Agricultural Science Commons^™

Fire And Grazing Interact To Manipulate Pasture Composition In Heteropogon Contortus (Black Speargrass) Pastures, D M. Orr, C J. Paton

IGC Proceedings (1977-2023)

Aristida spp, (wiregrasses) are invading areas of Heteropogon contortus (black speargrass) pastures in southern Queensland. Interim results from 2 field experiments indicate that increasing the frequency' of annual spring burning over 3 years, with and without grazing, results in a progressive reduction in the yield of Aristida spp. H. contortus yields also increased with increasing frequency of burning under non-grazing but not when grazed, H. contortus yields have increased after burning when grazing has been deferred or where the stocking rate has been halved after the fire. The results suggest that botanical composition in these pastures can be manipulated readily …

Impact Of Grazing Pressure On The Plant Population Dynamics Of Heterpogon Contortus (Black Speargrass) In Subtropical Queensland, D M. Orr, C J. Paton

IGC Proceedings (1977-2023)

Heteropogon contortus is a palatable pasture grass which is being threatened by , increases in grazing pressure, particularly during drought. This paper presents interim results plant population dynamics of H. contortus., as affected by stoc.1s tak. legume augmentation (mainly Stylosanthes sabra cv. Seca) and p1 Jvision of a dry-season supplement for cattle. The study began in 1%8. By 1991, basal ara of H. co11tortus was highest at the light .. Jt stocking rate of 0.187 steers/ha and declined linearly to be longest at the heaviest stocking rate of 0,5 steers/ha. Similarly, survival of the H. contortus tussocks initially present …

Seca Stylo (Stylosanthes Scabra Cv. Seca) Populations Increase Faster Under Light Grazing, D M. Orr, C J. Paton

IGC Proceedings (1977-2023)

Augmentation of native pastures with legumes such as Stylosanthes scabra can increase cattle live-weight gain relative to that from native pasture. In the longer term, however, Stylosanthes spp, density can increase and populations of native grasses may become unstable. This paper reports interim results from a study aimed al monitoring changes in the density of S. scabra cv. Seca in relation to stocking rates, The density of Seca monitored in permanent quadrats increased from 15 plants/m2 in 1988 to 100 and 25 plants/m2 in 1992 at 0.25 and 0.5 beasts/ha respectively. These increases resulted from both the survival of the …

Clover-Based Pasture Systems For Intensive Sheep Production In The Central Highlands Of Papua New Guinea, S Sivasupiramaniam, A K. Benjamin, J Pitala

IGC Proceedings (1977-2023)

This paper describes some of the studies that have been conducted since 1985 to develop clover-based pasture systems for intensive sheep production in the central highlands of Papua New Guinea. The clovers tested were Trifolium repens cv. Haifn (Haifa white clover) and Trifolium semipilosum cv. Safari (Kenya white clover). They were sown together, with setaria (Setaria sphacelata cv. Nandi) and signal grass (Brachiaria decumbens cv. Basilisk) at Menifo (1400 m asl) and with setacia and kikuyu (Pennisetum clandestinum cv. Whittet) at Tambul (2240 m) and Yogos (1950 m) in the central highlands. At Menifo, when rotationally grazed …

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.

The Role Of Social-Psychological Factors In The Adoption Of Push-Pull Technology By Small-Scale Farmers In East Africa: Application Of The Theory Of Planned Behavior, Denis Waiswa, Beatrice Wambui Muriithi, Alice W. Murage, Dave Mwangi Ireri, Fredah Maina, Frank Chidawanyika, Fahri Yavuz

All Peer-Reviewed Publications

Push-pull technology (PPT) continues to gain relevance among smallholder farmers across the East African region in managing the constraints affecting cereal crop yields including stemborers, fall armyworm, striga weed, and low soil fertility. While previous research has emphasized the significance of socioeconomic factors in explaining farmers' decisions to adopt PPT, the social-psychological factors that influence farmers' adoption intentions have not been extensively studied. Therefore, this study investigated the influence of social-psychological factors on the intention to adopt or increase the land area under PPT based on the theory of planned behavior (TPB). Moreover, this study extends the applicability of the …

Performance Of Eight Lettuce Cultivars In A Water Culture System, Ricky C. Young, Hudson M. Cox, Jacob D. Frodge, Mollie K. Mayabb, Brycen C. Shephard, Alireza Rahemi

Posters-at-the-Capitol

Lettuce (Lactuca sativa L.) is one of the most well-known vegetables in the world. About 27 million tons of lettuce were produced in the world in 2022 and global demand for lettuce is increasing steadily, driven by the importance of fiber consumption. Lettuce can be grown in multiple media, including hydroponic systems in a controlled environment agriculture (CEA) system. Growing lettuce in hydroponic systems is an alternative to lettuce production optimization. Since little information is available about lettuce cultivar trials in hydroponic systems, a research project was developed and executed to study the ability of different types of lettuce …

Microbial And Plant Biodiversity In Appalachian Agroecosystems And Their Implications For Soil Health, Kinsey Reed Close

Graduate Theses, Dissertations, and Problem Reports (ETD)

The sustainability of agricultural landscapes depends on understanding the complex interactions between plants, soil, and microbes. In Appalachia, a region shaped by complex terrain and long histories of human and ecological interaction, small family farms produce hay, livestock, and row crops. These agroecosystems, though often treated as “artificial” by many ecologists, have the potential to support both food production and biodiversity conservation if managed with an understanding of ecological complexity. This dissertation examines how plant and microbial diversity interact with soil and management to influence nutrient cycling, soil health, and long-term resilience in Appalachian agricultural systems. A literature review revealed …

Wa Insecticide Guide 2025 - Autumn Winter, Rebecca Severtson

PestFacts WA

Registered chemicals for broadacre crops in Western Australia.

The insecticides listed in the tables within this guide can be used on any crop appearing on the chemical label, if the rate used does not exceed the highest rate that is registered for use on that crop.

There are many products with different trade names that contain the same active ingredient. This list is not exhaustive and does not imply any specific recommendations of brand names.

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.

Adaptation For Whom? Understanding The Impacts Of Dyke Policies On Small-Scale Farmers In Ca Mau Province Of Vietnam, Nguyen Minh Quang, Nguyen Van Minh, Nguyen Vo Chau Ngan, Martha B. Lerski

Publications and Research

Low-lying deltas worldwide are extremely vulnerable to sea-level rise. As the risks of climate-induced flooding become increasingly clear, the thirst for infrastructure-driven adaptation increases. This highlights a patent need to understand the impacts of engineering adaptation solutions, especially those targeting built structures such as dykes and sluices, on farmers from a bottom-up, farmer-centred perspective. The study addresses this call by examining cases where dyke policies, while successful in some dimensions, have undermined small-scale farmer livelihoods in Ca Mau ― Vietnam’s southernmost rural province. It identifies areas in need of attention and adds empirical data related to this group of farmers. …

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.

The Direct And Indirect Effects Of Mobile Phone Ownership On Maize Yields In Tanzania, Cool Dady Mangole, Kelvin Mulungu, Christian Kamala Kaghoma, Menale Kassie

All Peer-Reviewed Publications

The study uses the Living Standards Measurement Study-Integrated Surveys on Agriculture to evaluate mobile phone ownership's direct and indirect effect on yields in Tanzania. The results indicate that transitioning from not owning to owning a mobile phone improves maize yields by about 16%. Mobile phones indirectly affect maize yield by facilitating farmers' access to extension services - regardless of the type of provider - but only account for about 2% of the total effects. Considering both direct and indirect effects, this study suggests that extension services partially moderate this causal relationship. Further, the impact of mobile phones is stronger among …

Modeling The Impact Of Climate Change On Plant Hardiness Zones Across The Contiguous United States Using Empirical Bayesian Kriging Regression Prediction, Daniel Donkor

Graduate Theses/Dissertations

Mapping plant hardiness zones is crucial to understanding and predicting the spatial distribution of plants in response to climatic conditions. The United States Department of Agriculture (USDA) developed the plant hardiness zones based on the average of annual extreme minimum temperatures using the Parameter elevation Regression on Independent Slope Model (PRISM). While the USDA’s 2012 and 2023 Plant Hardiness Zone maps remain standard references, they offer limited geostatistical transparency that causes more complications in replicating. This study applies Empirical Bayesian Kriging Regression Prediction (EBKRP) method to generate Plant Hardiness Zone maps, analyze spatial and temporal shifts in the plant hardiness …

Generational Exposures To Cerium Oxide Nanoparticles And Perfluorooctanesulfonic Acid Affect The Performance Of Daughter Plants, Preston Clubb

Graduate Theses/Dissertations

The effects of parental stress on the performance of next generation exposed to another contaminant were investigated. Wheat was exposed to cerium oxide nanoparticles (CeO2-NPs) in first and second generations and exposed to perfluorooctanesulfonic acid (PFOS) in the third generation. Phenotypic or metabolic responses were assessed at 21-day (short-term exposure) or 90-day (long-term exposure) exposure periods. Biomass production, chlorophyll content, enzyme activity, and membrane damage were measured at short-term exposure, while elemental and PFOS concentrations, and grain metabolites were analyzed in long-term exposure. Results showed that continued exposures to CeO2-NPs and PFOS enhanced chlorophyll content but reduced concentrations of important …

Quantification Of Auxin-Cytokinin Response During Primary Root And Lateral Root Development In Common Bean, Gurdeep Singh

Electronic Theses and Dissertations

Roots support water and nutrient uptake, anchorage, and soil interactions through continuous growth at the primary root tip (PRT). In common bean (Phaseolus vulgaris), new cells are produced in an open root apical meristem and subsequently elongate in the elongation zone, and together these processes drive root tip progression through the soil. Lateral roots (LRs) arise in the differentiation zone, where pairs of pericycle founder cells dedifferentiate, divide asymmetrically, and form lateral root primordia (LRP) that pass through defined developmental stages before emergence. Auxin and cytokinin (CK) are central regulators of both primary root growth and LR development, yet their …

Role Of Chemotype In Aggressiveness, Toxicity, And Competitive-Ness Of Fusarium Graminearum On Wheat, Simran Goyal

Theses and Dissertations--Plant Pathology

Fusarium Head Blight (FHB) of wheat, caused by the fungus Fusarium graminearum, is a devastating disease that led to epidemics in the U.S. during the 1990s, resulting in economic losses exceeding $2.6 billion. Typical symptoms include bleached spikelets and shriveled grains, often contaminated with trichothecene mycotoxins that make them unsafe for food or feed. FHB severity and mycotoxin production are influenced by a complex interplay between host genotype, environmental factors, and pathogen genotype. Integrated management practices that include the use of more resistant cultivars, crop rotation, and fungicide applications help to reduce disease incidence and severity. Disease forecasting models …

Selective Lure For Bactrocera Dorsalis Based On Shared Palpal And Antennal Responses Across Three Economically Important Tephritid Species, Tibebe Dejene Biasazin, Raphael Njurai Miano, Xavier Cheseto, Shepard Ndlela, Samira A. Mohamed, Teun Dekker

All Peer-Reviewed Publications

The oriental fruit fly Bactrocera dorsalis is a highly destructive and invasive pest that threatens global horticulture, causing economic losses due to fruit damage and quarantine regulations. While attract-and-kill baits are widely used to suppress fly populations, these baits also impact many non-target species. To achieve ecological sustainability, our study aimed to develop a method that selectively targets female fruit flies. Using gas chromatography coupled to electro-antennal or palpal detection (GC-EAD/GC-EPD), we identified compounds that elicited responses in the maxillary palp and antenna of three different fruit flies including B. dorsalis, Ceratitis capitata, and Zeugodacus cucurbitae. As previous studies indicated …

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 …

In-Season Nitrogen Mmanagement: Leveraging Data Visualization For Precision Agriculture, Chathurika Harshani Narayana

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

Effective nitrogen management is vital for sustainable agriculture, impacting both crop yield and environmental health. Traditional methods often use fixed application rates set before planting, which do not adapt to changing crop needs during the season. This can lead to over- or under-application, reducing efficiency and sustainability. While modern tools like sensors, satellites, and UAVs provide valuable real-time data on crop and field conditions, integrating and using this data to guide timely nitrogen decisions remains a major challenge. In-season nitrogen management offers a solution by allowing for dynamic adjustments to nitrogen applications, addressing crop needs as they arise. This approach …

Comparison Of Compositional Characteristics Of Protein Extracted From Spent Hemp Seed Cakes By One-Step Defatting With Organic Solvents Followed By Isoelectric Solubilization Precipitation Using Strong And Weak Acids, Miah Nicole Gathman

Graduate Theses, Dissertations, and Problem Reports (ETD)

Hemp seed cakes (HSC) are the byproduct of pressing hemp seeds for oil and are a significant agricultural waste product, with hundreds of tons produced annually. These nutrient-rich cakes have potential for sustainable applications in animal feed and food products. However, they could offer even greater value to the food industry through further extraction of the lipids and separation of the proteins they contain. Protein is a key nutritional component and companies are seeking cost-effective, time-efficient processes to concentrate protein from underutilized resources like HSC. Hexane (HEX) is a common solvent used in one-step defatting processes but may cause issue …

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 …

Longitudinal And Ensemble Modeling Of Beef Cattle Feed And Water Intakes, Nathan El Blake

Graduate Theses, Dissertations, and Problem Reports (ETD)

Beef cattle production remains a cornerstone of global food systems, providing highly bioavailable protein and essential micronutrients that are difficult to secure from plant-based foods alone. Yet this production is also resource-intensive, requiring substantial land, feed, and water inputs while contributing significantly to greenhouse gas emissions. Efficiency of dry matter intake (DMI) and water intake (WI) is central to both productivity and sustainability, but accurate measurement of these traits—particularly in grazing systems—remains a major limitation. National WI standards continue to rely on pen-level data collected in the 1950s, while most existing DMI prediction equations perform poorly when applied beyond the …

Characterizing Agroecosystem Effects Of Industrial Hemp On A Rotational Row Cropping System And Microbial Communities, Kent D. Pham

Theses and Dissertations--Plant and Soil Sciences

The implementation of crop rotation on a farm can have many benefits for agroecosystem health and production. This practice can potentially reduce nutrient amendments, disrupt pest and disease cycles, and increase crop yields. In Kentucky, one common rotation consists of either corn or soybean grown the first year, followed by the other crop, repeated every two years. Industrial hemp, grown for fiber or grain, is an emerging crop that has shown promise as a rotation alternative, although not much is known about its effects on soil health, agroecosystem functioning, and microbial communities. To better characterize hemp’s role within American agriculture, …