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Articles 1 - 30 of 194
Full-Text Articles in Weed Science
Potential Contribution Of White Clover To The Economics And Support-Energy Inputs Of Grass-Based Beef-Production Systems, T A. Stewart, R E. Haycock, A S. Laidlaw
Potential Contribution Of White Clover To The Economics And Support-Energy Inputs Of Grass-Based Beef-Production Systems, T A. Stewart, R E. Haycock, A S. Laidlaw
IGC Proceedings (1977-2023)
Biological output, gross margins, and efficiency of support-energy usage in an 18-month beef-production system on grass-white clover swards receiving either 50 kg N/ha stocked at 3.3 head/ha (low N) or 300 kg N/ha stocked 4.5 head/ha (high N) were compared. To date, two production cycles (1977-1979 and 1978-1980) at two sites have been completed. Mean live-weight and carcass gains/ha were, respectively, 17.5% and 14% higher from the high-N than from the low-N system. Gross margin/head was higher from the high-N system in the first production cycle but not in the second. In the low-N system as com· pared with the …
Pasture Demonstration Program For Beef: Economic Considerations, P R. Hasbargen, R H. Craven, N P. Martin
Pasture Demonstration Program For Beef: Economic Considerations, P R. Hasbargen, R H. Craven, N P. Martin
IGC Proceedings (1977-2023)
This study made an economic evaluation of several alternative pasture improvement programs on beef farms in northern Minnesota. Three questions were addressed relative to several pasture improvement systems. These were (1) Will it pay? (2) Is there a cheaper way? and (3) Is there a more profitable system for a particular farm resource situation? Partial budgeting and computerized linear programming techniques were used to analyze pasture cost and return data obtained from several ranches in northern Minnesota. Study results show that rented pastures, when available, provided the cheapest source of additional summer feed, and that legume pastures provide cheaper sources …
Stockpiling Of Cool-Season Grasses In Autumn, C T. Dougherty
Stockpiling Of Cool-Season Grasses In Autumn, C T. Dougherty
IGC Proceedings (1977-2023)
The practice of accumulating growth of cool-season grasses in the late summer and early autumn for subsequent grazing in late autumn and winter, known as stockpiling, has been widely accepted by beef cow-calf producers. The objectives of our study were to determine the growth characteristics of cool-season grasses in the autumn under nitrogen (N) fertilization and to investigate utilization of stockpiled forages. Tall fescue (Festuca arundinacea Schreb.) has many attributes that make it highly suited to stockpiling. On Maury silt loams, Kentucky 31 tall fescue accumulated 6,500 kg/ha of dry matter from 16 August 1979 to 12 December 1979 …
Influence Of Pesticide, Fertilizers, Row Spacings, And Seeding Rates On No-Tillage Establishment Of Alfalfa, L R. Vough, A M. Decker, R F. Dudley
Influence Of Pesticide, Fertilizers, Row Spacings, And Seeding Rates On No-Tillage Establishment Of Alfalfa, L R. Vough, A M. Decker, R F. Dudley
IGC Proceedings (1977-2023)
Two experiments were conducted to investigate seeding techniques associated with no-tillage establishment of alfalfa (Medicago sativa L.) in barley (Hordeum vulgare L.) stubble. The objective of experiment 1 was to evaluate the influence of carbofuran (CF) insecticide/nematocide and of P and N fertilizers on seedling weight, plant population, and forage yield. All materials were applied in the row with the seed. The largest seedlings at 10 weeks after seeding occurred with CF + P + N. The smallest seedlings were associated with the check and P treatments. The highest plant populations at 6 and 30 weeks after seeding …
Fate Of Nitrogen Applied To Grassland In Animal Wastes, M Sherwood
Fate Of Nitrogen Applied To Grassland In Animal Wastes, M Sherwood
IGC Proceedings (1977-2023)
The experiment was designed to determine the effects of land spreading of animal manures on the nutrient content of surface runoff water and infiltrating soil water. This report deals only with nitrogen (N) and attempts to quantify the losses through runoff, leaching, and volatilization of ammonia (NH3) as well as N uptake in the grass over a 3-year period. Experimental plots sited on grassland, on two soil types (a moderately drained loam and an impermeable gley), were equipped to collect surface runoff water. Ceramic probes were installed in each plot at 15-, 30-, 60-, and 100-cm depths to extract infiltrating …
Prediction Of The Supply Of Soil Nitrogen To Grass, D C. Whitehead
Prediction Of The Supply Of Soil Nitrogen To Grass, D C. Whitehead
IGC Proceedings (1977-2023)
Predictions of the supply of soil nitrogen (N) to grass over a growing season requires an assessment of nitrate N plus ammonium N (1) present in the soil at the beginning of the season and (2) likely to be released from the potentially mineralizable organic N during the season. Although a number of methods have been proposed for predicting soil N supply, and in particular the component arising from the potentially mineralizable N, many are too time consuming for routine use, and others have not been proven effective over a range of soils. However, in recent studies, the measurement of …
Waste- Water Application, Dry-Matter Production, And Nitrogen Balanced Rhodesgrass Grown On Fine-Textured Soil Or On Sand Dunes, T Kipnis, A Feigin, I Vaisman, J Shalhevet
Waste- Water Application, Dry-Matter Production, And Nitrogen Balanced Rhodesgrass Grown On Fine-Textured Soil Or On Sand Dunes, T Kipnis, A Feigin, I Vaisman, J Shalhevet
IGC Proceedings (1977-2023)
The shortage of irrigation water in the semiarid zone of Israel necessitates the use of partially treated municipal effiuents for irrigation of forage grasses. Irrigation with sewage effiuents is being considered very carefully with the aim of maximizing production and minimizing the pollution ha.zarc;l. A high nitrogen (N) input originating from intensive application of effiuent water may well increase dry-matter production, but it also increases t,he pollution hazard. Frequent application of relatively small quantities of effiuent water was suggested as an efficient method of improving N uptake by rhodesgrass ( Chloris gayana Kunth.) swards. It was expected that nitrate pollution …
Trials On Time Of Nitrogen Application In The Spring To Various Grasses Grown For Seed Production, A Nordestgaard
Trials On Time Of Nitrogen Application In The Spring To Various Grasses Grown For Seed Production, A Nordestgaard
IGC Proceedings (1977-2023)
With most of the grasses grown for seed in Denmark, a series of trials has been carried out on increasing nitrogen rates in the autumn combined with increasing rates in the spring. The results of these trials show that an autumn application of nitrogen is very important to most of the grasses and necessary if the optimum yield of seed is to be achieved. In order to find the best time to apply nitrogen in the spring when producing grass seed, a number of trials have been carried out in recent years with various grasses. Up to and including 1980, …
Nitrogen Relationships In Grassland Ecosystems, A Lazenby
Nitrogen Relationships In Grassland Ecosystems, A Lazenby
IGC Proceedings (1977-2023)
Some recent findings affecting nitrogen (N) cycling in grassland ecosystems are discussed, and an indication is given of major problems requiring research and development. The importance of modern techniques is stressed to enable further quantification of the pathways and processes of the nutrient in grassland; such data are needed both to improve understanding and to enable more efficient use of N in practice. A brief description of the N in soil organic matter is followed by an account of symbiotic N fixation by legumes, including estimated levels and rates of fixation and factors affecting the process. Data are presented on …
Effect Of Cultivar, Level Of Fungal Endophyte (Acremonium Coenophialum) And Nitrogen Fertilization Of Tall Fescue (Festuca Arundinacea) On Steer Performance, J A. Stuedmann, S R. Wilkinson, D P. Belesky, C S. Hoveland, O J. Devine, D L. Breedlove, H Ciordia, F N. Thompson
Effect Of Cultivar, Level Of Fungal Endophyte (Acremonium Coenophialum) And Nitrogen Fertilization Of Tall Fescue (Festuca Arundinacea) On Steer Performance, J A. Stuedmann, S R. Wilkinson, D P. Belesky, C S. Hoveland, O J. Devine, D L. Breedlove, H Ciordia, F N. Thompson
IGC Proceedings (1977-2023)
Tall fescue (Fescuca arundinacea) toxicosis has been associated with 'increased levels of fungal endophyte (Acremonium coenophialum) and increased rates of nitrogen (N) fertilization. This study determines the performance of steers grazing a 2 factorial of Kentucky-31 tall fescue at low fungus (LF) and high fungus (HF) levels at both 134 (LN) and 336 kg N·ha-1• 2 yC1 (HN) as well as steer performance on two new LF tall fescue cultivars, AU-Triumph and Johnstone fertilized at the LN rate. Eighteen 0.7 ha paddocks were used in a randomized block design with three blocks of the six treatments. Paddocks were stocked with …
Seasonal Distribution Of A Fungal Endophyte In Tall Fescue Pastures, D P. Belesky, O J. Devine, S R. Wilkinson, J A. Stuedemann, D M. Hildreth
Seasonal Distribution Of A Fungal Endophyte In Tall Fescue Pastures, D P. Belesky, O J. Devine, S R. Wilkinson, J A. Stuedemann, D M. Hildreth
IGC Proceedings (1977-2023)
The presence of a fungal endophyte (Acremonium coenophialum) in tall fescue (Festuca arondinacea) and high nitrogen (N) fertilizer input, has been associated with tall fescue toxicosis symptoms in beef cattle. Expression of toxicosis symptoms vary with season, however the dynamics of endophyte levels in a tall fescue over a growing season have not been described. Our study characterizes seasonal distribution of the endophyte in grazed fescue swards as influenced by cultivar and N fertilizer over two years (1983 and 1984). Three replicate 0.7 ha paddocks of 'Johnstons', 'Triumph' and 'KY-31' (low and high endophyte status; and 134 …
Relations Between Nitrogen Fertilization, Herbage Production And Milk Yield, E A. Lantinga, L T'Mannetje, H Schlepers
Relations Between Nitrogen Fertilization, Herbage Production And Milk Yield, E A. Lantinga, L T'Mannetje, H Schlepers
IGC Proceedings (1977-2023)
The response to N-fertilizer of animal output and of herbage production was compared. There appeared to be no difference in the responses to applied nitrogen between intensive continuous grazing and weekly cutting in the range of 300 to 500 kg N/ha/yr. It is hypothesized that the response to applied nitrogen in a continuously grazed sward is mainly determined by the intensity of grazing and that the benefit from nitrogen circulation through excreta has little meaning for the pasture as a whole.
Winter And Spring Growth Variability Of Grazed Permanent Meadow: The Case Of The Pyrenees Mountains, M Duru
Winter And Spring Growth Variability Of Grazed Permanent Meadow: The Case Of The Pyrenees Mountains, M Duru
IGC Proceedings (1977-2023)
In the Central Pyrenees, winter and early spring growth of permanent meadows provides available feed for flocks. Therefore, we studied the main factors of variation of this growth (soil fertility level, nitrogen fertilization, climate, ... ) to improve pasture availability. During three winters and springs, we measured the growth on three plots of different fertility level (0.108 % - 0.045 % - 0.018 % P205 Dyer) at an altitude of 1250 m. We set a value on growth by measuring cumulated dry matter every three weeks (or less often it there was snow) from November to April. The harvested dry …
Effect Of Fertilization On The Grass Tetany Potential And Organic Acid Composition Of Tall Fescue, D L. Grunes, S R. Wilkinson, P K. Joo, W A. Jackson, R P. Patterson
Effect Of Fertilization On The Grass Tetany Potential And Organic Acid Composition Of Tall Fescue, D L. Grunes, S R. Wilkinson, P K. Joo, W A. Jackson, R P. Patterson
IGC Proceedings (1977-2023)
Grass tetany has caused the death of beef cattle grazing Kentucky-31 (KY-31) tall fescue (Festuca arundinacae Schreb) fertilized with high rates of ammonium nitrate (NH4NO3) and potassium chloride (KCl), or with broiler litter. A field experiment was carried out to determine the effect of fertilization on the chemical composition of the forage. The addition of either inorganic fertilizer or broiler litter markedly increased concentrations of nitrogen (N) and potassium (K) in the plants. Fertilization with 448 kg N/ha markedly increased the concentrations of magnesium (Mg) and, to a lesser extent, calcium (Ca) in the plants. Fertilization with broiler litter markedly …
The Response Of Photosynthesis In Digitaria Eriantha (Steud) Subsp. Eriantha To The Application Of Different Forms And Concentrations Of Nitrogen, M M. Wolfson, C F. Cresswell
The Response Of Photosynthesis In Digitaria Eriantha (Steud) Subsp. Eriantha To The Application Of Different Forms And Concentrations Of Nitrogen, M M. Wolfson, C F. Cresswell
IGC Proceedings (1977-2023)
Digitaria eriantha (Steud) subsp. eriantha plants were grown under controlled conditions and treated with different forms and concentrations of nitrogen in order to determine its effect on photosynthetic activity. Single leaf and whole plant net photosythetic rates were meaured and appeared to vary according to the units in which the activity was expressed. Although single leaf photosynthesis was measured on young leaves, near the meristematic tip, the rates had decreased to very low levels by the fourth of month of treatment, irrespective of the mode of expression used. A similar trend was observed when the whole plant net photosythetic rates …
Comparison Of Nitrogen Utilization From Wilted And Direct-Cut Silages By Growing Sheep, Elisabeth Grenet, C Demarquilly, C Beranger, D Micol
Comparison Of Nitrogen Utilization From Wilted And Direct-Cut Silages By Growing Sheep, Elisabeth Grenet, C Demarquilly, C Beranger, D Micol
IGC Proceedings (1977-2023)
The influence of wilting on the conservation quality, intake, digestibility and nitrogen balance of silages was studied. 32 silages made from 10 fresh crops were fed to growing sheep. For each crop a direct-cut silage without additive, a direct-cut silage with formic acid and a wilted silage were prepared. Conservation of wilted silages was not as good as that of direct-cut silages with formic acid but was better than that of silages without additive. However, both intake and protein digestibility of wilted silages were the lowest of the three types. The nitrogen balance was also lower with wilted silages than …
Leaching Effects On Composition And Digestibility Of Leaf And Stem Of Alfalfa And Red Clover, Michael Collins
Leaching Effects On Composition And Digestibility Of Leaf And Stem Of Alfalfa And Red Clover, Michael Collins
IGC Proceedings (1977-2023)
Rainfall during field drying of legume hay reduces both yield and nutritive value of the forage. An experiment was conducted to evaluate leaching effects on composition of dry leaf and stem tissue of alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.). Leaching increased neutral detergent fiber, acid detergent fiber, cellulose and acid detergent lignin concentrations in every case although leaf increased more. Stem tissue of red clover differed less from leaf in fiber composition than did leaf and stem of alfalfa. Leaching did not significantly affect nitrogen concentration but decreased in vitro true digestibility of both …
Pasture Production And Quality In A Cool Oceanic Climate, H Bjornsson, J Hermannsson
Pasture Production And Quality In A Cool Oceanic Climate, H Bjornsson, J Hermannsson
IGC Proceedings (1977-2023)
In Iceland cool oceanic climate prevails, as the geographic location extends from the polar circle to three degrees latitude to the south and the island is warmed by a branch of the Gulf stream. Animal production is the main agricultural activity and it relies on good conditions for grass growth. In the following we sumarize some recent experimental results on the production of herbage in Iceland.
Soil Fertility And Beef Production In The Semi-Arid Sub-Tropics, P C. Kerridge, R W. Mclean
Soil Fertility And Beef Production In The Semi-Arid Sub-Tropics, P C. Kerridge, R W. Mclean
IGC Proceedings (1977-2023)
Two-thirds of the grazing lands in Queensland are on infertile soils, low in organic matter, phosphorus (P) and nitrogen (N) (Weston et al., 1981). Pasture quality is low and average liveweight gain (L WG) of steers on these soils ranges from 0.10 to 0.30 kg/day compared to 0.40 to 0.50 kg/day on more fertile soils. Low herbage production limits carrying capacity to 3-10 ha/animal. The nutritive value can be improved by (i) direct supplementation of animals with N and P, (ii) introduction of a legume together with fertilizer and/or supplement P or (iii) use of heavily fertilized improved grasses ± …
Long-Term Productivity Of Legumes-Based And Pure Grass Pastures In The Eastern Plains Of Colombia, C Lascano, J Estrada
Long-Term Productivity Of Legumes-Based And Pure Grass Pastures In The Eastern Plains Of Colombia, C Lascano, J Estrada
IGC Proceedings (1977-2023)
The savannas of Colombia have acid soils of low fertility, a well defined dry season and an herbaceous native vegetation of low nutritional value (Lascano and Spain, 1986). As a consequence, traditional livestock production is extensive and of low productivity in terms of animal growth and reproduction (Vera and Sere, 1985). An economically attractive alternative to increase cattle production in the savannas of Colombia is through the use of legume-based pastures, provided they are productive and persistent (Nores and Estrada, 1979). This paper presents results on animal production and forage attnbutes of a long-term grazing experiment which includes a grass …
Prospects For Legume-Based Dairying In Cool Temperate Conditions, M Ryan
Prospects For Legume-Based Dairying In Cool Temperate Conditions, M Ryan
IGC Proceedings (1977-2023)
There is increasing interest in exploiting legume-based pastures in the temperate zones of NW Europe-their value for lamb and beef production being recently documented (Stewart, 1984; Davies and Munro, 1988). Legume-based intensive dairying is currently not prevalent north of - 49 NL but quota restrictions leading to fewer cows may create conditions favourable to legumes within dairying. This paper describes the results of experimentation comparing N and legume-based dairying in cool temperate conditions and assesses future prospects.
Potentials Of Summer Fodders Under Intensive Cropping System In India, M S. Tiwana, Thakur Singh
Potentials Of Summer Fodders Under Intensive Cropping System In India, M S. Tiwana, Thakur Singh
IGC Proceedings (1977-2023)
One of the reasons for low milk production in India is the non-availability of good quality fodders in sufficient quantity. Therefore, it is necessary to bridge the gap of this acute shortage of fodder for increasing the milk production. There seems to be no possibility of increasing area under fodders and the only alternative looks to be the ulilization of vacant land (70 days) after harvesting wheat and before the sowing of main summer season crops. However, the growing of these crops may have some effect on the yield of succeeding crops by depleting or replenishing the nutrient status of …
Comparison Of Ryegrass-White Clover And Competitive Interactions In New Zealand And Wales, W Harris, I Rhodes
Comparison Of Ryegrass-White Clover And Competitive Interactions In New Zealand And Wales, W Harris, I Rhodes
IGC Proceedings (1977-2023)
New Zealand and Wales have temperate climates suitable for ryegrass (Lolium species) and white clover (Trifolium repens) pasture. However, pasture management in New Zealand and Wales in fundamentally different. New Zealand pastures are grazed all year, whereas in Wales pastures are mostly not grazed in winter. Moreover New Zealand pastures mostly rely on nitrogen fixed by legumes, whereas nitrogen fertiliser is commonly applied to Welsh pastures. To consider the basis of differences of pasture management in New Zealand and Wales, data from field experiments at Aberystwyth, Wales (Lat. 52°25'N) and Palmerston North, New Zealand (Lat. 40°20'S) are …
Ammonia Volatilisation And Loss From Grassland Systems, S C. Jarvis, B F. Pain, D J. Hatch, R B. Thompson
Ammonia Volatilisation And Loss From Grassland Systems, S C. Jarvis, B F. Pain, D J. Hatch, R B. Thompson
IGC Proceedings (1977-2023)
There is considerable interest in monitoring flows of nitrogen (N) through various parts of grassland systems. Until recent developments in methodology it had been particularly difficult to assess the contribution of NH3 volatilisation to N cycling. Emission rates for NH3 over Europe are thought to have increased by 50 % over the past 30-40 years and to arise largely from livestock excreta. This occurs after the hydrolysis of excreted urea and, with cattle, takes place directly from grazed swards, animal houses (during overwintering) and stored or applied slurry. As well as the economic losses, NH3 fluxes have important environmental consequences …
The Effects Of Fertilizer/Urine Interactions On Nh3 -N Losses From Grassland Soils, R D. Meyer, S C. Jarvis
The Effects Of Fertilizer/Urine Interactions On Nh3 -N Losses From Grassland Soils, R D. Meyer, S C. Jarvis
IGC Proceedings (1977-2023)
Recent studies (Black et al., 1984) have indicated that the volatilisation of ammonia (NH3) from urea granules broadcast on to pastures at application rates of 50-100 kgN/ha often exceeds 20 % of the N applied. The extent of this loss becomes an important consideration when manipulating management systems to maximise N efficiency and minimise losses to the environment. This will become especially important as the use of urea fertiliser increases because of relative cheapness and as technological advances in production and in farm handling are made (Gould et al., 1986). The factors influencing the volatilisation of urea in simple systems …
Physiological Ageing In Young Leaves Of Digitaria Eriantha (Steud), M M. Wolfson, C F. Cresswell
Physiological Ageing In Young Leaves Of Digitaria Eriantha (Steud), M M. Wolfson, C F. Cresswell
IGC Proceedings (1977-2023)
In a previous paper, Wolfson and Cresswell (1985) demonstrated that single leaf photosynthetic rates measured on successive leaves near the meristematic tip, in plants treated with different forms and concentrations of nitrogen, decreased reaching very low levels after four month's growth, irrespective of the treatment applied. As the leaves were considered to be young and they were not shaded in any way, it was expected that the photosynthetic rate would remain fairly high throughout the growing period. Therefore it was suggested that the leaves underwent some form of programmed metabolic ageing even though they were still structurally and physiologically young. …
Stand Characteristics Of Irrigated Cocksfoot Regrowth And Leaf Area Increasing, M Duru, A Langlet, S Rouzies
Stand Characteristics Of Irrigated Cocksfoot Regrowth And Leaf Area Increasing, M Duru, A Langlet, S Rouzies
IGC Proceedings (1977-2023)
For grasses, high leaf area index (LAI) extension rate is necessary to intercept much radiation and to increase the growth rate (Gosse et al., 1986). The LAI extension rate depends on stand status just after the cut : tiller density (Nelson and Zarrough, 1981), residual leaf area and reserves level (Smith, 1974), plant nutrition (nitrogen especially). We study the setting up of LAI for vegetative regrowths according to nitrogen nutrition and different stand status : tiller number and size.
Variability Of Leaf Area Index Extension Rate On Permanent Grasslands, M Duru
Variability Of Leaf Area Index Extension Rate On Permanent Grasslands, M Duru
IGC Proceedings (1977-2023)
Canopy growth is related to solar radiation intercepted (PARa), (Greenwood et al., 1986; Gosse et al., 1986). The canopy interception efficiency ( i: i = P ARa/P ARc) is related to leaf area index (LAI). In spring, for grasses i: i = 70 % when LAI = 2 (Lemaire, 1985). The faster the LAI extension rate is, the greater the dry matter yield is. We study nitrogen and grassland type effects, with phosphopotassic soil fertility level and botanical criterion.
Mutualistic Symbiosis Of Tall Fescue And Fungal Endophyte, C S. Hoveland, C W. Bacon, N S. Hill
Mutualistic Symbiosis Of Tall Fescue And Fungal Endophyte, C S. Hoveland, C W. Bacon, N S. Hill
IGC Proceedings (1977-2023)
The greatly improved performance of livestock consuming low-endophyte tall fescue (Festuca arundinacea) forage has stimulated production of endophyte-free seed and replanting Acremonium coenophialum infected pastures (Stuedemann and Hoveland, 1988). Since endophytic fungi co-evolved with their host and are non-pathogenic, the endophyte-plant relationship is likely a mutualistic symbiosis (Bacon and Siegel, 1988). An important question arises as to whether tall fescue free of the endophyte will have the same productivity and persistence as infected grass in stressful environments. If the fungus benefits from the association by receiving nutrients, protection, reproduction, and dissemination, then the plant may be aided by …
Contribution Of Red Clover To Maize Grain Yields, K D. Johnson, D K. Greene, J H. Cherney
Contribution Of Red Clover To Maize Grain Yields, K D. Johnson, D K. Greene, J H. Cherney
IGC Proceedings (1977-2023)
Renewed emphasis has been placed on crop rotation systems that include a perennial legume. Reasons for this interest include protection of soil from erosion, protection of ground water from nitrate contamination, reduction of soil compaction, and potential for fewer inputs which could reduce costs of grain production. Barnes et al. (1985) reported that a nondormant alfalfa (Medicago sativa L.) selected for increased Nin the root and crown had similar summer herbage yield as adapted dormant cultivars, but provided 62 % more symbiotically fixed N for a following crop than dormant cultivars. If most benefit is to be derived from cultivars …