Effect Of A Legume (Arachis Pintoi) On The Regrowth And Mineral Nutrition Of Associated Pangola Grass (Digitaria Decumbens), P Cruz, H Sinoquet, O Sobesky
IGC Proceedings (1977-2023)
The effect of a companion legume (Arachis pintoi) on the growth and nitrogen nutrition of an associated grass (Di'gitaria decumbems) was studied during 2 regrowth periods. Digitaria growth was expressed as a function of the cumulative absorded PAR (photosynthetically active radiation) i.e., by using the radiation-use efficiency concept. For this purpose, PAR intercepted by both the pure and mixed swards was estimated by using a radiative transfer model. Nitrogen nutrition status of Digitaria was characterised by the relation between N uptake and dry matter production. Results show a close agreement between N nutrition level and radiation-use efficiency of the grass. …
Varietal Differences In Brassica Fodder As Affected By Nitrogen Topdressing And Seeding Date,
2024
Nigata University
Varietal Differences In Brassica Fodder As Affected By Nitrogen Topdressing And Seeding Date, S H. Moon, H Hirota
IGC Proceedings (1977-2023)
Two experiments were carried out both in spring and fall with cultivars of rape (Brassica napus spp.) and C.O. (B. campestris x B. oleracea). Both cullivars showed lillle increase in plant length in spring sowing with nitrogen topdressing, but the increments were higher in earlier topdressing (T l) and later topdressing (T2) than in control in autumn sowing, although the difference was not significant. There was no difference in the number of leaves throughout the growing stages between the N topdressing treatments in spring and autumn sowing. Leaf area was greater in Tl and T2 than in control in early …
Reserve Mobilization During Regrowth After Cutting Of Forage Species: Quantification And Physiological Mechanisms In Ryegrass And Lucerne, A Ourry, J Bigot, T Kim, J Boucaud, J Salette
IGC Proceedings (1977-2023)
Time course of remobilisation of reserves was studied during the regrowth of Loli11m perem1e and Medicago sativa by 15N labelling, carbohydrate analyses and by measuring time course of several enzymes activities. When photosynthesis decreased during early regrowth, and consequently reduced availability of carbon skeletons within the plant, both nitrogen (N) uptake (lolium perene) and N2 fixatlon (Medicago saliva) decreased. Nilrogenase, as well as nitrate reductase activities, decreased. Reduction of external N assimilation was compensated for by intensive mobilization of endogenous N in roots of lucerne and in stubble of ryegrass. In the same manner, some of …
Effect Of Temperature On Nitrogen Fixation Rates In Seven Clover Cultivars,
2024
AgResearch, NZ
Effect Of Temperature On Nitrogen Fixation Rates In Seven Clover Cultivars, J R. Crush, B D. Campbell, J R. Caradus
IGC Proceedings (1977-2023)
Seven white clover (Trifolium repens L) cultivars were grown in growth rooms at S different temperatures between S and 2S°C. Plant growth and nitrogenase activity (acetylene reduction) were measured. There were significant effects of temperature on total plant ay matter (DM) accumulation and nitrogenase activity. Temperature x cultivar interactions were significant for DM accumulation, nitrogenase activity per pot and nitrogenase activity/g DM. There was a strong correlation between DM increment/°C rise in temperature over the range 10-20°C, and nitrogenase activity/g DM. Three cultivars had maximum nitrogenase activity/g plant DM at 200C and 4 cultivars peaked at 15° C. These differences …
Physiological Characteristics Of Nitrate Uptake By Different Catch Crop Species,
2024
IRBA
Physiological Characteristics Of Nitrate Uptake By Different Catch Crop Species, P Laine, A Ourry, J Boucaud, J Salette
IGC Proceedings (1977-2023)
The pollution of aquifers by nitrate is aggravated by farming practices that leave the ground bare during winter. Establishment of catch crops during this time could be suitable farming strategy to decrease nitrate loss from the soil. Only a few studies are available on the physiology of nitrate uptake by these species. Experiments were conducted on Lolium perenne, Secale cereale, Trifolium incarnatum, Trifolirim alexendrnum, Phacelia tanacetifolia, Brassica rapa, Brassica napus, Sinapsis alba and Raphanus sativus grown in hydroponic conditions, in order to investigate the physiological basis of the NO3- uptake system when plants are grown with optimum ocniditons of light, …
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 …
