Use Of Natural 15n Abundance In Estimating Nitrogen Fixation By Centrosema Spp: Influence Of Phosphorus And Strain Of Bradyrhizobium,
2025
University of London
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,
2025
EMBRAPA-CPAC
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,
2025
University of Adelaide
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,
2025
USDA, Soil Conservation Service
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,
2025
Queensland Department of Primary Industries
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,
2025
Queensland Department of Primary Industries
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,
2025
Queensland Department of Primary Industries
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,
2025
Menifo Sheep Research Centre
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,
2025
CSIRO
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,
2025
NSW Agriculture
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?,
2025
CSIRO
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,
2025
San Isidro, Peru
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,
2025
CSIRO
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.
Landslide Susceptibility Assessment Of The Wanzhou District: Merging Landslide Susceptibility Modelling (Lsm) With Insar-Derived Ground Deformation Map,
2025
China University of Geosciences Wuhan
Landslide Susceptibility Assessment Of The Wanzhou District: Merging Landslide Susceptibility Modelling (Lsm) With Insar-Derived Ground Deformation Map, Chao Zhou, Lulu Gan, Ying Cao, Yue Wang, Samuele Segoni, Xuguo Shi, Mahdi Motagh, Ramesh P. Singh
Mathematics, Physics, and Computer Science Faculty Articles and Research
The prevalent catalog-based Landslide Susceptibility Modelling (LSM) operates under the assumption that future landslide occurrences mirror past and current patterns. Due to growing urban expansion and climate change, certain landslides follow new patterns of occurrence, disrupting the foundational assumption of catalog-based LSM and leading to constraints in the effectiveness of traditional susceptibility maps. Here, to address this problem, we proposed a method to produce more accurate and dynamic landslide susceptibility maps by coupling advanced Ensemble Machine Learning (EML) and Multi-Temporal Interferometric SAR (MT-InSAR). The Wanzhou District in Three Gorges Reservoir area of China is considered as the test site. The …
Can Trichoderma Spp. Contribute To The Bioremediation And Biostimulation Of Plants In Soil Contaminated With Herbicides?,
2025
The University of Texas Rio Grande Valley
Can Trichoderma Spp. Contribute To The Bioremediation And Biostimulation Of Plants In Soil Contaminated With Herbicides?, Elaine Damiani Conte, Elton José Da Rosa, Gabriel Rieth Silvestrini, Daiane Da Silva Motta, Christiane Fernandes De Oliveira, Carine Cocco, Gabriel Fernandes Pauletti, Taísa Dal Magro, Joséli Schwambach
School of Earth, Environmental, & Marine Sciences Faculty Publications
This work aimed to evaluate the potential of Trichoderma spp. in the bioremediation of herbicides and biostimulation of plants in herbicide-contaminated soils. In the first phase, the experiment followed a completely randomized design in a 4 × 3 × 4 factorial scheme with five replications, four strains of Trichoderma spp., three herbicides, and four herbicide doses. The mycelial growth speed index (MGSI) of Trichoderma spp. was obtained by growing it in a Petri dish with PDA associated with different doses of herbicides and evaluated every 24 h for 10 days. Results indicated the selection ofTrichoderma harzianumT1A to continue …
Influence Of Biochar On Rooting And Establishment Of Chamaecyparis And Thuga Species,
2025
Western Kentucky University
Influence Of Biochar On Rooting And Establishment Of Chamaecyparis And Thuga Species, Megan Mudd
Masters Theses & Specialist Projects
This study investigated the effects of biochar amendment on the rooting and establishment of evergreen propagules, thus addressing the critical need for improved nutrient use efficiency and water retention in containerized substrates within the horticulture and floriculture industry. Biochar, a product of biomass pyrolysis, offers promising potential due to its high porosity and surface area, which contribute to enhanced soil fertility and water retention. Two experiments were conducted, one in a greenhouse and the other in a cold frame, using cuttings from Chamaecyparis obtusa, Chamaecyparis pisifera ‘Vintage Gold’, and Thuja occidentalis ‘Emerald Green’. Treatments included varying percentages of biochar …
Bridging Prairie Restoration And Regenerative Agriculture With Compost Tea / The Rocket Incident: Post-Fire Soil Microbe Recovery On The Eastern Washington University Restoration Site,
2025
Eastern Washington University
Bridging Prairie Restoration And Regenerative Agriculture With Compost Tea / The Rocket Incident: Post-Fire Soil Microbe Recovery On The Eastern Washington University Restoration Site, April Hersey
EWU Masters Thesis Collection
Inland Pacific Northwest prairie is an endangered ecosystem that has been reduced by conversion to agriculture. There is growing interest in the role of soil microorganisms in prairie ecosystems, which may be crucial for restoration of the plant community through interspecies interactions within the rhizosphere. One method for improving soil microorganism community composition is compost tea: enriched liquid compost extract. Compost tea is used in regenerative agriculture to improve crop yields and protect against pathogens. While research has supported compost tea application in regenerative agriculture, it has not been widely studied in the context of ecosystem restoration. After beginning a …
Examining Short Term Drainage Impacts To Soil Health In Hydric And Non-Hydric Soils Of Waseca County, Minnesota,
2025
Minnesota State University, Mankato
Examining Short Term Drainage Impacts To Soil Health In Hydric And Non-Hydric Soils Of Waseca County, Minnesota, Ely Hartl
All Graduate Theses, Dissertations, and Other Capstone Projects
Subsurface drainage is implemented throughout the Midwest United States to remove excess moisture from soil to enhance crop growth. Hydric soils are ubiquitous throughout Minnesota and are commonly drained due to their historically saturated conditions. Changing a soil's hydrology can impact its formation and properties. The alteration of physical, biological, and chemical soil properties can occur to both hydric and non-hydric soils, impacting overall soil health. The purpose of this study is to examine the short-term effects of tile drainage on the soil health of hydric and non-hydric soils in southern Minnesota. Research methods include: 1) collect soil-sediment cores to …
