?, Hannah Voye

Electronic Theses and Dissertations

Soil tarping (solarization and occultation) is a no-till weed management practice gaining popularity in the United States for small scale vegetable growers. While many studies have been conducted using variations of this tool in the Northeast United States, minimal research has been done in the windier, sunnier, Midwest climate. Our research explored the effectiveness of early spring solarization and occultation to manage weeds and produce viable onion yield in Eastern South Dakota. Occultation tarps placed in early spring included double sided black and white silage tarps with tarps placed black side up or white side up, each placed 6-, 4-, …

Cover Cropping Strategies For Improving Weed Suppression, Yashar Askarzadeh

Electronic Theses and Dissertations

Cover crops (CCs) play an essential role in sustainable agriculture by providing multiple ecosystem services. However, adoption remains low due to concerns about economic returns, management complexity, and potential yield reductions in cash crops. Applying CCs uniformly across fields without accounting for spatial variability can result in inconsistent outcomes. A precision cover cropping system (PCCS), which incorporates site-specific management zones (MZs), offers a more targeted approach to improving performance while minimizing costs and uncertainties. This study explores the interaction between CCs and field variability through complementary field and greenhouse experiments. The field experiment demonstrates that field heterogeneity significantly influences CC …

Impact Of An Herbicide Treatment In An Annual Grass Invaded Sagebrush Steppe, Jordan Dino Santia

Undergraduate Scholarship

Globally, rangelands are being threatened by invasive annual grasses (IAGs) that alter fire regimes, drive vegetation type conversion, and alter ecosystem function. This study evaluates vegetation responses to an Imazapic treatment applied in 2020 to control a population of Taeniatherum caput-medusae, an IAG, that flourished following a severe wildfire in 2013. The site, located on a Bureau of Land Management (BLM) grazing allotment east of Klamath Falls, Oregon, has been monitored annually using the Assessment, Inventory, and Monitoring (AIM) protocol since the Summer of 2022. Over this period, very little T. caput-medusae has been detected while bare ground has …

Aquatic Plant Threats To The Columbia River, Jacob Rose, Gabriel Campbell

Center for Lakes and Reservoirs Publications and Presentations

These presentation slides provide an overview of some of the invasive aquatic plants that pose an emerging threat to Oregon waterways. It contains botanical notes and high-quality photographs of approximately nine different plant species. Additional slides emphasize the importance of early detection and rapid response, as well as existing resources for invasive species outreach. This presentation was given orally at the Oregon Department of Agriculture's Interagency Noxious Weed Symposium to an audience of natural resource practitioners.

Emerging Aquatic Plant Threats To Oregon Waterways, Jacob Rose, Gabriel Campbell

Center for Lakes and Reservoirs Publications and Presentations

This brief presentation provides an overview some of two invasive aquatic plants that pose a threat to the Columbia River, where it borders Oregon and Washington. Flowering rush (Butomus umbellatus) and fragrant waterlily (Nymphaea odorata) threaten aquatic habitats up and down the Columbia River. Staff from the Center for Lakes & Reservoirs promoted a quick, picture-based key for flowering rush and lookalikes. This presentation was given orally at the Oregon Department of Agriculture's Interagency Noxious Weed Symposium to an audience of natural resource practitioners.