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  • Blackwell Publishing Ltd  (4,723)
  • 1980-1984
  • 1970-1974  (4,723)
  • 1974  (2,631)
  • 1970  (2,092)
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  • 1980-1984
  • 1970-1974  (4,723)
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  • 101
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The drying of small herbage samples should be as rapid as possible so as to limit respiratory loss and enzymatic interconversions, especially if certain nonstnictnral carbohydrates are to be assayed. An inexpensive thermo-switch is described that indicates the time required to heat a mass of tissue in an oven to a given temperature. The time required to heat green herbage to a temperature (55°C) that will inactivate respiratory enzymes can be determined.
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  • 102
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A linear programming model of a high-temperature grass-drying enterprise is described. From information about seasonal crop response, area of crop available and management constraints, the model determines the harvesting schedules which give greatest returns, less costs, from the enterprise over the season. This information can be used to examine the effects of long-term strategic decisions or to evaluate economically data on new crops from field experiments. For example, assuming a fixed cost of λ70,000/year for a high-temperature grass-drying installation and what is considered to be reliable input data for 1972, the returns less costs for optimum harvest schedules from different areas or crop varieties are:〈table colsep="0" rowsep="0" frame="topbot" pgwide="1" orient="port"〉〈tgroup cols="5" align="left"〉〈colspec colnum="1" colname="col1" align="center"/〉〈colspec colnum="2" colname="col2" align="center"/〉〈colspec colnum="3" colname="col3" align="center"/〉〈colspec colnum="4" colname="col4" align="center"/〉〈colspec colnum="5" colname="col5" align="center"/〉〈thead valign="bottom"〉〈entry namest="col1" nameend="col2" align="left"〉Corp areaSurplusGrass ac (ha)Lucerne ac (ha)Return, £Less costs £/ac(£/ha)crop ac (ha)〈tbody valign="top"〉800(324)0(0)42,849536(132.3)0(0)1000(405)0(0)60,286603(1489)205(83)600(243)200(81)46,73158.4(1442)0(0)800(324)200(81)65.66165.7(1621)109(44) The model can also provide information con cerning tbe limitations imposed by equipment stage of tbe process and management re straints sucb as limitations on overtime and shut downs for holidays or maintenance.
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  • 103
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Newly-sown S24 perennial ryegrass at Hurley and old established ryegrass-dominant mixed pasture at Rothamsted were treated with several pesticides, singly and in combination, over the period 1969–73. Yields were either unaffected or increased by up to 30% in any one year, depending on the treatment, the newly-sown sward giving the more consistent response from year to year.
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  • 104
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The DM production from INRA 200, an early maturing hybrid maize grown for silage, was 10±6 and 14 5 t/ha in mid-October 1972 and 1973 (4±2 and 5±8 tons/ac). The plant population in both years was approximately 112,000/ha (45,320/ac). Whole-crop and cob DM percentages were 18±2 and 21±3 for 1972 and 39±9 and 53±0 for 1973, respectively. The cob yields were 49 and 10±4 t/ha (2±0 and 4±1 tons/ac) in 1972 and 1973 and cob in the two years accounted for 46 and 72% of total yield. At harvest the 1973 crop was 4–6 weeks more mature than the 1972 crop. These differences were attributed to the difference in accumulated temperature recorded from May till October, which was 567°C days in 1972 and 817 in 1973. Whole-crop DM content, yield of cob and yield of cob as a percentage of total yield were studied against seasonal temperature accumulation. In the case of DM percentage there was a highly significant linear regression which showed that 627°C days were needed to mature maize to 24% DM content.
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  • 105
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Experiments were carried out with different depths of added topsoil, with different methods of cultivation and with different rates of application of fertilizers on an ash disposal site near Newark. Good yields of hay and wheat were obtained and were shown to vary systematically with the treatment of the plots. Good yields of wheat were obtained with a top dressing of 125 kg N/ha even on bare ash but, in contrast with the yields of DM from grass, yields of grain tended to increase with increasing depth of added soil. This pattern appeared to be influenced by the variations in spring rainfall. There appeared to be no adverse effects of uptake of trace elements from the ash.
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  • 106
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The DM and N contribution of S184 white clover in mixed ryegrass/clover swards was recorded at Pant-y-dwr Hill Centre (305 m) for 4 years, 1967–70. By direct comparison with fertilized grass swards it was estimated that the clover N contribution on peaty gley soil averaged 100 kg N/ha per year (89 Ib N/ac) under cutting and 98 kg N/ha (87 ib/ac) under grazing with faecal return. On more fertile acid brown earth the corresponding contributions were 81 and 90 kg N/ha (72 and 80 Ib/ac). Full replacement of clover by N fertilizer would require average annual applications of 268, 229, 156 and 128 kg fertilizer N/ha, respectively (239, 204, 139 and 114 Ib N/ac).
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  • 107
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Book reviewed in this article:EYRE, S. R. (Editor) World vegetation types.SCHMIDT, W.; WETTERAU, H.; BEYRICH, H.; MÜLLER, M.; GOTTSCHLING, E.-M. [Silage production.] Silageherstellung.LAMBRECHTSEN, N. C. What grass is that? A guide to identification of some introduced grasses in New Zealand by vegetative characters.LEIGH, J. H.; NOBLE, J. C. (Editors) Plants for sheep in Australia.THURM, R. [Technology of agricultural production.] Technologie der landwirtschaftlichen Produktion.TAYLOR, S. A.; ASHCROFT, G. L. Physical edaphology. The physics of irrigated and nonirrigated soils.DAVIES, D. B.; EAGLE, D. J.; FINNEY, J. B. Soil management. Ipswich, Suffolk, UK, Farming Press Limited.OLSON, R. A.; ARMY, T. J.; HANWAY, J. J.; KILMER, V. J. (Editors) Fertilizer technology & use.PAPADAKIS, J. Auxins, biochemical plant interaction, growth retardants and dense high yielding crops. Córdoba, Argentina, J. Papadakis.
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  • 108
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: An electronic pasture-meter was found to be of limited use for the routine estimation of DM production of oat cultivars for the reason that the relationship between the meter reading and DM varied with different cultivars.
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  • 109
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 110
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 111
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The duration of the juvenile phase in early-flowering (Dorset Marl) and late-flowering (S123) red clover is described. Neither cultivar responded to inductive conditions at the first leaf stage but Dorset Marl attained maximum sensitivity by the 3-leaf stage. A comparable response was obtained with S123 only after the production of 12–13 leaves. The growth characteristics of the two types under continuous long or short days are described and possible explanations are advanced for the characteristic differences in tillering and stem internode number.
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  • 112
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: For three weeks after emergence, micro-swards of Lolium rigidum were defoliated to a height and at a frequency which represented a range of set stocking rates of less than, similar to, and more than 7–8 sheep/ha as based on the results of Greenwood and Arnold (6) and referred to as D1, D2 and D3 respectively. The effects of these defoliation regimes on the growth and development of emergent swards were evaluated according to their effect on increments of DM from plant parts, rate of appearance of leaves and tillers, concentration of soluble carbohydrates, and on the uptake and concentration of inorganic nutrients.Defoliation began five days after emergence, when the dry weight of the shoot was 3g/m2. After 20 days of treatment, 6±7 g/m2 of DM had been removed from D1, 5±5 g/m2 from D2 and 51 g/m2 from D3; and the dry weight of shoot remaining was 13, 7 and 4±5 g/m2 on D1, D2 and D3 respectively. The effect of defoliation on dry weight of plant parts increased in severity in the order leaf 1, stem+sheaths, leaf 2, roots, leaf 3, tiller 1, tiller 2, leaf 4. Average relative growth rate of the sward was reduced from 17% per day on D1 to 13% per day on D3. There was no necrosis of root tissue. Emergence of the later leaves and of the tillers was retarded by up to three days by more frequent defoliation. Alcohol-soluble carbohydrates in the root fell from over 6% to about 1±5% on all treatments. Uptake of N. P and K was limited by increasing intensity of defoliation and because concentrations of those elements were not greatly affected, the limitation could be ascribed mainly to the effects of defoliation on plant size.The plausibility of the technique for the experimental simulation of grazing of emergent annual grass swards in Western Australia is discussed. It is concluded that for set-stocking rates of less than about 12 sheep/ha, grazing, while reducing DM production just after emergence, is unlikely to produce severe physiological stresses in the sward.
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  • 113
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The uptake of N was measured in 2 successive regrowths harvested on 12 June and 13 Aug. following harvests of primary growths 8, 12, 16, 23, 29, 45 and 57 (12 June) days after applying N at 59, 118 or 177 kg N/ha on 16 Apr.Residual responses were obtained to both increments of N, leading to high apparent recoveries of fertilizer N, especially to the higher increment. This increased availability of soil N when high rates of N are applied is shown to vary with date of harvest of primary growth, reaching a maximum equivalent to 151% apparent fertilizer N recovery 23 days after N application.In the second regrowth, percentage N in the herbage showed a negative response to N applied to the primary growth. This appears to reflect a reduction in available soil N brought about by its increased availability and uptake in primary growth and first regrowth.The possibilities of improving the efficiency of fertilizer N by exploiting soil N are considered against the possible reduction in available N for future regrowths.
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  • 114
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 25 (1970), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A great number of experiments with varying dates of N application to grassland showed that the most suitable time of applying spring N in tbe Netberlaods varies, as a result of weather conditions, from year to year from mid-February to mid-April. In such experiments the best time of spring N application, which needs to be known in advance, can only be determined after the grass bas been harvested and weighed. The results of these experiments supported the opinion that the best application date coincides with the banging of grass growth. However, at that time it was not possible clearly to define the begimiing of grass growth.When in 1959 a measuring disc was put into use the beginning of grass growth could be precisely determined and it was then found that the beginning of grass growth was closely correlated to a certain accumulated temperature from 1 Jan. from which the date of the beginning of grass growth can be predicted. This date is the most suitable one for applying spring N to grassland.
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  • 115
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 25 (1970), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: An experiment was set up to measure the production from donally propagated micro-swards of four contrasting ryegrass genotypes, grown in monocultures and in all possible combinations of mixed cultures consisting of two, three and all four genotypes. Water and nutrients were supplied frequently in non-limiting quantities and the swards were subjected to two cutting frequencies.The yield ranking of the monocultures and mixed cultures diifered at the two cutting frequencies. Under infrequent cutting, though not under frequent cutting, two mixtures, each containing two genotypes, were more productive than their highest yielding components in monoculture. The physiological basis of this apparent synergy is hriefly discussed and it is suggested that the increased yield may he due to more efficient light utilization hy the mixtures. In general, yields of other mixtures, including those consisting of 3 or 4 genotypes were intermediate between the highest and lowest yielding components in monoculture.The agronomic and plant-breeding implications of the results are discussed.
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  • 116
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 25 (1970), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The application of an electronic pasture probe to the measurement of rape is described. Measurements taken over two years demonstrated that good relationships could be established between probe readings and parameters of crop yield. Crop height, spatial distribution of crop profile, crop density and percentage DM were found to he significant factors in obtaining meaningful results.
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  • 117
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 25 (1970), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Two experiments are described in which ground harley meal was added to freshly-cut grass hefore ensiling it in small air-tight metal containers and polythene containers. The mean DM loss from the air-tight metal containers was 1 % and from the polythene containers 18.8%. The silages were all of satisfactory fermentation quality, as assessed hy pH, voladle acids, lactic-acid and Tolatile-hase content. The addition of the harley meal significantly improved the nutritive content of the ensiled material, and the resulting silage in the air-tight metal containers. Sheep were used to measure the voluntary intakes of the silages conserved in the polythene containers.
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  • 118
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    Geophysical prospecting 22 (1974), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Qureshi and Mula have suggested a computer method for the calculation of the shape of a two dimensional body from the gravity anomaly profile associated with it. The application of the method, however, was restricted to those bodies which have their top or base horizontal and end sides vertical. In this paper study has been made to investigate the possibility of eliminating the above mentioned restrictions and has arrived at the affirmative conclusion.
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  • 119
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    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 22 (1974), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
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  • 120
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    Geophysical prospecting 22 (1974), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Consideration is given to the form of apparent resistivity sections obtained by varying electrode array position and spacing over two dimensional features.Since basic solutions exist for horizontally layered media and for vertical or dipping single interfaces, simple rules are proposed whereby these solutions can be directly combined to give solutions for more complex sections. Substantial approximations may be involved as the rules do not fully allow for interactions between the constituents.The range of error incurred in application of the rules is explored, with particular reference to the square array system of resistivity measurement. The two extremes- of orientation of the square array with respect to the line of section are separately considered in this survey.Within appropriate limits, the rules appear extendable to a wide variety of simple structures for which rigorous solutions would be formidable. The rules are finally discussed in relation to practical applications.
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  • 121
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    Geophysical prospecting 22 (1974), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: In modern oil exploration layers of prospective interest with rather simple structural features are often overlain by very complicated bodies as e.g. saltdomes or other kinds of diapirs, olistostromes, or front zones of overthrusted blankets. In all these cases normal reflection seismic investigations, where downgoing and upgoing rays are rather close to each other, mostly fail, either because no reflections from underneath the complicated bodies are obtained, or because a reliable migrated depth presentation becomes practically impossible due to the inhomogeneity of the overlying bodies.The undershooting technique avoids these difficulties by using ray paths which do not traverse the complicated bodies e.g. by shooting on one side of a saltdome and recording on the other side. On account of the large shot-geophone distances in this method special considerations and computer processes were developed concerning moveout corrections for common depth point stacking and migrated depth presentation.In many cases the location of the disturbing complicated bodies is known in advance. The shooting and recording program can then be adjusted to this knowledge and thereby kept to a minimum. If the location of the complicated bodies is unknown a more extended seismic program has to be carried out encompassing a great variety of shot-geophone distances. But in this case the approximate location of the complicated bodies can be deduced from the survey too.Results are presented in order to give an idea of the efficiency of the new seismic tool.
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  • 122
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    Geophysical prospecting 18 (1970), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: The seismic velocity of sedimentary rocks is determined by the porosity, the velocity in the matrix and that in the fluid. The last two are known experimentally. The velocity can be measured from the surface. By applying the time average equation we can find the porosity. If the only difference at two points is the nature of the fluid in one layer, the ratio of the reflectivities of the layer at these points determines the nature of the fluid; this ratio is equal to the ratio of the amplitudes at these points. The size of the reservoir can then be found.The method can be applied to both oil exploration and production. It is more accurate in the latter case because more information is available than in the former case. The method is also more effective in developing discovered fields than the conventional method of relying only on the geological structural configurations.
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  • 123
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    Geophysical prospecting 22 (1974), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: This paper describes the procedure for interpreting the apparent resistivity data measured with the two-electrode array directly with the help of kernel function. The calculation of kernel function from the observed resistivity curve is done by the method of decomposition. In the method of decomposition the resistivity curve is approximated by a sum of certain functions, whose choice is only restricted by the requirement that the contribution to the kernel function corresponding to them should be easily computable. A few such functions are classified. These, and the standard curves for corresponding kernel functions obtained by utilising an integral expression for two-electrode array expressing the kernel explicitly in terms of the apparent resistivity functions, are plotted on log-log scale. The determination of layer parameters, that is, the layer resistivities and thicknesses from the kernel function can be carried out by a method proposed by Pekeris (1940).
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  • 124
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    Geophysical prospecting 22 (1974), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: A six-channel wide-band digital system for magnetotelluric measurements is described The system is designed to operate in the frequency band 10-.0001 Hz. The recording is made on a 7 track tape in an IBM compatible 12 bit format. The amplitude and phase responses of the system and sample records are presented.
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  • 125
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    Geophysical prospecting 22 (1974), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Several types of multichannel filters have been introduced in the past with the purpose of rejecting, in a seismic section, coherent noise having a slope different from that of the signal.These filters, generally, tend to introduce a certain amount of mixing and therefore the output trace shows increased horizontal coherence. This is due to the model on which these filters are based, since the hypothesis is posed that the reflectors are continuous. This may be dangerous since it could lead to mistaken interpretations, for example when small faults or breaks are made to disappear in the output section.Other problems that could arise in the application of multichannel filters after-stack are space-aliasing and high-pass filtering. The former occurs when coherent noise is rejected with apparent Velocity V and frequency fa=V/X, where X is the distance between traces. In this case, the signal also is distorted since it is rejected in the same frequency range. The high pass filtering effect occurs when the multichannel filter is designed to remove low coherent noise with high apparent velocity.In the paper a family of multichannel filters is presented based on a model of the seismic section such that minimum mixing effects appear. The filters are designed to give good results even in the case of low frequency and high velocity coherent noise.Some practical examples are shown.
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  • 126
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    Geophysical prospecting 18 (1970), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: It is pointed out that after identifying reflection events from the same horizon on two records obtained on the same spread from two different shotpoints, one can simultaneously estimate parameters of reflection events and relative static corrections. The parameters of reflection events are treated as quantities to compute whereas relative static corrections are treated as quantities to minimize by the least squares method. Static corrections obtained from different horizons for the same point on the spread are averaged.The case of more than one pair of records for the same spread (or part of the spread), vital for multiple coverage, is also discussed.
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  • 127
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    Geophysical prospecting 18 (1970), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Après avoir essayé?analyser, par voie optique, ľeffet de la réflexion fantôme sur des enregistrements sismiques, on montre ľapplication de deux méthodes de filtrage de ce fantôme sur des exemples réels.La première méthode utilise là mise à feu séquentielle de charges situées à différentes profondeurs dans un même trou; il s'agit ?un filtrage réalisé sur le terrain. Le deuxième procédé consiste à filtrer, au central, des enregistrements réalisés à des profondeurs de tir différentes avant de les sommer.
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  • 128
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    Geophysical prospecting 18 (1970), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: A high sensitivity thermometer using a thermistor sensing element was designed for practical measurements in the field.The most suitable procedures for the elimination of diurnal and seasonal variation of temperature, the influence of vegetation cover and of other effects were investigated.Positive results of geothermic measurements have been acquired on sulfide deposits. By far the most important results of geothermic measurements have been obtained in hydrogeological problems, e.g. the investigation of circulation of underground water. In the case of prospection for cold mineral waters the combination of geothermic measurements with gasometric analyses is very useful. As the classical domain for geothermic investigation, prospection for hot water is to be mentioned.
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  • 129
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    Geophysical prospecting 18 (1970), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: The conditions for creating and recording converted waves in the area of the Panonien basin are considered. Comparison between the characteristics of converted waves recorded in the field and characteristics of converted waves calculated for the model which approximately corresponds to lithophysical conditions of the area is made.The comparative interpretation of the crustal structure along the profile, using different types of waves, is given.
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    Topics: Geosciences , Physics
    Notes: Direct interpretation methods of resistivity curves are discussed, which use the kernel function of the apparent resistivity. This function results from the consideration of the problem of diverse electrodes configurations.Several expressions for the determination of the kernel function of the potential from the kernel function of the apparent resistivity are given.
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    Topics: Geosciences , Physics
    Notes: A method to analyse aeromagnetic profiles is proposed: several horizontal (width-) and vertical (amplitude-) parameters are deduced from the anomalies. These parameters are then compared with diagrams drawn on a logarithmic scale. The comparison yields depth and magnetization of the causative bodies.The method lends itself equally well to a quick estimate and to a thorough interpretation, depending on the number of parameters deduced and on the number of diagrams. It can be applied also to the anomalies of the total field and its vertical gradient.
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    Topics: Geosciences , Physics
    Notes: Book review in this Article:H. Wöhlbier, R. H. Wöhlbier, F. H. Wöhlbier, H. Baston, Worldwide Directory of Mineral Industries Education and Research.
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    Topics: Geosciences , Physics
    Notes: Water seepage from reservoirs causes appreciable anomalies of natural electric fields. The possibility of mapping leakage places by means of the SP method has been discussed by the authors in an earlier report. Further work has shown that detailed measurements of the natural electric field allow to determine the seepage rates from individual areas of a water reservoir in relative units. If data on the total discharge from a water reservoir are available, the conventional seepage units can be converted into absolute ones. Using this technique on a water reservoir in Armenia has permitted to control the change of the leakage rate as hydroinsulation operations were in progress. It has been established that as a result of shielding the bottom with clay material leakage from the central part of the reservoir has stopped. On the other hand, construction of cement seepage-proof protection has had so far no appreciable positive effect.
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    Topics: Geosciences , Physics
    Notes: The seismometer-ground system is represented by a damped oscillatory system. Relatively simple approximation formulas are derived to express the coupling between ground and seismometer. These expressions are applicable in seismic exploration. The coupling is that of a mass, suspended by a spring, to the surface that the ground would have in absence of the seismometer. It results in a low-pass filtering of the ground motion, which is due to the presence of the seismometer. This effect is expressed in a unit-impulse response. It appears that, over a sufficiently homogeneous ground and for low frequencies, one has a true coupling between ground and seismometer. To obtain a sufficiently large pass-band, a low seismometer housing-mass together with a not too small housing radius are necessary.
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  • 135
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    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In the management of British grassland lay there appears to be a marked divergence between the policies advocated by grassland science and general grassland practice. While science places emphasis on monocultures of sown species (mainly perennial ryegrass), heavily fertilized and intensively stocked, grassland farmers for the most part rely on lonstablished or indigenous swards composed of a variety of species and receiving modest applications of fertilizer. Since the gap between the two approaches is both substantial and of long duration the subject appears to be worth fresh attention. The purpose of this paper is to examine the current situation in relation to improvement in botanical composition and to suggest new approaches to that end.
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  • 136
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    Grass and forage science 29 (1974), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The last 10 years have seen a marked shift in Britain from the growing of legumes towards the use of fertilizer N. Many farmers are now reassessing the position Decause of increasing fertilizer prices and because of improvements in clovers and lucerne through plant breeding.On the intensive dairy farm legumes can play an important part in the conseravation block. The yield of lucerne without applied N is as high as from ryegrass with 250 units N/ac. Red clover is also useful over a wide range of soil types.On the less intensive farm, white clover should be contributing throughout the grazing area. there are many reasons for poor white clover populations in pastures; one of these is the fungus disease Sclerotinia trifoliorum, commonly known as clover rot. Varieties resistant to this disease are available in both red and white-clover. Verticillium wilt in lucerne bas also been checked by the plant breeder.Improved legume varieties justify a completely new look at these crops and the possibilities for lucerne in this country appear to be particularly good.
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  • 137
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Irrigated plots of a mixed sward of Lolium perenne, Paspalum dilatatum, Bromus unioloides, Dactylis glomerata and Trifolium repens were used in 2 experiments during 4 years. In the first experiment, die treatments comprised factorial combinations of heights of cutting of 3, 6 and 10 cm (1.2, 2.4 and 3.9 in.) above ground level, and heights of growth of 5, 13 and 20 cm (20, 5.1 and 8.0 in.) above the height of cutting. In the second experiment, 8 combinations of dose (3 cm or 1.2 in.) or lax (10 cm or 3.9 in.) cutting were applied at various times during each year.In the first experiment, DM production for cutting heights of 3, 6 and 10 cm was 50, 44 and 43 t/ha (198,17.5 and 171 ton/ac), respectively; the DOM production was 37, 32 and 32 t/ha (147, 12.7 and 12.7 ton/ac). DM production for growth heights of 5, 13 and 20 cm was 45, 46 and 48 t/ha (17.9, 183 and 191 ton/ac), respectively. DOM production, 34 t/ha (13.5 ton/ac), was not affected by height of growth.Percentages of protein (26, 22 and 20) and DOM (76, 72 and 71) declined as the height of growth was increased; but cutting height produced no significant effects in them. As cutting height was increased the percentage of clover declined (40, 31 and 23) and that of grasses increased (52, 66 and 72); diere were smaller changes with changes in height of growth.Hie second experiment showed that the difference between close and lax cutting became significant only when lax cutting was applied for at least half of the cuts each year. DM production was similar for treatments witii the same number of close or lax cuts, regardless of the time of year at which the two heights of cutting were applied.
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    Grass and forage science 29 (1974), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The effect of increasing annual fertilizer N application rate from 400 to 800 kg/ha (357 to 714 lb N/ac) and stocking rate from 5.0 to 7.5 animals per forage ha (2.02 to 3.04 animals per forage ac) on herbage availability, digestible OM intake and live weight gain was investigated in a grazing experiment repeated in 3 consecutive years. A 21×1 day rotational paddock grazing system was used in which the grazing area was increased in the ratio of 1:1.5:3 on two predetermined occasions.Increasing the fertilizer N application rate increased herbage availability by 12% but failed to increase live weight gain. Increasing stocking rate decreased herbage availability per ha and per animal, and also live weight gain per animal, but increased live weight gain per forage ha by 17.6%.
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  • 139
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    Grass and forage science 29 (1974), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A model is described which can be used to synthesize dairy systems under various price environments and sets of decision rules.The potential use of the model is illustrated with reference to the seasonal calving pattern as an economic decision.
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  • 140
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    Grass and forage science 29 (1974), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Different grazing treatments applied to pastures in which perennial ryegrass was dominant had little influence on DM production during the main reproductive growth period in late spring and early summer. Lax and infrequent grazing at this time did, however, reduce tiller density. During the dry summer period lax infrequent grazing increased production by 20%, while in the vegetative growth period in autumn those pastures which were alternately lax- and hard-grazed outyielded those which were hard grazed by 63%.In all treatments, initial recovery growth resulted almost exclusively from the production of leaf tissue. The rate of leaf growth declined three to five weeks after grazing, depending on treatment and season, and subsequent yield increase was dominated by sheath and stem growth.
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    Grass and forage science 29 (1974), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The liveweight gain was measured of beef cattle on pastures stocked at 5.9 to 11.8 cattle/ha and receiving 50, 182 or 329 kg N/ha in a 12-week season. N levels and stocking rates were so adjusted that similar yields of herbage per animal were expected. Results showed that similar liveweight gains per animal, averaging 1.03 kg/day, occurred at all N levels. Liveweight gain/ha ranged from 547 to 1037 kg in 12 weeks and the corresponding quantities of metabolizable energy utilized were 9890 and 17590 Meal. The results confinn earlier work (4, 7).
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    Grass and forage science 29 (1974), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Three cutting heights, 2±5, 7±6 and 12±7 cm (1, 2±5 and 5 in.) and three levels of fertilizer N, 168, 280 and 392 kg N/ha (150, 250 and 350 Ib N/ac) were imposed on a sward of Italian ryegrass (Lolium multiflorum) cv. Irish. Lowering the cutting height and increasing the level of applied N increased the yield of herhage DM. Increasing the level of applied N had a greater effect on the chemical composition of the herbage than altering the cutting height
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    Grass and forage science 25 (1970), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: An experiment was carried out on a grass/white-clover sward at North Wyke to evaluate the use of mixtures of inorganic and organic nutrient sources to simulate the nutrient effect of animal excreta, both with and without overall PK fertilizer. Grazing with sheep and the return of excreta from caged sheep both increased herbage yields, as did artificial return treatments. Artificial return treatments giving 75% of the nutrient level returned by excreta gave yields comparable with grazing. The effect of the simulated return treatments was not influenced by PK application. Grazing gave a very different botanical composition to that from the treatments in wbich natural or simulated excreta were returned to cut swards.Mixtures simulating excreta may replace the nutrient effect of the grazing animal, but not its physical effect, in some forms of grassland experimentation. They are not recommended for fertilizer trials.
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  • 145
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    Grass and forage science 25 (1970), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Grass production was measured at 24 sites in the Strathdon area of West Aberdeenshire. The mean total yields of DM from two cuts taken from unfertilized plots in 1967 and from three cuts taken in 1968 were 3014 and 3864 kgJha, respectively. Yields from soils formed on basic parent material were 30–40% more than yields from soils formed on more acidic material; and well-managed swards yielded over 40% more than poorly-managed ones. Aspect did not affect yields significantly, nor did elevation within the range 260–440 m.NItrochalk applied at the rate of 75 kg N/ha in 1968 increased the DM yield by an average of 35% but the efifect of 75 kg P2O5/ha, applied as triple superphosphate, was not significant at the 10% level. The benefits from N declined, wbereas those from P tended to increase, with elevation. There was no significant NP interaction overall, but tbe response from this treatment was better than from N alone on sites with acidic parent material.In 1968, 46% of the total yield was obtained by the end of June and only 10% after the end of August. Whereas yield declined with elevation in May–June, it increased during July–August
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    Grass and forage science 25 (1970), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Three grass silages, all made in mid-Jnne from the same herbage, were compared in a 12-week winter-feeding experiment with 12 Ayrshire cows. The silages were fed ad lib. with a supplement of moist barley and gronndnut cake. Silage A was made from unwilted berbage with no additive, silage B from identical berbage treated with 1/2 gal of formic acidJton (2.24 L/tonne) of berbage, and silage C from the herbage after wilting for 28 b. the DM contents of silages A, B and C were 20.5, 21.1 and 31.8%, respectively, and the contents of digestible organic matter in the DM were 58.9, 68.8 and 67.8%. Silage and total DM intake were bigbest on the treatment containing silage B. the mean dafly milk yields on the treatments with sflages A, B and C were 35.1, 38.0 and 34.3 Ib (15.9, 17.2 and 15.6 kg), respectively and the solids-not-fat (S.N.F.) contents of the milk averaged 8.53, 8.54 and 8.50%. It is concluded tbat silage B, the unwilted silage with formic-acid additive, was superior to botb the untreated and the wilted silage as a feed for dairy cows.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The ability of ribgrass to germinate and subsequently develop in a sward was investigated as part of a competitive study between this species and perennial ryegrass S23. The experimental model emphasized that seedling development was greatly influenced by the frequency and the intensity of cutting to which the associated grass species was subjected.
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  • 149
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Two studies are described in which the behaviour of 24 seven-month-old Friesian steer calves was observed. The first study (G1) was undertaken at the time of turnout to pasture, and the second (G2) 5 days later. The calves appeared to adapt rapidly to the change in environment, though in study G1 grazing was frequently interrupted. In study G2 the calves showed normal behaviour patterns and spent a total of 4.25 hours grazing.There was a positive correlation between age and weight at turnout and time spent grazing in study G1. However, this relationship was not apparent in G2, and there was no relationship between time spent grazing in G1 and G2.Mean weight loss upon turnout was 7.44% of live weight, in spite of the feeding of hay and barley at grass. There was no relationship between weight at turnout and subsequent weight loss.The results confirmed other experimental findings which suggest that weight loss at turnout is largely a reflection of changes in the weight of alimentary tract contents, rather than an inability to adapt to the change in environment.The calves were grazed at two intensities (‘low’ and ‘standard’) during the grazing season. Growth rate in winter and weight at turnout were negatively correlated with growth rate in the first month of the grazing season. This relationship was more apparent in the ‘low’ intensity group which received a liberal daily herbage allowance at this stage of the season. Partial correlation analysis, in which pre-grazing growth rate was held constant, indicated that weight and age had little independent influence on growth rate at grass, though there was a positive relationship between weight for age at turnout and gain during the grazing season.The importance of a target weight at turnout is discussed in relation to the 18-month beef production system. It is concluded that younger, lighter, cattle at turnout may not be at a disadvantage when adequate amounts of herbage are on offer early in the grazing season.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Book reviewed in this article:LOWE, J. [Ed.] White Qover Research.CAMPBELL, J. B. [Compiler.] Experimental methods for evaluating herbage.BRADY, N. C. [Ed.] Advances in agronomy.McVEAN, D. N.; LOCKIE, J. D. Ecology and land use in upland Scotland.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Studies were made in S.W. Scotland of the effect of winter grazing (October to March) by sheep on subsequent spring and early summer pasture production from a sward in its first harvest year and from a permanent pasture. Averaged over the two swards, DM yields in April, May and June were reduced by 38%, 8% and 5%, respectively, as a result of various times and frequencies of grazing, compared with no grazing. Reductions were greatest after grazings in the January to March period, especially grazings involving the month of March. In a trial in which fertilizer N was used to compensate for March grazing, 50 kg NJha raised DM yields in April to the level of those from no grazing, while only 15 kg NJha were needed to raise June yields to parity. Controlled winter grazing of sheep and the use of fertilizer N to restore production losses after early spring grazing are justified.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Whole crops of barley were conserved and fed to sheep and cattle. In the first experiment the barley was cut at the mealy-ripe stage of growth and conserved by ensilage or by drying artificially. Cattle and sheep lost weight when the resulting silages were fed ad lib.; wilting the crop before ensiling did not improve the performance. Sheep fed artificially-dried whole-crop barley increased in liveweight; and the intake of this was significantly higher than that of the silages.In the second experiment, barley was cut and ensiled at the watery-ripe, mealy-ripe and late mealy-ripe stages of growth. Intakes and levels of performance by sheep fed these silages did not differ with the growth stage at which the crop was harvested, but supplementation of the silages with lucerne pellets resulted in large improvements in performance.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The problems of designing, conducting and interpreting the results of grazing trials to evaluate tropical pasture mixtures are discussed in relation to an experiment wbich measured the effect of three fixed stocking rates upon two grass/legume pastures. A uniformity trial prior to grazing indicated considerable soil variability, which necessitated ground replication. Sequential grazing of three pasture replicates at a fixed stocking rate and a fixed interval of grazing resulted in sites of low fertility being heavily penalized. Such a form of replication was of value for measuring the effect of treatments upon sward composition, and, to a lesser extent, variation in animal production, within the experiment area. Differences in animal production between pasture species were small when compared with the effect of various stocking rates, emphasizing the need for an objective assessment of stocking rate when evaluating pasture species. Fixed-stocking-rate designs have more general application in the tropics because they are easier to conduct, and the results are repeatable and can be extrapolated to farm practice.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Two trials with eight cultivars of winter beans were harvested as whole-crop in 1967/8 and 1968/9. The aim was to investigate the potential of heans nnder whole-crop management, and to assess their value as a proteio-rich supplementary feed. Average DM yields of 106 hkg/ha were obtained for the control, and from 91 to 122 hkg/ha for other coltivars. Significant differences were found between the cultivars. At the cutting dates the crude-protein content was in the range 13 to 18%, and digestihility (D) 55 to 67%. DM varied hetween the two seasons and was within the range of 15 to 29 and 16 to 38%, respectively. The optimum time for harvesting beans for whole-crop conservation is when all the pods contain fully developed seeds.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The dates of their first appearance and the dates of flowering were recorded monthly over three years from time of sowing for all tillers produced by S215 meadow fescue plants growing in simulated sward conditions in large concrete pots outdoors. The results are expressed and discussed in terms of the percentage contribution of inflorescences by tillers in relation to their chronological and ontogenetic age. The latter appeared the more important. The major contribution of inflorescences was made by primary tillers in the first harvest year, by secondary and tertiary tillers in the second year and by tertiary and quaternary tillers in the third year. The chronological age at which tillers could flower ranged from 3 to 33 mouths.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Hays made, mainly in May, from pure swards of perennial ryegrass, timothy and meadow fescue were fed to 8-month old steers in 1963 and to yearling steers in 1964. High-quality hay was obtained, but no significant differences in growth rate were observed between calves fed on hays from the 3 species. In 1963, barley (1.5 kg DM/ head per day) was fed, in addition to the hays, to half the animals and resulted in a significant increase in live weight gain.The productivity, in terms of liveweight gain/ unit area, of each species when managed for hay and‘zero grazing', or hay and grazing, was calculated. On this calculation perennial ryegrass was the most productive species.
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A comparison was made of the effects of grazing with cattie and sheep separateiy hy two methods, continuous and rotationai on two forage mixtures. The two mixtures were timothy (Phleum pratense L.) with iadino white ciover (Trifolium repens L.); and brome grass (Bromus inermis Leyss) witii aifalfa (Medicago sativa L.). The rotationai system of grazing created different effects on sward composition from those caused hy the continuous grazing system. The legumes survived hetter under rotational than continuous grazing. Sheep, under both grazing systems, grazed more severeiy than cattie; they defoliated the ieaf portion of the plants and ieft more stem standing than did the cattle. Protein of the sward increased with the leaf portion, but in vitro digestibility was not altered as leaf to stem ratios changed. Although the gross effects of sheep and cattle were similar, there were differences in detail in the effect on these swards.
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    Grass and forage science 25 (1970), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The effect of a range of N rates on herbage production from grass/white-clover and grass swards was investigated in two long-term grazed experiments. The mixed sward yielded more than the grass swards over the range of fertilizer rates tested which were 0–120 lb N/ac (134.5 kg/ha), but the response of the mixed sward to fertilizer N was less than that of tbe grass sward. Tbis was due to the direct and indirect effect of clover, which was considerable with no fertilizer N but decreased witb increasing rates of application. However, clover was not completely suppressed by N at eitber site and contributed to berhage yields at all N rates.Rate and time of N application and the amount of clover in tbe sward affected tbe seasonal distribution of DM yields. The mid-season decline was less marked at bigb- tban at intermediate-levels of N supply.
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    Grass and forage science 25 (1970), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Three grass- and two lucerne-based harvest schedules were applied to pure sowings of timothy, smooth hrome grass, lucerne and the single grass/lucerne mixtures. Harvesting at the medium-bud stage of development of lucerne was selected as the criterion which provided the highest DM yield in conjunction with high and consistent levels of rVD and CP from harvest to harvest, as well as persistence of the species in the pure sowings of lucerne/grass mixtures. On the same basis, the heads-emerged stage of development proved most satisfactory for harvesting pure sowings of timothy and hrome grass.
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    Grass and forage science 25 (1970), S. 0 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Book reviewed in this article:HUBBARD, C. E. Grasses. A guide to their structure, identification, uses, and distribution in the British Isles.CHASE, A.; NILES, C. D. Index to grass species maintained in the Division of Grasses, Museum of Natural History, Smithsonian Institution.CRAGG, J. B. [Ed.] Advances in ecological research.SKOROPANOV, S. G. Reclamation and cultivation of peat-hog soils.WHITTINGTON, W. J. [Ed.] Root growth. Proceedings of the fifteenth Easter School in Agricultural Science, University of Nottingham, 1968. London: Butterworths, 1969, pp. 450.
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  • 163
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    Geophysical prospecting 22 (1974), S. 0 
    ISSN: 1365-2478
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    Topics: Geosciences , Physics
    Notes: Sub-bottom profilers achieve high resolution but limited penetration beneath the seabed. Marine seismic surveys with long streamers and conventional sources suffer from an incomplete CDP stack and an unnecessarily low signal frequency in the early part of the section. Consequently there is a depth interval over which the optimum resolution of the seismic reflection method is not achieved. This paper describes the design, conduct, and results of an experimental survey made to obtain high resolution sections (predominant frequency about 200 Hz) with reflection times up to one second in the northern North Sea. The prime motivation for the experiment was to assess the possibility of mapping a shallow gas sand which had been encountered by the drillers.The design concept of the survey was to keep all the benefits of conventional marine seismic data gathering and processing, but to reduce their dimensions and time scales by a factor of five to ten. The survey in 1972 recorded a total of twenty-four lines using twenty-four fold cover with 5 m spacing between the reflector points, and a separation of 50 m between adjacent lines. Multi-electrode sparkers were used with a shallow purpose-built twenty-four channel 240 m hydrophone streamer. The recording sample interval was 1 ms. The final sections, obtained after conventional data processing, were of good quality. The results of velocity analysis helped to distinguish primary and multiple energy. Reflections with large negative reflection coefficients were seen in some parts of the survey area, and these are thought to indicate thin gas sands.
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  • 164
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    Geophysical prospecting 22 (1974), S. 0 
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    Topics: Geosciences , Physics
    Notes: This paper deals with a case study on the application of auto-correlation and spectral analysis methods to mineral assay data taken along seven drives and two winzes concerning the McTaggart's (West) lode of Kolar gold fields. The general model conceived in this study is: measured (estimated) ore grade at jth location =true value + error at jth location. Employing an auto-correlation function of the form C e- a |k| for signals, the respective contributions of signals and noise to the total logarithmic variances for the data along drives and winzes are analysed. Smoothed spectral density estimates and their 90% confidence limits are computed for the series of data.
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  • 165
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    Notes: Methods and typical case histories of EM and IP surveys are compared in order to check their compatibility for the investigation of large areas for base metal sulphides. It is demonstrated that the fast, low cost EM may miss sulphide concentrations which cause no reduction of apparent resistivity, or which act like horizontal slabs, where EM anomalies occur marginally. In such cases only IP can recognize the whole extent of the mineralization. The misleading role of graphite exists for both methods.The conclusion is that EM remains the only economical method to survey whole ore districts, but that the shortcomings should always be taken into account in the interpretation. They can be overcome by employing geological, geochemical or other geophysical indicators in selecting promising targets for follow-up IP. Even if less than 20% of the area is covered by the expensive IP, there is a fair chance that all sulphide bearing rocks will be found. Therefore, the question is not whether to apply EM or IP methods, but how to combine them best.
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    Geophysical prospecting 22 (1974), S. 0 
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    Topics: Geosciences , Physics
    Notes: The paper deals with the prerequisites of application, specific peculiarities and methods of electrometric and thermometric investigations aimed at the solution of certain engineering-geological problems in offshore areas. Practical examples are supplied.
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    Geophysical prospecting 22 (1974), S. 0 
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    Notes: The voltage induced in a horizontal loop on a layered ground has been calculated for the case where the loop is excited by a step current and measurements are made during the off-cycle.The expressions derived for a uniform ground show that for large time t the induced voltage E(t) is approximately given by E(t)≃— (Ibαμ/20t) (σμ2/t)3/2 where σ is the conductivity of the ground, μ the permeability, b the loop radius, and I the amplitude of the current step. For small times the corresponding result is E(t)≃—Ibμ/2t.When the ground is composed of a number of layers a numerical procedure for calculating the induced voltage is described.The calculated responses of various multilayered structures show that at short times the induced voltage is asymptotic to that produced in the case of a uniform ground of conductivity equal to the top layer.Interference effects in the top layer can lead to anomalous decay curves which may result in the underestimation of the conductivity of a buried layer.
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    Topics: Geosciences , Physics
    Notes: Marine geophysical work requires accurate navigation on a continuous basis. A repeatability of 150 m CEP (circular error probable) with sequential positioning of 15 m CEP is usually acceptable. Quoted figures for many presently available navigation systems yield nearly the required accuracy. In actual operations, however, such accuracies may not be achieved, and usually the performance actually realized cannot be determined for want of independent measurements for comparison. If more redundancy in navigation measurements were available on an integrated basis, the limitations of individual systems would no longer be so critical and the accuracy of measurements could be assessed in real time. Failures in navigation continue to occur. Such failures usually result from ignorance of the capabilities of the navigation system and limitations and consequent choice of a system which is not appropriate to the demands of a particular survey. The points to be covered in work standards are listed.
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    Geophysical prospecting 22 (1974), S. 0 
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    Notes: The acceptance of articles in Geophysical Prospecting is strictly based on the originality and relevance of the contents. In order to be published a paper has to satisfy additional requirements on its external form and on its style and language: it should be written preferably in English though articles in French and German are permitted. A paper should consist of (i) a title page, (ii) an abstract, (iii) the text, (iv) list of references, (v) captions to illustrations, if any, (vi) tables, if any, and (vii) illustrations, if any. These seven parts should be mailed together but be physically separable and should be prepared according to rules which are either based on printing necessities or on the editorial style of the Journal.Failure to comply with these rules may result in delay in further processing of the article. Since Geophysical Prospecting is edited with a minimal budget correspondence with authors is kept to a minimum.
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    Geophysical prospecting 22 (1974), S. 0 
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    Notes: Depths of investigation for normal (bipolar) and focusing (unipolar) linear electrode arrays have been computed following the method given earlier (Roy and Apparao 1971) both in homogeneous and layered earth. The focusing arrangement is found to be superior to normal arrangement both in regard to depth of investigation and zone of uniform depth of investigation. This analysis holds good in layered media too. Further, the depth of investigation increases with the increase in the length (2M) of the electrode and reaches a limit, 0.29L for normal and 0.50L for focusing, when the electrode attains an optimum length to satisfy the infinite condition. This optimum length of the electrode is six times the distance L of the observation point from the electrode for normal and about ten times for focusing. A contour diagram for contributions of individual ground elements to the total signal measured at the centre of focused system is also discussed.
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  • 171
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    Notes: The authors generalize a method expounded in a previous paper (1971, Geoph. Prosp. 18, 786-799) to the case of a local conductivity σ(M) of the infinite medium satisfying the relation 〈displayedItem type="mathematics" xml:id="mu1" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR246:GPR_246_mu1"/〉 where the Ri's are the distances from the point M to n fixed points Si (i= 1,. n), k is a positive real constant and Ci, Cii are constants ensuring the condition α 〉 O.The sub-surface conductivity distributions (half-spaces) complying with (1) provide a wide variety of conducting structures, which can fit quite successfully the rather complicated distributions of conductivity occurring in natural ore bodies.An exact algebraic calculation of the apparent resistivity for these grounds, valid for any dc electrical prospecting devices (Wenner, Schlumberger, dipole, etc.) leads to a set of simultaneous linear equations, with a matrix which is invariant with respect to the position of the quadrupole being used. This greatly simplifies the numerical computation.We also present some examples of cross sections for the real and apparent resistivity obtained by this method.
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    Notes: Section migration after stack has been widely accepted by the industry. From a theoretical point of view, section migration before stack should provide superior results, the improvement warranting the drastically increased cost is not realized in most cases.There are a number of reasons that explain the discrepancy between actual and theoretically expected quality: Long period statics, refraction of rays, two-dimensional treatment of an actually three-dimensional problem.The section migration package subject to this paper allows(i) to take refraction into account,(ii) to discriminate against noise with a variety of statistical and geometrical criteria,(iii) to adapt processing time to problem complexity by a special process called SEMI-STACK.A number of examples will demonstrate the effects of section migration.
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    Geophysical prospecting 22 (1974), S. 0 
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    Notes: A seismic trace after application of suitable amplitude recovery may be treated as a stationary time-series. Such a trace, or a portion of it, is modelled by the expression 〈displayedItem type="mathematics" xml:id="mu1" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR627:GPR_627_mu1"/〉 where j represents trace number on the record, t is time, αj is a time delay, α (t) is the seismic wavelet, s(t) is the reflection impulse response of the ground and nj is uncorrelated noise. With the common assumption that s(t) is white, random, and stationary, estimates of the energy spectrum (or auto-correlation function) of the pulse α(t) are obtained by statistical analysis of the multitrace record. The time-domain pulse itself is then reconstituted under the assumption of minimum-phase. Three techniques for obtaining the phase spectrum have been evaluated: (A) use of the Hilbert transform, (B) Use of the z-transform, (C) a fast method based on inverting the least-squares inverse of the wavelets, i.e. inverting the normal time-domain deconvolution operator. Problems associated with these three methods are most acute when the z-transform of α(t) has zeroes on or near the unit circle. Such zeroes result from oversampling or from highly resonant wavelets. The behaviour of the three methods when the energy spectra are perturbed by measurement errors is studied. It is concluded that method (A) is the best of the three. Examples of reconstituted pulses are given which illustrate the variability from trace-to-trace, from shot-to-shot, and from one shot-point medium to another. There is reasonable agreement between the minimum-phase pulses obtained by this statistical analysis of operational records and those estimated from measurements close to the source. However, this comparison incorporates a “fudge-factor” since an allowance for absorption has to be made in order to attenuate the high frequencies present in the pulse measured close to the shot.
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    Notes: The implementation of a stacking filter involves the filtering of each trace with an individual filter and the subsequent summing of all outputs. The actual position of a trace in space as well as certain simultaneous shifts of traces and filter components in time do not influence the process. The resulting output is consequently invariant to various arbitrary coordinate transformations. For a certain useful class of ensembles of non-linear moveout arrival times for signals a particular transformation can be found which transforms a given ensemble into one consisting only of straight lines. It is thus possible to reduce, for instance, the analysis of a stacking filter designed for hyperbola-like moveout curves to the analysis of a velocity filter with linear moveout curves. As the (f—k) transform is a very useful concept to describe a velocity filter, it can consequently be applied to characterize a stacking filter in regard to its performance on input signals with non-linear moveout.
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    Notes: The technique of linear digital filtering developed for the computation of standard curves for conventional resistivity and electromagnetic depth soundings is applied to the determination of filter coefficients for the computation of dipole curves from the resistivity transform function by convolution. In designing the filter function from which the coefficients are derived, a sampling interval shorter than the one used in the earlier work on resistivity sounding is found to be necessary. The performance of the filter sets is tested and found to be highly accurate. The method is also simple and very fast in application.
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    Geophysical prospecting 22 (1974), S. 0 
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    Notes: A case history is presented for the exploration of barite with the electrical resistivity method. Altogether eight locations were recommended out of which six correspond to barite bodies. In the present case the gravity method, which is commonly used for the location of barite because of its high density contrast with the host rocks, has failed, perhaps due to small size of the ore bodies.
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    Notes: A correct derivation of rms, average and interval velocities from one another and from common depth point stacking velocities requires a clear understanding of the relationships between these velocities. We relate the average velocity to the rms velocity through a “heterogeneity factor” which is a quantity that gives a measure of the degree of velocity heterogeneity in the ground. The interval velocity is a quantity which varies according to the method of its derivation. The difference between rms and stacking velocities depends on the heterogeneity factor and on the length of the spread. Unless allowed for, this difference can reverse the advantages of long spreads and cause large errors in interval velocity determinations. It may be removed through a number of techniques. The accuracy of stacking velocities in the presence of random “noise” is independent of the heterogeneity factor. Relevant expressions can be broken down into simple formulae which give the accuracy quickly and with good precision.
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    Geophysical prospecting 18 (1970), S. 0 
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    Notes: One of the most important aspects in interpretation of gravity and magnetic anomalies, which generally represent the sum of many effects from the subsoil, is that these effects cannot be adequately separated into individual effective anomalies by means of known procedures. Moreover, the concept itself of anomaly separation must be expanded in a certain sense, because the addition of these effects in the mapped anomalies can arise from many structures situated in the subsoil in different relative positions to one another. A combined procedure is proposed, based on Fourier analysis utilising both periodic complex functions and nonperiodic ones, by use of which the number of individual effective anomalies cumulated in the mapped anomalies is obtained. In order to illustrate the use of this procedure and the advantages of obtaining more valuable informations on geological causes of anomalies, one example from Romania is given.
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    Notes: A number of electrical resistivity arrays are available to the exploration geophysicist in the conduct of vertical or horizontal profiling. The advantage of using central-type arrays which produce large potential drops, such as the Wenner or the Schlumberger, must be weighed against the ease of acentral arrays such as the polar and equatorial arrays.A series of nomograms has been designed to provide a means of rapid calculation of the potential drop to be obtained by any of the various central and acentral arrays, as a function of apparent resistivity, electrode spacings and available transmitter power. The same nomograms may also be used for approximate computation of the apparent resistivities in routine surveys. However, the accuracy of resistivity calculation is directly related to the accuracy of drawing lines between the scales and hence is rather limited in reduced-size nomograms in this paper.
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    Notes: In the theoretical part of the present paper, formulas have been analyzed for a magnetic dipole in a homogeneous and unbounded medium. The magnetic field is elliptically polarized in the region between the quasistatic zone and the far field. Since the position and the shape of the polarization ellipses depend on the complex wave number, k, it is possible to determine k by measuring the polarization ellipses. From k, the conductivity and the dielectric constant of the medium are easily calculated. The functions required for the measuring method have been computed and plotted in graphs.In the experimental part it was examined how far the theory may be applied to measurements of propagation through rock at frequencies ranging from 100-1000 kHz. These measurements showed that reasonably defined mean values of rock parameters can be given only if the deviations of the field from the theoretically expected field are not too high. These deviations have been named field distortions and have been examined by means of statistical methods (variance ratio tests). Gallery cavity and inhomogeneity or anisotropy of the medium account for these distortions.
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    Notes: Non dynamite seismic energy sources have shown only limited success in difficult shallow-water or marsh prospect areas, and none have applicability to both environments. Recently, a method has been devised to adapt a marine pneumatic source for operation in abrasive surroundings. A system composed of four of these modified sources together with associated emplacement and retrieval mechanisms has been developed and has proven to be a reliable and efficient seismic energy source for both shallow-water and marsh applications.
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    Notes: On présente des profils de sismique réflexion obtenus dans la partie Sud-Est du Golfe de Gascogne en eau profonde avec raccordement au plateau continental.La technique employée était celle du Flexotir à un ou deux canons en couverture triple. La charge totale par tir était égale à 50 ou 100 grammes suivant les cas. La vitesse du navire était ?environ 6,5 nœuds, ce qui a permis de couvrir 1000 kilomètres de profil en 9 jours de travail. La distance entre traces sur les coupes est de 60 mètres, ce qui per-met une étude assez détaillée.De bons résultats ont été obtenus par des fonds allant jusqu à 4000 mètres. La pénétration sous le fond atteint souvent 5 secondes (temps double).Le Flexotir constitue une méthode de prospection sismique bien adaptèe àľocéano-graphie de grande reconnaissance.
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    Notes: A second deep Schlumberger sounding has been carried out in South Africa, this time using a newly completed power transmission line, not yet in sevice, as emission line. The maximum current electrode separation attained was 600 km. The sounding was situated on a shield area with a thin cover of sedimentary rocks (Karroo System) overlying the archaean granite. The center was chosen near to the village of Dealesville.It is shown that lateral effects at large AB spacings are unlikely, but due to numerous dolerite intrusions in the sediments surface electrode effects must be guarded against; thus AB positions were chosen by geologists. Because of a low signal/noise ratio at large AB spacings the measurements were treated statistically; in particular, the elimination of non-random events improved the measuring accuracy.Although a thin conducting layer at the base of the sedimentary succession decreased the resolution of the sounding curve, the results, which were interpreted with the aid of a computer, show positively that〈list xml:id="l1" style="custom"〉(a). the crust is multi-layered with a highly resistant portion having a minimum resistivity of 15000 ohm.m and(b). a good, thick conductor appears as the final layer.The Dealesville results are in complete agreement with those obtained from the first deep Schlumberger sounding at Pofadder (Van Zijl 1969) except that the transverse resistance of the lowermost resistant crust is about 100% larger at Pofadder due probably to a second period of metamorphism. Both electrical studies support the view of a dehydrated lower crust (granulite facies).
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    Notes: A two-coil induction logging system in an infinite homogeneous medium has been theoretically analysed for the relative contributions of various ground elements to the total signal at the receiver. Unlike an earlier approximate treatment by Doll (1949), the present analysis takes skin effect into account (while neglecting displacement currents). Contour diagrams depicting relative contributions from every ground point and diagrams for vertical and radial/lateral investigation characteristics are presented. The results differ significantly from Doll's in the following points:〈list xml:id="l1" style="custom"〉1The relative contribution is frequency and conductivity dependent;2It does not show symmetry with respect to the center of coil system;3It alternates between positive and negative values with distance;4Real and imaginary contributions for a given conductivity and frequency are different from each other.The possibilities of a horizontal-horizontal sonde is briefly examined and found to be inferior to the usual sonde because of its higher sensitivity to the mud column and the invaded zone.
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    Notes: The paper deals with the early stages of development of a convenient form of electromagnetic induction method of sounding referred to as ‘Central Frequency Sounding’ and abbreviated as CFS. The method is introduced as a rapid and useful technique for investigation of shallow engineering and hydro-geological problems. Sets of theoretical two-layer master curves, suitable for interpretation of field data involving measurement of the vertical magnetic component of the field induced at the center of a loop placed on a two-layer earth, have been presented.The approximate but reasonably accurate solutions for a two-layer earth of any arbitrary resistivity contrast have been considered for the purpose and expressed in a form suitable for computation. The computed results have been presented in sets of curves useful for interpretation of field data.
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  • 188
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    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 18 (1970), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Book reviewed in this article:J. A. Jacobs, Geomagnetic Micropulsations.G. Kunetz, Principles of direct current resistivity prospecting.T. Rikitake, Electromagnetism and the Earth's Interior.E. Orellana and H. M. Mooney, Master Tables and Curves for Vertical Electrical Sounding.
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  • 189
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    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 18 (1970), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: La polarisation provoquée (P.P.) est un phénomène particulièrement complexe non seulement du point de vue des mécanismes physiques qu'elle met en jeu, mais aussi du point de vue mathématique. A cause de ľanalogie que présentent les techniques expérimentales de sondage électrique classique de résistivité?une: part, et de sondage P.P. ?autre part, on éprouve une certaine tendance à interpréter les données du second à la manière du premier. C'est pourquoi il nous a semblé utile de calculer un modèle mathématique idéalisé et schématisé qui permette tout au moins de se rendre compte de ľallure générale du phénomène auquel on peut s'attendre. On s'est placé dans le cas le plus simple, celui ?une couche mince polarisable qui présenterait la même conductibilitéélectrique que le milieu dans lequel elle est intercalée. On se propose de fournir le résultat de ce calcul pour le cas simple ?une seule électrode ?injection et ?une seule électrode de mesure et, à partir de ces données, de calculer ľallure ?un sondage P.P. de type classique avec quadripôle Wenner.On compare ensuite le diagramme calculé avec une courbe expérimentale obtenue sur un modèle figurant une couche mince de minerai disséminé II s'avère, en fin de compte, que ľallure générale du phénoméne fournit une base de contrôle solide àľexpérimentation sur modèles réduits.
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  • 190
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    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 18 (1970), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: In seismic studies being carried out to elucidate the structure at depth of the Midland Valley rift and the Tertiary igneous province in the West of Scotland, a lack of deep boreholes makes the collection of velocity data imperative for identification of seismic events and for determinations of depth. Three methods are used to investigate the correlation of seismic velocities and geological formations. The results show as strong a dependence of velocity on method of measurement as on lithology and the wide spread of values within a given formation makes the attribution of discrete velocity ranges to specific formations impossible. Changes of velocity are more significant than absolute values. The variations in both are discussed.
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  • 191
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 192
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Six perennial ryegrass varieties which were known to differ in winter hardiness were subjected to ten managements comprising two N rates and fire autumn cutting treatments. Autumn yields and soluble carbohydrate contents were measured, also the amount of winter damage in February and subsequent spring yields.The winter was mild, herbage damage was slight and no plant deaths were recorded, but significant differences were found between cutting treatments and varieties. The amount of winter damage increased with the length of the autumn rest period and with the degree of winter dormancy of individual varieties, indicating that natural senescence was a more important causative agent than frost action. Spring yields were affected by the amount of winter damage but there were considerable interactions between varieties and environments.The results are discussed in relation to autumn management practices, choice of variety for different locations and measurements of winter hardiness. The induction of winter dormancy by day length or low temperature reactions is considered in the breeding of varieties for maximum production in different parts of the country.
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  • 193
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Two experiments, each of 6 weeks dehydration, were conducted in 1972. In Expt 1, 24 cattle were grazed in individnal paddocks during July and August and received one of 4 treatments over a 6-weeks period: no supplements; straw ad lib; 3.3 kgj. day sugar-beet pulp; 4.0 kg/day molasses. Mean daily live weight gains were significantly increased by the sugar-beet pulp and molasses supplements; which also increased OM and DOM intake significantly. The increase in total OM intake per kg OM in the supplement was 0.48 for sugar-beet pulp and 0.67 for molasses.In Expt 2, 18 cattle grazed in groups of 3 during November and December. Two groups each received 0.5, 3.5 or 6.5 kg/day sugar-beet pulp over a 6–weeks period. There was no significant difference in live weight gain between treatments, and no significant difference in total intake. Intake from pasture declined with increasing level of supplement, so that the average increase in OM intake per kg OM in the supplement was 0.28.Hie results are discussed in relation to availability of pasture and the effects of the supplements on intake.
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  • 194
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Book reviewed in this article:GARNER, F. H. (Editor) Modem British fanning systems.HANSON, C. H. (Editor) Alfalfa science and technology.GIMINGHAM, C. H. Ecology of heathlands.FUSSELL, G. E. Farming technique from prehistoric to modern times.DURING, C. Fertilizers and soils in New Zealand fanning.KOSTROWICKJ, J.; SZCZESNY, R. Polish agriculture.ODINGO, R. S. The Kenya Highlands. Land use and agricultural deTelopment.
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  • 195
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Irrigated plots of a mixed sward of four grasses and white clover were cut to a height of 3 cm in either June, August, October, December or February. The plots cut at each commencement date were harvested when the height of growth of the pasture was either 10, 18, 25, 32, 40, 48 or 55 cm. At each harvest, the pasture was cut at 7 to 8 cm intervals down to a height of 3 cm. DM production, botanical composition, in vitro digestibility (DOM) and CP of each layer was determined.DM production declined from the lower to the upper layers for pastures shorter than 32 cm. For pastures taller than 32 cm, DM production declined from the lower to the middle layers, then increased in the upper layers, due mainly to the presence of seed heads.Maximum percentages of DOM and CP were observed for the middle layers of the pastures taller than 25 cm. For pastures shorter than 25 cm, DOM and CP percentages increased from the lower to the upper layers, for all commencement dates. The percentages of DOM and CP of each layer decreased as the height of growth increased.The percentage of DOM showed a positive correlation with the percentages of Lolium perenne, Bromus unioloides and Trifolium repens, and a negative correlation with the percentages of Paspalum dilatatum and chlorotic material. The percentage of CP showed a positive correlation with the percentages of Paspalum dilatatum, Dactylis glomerata and Trifolium repens and a negative correlation with the percentages of chlorotic material and the total of the four grasses within the pasture layers.The lower layers of the pasture produced large quantities of DM and, despite the lower in vitro digestibility of these layers, they produced more DOM than the other pasture layers. The DOM production of the pasture increased with increasing height of growth, but decreased as the commencement date was altered from winter through to the end of summer.
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  • 196
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Data are presented demonstrating the effects of applying fertilizer N at 59, 118 or 177 kg/ha on 16 Apr. on uptake of K, P. Ca, Mg and Na in primary growth (PG) harvested 8, 12, 16, 23, 29, 45 and 57 days afterwards, and residual effects in two successive regrowths (RG1 and RG2) harvested on 12 June and 13 Aug., respectively.Significant residual responses as uptake of K, P, Ca, Mg and Na were shown in RG1 and RG2 after all dates of harvesting PG. The residual responses compensated for poor uptake in PG. Thus, low uptakes to the second increment of N were followed by high residual responses in both regrowths; and low uptakes in PG harvested shortly after applying the fertilizer N were followed by high residual responses.Averaged over the seven dates of PG harvest, the sum of responses (PG+RG1+RG2) to the second N increment was greater than total response to the first increment in P and Mg, considerably greater in Ca and Na and slightly lower in K. These marked residual responses to the second N increment were most noticeable where PG was harvested 23 days after applying fertilizer N and became less marked as date of PG harvest was advanced.Percentage K, P, Ca, Mg and Na in DM of the PG and of RG1 increased as N application was raised. By RG2, the residual effects of fertilizer N on percentage K. P and Mg were reversed to give reduced percentages with increased N application to PG. indicative of deficiencies in availability of these elements.The application of 177 kg N/ha to PG resulted in the release of additional soil N and of other mineral elements which could lead to their depletion.
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  • 197
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: An experiment was conducted in 1971 and 1972 to study the effects of two levels of fertilizer N (50 and 504 kg/ha) on the productivity of pastures grazed by young beef cattle. Two stocking rates were imposed at the lower N level and three at the higher. In addition to rotational grazing, set-stocking and an integrated grazing-conservation system were included. The responses/kg N were approximately 1 kg live-weight gain, 19–24 Meal ME and 8–9 kg DM. Maximum yields of 1200–1300 kg live-weight gain/ha and 25,000–27,000 Meal ME/ha were recorded. Productivity of set-stocked pasture was similar to rotational grazing at the high N level, but lower at low N. The integrated system yielded comparable results to high-N rotational grazing. Performances and herbage intakes per animal reflected the stocking rates imposed.
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  • 198
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 199
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: An experiment designed to compare the nutritive values for milk production of dried grasses harvested in spring and autumn is described. The DM digestibility of the spring- and autumn-dried grass was 67±7 and 66±0%, respectively. Both dried grasses were fed at two levels, 0±4 and 0±5 kg/ kg milk (4 and 5 Ib/10 Ib milk), to lactating cows in a randomized-block design experiment using 24 animals. Each animal was also given 2±5 kg hay/day (5±5 Ib) and in addition sufficient of the dried grass under investigation to meet maintenance requirements.Milk yield, milk energy output, live-weight gain and the solids not fat (SNF) and protein contents of the milk increased with feeding level. Season of dried grass harvesting had no effect on milk yield, milk energy output or live-weight change. The spring-harvested dried grass resulted in a significantly higher milk SNF content than the autumn-dried grass and also tended to reduce milk butterfat level.
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  • 200
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    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 29 (1974), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The grass intake of three breeds of ewe was measured in the 5th–7th week (Period 1) and the 9th–11th week (Period 2) of lactation. The breeds of ewe were Finnish Landrace × Scottish Halfbred (FH), Finnish Landrace × Scottish Blackface (FB) and Thornber Colburn Colbred × Scottish Blackface (TC2). The immature FH ewes had a lower intake of digestible OM (26±1g/kg LW per day) than the mature FB (32±2g/kg LW per day) and TC2 ewes (33±5g/kg LW per day) in Period 1, but there were no difference between the breeds in Period 2. The intakes in Period 2 were significantly lower than those in Period 1.
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