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A System For Objective Condition Assessment Of Astrebla Spp. Pastures At The Paddock Level For Better Grazing Management, D G. Phelps, J J. Bushell, O.J H. Bosch, D J. Kent, I F. Beale

IGC Proceedings (1977-2023)

Degradation gradients due to grazing were determined from floristic data collected between January 1990. and November 1991 in the Astrebla correlation between grasslands of Longreach, abundance and Australia. condition A score linear correlation between Astrebla abundance and condition score confirmed strong confirmed linear the presence of gradients. Astrebla Degradation models were further validated by the presence of known grazing gradients. A model constructed from data collected in late to mid summer was then used to illustrate changes in the condition of 4 monitoring sites. A site ;initially in "poorer" condition, and an overgrazed site did not markedly improve in condition. …

Case Studies And Causes Of Weed Invasion Of Sown Pastures On The Wet Tropical Coast Of Eastern Australia, H G. Bishop, T B. Hilder, G A. Lambert, E R. Anderson

IGC Proceedings (1977-2023)

Viability of large and successful sown pasture development on the wet tropical coast of eastern Australia is threatened from invasion of these pastures by unpalatable grass and legume weeds. The main threats discussed are invasion by the unpalatable grass weeds Sporobolus diandrus (tussocky sporobolus) and Sporobolus pyramldalis (giant rat's tall grass) and the unpalatable, annual legume weed Senna obtusifolia (sicklepod). Specific cases of invasion and suggested causes for the problems are discussed. The major causes· suggested for pasture decline and invasion by less productive weedy species are: disease that can suddenly wipe out an otherwise …

Standing Root Biomass And Root Distribution In Brachiaria Decumbens- Arachis Pintoi Pastures Under Grazing, M A. Ayarza, I M. Rao, R J. Thomas, M J. Fisher, C E. Lascano, P Herrera

IGC Proceedings (1977-2023)

A vigorous rooting system is a vital strategy developed by acid•soil• tolerant forage species to cope with soil acidity constraints. The biomass of standing roots and its distribution was characterised under grazing in pastures of Brachiaria decumbens and Arachis pintoi grown alone and in association. Soil cores showed that standing root biomass to the depth of 100 cm was higher than the above ground biomass in the single species pastures. However, the relation was reversed in the grass•legume association. Root mapping showed that while the largest percentage of roots was located in the 0·20 cm depth of soil of the …

Dynamics Of The Vegetation Of A Natural Pasture Under Different Levels Of Forage-On-Offer And Soil Types, Ilsi I. Boldrini, Gerzy E. Maraschin, Joao Riboldi

IGC Proceedings (1977-2023)

To document changes in species composition during 5 years of grazing al different levels of forage,-on-offcr, 60 permanent quadrals of 0.25 m1 were established in 30 ha of annual posture at the Estacno Experimental Agronomica, UPROS, Brazil. Rhizomatous and stoloniferous species dominated In low forage-on-offer treatments while caespitose species dominated in higher forage-on-offer levels. Soil organic matter and water contents increased with increasing levels of forage-on-offer.

First-Year Stand Development Of Subtropical Grass Seedlings And Influence By Initial Plant Density, Bruce Anderson, L E. Moser

IGC Proceedings (1977-2023)

Stands of subtropical grasses develop slowly in mid-continent North America and this may be due partly to initial plant density. Panicum virgatum L. and Andropogon gerardii Vitman seedlings were transplanted from a greenhouse into field plots as pure stands in equidistant spacings at initial plant densities of 2.5, S, 10, 20, 40 and 80 plants/m1. P. virgatum produced higher yields, fewer tillers/plant and leaves/tiller, less basal density and shorter plants than A. gerardii during the first year of growth. Light interception was higher and soil temperatures lower for A. gerardii. Basal density and height increased while tillers/plant decreased …

Use Of Natural 15n Abundance In Estimating Nitrogen Fixation By Centrosema Spp: Influence Of Phosphorus And Strain Of Bradyrhizobium, G Cadisch, S F. Ledgard, J Noseberger, R Sylvester-Bradley

IGC Proceedings (1977-2023)

Isotopic ¹⁵N fractionation during N2 fixation by Centrosema acutifolium, C. brasilianum and C. macrocarpum grown in N·free sand-nutrient solution was investigated as a prerequisite for the use 9f the natural ¹⁵N abundance method to estimate N2 fixation. The natural abundance of ¹⁵N was always lower in shoots than in roots and nodules, and there was little difference between species. In contrast, inoculation strongly influenced isotopic fractionation, leading to average o15N shoot values of -0.64 and -1.37 for Bradyrhizobiumstrains CIAT3101 and 1670 respectively, given adequate phosphorus. P deficiency led to a small legume x P interaction …

Importance Of Legume Nitrogen Fixation In Sustainability Of Pasture In The Cerrados Of Brazil, G Cadisch, E F. Carvalho, A R. Suhet, L Vilela, W Soares, J M. Spain, S Urquiaga, K E. Giller, R M. Boddey

IGC Proceedings (1977-2023)

A pure Andropogon gayanus sward was compared with a Stylosanthes spp.-A. gayanus mixed sward in order to assess the benefit of introducing N2-fixing legumes on the long-term sustainability of grazed pastures. There was no difference between the total dry matter and animal production of the 2 pastures, although the legumes fixed 67-117 kg/ha of N in 1991 with 80% of the legume N obtained from N2 fixation. Litter deposition was 20-35% greater in the mixed sward and the % N in this litter was also higher, leading to twice the amount of N mineralised in the 0-5 cm …

Attainment And Distribution Of Competitive Equilibrium In Tropical Grass-Legume Mixtures, P G. Tow

IGC Proceedings (1977-2023)

An experiment under controlled conditions, using the de Wit competition model, has provided an explanation of competitive relationships in mixtures of Panicum maximum var. trichoglume (green panic) cv. Petrie and Neontonia wightii cv. Tinaroo glycine. Experiments in a tropical upland environment with summer rainfall dominance (to which they ore adapted) have provided further understanding of their relationships. Over a period of 2 years for well-wafered plants in containers and 4 years in a rain-fed field experiment, competitive gains by one species alternated with-gains by the other, and neither species gained significantly overall. Gains by the grass were favoured by …

Managing Woody Weeds In Grazing Ecosystems: Application For Tropical Woodlands Of North-Eastern Australia, Joel R. Brown, John G. Mcivor, Andrew J. Ash

IGC Proceedings (1977-2023)

Shrub invasion of tropical woodlands is reducing the viability of native ecosystems as well as the livestock industry, After shrub invasion, forage supply is reduced and over-grazing and soil erosion are exacerbated. We propose a non-equilibrium model of the system and use that model to develop hypotheses and design experiments to test both competition- and disturbance-based management regimes. This model proposes that disturbance in the form of burning is the primary limiting factor in excluding and limiting shrub seedling establishment and suggests that management decisions focus on maintaining adequate herbaceous biomass for a burning regime that limits woody plant success.

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.

Timber Harvesting Was The Most Important Factor Driving Changes In Vegetation Composition, As Compared To Climate And Fire Regime Shifts, In The Mixedwood Temperate Forests Of Temiscamingue Since Ad 1830, Daniela Robles, Yan Boulanger, Jesus Pascual, Victor Danneyrolles, Yves Bergeron, Igor Drobyshev

Aspen Bibliography

Context The vegetation composition of northeastern North American forests has significantly changed since pre-settlement times, with a marked reduction in conifer-dominated stands, taxonomic and functional diversity. These changes have been attributed to fire regime shifts, logging, and climate change.

Methods In this study, we disentangled the individual effects of these drivers on the forest composition in southwestern Quebec from 1830 to 2000 by conducting retrospective modelling using the LANDIS-II forest landscape model. The model was run based on pre-settlement forest composition and fire history reconstructions, historical timber harvest records, and climate reanalysis data. We compared counterfactual scenarios excluding individual factors …

Tropical Fruit-Derived Lactiplantibacillus As Potential Probiotic And Antifungal Agents Against Fusarium Oxysporum, R. Vasundaradevi, M. Sarvajith, S. Divyashree, N. Deepa, M. Y. Sreenivasa, Premila Achar

Faculty Articles

Fifty-five lactic acid bacteria (LAB) were isolated from seven selected tropical fruits, with Solanum nigrum exhibiting the highest LAB prevalence and Couroupita guianenis and Musa fruits showing the lowest counts. Two strains isolated from Ficus racemosa demonstrated significant antifungal activity against Fusarium oxysporum. 16S rDNA sequencing identified these strains as Lactiplantibacillus plantarum MYSVCF3 and Lpb. argentoratensis MYSVCF5. The isolates displayed adaptability to a broad range of environmental conditions, including temperatures of 10–45 °C, pH 2–6, and salt up to 7%. The strains tolerated simulated gastrointestinal conditions of acid (pH-2), phenol (0.6%), and bile (0.3%) suggesting potential probiotic attributes. Lpb. …

Soil Residual Activity Of Tetflupyrolimet And The Influence Of Soil Moisture And Flood Timeliness On Barnyardgrass Efficacy, Mason C. Castner, Jason K. Norsworthy, Trenton L. Roberts, Travis R. Faske, Thomas R. Butts, Nick R. Bateman

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Tetflupyrolimet is the first herbicide with a novel site of action to be commercialized for use in agronomic crops in three decades. Direct-seed rice field experiments were conducted at research facilities near Stuttgart (silt loam), AR, and Keiser (clay), AR, to evaluate tetflupyrolimet as a preemergence herbicide versus commercial standards. Greenhouse experiments determined the influence of soil moisture on pre- and postemergence barnyardgrass control with tetflupyrolimet and clomazone and the impact of a delayed flood on efficacy when POST-applied. For the field experiments, clomazone, tetflupyrolimet, and quinclorac were applied individually PRE at 336 and 560, 134 and 224, and 336 …

Root Decomposition And Nutrient Dynamics In Multifunctional Forage-Biomass Buffer-Strip Systems, Helen C.S. Amorium, Amanda J. Ashworth, Taylor C. Adams, Mary C. Savin, Philip A. Moore Jr

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Perennial crops are thought as a solution for enhancing food security and providing ecosystem services under a changing climate, including forage-biomass production, reduced erosion and nutrient leaching, and soil C accumulation. However, the drivers of root decomposition and C allocation in perennial multifunctional forage-biomass buffer-strips as affected by fertility management are poorly elucidated. Thus, study objectives were to assess root decomposition and soil CO2 efflux on switchgrass (Panicum virgatum L.), eastern gamagrass (Tripsacum dactyloides L.), silphium (Silphium integrifolium Michx.), and intermediate wheatgrass Kernza (Thinopyrum intermedium [Host] Barkworth & D.R. Dewey) treated with poultry litter (PL) relative to the unfertilized control. …

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 …

Role Of Arbuscular Mycorrhizal Fungi In Maintaining Sustainable Agroecosystems, Anju Chaudhary, Shital Poudyal, Amita Kaundal

Plants, Soils, and Climate Faculty Publications

Arbuscular mycorrhizal (AM) fungi play a crucial role in maintaining sustainable agroecosystems by forming mutualistic relationships with plant roots, improving soil health, facilitating nutrient uptake, and enhancing resilience to abiotic stresses. The mutualistic relationship between AM fungi and plants promotes a balanced microbial community and improves soil structure by forming stable soil aggregates. Additionally, AM fungi can lower the adverse effects of high soil phosphorus (P) while also enhancing plant tolerance to drought, salinity, and heavy metal toxicity through osmotic regulation and antioxidant production. Arbuscular mycorrhizal fungi also support beneficial microorganisms, such as potassium (K)-solubilizing microbes and nitrogen (N)-transforming bacteria, …

Molecular Identification And Functional Characterization Of A Stilbene Synthase Gene In Rheum Officinale, Gaoxin Hao, Mengmeng Liu, Qiao Du, Xia Zhao, Feng Yan, Xiaochen Hu, Jing Gao, Liang Peng, Yimin Li, Gang Zhang

Turkish Journal of Botany

Stilbene synthase (STS), is a pivotal gene involved in the biosynthesis and regulation of stilbenes compounds, playing a crucial role in plant growth, development and stress adaptation. Meantime, stilbene compounds hold promising prospects of the wide-ranging clinical applications. Rheum officinale contains abundant stilbene compounds, yet the precise regulatory genes governing their biosynthesis remain elusive. In this study, the ORF of RoSTS gene was amplified, yielding a length of 1,140 bp and encoding a protein consisting of 379 amino acids with a relative molecular mass of 41 640.25 Da. The RoSTS protein contained the conserved residues (Cys 164, His 303, and …

Effects Of Pericarp Removal And Different Germination Conditions On Seed Germination And Saline-Alkali Tolerance Of Amorpha Fruticosa, Zhan-Wu Gao, Yong-Guang Mu, Feng Chen, Li-Jie He, Xin-Ning Li, Jia-Tong Li, Ke-Jia Ding, Yan-Hui Cu, Chun-Sheng Mu, Adnan Rasheed

Turkish Journal of Botany

In this paper, neutral salt NaCl and basic salt Na2CO3 were used to simulate salt stress and alkali stress respectively, and the effects of salt stress and alkali stress on seed germination and growth changes in natural saline-alkali soil were studied, in order to provide theoretical basis for making full use of plant resources and improving production efficiency. The fruit peel of Amorpha fruticosa contains a lot of lipids, which has a significant effect on seed germination. Under salt stress, removal of pericarp significantly increased germination rate, germination potential and germination index (P< 0.05), and significantly shortened germination time of seeds (p< 0.05), which accelerated the establishment of seedlings, reduced the stress time during germination, and advanced the transition from heterotrophic to autotrophic, accumulating more anions and organic solutes to adapt to salt stress. Therefore, when planting in neutral salt soil, it can be used to remove the peel for sowing to improve the planting effect. However, under alkali stress, the growth is inhibited by the absorption of a large amount of Na+ and high pH value, so it is not suitable for removing the peel for sowing. Different germination conditions had significant effects on seed germination. The length and biomass of radicle and germ in sand culture were significantly higher than those in paper culture (P< 0.05). Under the condition of sand culture, the concentration of the treatment solution can be well maintained, which is conducive to fixing the seedlings and reducing the interference of other mineral elements. Therefore, sand culture method is recommended for seed germination experiments under stress, especially for plants with developed roots.

Acetylcholine Treatments Enhance Growth, Photosynthesis Efficiency And Stress Resilience In Maize Seedlings Exposed To Arsenic, Büşra Arikan-Abdulveli

Turkish Journal of Botany

Arsenic (As) is a widespread and highly toxic metalloid that adversely affects plant health, leading to reduced yields, impaired photosynthesis, and compromised root structures. Although acetylcholine (ACh), a neurotransmitter implicated in plant growth and stress responses, has shown potential in mitigating heavy metal stress, its effects on As stress in maize (Zea mays L.) remain largely unexplored. This study investigated the impact of ACh treatments on maize seedlings exposed to As stress (100 µM), focusing on physiological responses, growth rates, photosynthesis, and the antioxidant system. Our findings revealed that ACh treatments conferred differential protective effects against As stress. The lowest …

Impact Of Anoxygenic Phototrophic Bacteria On The Growth Of Arabidopsis Thaliana Under Salt Stress, Behi̇ye Nur Aksoy, Hamza Ettadili, Caner Vural

Turkish Journal of Botany

The effect of a microbial mixture containing anoxygenic phototrophic bacteria (APB) on the growth of Arabidopsis thaliana ecotype Col-0 under salt stress was investigated. To induce salt stress, 150 mM NaCl was applied to A. thaliana. Four treatments were employed to assess the impact of APB: (1) control plants, (2) plants inoculated with a mixture of enriched photosynthetic bacteria, (3) plants inoculated with a mixture of enriched photosynthetic bacteria and irrigated with 150 mM NaCl solution, and (4) plants irrigated with 150 mM NaCl solution. The analysis demonstrated that the inoculated plants exhibited increased leaf formation and leafsize. Furthermore, an …