Relationships Between Growth And Carbon Isotope Discrimination For Some Pasture Species,
2024
Australian National University
Relationships Between Growth And Carbon Isotope Discrimination For Some Pasture Species, J Virgona
IGC Proceedings (1977-2023)
Carbon isotope discrimination (A) by plants can be directly related to plant water-use efficiency (W, total plant dry matter, OM, per water transpired) and used in selection to achieve greater W. As \V (and A) is a complex characteristic, there maybe inherent relationships between it and plant productivity. A range of pasture cultivars (of temperate grasses and legumes) were grown in pots (lo c. 50 days) and \V, A and total dry mailer measured. Among cultivars the relationship between W and A was negative and significant as was the relationship between A and total OM accumulation. A further experiment showed …
Acquisition And Allocation Of Phosphorus In A Population Of White Clover Plants In A Rotationally Grazed Pasture,
2024
AgResearch, NZ
Acquisition And Allocation Of Phosphorus In A Population Of White Clover Plants In A Rotationally Grazed Pasture, M.J M. Hay, D F. Chapman
IGC Proceedings (1977-2023)
This paper quantifies the processes of acquisition, allocation and retranslocation of phosphorus (P) within a white clover (Trifolium repens L.) population in a mixed grass-clover pasture during a regrowth period in early winter (13 May-8 July 1991). The work described is part of a broader study examining seasonal variation in these processes. The data allows an analysis of the changing P economy of plants and of whole populations. White clover plants were grouped by !heir hierarchy of branching. Within plants, stolons were grouped by order of branching, dissected into leaf, stolon and root, oven-dried, weighed and analysed for P …
Defoliation Of Young Branch And Parent Stolons Of White Clover In Rotationally Grazed Pastures,
2024
AgResearch, NZ
Defoliation Of Young Branch And Parent Stolons Of White Clover In Rotationally Grazed Pastures, M.J M. Hay, M Kim, R W. Mclean, A Gonzalez-Rodriguez
IGC Proceedings (1977-2023)
This study was undertaken to examine the relative severity of defoliation of young branches (those comprising <4 nodes) and parent stolons of white clover (Trifolium repens L.) in rotationally grazed pastures stocked al either 2.5, 5.0 or 7.5 bulls/ha. On 7 occasions over a year, the defoliation of expanded leaves of parenl and branch stolons was assessed using tagged stolons. Petiole length of leaves ,vas measured before grazing. Leaves of young branch stolons (43% of the total number of leaves defoliated) were less severely defoliated than leaves of parent stolons (64%). Defoliation of branch stolon leaves was relatively greater at the higher stocking rates which had lower residual …
Effects Of Temperature, Nitrgoen Fertilizer, And Cutting Height On Regrowth And Dry Matter Production,
2024
Korea Air and Correspondence University
Effects Of Temperature, Nitrgoen Fertilizer, And Cutting Height On Regrowth And Dry Matter Production, Hyo Won Lee, Mu Hwan Jo, Chang Ho Kim
IGC Proceedings (1977-2023)
Orchardgrass (Dactylis glomerata L.) is used extentively in South Korea for green-chop and pasture mixtures. Maintaining orchardgrass stands over summer is a major problem in South Korea. Orchardgrass was grown in soil in growth chambers to evaluate the effect of temperature (day/night:20/JO, 27/17 and 3S/25°C), nitrogen (N) application (0, 5 and 10 kg/ha) and cutting height (5 and IO cm) on plant height, aboveand below-ground dry matter yield, and leaf area accumulation. High temperatures (35/25°C) greatly reduced plant height, DM yields and leaf area expansion, Cutting to 10 cm gave greater DM yields and leaf areas, compared to cutting to …
Lucerne Dry Matter Accumulation Rate In Yield Differences,
2024
Washington State University
Lucerne Dry Matter Accumulation Rate In Yield Differences, D W. Evans, R N. Peaden, W P. Ford
IGC Proceedings (1977-2023)
Lucerne (Medicago sativa L.) improvement historically has been directed at pest resistance, adaptation to climatic conditions and yield. Successful methods of detecting and increasing natural resistance to a range of insect and disease pests have been developed. Knowledge of what plant factors can be successfully manipulated to increase yield per se is less advanced. This research compared several lucernes differing in type and in date of release to determine if different rates of closed-canopy, forage dry matter accumulation have been a factor in yield increases, particularly between older and more recent material. Ten entries ranging in release date from …
Improving Germination And Seedling Establishment Of Chicory,
2024
Chonbuk National University
Improving Germination And Seedling Establishment Of Chicory, S N. Hur, W F. Hunt
IGC Proceedings (1977-2023)
Chicory (Cichorium intybus L.) seeds were treated before sowing with polyethylene glycol (PEG 6000) under different PEG concentrations, treatment period and temperatures, and tested for uniformity of germination, establishment and drought tolerance. Suitable seed coating materials were found that improved emergence, establishment and seedling growth when surface sown on established swards. The best primed or coated seeds in germination tests were surface sown in growth cabinet and field.Osmotic priming with PEG accelerated germination of chicory and significantly reduced time taken for germination compared with coated seeds in Petri-dishes, but not in the field. In contrast, coated seeds germinated more slowly …
Growth Of Temperate Perennial Legumes Over Three Cycles Of Defoliation At Different Temperatures,
2024
University of New England
Growth Of Temperate Perennial Legumes Over Three Cycles Of Defoliation At Different Temperatures, M A.P Duarsa, M J. Hill, J V. Lovett
IGC Proceedings (1977-2023)
Summer-active legumes such as big trefoil (Lollis ped11nc11lat11s), birdsfool trefoil (Lot11s comic11la111s), crownvelch (Coronilla varia) and cicer milkvetch (Astraga/11s cicer) are needed for summer rainfall areas of the perennial pasture zone in eastern Australia where soil conditions and grazing management do not suit lucerne (Medicago sativa). The growth of these species was compared at 4 temperatures regimens (14/10, 18/14, 22/18, 26/22°C, 12:12 h) for 3 cycles of regrowth where soil moisture was serially changed from field capacity (FC) to 50% PC and back to PC in a growth cabinet pot experiment. Growth rates in lucerne always exceeded those of the …
Nutrient Cycling In Semi-Arid Grasslands And Savannas: Its Influence On Pattern, Productivity And Stability, Robert J. Scholes
IGC Proceedings (1977-2023)
The grazing animal carrying capacity of tropical semi-arid rangelands is largely controlled by rainfall, but above about 500 mm per annum, soil nutrient status has an overriding role. On low-nutrient soils, which cover vast areas of the ancient land surfaces of Africa, South America and Australia, it is the amount of grass eaten and digested that controls animal production, not the amount produced. On nutrientpoor soils (particularly those deficient in nitrogen and phosphorus) the primary production continues to increase with increasing rainfall, but the acceptability of the forage to ruminants declines, On the nutrient-rich soils of younger land surfaces, both …
Soil Characteristics And Processes Critical To The Sustainable Use Of Grasslands In Arid, Semi-Arid, And Seasonally Dry Environments, John Williams, Keith R. Helyar, Richard S.B Greene, Rosemary A. Hook
IGC Proceedings (1977-2023)
The focus of this paper is a framework for determining the soil and land properties and processes which are critical to managing grasslands in an ecologically sustainable manner. Essential to the discussion is the development of concepts which allow description of the stability, resilience and sustainability of the agroecosystem as a whole as well as the land resource base. The regions of Australia with arid, semi-arid and seasonally dry environments are defined and related to the dry environments of the world. This provides a background for a brief consideration of major vegetation types and soils within the dry environments of …
Soil Animal Composition And Distribution In The Leymus Chinensis Grassland Region In Central Part Of North-East Of China,
2024
Northeast Normal University
Soil Animal Composition And Distribution In The Leymus Chinensis Grassland Region In Central Part Of North-East Of China, Yin Xiuqin, Li Jiandong, Zhu Tingcheng
IGC Proceedings (1977-2023)
Since 1990, we have investigated the soil animal composition and distribution in the Leymus chinensis (Aneuro chinensis) grassland region in central part of north-east of Chinn. Soil animals were studied in 20 plant communities in 4 habitats. A total of 15 797 soil animals belonging to 4 phyla, 6 classes, 28 orders and 86 families were obtained. Among them, 26 families and 22 species were new records in norlh-easl of China. The dominant groups were Formicidne, Actinedida, Oribatidn, lsotomidne, Rhnbditidae, Dorylainidae. Sparse woods of Ulmus, and the most animal groups (40) and Puccinellia chinapoesis and Heleochalis intersiIa …
Breeding Phalaris For Tolerance To A Range Of Acid Soils,
2024
CSIRO
Breeding Phalaris For Tolerance To A Range Of Acid Soils, R N. Oram, A M. Ridley, J Hunter, H E. Schroeder, J Taylor
IGC Proceedings (1977-2023)
Phalaris (Phalaris aquatica L.) is a persistent, drought-hardy grass adapted lo mediterranean climates, but it is sensitive to free aluminum in acid soils. P. arundinacea L is more tolerant of soil acidity, and therefore it has been crossed to P. aquatica, followed by 1 or 2 backcrosses to P. aquatica. Open-pollinated progenies generated by I or 2 generations of random mating without selection were tested at 3 acid soil sites in Victoria and ACT. The mean herbage yields in winter were lower than the phalaris controls, but heritability and expected selection responses were high. There are good prospects …
Intraspecific Variation For Salt Tolerance In White Clover,
2024
Institute for Sustainable Agriculture
Intraspecific Variation For Salt Tolerance In White Clover, M E. Rodgers, C L. Noble, M E. Nicolas, G M. Halloran
IGC Proceedings (1977-2023)
Variation in the salt tolerance of 10 commercial cultivars of white clover (Trifolium repens L.) was evaluated in greenhouse and field· experiments over a range of NaCl concentrations. Cultivars differed significantly in terms of yield, shoot ion concentrations and parameters of growth such as leaf expansion and petiole elongation rates but not in the root concentrations of Cl or Na. The ability to control the entry and distribution of Cl and Na into the shoot (demonstrated by tolerant cultivars Haifa and irrigation compared with sensitive cultivars Ladino and Tamar) was related to the salt tolerance rankings observed in both …
Breeding For Tolerance To Toxic Levels Of Aluminum In Alfalfa,
2024
USDA, Agricultural Research Service
Breeding For Tolerance To Toxic Levels Of Aluminum In Alfalfa, T A. Campbell, Z L. Xia, P R. Jackson, C D. Foy, G R. Bauchan
IGC Proceedings (1977-2023)
An estimated 40% of all arable soils are acidic, and aluminum (Al) toxicity is often the primary plant-growth-limiting factor in these soils. Bxcess exchangeable Al is especially harmful in subsoils because it reduces rooting depth and branching and predisposes plants,to injury by drought. Our research to date indicates that there is substantial genetic variation in alfalfa (Medicago sativa L.) in response to toxic levels of Al, but that phenotypic recurrent selection appears to have been only marginally effective in selecting for Al tolerance. Possible alternative breeding approaches would entail re-evaluating selections to help obviate the effects of genotype x environment …
Evaluating Livestock Selling Strategies Based On Forage Availability,
2024
University of Arkansas
Evaluating Livestock Selling Strategies Based On Forage Availability, Lucas D. Parsch, W M. Watts, O J. Loewer, P L. Luster
IGC Proceedings (1977-2023)
The ORAZB simulation model was used to evaluate 4 alternative decision rules to trigger the removal of stocker steers from pasture in order to avoid risk when pasture conditions are suboptimal, Each of the four decision rules was simulated for 8 stocking rates over a 13- year period, Results of the analysis indicated that decision rules which trigger livestock removal based on minimum herbage availability result in shorter grazing periods and higher average daily gain compared with decision rules which trigger removal based on livestock weight loss. Although decision rules based on minimum herbage availability thresholds resulted in the highest …
Grazing System And Grazing Pressure Effects On Herbage And Lamb Production From Subclover Interseeded Annual Grassland,
2024
University of Idaho
Grazing System And Grazing Pressure Effects On Herbage And Lamb Production From Subclover Interseeded Annual Grassland, Thomas C. Griggs, Milton B. Jones, Montague W. Demment
IGC Proceedings (1977-2023)
Information on management effects on the productivity of improved mediterranean annual grassland pastures in California is limited, Our objectives were to compare herbage and lamb production in subclover (Trlfolium subterraneum L.)-seeded annual grassland under different intensities of continuous and rotational systems of grazing. Grazing systems at 3 grazing pressures were applied in a factorial arrangement to 12 0.6S-ha pastures in a randomised complete block design replicated twice. Targhee lambs grazed pastures from 28 February to 9 May in 1989 and from S March to 1 May in 1990. Lambs occupied each of the eight paddocks in rotations for 1-4 …
Intensive Grazing Of High Producing Holstein Cows: Milk Production, Forage Utilization And Profit Potential At Three Stocking Rates,
2024
The Pennsylvania State University
Intensive Grazing Of High Producing Holstein Cows: Milk Production, Forage Utilization And Profit Potential At Three Stocking Rates, S L. Fales, L D. Muller, M O'Sullivan, L E. Lanyon, R J. Hoover, L A. Holden
IGC Proceedings (1977-2023)
A farmlet study was conducted to investigate lhe potential for improving dairy productivity and profit potential through increasing stocking rates above those commonly used in 1he north-eastern USA. High-producing Holstein cows were grazed at seasonal stocking rotes (SR) of 3.9 (HSR), 3.2 (MSR) and 2.5 (LSR) cows/ha. Measurements were taken of quantity and quality of pasture offered to cows, silage harvested and fed and milk production during 175 days of grazing in 1990. Results showed a direct relationship between stocking rote and pasture quality and a negative relationship with the percentage of the pasture rejected by cows. Milk production (mean, …
Intensive Grazing Systems And Methods For Beef Cattle,
2024
Virginia Polytechnic Institute and State University
Intensive Grazing Systems And Methods For Beef Cattle, V G. Allen, J P. Fontenot, M A. Cochran, A Brock, W Mcclure, J Wilkins
IGC Proceedings (1977-2023)
Three experiments were conducted to determine effects of grazing systems and methods on beef production. In experiment 1, cows, calves and stockers grazed tall fescue-clover (Festuca arundinacea-Trifolium repens) in a l 6-paddock system using rotational stocking or a 3-paddock system using continuous stocking as grazing methods. In experiment 2, stocker steers grazed orchardgrass-clover (Dactylis glomerata-Trifolium pratense) using buffer grazing with continuous stocking or a 14-paddock rotational stocking method. In experiment 3, 4 grazing systems were compared using sequence grazing combinations of cool-and warmseasoo perennial and annual forages. In experiments l and 2, there were no differences in …
Selection Pattern Of Holstein-Zebu Cows Grazing Stoloniferous And Tufted Type Tropical Grasses In A Cafeteria Type Trial,
2024
Livestock Research Sub-Division
Selection Pattern Of Holstein-Zebu Cows Grazing Stoloniferous And Tufted Type Tropical Grasses In A Cafeteria Type Trial, Francise E. Davis
IGC Proceedings (1977-2023)
Seven stoloniferous and 7 tufted grasses are being evaluated in a longterm trial on an acid ultisol in Trinidad in duplicate 3x3 m plots. The grasses were cut at five weekly intervals and nitrogen at 40 kg/ha applied after every harvest. A basal dressing of 125 kg P20��, and 100 kg '½O and a trace element mix was applied twice annually. After culling in May 4 milking cows were allowed to graze the area. There was no significant difference in dry matter yield between the stoloniferous and tufted grasses, but there were significant differences within each type of grass in …
Effect Of Percentages Calluna Vulgaris Cover And Cow And Ewe Physiological Status On Animal Production On Mountain Pastures,
2024
Instituto de Experimentacion y Promocion Agraria Apdo
Effect Of Percentages Calluna Vulgaris Cover And Cow And Ewe Physiological Status On Animal Production On Mountain Pastures, K Osoro, R Celaya, Mamen Olivan
IGC Proceedings (1977-2023)
The effect percentage cover of Calluna vulgaris (30 or 70%) on performance of dry and lactating ewes and cows with their lambs and calves was studied during 1990 and 1991. Lactating cows had greater body weight losses than dry ones, the difference being 0.3 and 0.S kg/day for 1990 and 1991 respectively. Percentage C.vulgaris cover (30 or 70%) caused differences in body-weight losses· similar to those caused by physiological status. Milk production from the cows, and therefore calf live-weight gain, were significantly higher in the group grazing on the plot with 30% Calluna (0.62 and 0.71 kg/day for 1990 …
Adaptation Of Some Grass Species To Grazing,
2024
INRA
Adaptation Of Some Grass Species To Grazing, Marc Ghesquiere, J C. Emile, X Charrier, R Traineau
IGC Proceedings (1977-2023)
To examine the grazing behaviour of some grass species, 2 linked trials were set up in Lusignan (France), Dry matter yields of 10 species were recorded by frequent mechanical cuts (every 15 days) and compared with the ability to feed sheep under continuous grazing management. The dry matter yield of the genotypes ranged from 5600 to 8600 kg DM/ha and the grazing yield from 86 to 183 days x animal. The well-known species, such as Bromus siIchensis L., 8. caIhar1ic11s L. and Dactylis glomerata L. usually used in farms allowed high dry matter and grazing yields, but some secondary species …
