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Evaluation Of Grazing-Tolerant Alfalfa Cultivars, J H. Bouton, S R. Smith Jr, C S. Hoveland, M A. Mccann

IGC Proceedings (1977-2023)

Alfalfa (Medicago saliva L.) does not persist under continuous stocking with grazing animals. The creeping-rooted cultivars developed in the past were low yielding and varied in grazing persistence. The method and results of a breeding effort to develop and test high yielding, grazing-tolerant alfalfa cultivars are reported here. Replicated small plots within grazing paddocks subjected to intensive,continuous stocking with beef cattle (Bos indicus) over 2 years were used for selection and testing. This procedure was successful in producing the Alfagraze cultivar; and when used to test for grazing persistence among available cultivars, Alfagraze was consistently the most …

Bromus Stamineus- A Potential New Species For Pastures In Dry Regions Of New Zealand, A V. Stewart

IGC Proceedings (1977-2023)

Bromus stamineus Desvaux is a fine-leaved perennial species closely related to prairie grass (B. willdenowil Kunth). It differs primarily by having a greater number of smaller tillers and excellent tolerance to close grazing. Such characteristics provide it with considerable potential in drier east coast districts of New Zealand. The release of the first cultivar of this species, Grasslands Gala grazing brome, is enabling this potential to be developed. Further research is required to determine the precise role of this species.

The Value Of Adapted, Annual Ryegrasses For Subtropical Dairy Production, K F. Lowe, T M. Bowdler, G K. Reason, R J. Moss

IGC Proceedings (1977-2023)

Cutting and grazing experiments were conducted in a subtropical environment to determine whether a relationship existed between differences measured in ryegrass cultivars from cutting experiments and milk production differences under grazing. Differences in dry mauer (OM) production under cutting between the standard annual ryegrass for the subtropics (Grasslands Tama) and a cultivar selected for superior performance under subtropical conditions (Midmar) averaged 31 %, differences in feed on offer under grazing averaged 21 %, while milk production differences averaged 10% in a 2-year study. The results indicate that increases in OM yield measured in cutting experiments will be consistent wlth differences …

Evaluation Of Dwarf Napiergrass, W W. Hanna, W G. Monson, G M. Hill

IGC Proceedings (1977-2023)

Napiergrass (Pennisetum purpureum Schum.), a robust perennial bunchgrass with high yield potential, rapidly loses quality and palatability without proper management as it matures. In 1985 and 1986, 2 dwarf napiergrass cultivars (Mott and Tift Nl29) and 2 tall cultivars (Merkeron and Tift N68) were evaluated for yield, quality and agronomic characteristics. Dwarf cultivars yielded about 1/3 as much as tall cultivars. Percentage leaf was 60-76 for dwarf cultivors and 43-46 for tall cultivars. Average In vitro dry matter digestibility (lVDMD) of whole plants was similar among cultivars except for Tift N68 which tended to be lower (605, 594, 610 …

Plant Improvement: The Evaluation And Extension Processes, A S. Laidlaw, K.F M. Reed

IGC Proceedings (1977-2023)

Registration and evaluation systems throughout the world range from voluntary registration to compulsory schemes involving assessment of taxonomic and agronomic characteristics. Evaluation can be confined to agronomic tests simulated under grazing management or extended to feeding-value trials. Criteria include adaptation to climate and soils, persistence and seasonal growth, annual dry matter production, resistance to pests and diseases, and association with beneficial organisms. The need for stress (e.g. drought, low nutrients, acidity, salinity, heat or cold) to be given more emphasis in programmes in specific localities is suggested. In developing regions the emphasis is screening a wide range of grasses and …

Breeding Grasses For Adaptation To Environmental Problems, M O. Humphreys, M W. Humphreys, H Thomas

IGC Proceedings (1977-2023)

Hybrids between perennial ryegrass (Lolium perenne L.) accessions from Romania and Hungary were produced in an auempt to improve cold lolerance. Winter survival of hybrids was poorer than expected on the basis of parent performance. In a second breeding programme, introgression of genes from toll fescue (Festuca arundinacea Schreb.) into Italian ryegrass (Lolium multiflorum Lam,) was achieved using pentaploid hybrids between letraploid Italian ryegrass and hexaploid all fcscue and backcrossing twice to diploid Italian ryegrass, Good response to selection for improved drought tolerance was obtained in backcrossed progeny. It appears that in breeding for improved tolerance to …

Relative Performance Of Three Cultivars Of Late-Heading Perennial Ryegrass Continuously Stocks By Ewes And Lambs, H Clark

IGC Proceedings (1977-2023)

Three cultivars of late-heading perennial ryegrass (Lolium perenne L.) were continuously but variably stocked with ewes and lambs so as to maintain steady state sward conditions. Net herbage production (NHP) was estimated by following the turnover of tissue on individually marked tillers and monitoring tiller numbers. Animal productivity was measured as lamb live-weight gain and ewe live­weight change and utilised metabolisable energy (UMB) estimated. The cultivars were S23, Melle and Mascot which were categorised outclassed, recommended and rejected, respectively, by the UK's National Institute of Agricultural Botany, NHP rankings for the cultivars (S23==100) were Melle 104 and Mascot 95 …

Grassland Investigation And Mapping Using Remote Sensing In Northern China, Liu Fuyuan, Li Znegyuan, Han Jinaguoguez, Xia Jingxin

IGC Proceedings (1977-2023)

A large area of grassland in north China is an important resource for animal production, The grassland vegetations of north China were investigated and mapped by means of remote sensing from 1986 to 1990, We adopted various multiple information and multitime phase satellite images which were taken to allow optical and computer processing for complicated cases and difficult areas of grassland classification, The grasslands were divided into 8 different types and 50 groups according to surface features of Landsat images, ecological environment and vegetation analysis, The warm shrub and herbosa grassland, which ls distributed mainly in the rocky mountainous regions, …

Effect Of Manipulative Management Options On A Degraded Pasture Within The Astrebla Spp. Grazing Lands Of Western Queensland, J J. Bushell, J A. Reynolds, D C. Cowan, D G. Phelps, J A. Milson

IGC Proceedings (1977-2023)

A reduction in Aslrebla spp., and an increase in less palatable and less desirable forbs (Malvastmm americanum Psoralea cinerea), was identified as a problem in some paddocks of the Astrebla grazing lands of central western Queensland's clay soils. To determine possible rehabilitation for these pastures and assist the recovery of Astrebla spp,, a 2-year experiment was conducted near Muttaburra, Queensland (460 mm average annual rainfall), Six main treatments (nil, tine ripping, herbicide, slashing, fire, and a pioneering grass) were combined in a 6x2x2 split piot structure with grazed/not grazed and with additional Astrebla lappacea seed sown/not sown. Interim …

Autumn Management Of Grass-Legume Pasture, D P. Belesky, J M. Fedders, A S. Laidlaw

IGC Proceedings (1977-2023)

Duration of autumn grazing may affect the long-term balance of grass and legume in a sward. Effects of early and late autumn closing dates were studied on productivity and morphology of orchardgrass (Dactylis glomerata) and white clover (Trifolium repens) in replicated grazed swards. Early-closed paddocks continued to accumulate herbage during autumn, resulting in greater winter senescence than late-closed paddocks. Spring-cut herbage mass was not affected by autumn management; however, late closing had significantly more clover than early closing. Early-closed paddocks were grass domlnanl, with few relatively large tillers and few clover growing points compared with late-closed …

Dynamics Of Stylosanthes Species In Mixed Pastures In A Marginal Environment, J G. Mcivor, C J. Gardener

IGC Proceedings (1977-2023)

The growth and population dynamics of Stylosanthes hamata cv. Verano and S. scabra cv. Seca were measured in mixed, oversown pastures at Hillgrove (AAR=535 mm) near Charters Towers. Over a 10-year period mean stylo yields ranged from 20 kg/ha to 1800 kg/ha. During the first 3 years Verano outyielded Seca but in the last 7 years Seca had greater yields. Plant density was greater for Verano lhan Seca during the early years but the situation was reversed in later years. The Seca plants lived longer than Verano plants and there was a greater proportion of perennial plants in the Seca …

Analysis Of A Natural Pasture Of The Karst Region (North-East Italy) Under Chemical Fertilization, G Parente, R Ardiani, F Bozzo, M Onofrii, M Scimone, S Venerus

IGC Proceedings (1977-2023)

To characterise the vegetation changes in a natural pasture, a mineral fertilisation and a 4-year grazing test (1987-1990) were carried out on a typical karstic natural grassland, at that time not grazed by livestock and frequently devastated by fire. Mineral fertiliser and year-long animal grazing have modified the vegetation and seem not to have damaged the agro-ecosystem. An increase of the Arrhenatheretum species and, consequently, higher dry matter production, have been recorded, as well as an extension of the growth period and a greater quantity of grass during the summer. Animal performance has been quite satisfactory as the milk production …

Combining Agricultural Agent Training In Forages With Graduate Credit, Garry Lacefield, Jimmy Henning, M Rasnake, C Forsythe, L Davis

IGC Proceedings (1977-2023)

An intensive agent training programme in alfalfa (Medicago sativa L.) production nnd utilisation was initialed in 1990. The training was organised by slate extension forage specialists to meet the needs of agricultural agents. Previous programmes have offered similar training but did nol resull in graduate credit. This unique approach offered intensive training to agents presented by a multidisciplinary learn of scientists. All requirements for graduate credit were met and the course completion resulted in 3 hours of graduate credit. The course has been rated "superior" by students. When properly organised and implemented, intensive agent training can be offered that …

A Grazing Land Conservation Plan, R G. Hendricks

IGC Proceedings (1977-2023)

In a sample planning scenario, a ranching operation in the USA demonstrates a typical conservation problem on grazing lands. Using SCS conservation planning techniques, problems and objectives are identified, resources are inventoried, data are analysed, solutions formulated and conservation practices implemented to solve the resource problem. With use of the economic analysis routine in Grazing Land Applications (OLA) version 1.1 decision suppott software, return on investment was largest when the client installed a combination of rest-rotation grazing, prescribed burning, and initiated a hunting lease programme.

Range Conservation Planning: The Usda- Soil Conservation Service Method, Rhett H. Johnson

IGC Proceedings (1977-2023)

The USDA-Soil Conservation Service has responsibility for providing one-on-one conservation planning assistance with the private rangeland managers of over 160 million ha in the USA. This assistance is provided on voluntary basis at the request of the private land user through a local conservation district. Through SO years of experience, a successful planning process has evolved, known as the Ten Elements Of Conservation Planning. These elements are: (1) provide information, (2) request assistance, (3) develop resource inventories, (4) recognise problems and opportunities, (5) determine objectives, (6) develop and evaluate alternatives, (7) make decisions, (8) document decisions, (9) implement decisions, and …

Use Of Objective Planning Techniques In The Development Of Large Livestock Farm In New Zealand, K I. Lowe

IGC Proceedings (1977-2023)

Limestone Downs is a sheep and beef cattle property of 3200 ha near Port Waikato, and provides funds for the C Alma Baker Trust for "the furtherance of the science of agriculture". A development programme slatted in 1981 transformed the farm from an extensive "station" into an intensive farming operation, lifting animal performance and financial returns. This followed the adoption of well-proven and relatively inexpensive modifications to management. Similar programmes should have realistic goals, and established decision rules with priorities. These should be supported by an appropriate monitoring programme and the use of objective data in decision making.

Interdisciplinary Research: A Vehicle For Meeting The Information Needs Of Grassland Producers, Robert O. Burton Jr, K P. Coffey, J L. Moyer, L W. Lomas, P T. Berends

IGC Proceedings (1977-2023)

Representing the major academic disciplines involved in grassland research • agronomy, animal science and agricultural economics the authors discuss the benefits and pitfalls of interdisciplinary research. Factors discouraging interdisciplinary research include: (1) discipline chauvinism, (2) the time and effort required for communications .and co-ordination, (3) inadequate credit for multiple authorship and (4) importance of disciplinary research. However, link among disciplines are necessary because clientele commercially producing forage need information integrating agronomy, animal science, economics and other disciplines. Benefits of interdisciplinary research are ( I) stimulating highly specialised scientists to plan, perform and interpret their research in the context of whole-farm …

Effect Of Inoculants And Absorbents Incorporated In Grass Silage On Silage Quality, Effluent Production And Animal Performance, Raymond Jones

IGC Proceedings (1977-2023)

Unwilled ryegrass crops (151 kg DM) were enslled in 70-t bunker silos. Crop analysis (g/kg/DM) was water-soluble carbohydrates 153, nitrogen 24.1 and predicted digestibility (DOMD) 0.67. Molassed sugar beet feed pellets were incorporated at a rate of 25 kg/t in the harvested crop with or without inoculant treatment ("Live Systems", MMB, UK), and compared with a control silage with no additive. Absorbent addition with or without inoculant significantly reduced silage pH and ammonia-N compared with the control. Inoculant treatment further increased lactic acid content. Silage effluent production was reduced by up to 33% by absorbent inclusion with effluent DM losses …

Comprehensive Climate Vulnerability Assessment Of A Regional Karst Landscape For Hazard Mitigation Planning, Kara Brunot

Masters Theses & Specialist Projects

Climate change is the global phenomena affecting all sectors of society by creating conditions more conducive for the occurrence of extreme weather events. It is projected that the intensity and frequency of events will increase. Flooding, in particular, is projected to increase in frequency due to more intense precipitation events. Karst landscapes are especially vulnerable to climate change impacts because of their unique hydrology and geology. Karst flooding is most likely to occur from prolonged or intense rain events, which climate change will likely make more feasible. Areas are disproportionately affected by climate change due to population demographics and environmental …

Landuse And Microplastic Transport In Karst Groundwater Of South-Central Kentucky, Katie Norman

Masters Theses & Specialist Projects

Groundwater in karst areas is susceptible to contamination from various sources of pollution. Microplastics are a prevalent source of pollution entering groundwater. This study examines karst groundwater in three areas of investigation. One point of interest is an area that is impacted by urban activities, the Lost River Groundwater Basin, which includes water drainage from the City of Bowling Green, Kentucky. Another study location is Great Onyx (GO) Spring, which is a part of the Great Onyx Groundwater Basin located in Mammoth Cave National Park, Kentucky, and that is relatively unimpacted by urban activities. The third point of interest is …

Cover-Crop Effects On Near-Surface Soil Properties Over Time In The Lower Mississippi River Valley, Cooper Fanning

Graduate Theses and Dissertations

Human population growth and climate change are present stressors that continue to put pressure on current agricultural production systems, where typical row-crop agricultural practices can negatively impact soil health. Extensive use of cover crops (CC) to increase soil health remains widely unrealized. Soil health in Arkansas is a major concern for sustaining agricultural output, therefore research into CC implementation across Arkansas to maintain or improve soil health is needed. The objective of this study was to evaluate the effects of CC (i.e., with and without CC) across various physical, hydraulic, biological, and chemical soil indicators in the Lower Mississippi River …

Struvite Effects On Greenhouse Gas Emissions From Flood- And Furrow-Irrigated Rice In The Greenhouse, Chandler Arel

Graduate Theses and Dissertations

Over time, as the influences of climate-change and declining, mineable, global phosphorus (P) reserves begin to impact agricultural production systems, alternative fertilizer sources and management practices, such as struvite (MgNH₄PO₄ · 6H₂O) and furrow-irrigation, will be necessary to accommodate nutrient and water demands. The precipitation and use of struvite as a fertilizer-P source could reduce environmental damages caused by nutrient-rich wastewater streams, supplement domestic P supply, and improve the sustainability of flood-, and furrow-irrigated rice production by reducing greenhouse gas emissions. The study of struvite from both chemical and electrochemical precipitation processes is well documented, …

Applying Circuit Theory To Describe Changes In Structural Landscape Connectivity In Response To Wildfire, Christian Ross Nielsen

School of Natural Resources: Dissertations, Theses, and Student Research

Understanding and conserving ecological connectivity is critical to the preservation of vulnerable landscapes. Circuit theory, in which landscapes are imagined as circuit boards with varying resistances to the flow of current, is being increasingly used to model spatially explicit connectivity of landscapes and to inform land management and conservation decision-making. Utilizing continuous, quantitative estimates of percent cover by five land cover functional groups to create a conductance surface, this study expanded upon an established application of circuit theory that used the open-source software Circuitscape to model species-agnostic, omnidirectional connectivity. This model was automated using Python to create time-series connectivity maps …

Occurrence, Inputs, And Ecological Significance Of Antibiotics And Pharmaceuticals In Western Nebraska Streams, Katelyn F. Glause

School of Natural Resources: Dissertations, Theses, and Student Research

Few emerging environmental contaminants are as concerning as antibiotics. Human and animal health benefits greatly from the prudent use of antibiotics, yet we give little thought to environmental release of these biologically active compounds. Environmental occurrence of these and other pharmaceutical compounds must be measured in different environmental compartments such as municipal wastewater and in the vicinity of large animal feeding operations to understand potential effects. This study reports the results of a monitoring study in western Nebraska, with a large population of livestock and smaller but more concentrated population of humans, comparing the relative environmental concentrations and loading from …

Analysis Of Drought-Flood Abrupt Alternation Events And Their Impacts In Kenya, Betty Makena

School of Natural Resources: Dissertations, Theses, and Student Research

Drought-Flood Abrupt Alternation (DFAA) is a compound disaster event that refers to the abrupt shift of extreme drought events to extreme floods resulting in exacerbated impacts on already vulnerable communities and hindering their coping abilities. This study aimed to analyze drought-flood abrupt alternation events and their impacts in Kenya. The first chapter aimed to understand historical drought events in the Greater Horn of Africa and their impacts, while drawing comparisons with the recent 2020-2022 drought period, referred to as the ‘triple dip La Niña’. Datasets used in this study include the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS), Normalized …

Remotely Sensed Early Warning Of Algal Blooms In An Eastern Nebraska Reservoir: A Comparison Of Temporal And Spatial Indicators, Mercy Kipenda

School of Natural Resources: Dissertations, Theses, and Student Research

Cyanobacterial harmful algal blooms (CyanoHABs) detrimentally affect human, animal, and ecosystem health. Remotely sensed early warning systems for cyanoHABs in inland lakes could contribute to more proactive water quality monitoring and help mitigate negative impacts. Advances in freely available remote sensing imagery, with finer spatial, temporal, and spectral resolutions, present new opportunities for the development and comparative analysis of methods to detect sudden deterioration in lake water quality. In this thesis, I compared and tested for temporal and spatial early warning signals of cyanoHABs in field-based and remotely sensed datasets from 2019 to 2023 in Pawnee Lake in southeast Nebraska, …

Impacts Of Invasive Carp And Their Population Dynamics On Fish Communities In The Missouri River, Joshua F. Kocik

School of Natural Resources: Dissertations, Theses, and Student Research

Invasive Carp species: Silver Carp Hypophthalmichthys molitrix, Bighead Carp Hypophthalmichthys nobilis, Grass Carp Ctenopharyngodon idella, and Black Carp Mylopharyngodon piceus have both potential and realized abilities to negatively impact native species. Specifically, Bighead Carp and Silver Carp as filter feeders have been theorized to be detrimental not only to adult filter-feeding species, but to many fish which rely on plankton and algae in their early-life stages. The impact of Invasive Carp on the overall fish community remains underexplored. The fish communities below Gavins Point Dam (Invasive Carp present) and Fort Randall Dam (Invasive Carp absent) afford the …

Spatiotemporal Plasticity In Reproductive Readiness And Recruitment Of Ichthyoplankton Of Invasive Silver Carp Along A Western Invasion Front, Jessi L. Urichich

School of Natural Resources: Dissertations, Theses, and Student Research

Individuals of invasive species at the edge of their invasion distribution may exhibit enhanced reproductive capacity and phenotypic plasticity leading to accelerated range expansion. Environmental conditions in highly fluctuating environments at distribution edges may either promote or hinder such reproductive readiness and phenotypic plasticity. Dynamic habitat conditions and periodic disturbances experienced in prairie streams, such as drought (e.g., low-flow, high water temperatures), may potentially reduce suitable spawning environments and ichthyoplankton recruitment of invasive Silver Carp, potentially slowing range expansion or enabling management strategies that reduce abundance in the absence of a reproducing population. Female Silver Carp batch fecundity, Gonadosomatic Index …

Assessing, Restoring, And Centering Social–Ecological Relationships For Advancing Social–Ecological Resilience In The Northern Great Plains Grasslands, Katia Pilar Carranza Bernal

School of Natural Resources: Dissertations, Theses, and Student Research

The Northern Great Plains grasslands are social-ecological systems that were shaped by evolutionary and Indigenous social-ecological relationships. European colonization disrupted many of these interactions, including the coupling of fire and grazing, and degraded social-ecological resilience, shifting these grasslands to a new state. For those reasons, my research focused on assessing, restoring, and centering evolutionary and Indigenous social-ecological relationships for advancing social-ecological resilience in the Northern Great Plains grasslands. I first performed a study in the Nebraska Sandhillls assessing the potential of patch-burn grazing to support grassland resilience by comparing its effects to those of rotational grazing. Through vegetation and bird …

Integration Of Matlab And Machine Learning To Accelerate Evaluation Of Biological Activity In Agricultural Soils And Promote Soil Health Improvement Goals, Andrew Stiven Ortiz Balsero

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Traditionally, assessments of soil biological activity have been confined to laboratory settings, creating a disconnect with practical in-field methods. To bridge this gap, cotton fabric degradation has been used to illustrate soil microbial activity under different management practices. While effective, these demonstrations are subjective and labor-intensive.

Researchers have explored using image processing software like ImageJ and Adobe Photoshop to streamline this process. Although these tools accurately quantified fabric degradation under varying soil conditions, the methods remained labor-intensive and complex. Consequently, these methods were still not ideal for on-farm use by agricultural practitioners.

To further address labor and complexity limitations, the …