ALBERT

Notes: A description is given of the development, during the previous fifteen years, of gravity surveying methods in marshlands and marine areas. The methods described include the use of marshbuggies, weasels, helicopters, tripods, diving bells and remote control instruments. Special emphasis is placed on remote control instruments and a brief description of their construction is given. Finally, the corrections involved in marine gravity surveying are discussed, and the costs of the several methods are compared.

Notes: Uphole shooting during a reflection or refraction survey provides additional information about the velocities within the weathered layer if recorded with a complete spread of geophones on the surface. Wave-front diagrams can be constructed which give a genuine picture of the wave paths in the subsurface. Their construction is based on the assumption that the travel time from a shot in the hole to a geophone on the surface is the same as that from a fictitious shot on the surface to a fictitious geophone in the subsurface.

Notes: A filtered seismic trace often appears as an almost sinusoidal curve. The reflected energy arrivals are superimposed and interfere with the continuous oscillations of the trace, and are therefore often difficult to distinguish. This is the chief difficulty in picking reflections. The situation is similar to that met with in gravimetry when a strong regional anomaly conceals small local anomalies. However, a regional anomaly is regular and broad, and owing to these two characteristics it can be removed. In reflection seismology batches of energy may also be concealed by oscillations of a continuous character. The main difference lies in the fact that the background of continuous seismic vibrations is not static, as is the case in gravimetry, but variable with time. However, a fairly constant physical quantity corresponds to these vibrations, which are composed partly of noise, partly of undesired secondary reflections. This quantity is the energy of motion of the surface layer of the ground. It is this troublesome energy that we intend to remove, in order to keep only the useful, actually reflected, energy.These remarks clearly demonstrate the importance of an investigation of the energy contained in the surface layer of the ground. After showing that, in the simplest case, the density of this energy can be expressed almost exactly by the formula u ′2−uu′′in which u′ is the velocity of a ground particle, we show how the non-linear filtering defined by this formula can be realized, and we provide a few examples.

Notes: The method of induced polarization is being more and more used for sulphide ore exploration. The purpose of the present paper is to show that the decay-time of the polarization curve represents a characteristic property of polarized media and consequently of various ores. The decay-times for various minerals, determined by laboratory measurements, are given in table form. Although the intervals of the decay-times partially overlap, the decay-time does to a certain degree supplement the data of induced polarization. Further, a method of interpretation in cases in which there is a superposition of the polarization effects of bodies with different decay-times, is discussed. Laboratory results as well as examples of field and bore hole measurements, in cases in which standard geophysical methods did not yield satisfactory results, are given.

Notes: Laboratory investigation has shown that the resistivity of massive sulphide ores at specimen dimensions is of the order of 0–10 ohmcm. Several writers, on the basis of field results obtained with various electromagnetic methods, deny the possibility that natural orebodies could have correspondingly low resistivities. The question is of interest, since such conductors, because of their small imaginary response, would be undetectable by electromagnetic methods measuring only imaginary components or phase shifts.In the present paper anomalies obtained with the Loop-Frame electromagnetic method on massive sulphide bodies in different parts of Canada are discussed. It is shown, by means of model experiments, that the conductors all have very low resistivities which, where the effective thickness can be determined, appear to correspond to the order of magnitude of specimen resistivity. It is demonstrated that confusion of the total width of a conductor with its effective thickness may lead to erronous resistivity determinations.

Notes: The method of conformal transformation is applied to determine the distribution of telluric current density at the surface for several subsurface situations. To this end one starts of from a configuration of boundaries between media of different resistivities and of two equal and opposite current poles, for which the potential distribution can be easily determined. Then a suitable conformal transformation is applied, by which the two current poles are displaced to infinity, and the boundary between the media are made to correspond to typical layer configurations in the subsurface. Several examples of the method are discussed in detail, leading to typical subsurface structures as well as to typical topographic conditions.

Notes: The amplitudes of reflection coefficients as computed from well velocity logs are distributed according to approximately normal laws. The distribution in time of the reflection coefficients, the absolute value of which is greater than a certain threshold, is Poissonian. The amplitudes of real seismogram traces obey a normal law.The autocorrelation of a seismic trace is usually quite different from the autocorrelation of the corresponding impulse.

Notes: Comparison of synthetic seismograms with field records has shown, that, under favorable circumstances, a large part of what is present on the latter may be ascribed to direct or multiple reflections due to velocity contrasts as they appear on a nearby velocity log.Therefore it does not seem unreasonable to submit good field records to a series of transformations, inverse to those which lead from a velocity log to the synthetic seismogram, with the purpose of getting somewhat more detailed and more accurate information on the variation of velocities with depth.The main difficulty in this kind of problem is generally the lack of stability of the results, i.e. the great influence on the final outcome of even small and unavoidable inaccuracies in the data or in the assumptions.For this reason a theoretical case has first been examined, where both the data and the physical hypotheses, as well as the final result were perfectly well known,—as this allows estimation and if necessary improvement in the stability of the method employed.Thus the successive steps of the inverse procedure, leading from a filtered synthetic record with multiples back to the initial velocity log are briefly discussed and the results obtained are shown.Two main stages are distinguished:—suppression of the effect of filtering, called “deconvolution”—discrimination between direct and multiple reflection, called “analysis”.For the former stage, the largely unknown filtering effect of the earth has also to be taken into account. First the way of deducing the total filtering effect from the filtered record itself is examined; second (a certain shape of the “signal”, the impulsional response of this filter, being assumed) an inverse filter is calculated ensuring a compromise between a good recovery of the original impulse and a minimum amplification of noise.A complete example of the results of the inverse procedure is given, in the case of a filtered synthetic record without multiples. The only data, supposedly known, were the sampled ordinates of this record, drawn on the usual scale of a field record. Good correlation was nevertheless found between the output of the inverse filtering and the original impulsional record. Integration yielded a pseudo-velocity as a function of time, showing again good agreement with the true velocities, except for their absolute values. If, in addition, check-shot data are supposedly available, these pseudo-velocities can be tied in, and a second integration yields the values of depth in function of time.The analysis itself, discrimination of direct and multiple reflection, starts by a step by step reversal of the recurrent procedure used for introducing multiple reflections (p. 4 ref. 3). The rapidly increasing accumulation of errors, due to the noise on the record and to the approximate nature of the physical assumptions, is partially accounted for by a continous readjusting of the results obtained. Nevertheless, if this method allows, as shown by a last example, a very satisfactory analysis of a rather noisy synthetic record, it is still too unstable to be applied to field records. An alternative method of successive approximations is finally outlined.As a conclusion, the necessarily approximate nature of the solutions of these problems is stressed. If some of the methods presented are still too theoretical, others have already been applied with success to field records.

Notes: For the propagation of acoustic waves in formations, laboratory experiments yield an expression of the form:〈displayedItem type="mathematics" xml:id="mu1" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR370:GPR_370_mu1"/〉in which A is the amplitude (strain or stress) A 0 some constant coefficient x the coordinate according to which propagation takes placeα the attenuation coefficient C velocityω the angular frequency of sinusoidal oscillation.No analogy between this law and that of electromagnetic waves can be made, since:〈list xml:id="l1" style="custom"〉1) coefficient α is not independent of frequency: its expression is α=Kω (K constant);2) however, with present recording technique, no noticeable dispersion can be found.The present paper shows how results are compatible if losses of energy are accounted for by a hysteresis phenomenon that is analyzed (see Figure). Stress T is in abscissae, and strain δu/δx, multiplied by a coefficient E′ characteristic of the elastic properties of the solid, is in ordinates. The horizontal part of the curve is θ. It is supposed that the absorption properties of the ground are given by some dimensionless coefficientλ=θ/T−Then one getsα=ωλ/4CIf λ≪ 1, we get the propagation law〈displayedItem type="mathematics" xml:id="mu2" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR370:GPR_370_mu2"/〉An attenuation takes place without phase shift, and consequently without dispersion.The author reverts to the inapplicability of the superposition principle, and foresees theoretically, for instance, that a strain T′ cos ω′t, where T′ 〉 T and ω′ 〉 ω, can completely cancel coefficient α.

Notes: The synthetic seismogram is a geophysical instrument. Examples taken from several areas are presented in order to define this tool and to show how it may be utilised in all stages of the prospection.The synthetic seismogram translates the stratigraphic information obtained from exploration wells into seismic terms; it therefore deserves to be taken into consideration when choosing the methods to be employed for solving a given problem.The synthetic seismogram enables one to know the limitations imposed by the reflecting power of the different subsurface layers. The knowledge of these limitations, combined with an understanding of the difficulties inherent in the surface conditions, helps to determine the frame in which the survey and the interpretation must be set.During the actual survey the synthetic seismogram illuminates somehow the work of the seismologist. It is a reference base which defines the correlation criteria which permit him to analize the real traces and, at the same time, to increase their resolving power.The methods of utilisation are examined both with respect to the field work (attempts to determine the technique to be used in any area by reference to the synthetic traces; determination of the volume control; choice of filters) and in the field of interpretation (identification and picking of reflections; analysis of the signals in order to obtain stratigraphic information from them; study of the character of reflections on a regional scale and density of the synthetic seismograms to be made in any region; re-evaluation of the information contained in old seismic records).

Notes: Abnormal phenomenons such as refractions and diffractions are more readily seen on cross-sections produced in magnetic processing offices than on single records. The result is that the understanding of these phenomenons intervenes more and more in the interpretation of the data.Our purpose is to proceed here to a restatement of the geometric properties related to these phenomenons and to make an attempt to distinguish between what is useful for the interpretation and what is not.To begin with we shall call our attention on diffractions and refractions over faults permitting to recognize the faults or to precise them, then on diffractions caused by irregularities of the surface forming the common boundary of heterogeneous media (more or less deep erosion surface, basement rock, …). The following phenomenons are classified as parasites:〈list xml:id="l1" style="custom"〉1) refractions following very shallow horizons, mostly related to topographic accidents,2) diffractions on the upward path caused by shallow faults,3) diffractions in the horizontal plane, found either in marine seismic or in case of heterogeneities “wrapt up” inside of an homogeneous overthrust.

Notes: It has been observed in the course of a detailed investigation that Indian granites exhibit high ultrasonic velocities in contrast to the specimens obtained from other countries. An attempt has been made in this paper to offer an explanation of this peculiar behaviour. Firstly, the initial internal pressure and initial velocity at the time of formation of rocks are calculated by using the experimental results for the changes in velocity with pressure in Indian, American, Japanese and Russian rocks. Besides this, standard curves have been computed using the above named parameters. Also, their possible influence on the high velocity values of Indian rocks, even under atmospheric conditions is studied. The effect of time of the formation of rocks at specific depths is also calculated in detail. As one of the results of this investigation, it comes out that under high pressure (deeper depths) it requires longer time to complete the processes of formation of rocks than under low pressure (shallow depths) and under high pressure a lot of stress energy can be stored i.e., the initial velocity becomes high when the rock is formed at great depths while at shallow depths a less stress energy can be stored and consequently less velocity values. Thus the combined effect of time and physical conditions at the time of formation of rock on the velocity in the rock at a given time is investigated. It can be seen here that the elastic behaviour of rocks with pressure will provide a clue to the possible petrogenetic history and also the approximate age of the rock.

Notes: A method is developed for determining the propagation of a wave of arbitrary shape in an inhomogeneous medium in which both the density and the velocity change with depth according to an arbitrary continuous function. The solution is obtained by means of successive approximations. The successive terms in this approximation correspond to the direct wave, single reflections and multiple reflections of successive order. The general formulae are then applied to three particular types of transition layer.

Notes: It has been found that ore prospecting by suitable electromagnetic and electrical methods may under favourable conditions—such as occur in parts of Norway—be carried out to greater depths than have so far been realized. By 500 c.p.s. electromagnetic measurements at the surface there was located a deep ore body, occurring in the continuation of, but separate from, an old ore body, which had been worked down to its end at a depth of some 500 m. The new ore body, starting at a depth of some 700 m and continuing downward with a slightly more dipping axis, has been traced over a considerable distance by further electromagnetic measurements at the surface, with the energizing current led directly to the ore in drill holes. Possibilities, problems and further improvements in deep E.M. techniques of measurement and interpretation are discussed. By D.C. equipotential mapping at the surface, with the current led directly to the ore, the location and direction of the deep ore body was established in agreement with the electromagnetic findings. Problems and developments in deep Charged Potential prospecting and interpretation are discussed. By 500 c.p.s. electromagnetic and D.C. potential measurements in drill holes essential information has been achieved both in locating ore formations beside a drill hole and in deciding whether ore formations in different drill holes are connected or not.

Notes: Self-feeding of silage has been successfully practised at Tillycorthie for 5 years. With unrestricted access to the feeding face, daily grazing times for 9-cwt. animals varied from 4 periods totalling 121 minutes in the case of stronger animals to 7 periods totalling 378 minutes.In feeding, chopped silage was more wasteful than long silage. The daily intake of 7-cwt. animals was 68 lb. of silage and 4 lb. of oat straw. The labour requirement for 70 animals was 6–6 hours per week.Food and labour costs on the system were 10s. 11d. per week. The estimated cost of the same items on. turnips and straw feeding is 16s. 4d. per week.The health of the cattle was good and growth excellent, and the animals went out to graze in a condition which allowed them to make maximum liveweight gain on grass.

Notes: The production and use of cocksfoot foggage for winter grazing at the Hannah Dairy Research Institute in the period 1956–61 is described. Two acres of cocksfoot (S37) were sown broadcast in 1956 and two acres were drilled in rows 28 in apart in 1957. The average annual application of fertilizer nutrients was 118 lb. N, 51 1b. P2O5 and 142 lb. K2O per acre.The mean yield of the broadcast section was 7450 lb. dry matter/acre/annum compared with 6090 lb. from the rowcrop section. Normally two crops of grass were harvested from the field in the summer, and one grazing was made in the winter. The yield of winter herbage dry matter was 28% and 26% of the total annual yield of the broadcast and the rowcrop sections, respectively.The field was grazed for four successive winters by 5–10 bulling heifers each weighing 650–850 lb. They received no other feed during the grazing period. Grazing started in December and finished in February, March or April in different years. The mean intake of herbage dry matter was only 6 lb./day, and on average the heifers lost 80 lb. liveweight each winter. This loss was regained after 4–6 weeks when the winter grazing finished. Twenty-nine of the 30 heifers held to the first or second service while grazing the winter herbage.On average the broadcast section gave 340 heifer-grazing-days per acre during the winter and the rowcrop section 260 days. The cost of a heifer-grazing-day was 3id. and 4id. on the broadcast and rowcrop sections, respectively.The dry matter of the herbage cut on 19 December 1960 had a digestible crude protein content of 59% and a starch equivalent of 34.It is concluded that on well-drained land the technique of foggage production and of winter grazing can usefully extend the normal grazing season and hence reduce the costs of winter feeding.

Notes: Two cutting treatments were applied to a cocksfoot sward, and the changes in fructosan and soluble–sugar contents of the roots, stubble and herbage were studied over a complete year.Both the soluble-sugar and fructosan contents of roots were at a low level throughout the experiment. The total soluble carbohydrate in the roots never exceeded 4%. It is concluded that cocksfoot roots are not important storage regions for soluble carbohydrates.The total soluble carbohydrate in herbage varied with season and reached a maximum of 10%. It was not affected by cuuing treatment.In stubble the total stubble-carbohydrate content fluctuated markedly with season and reached a maximum of 18% in October; it was generally higher on the infrequently-cut swards than on those cut frequently. The soluble-sugar content was small and changed little with season or cutting treatment; the fructosan content, however, varied from 2 to 16–6% and accounted for most of the changes in the soluble-carbohydrate content. Stubble is apparently the major storage region for soluble carbohydrates in cocksfoot.Under sward conditions, the quantity of soluble carbohydrates in the stubble of cocksfoot may have a positive effect on the herhage growth immediately after winter defoliation. However, when swards are actively growing in spring, other factors, such as tiller size and number, may be equally important in determining the amount of herbage recovery growth.

Notes: One of the main problems associated with silage-making is the wastage which occurs through either the use of unsuitable silos or lack of care in filling the silo. The nutrient losses caused by waste can be very high, a fact which is seldom recognized, and it is imperative that wastage should be kept to a minimum. There need be very little side-waste when a container silo is properly filled, but surface waste is more of a problem, as applying and removing conventional sealing materials, such as soil or ground limestone, are laborious and costly. In many cases, however, the cost would be amply justified because of the quantity of silage which is wasted. Using plastic sheet as an airtight seal is a possible alternative, but it is not easy to ensure that it is completely airtight and the sheet is unlikely to be of use for more than one season. An increasing number of farmers are protecting their silage with permanent roofs, a practice which will lead to a general improvement in silage quality. Theoretically, however, the hermetically-sealed tower silo is ideal from the point of view of protecting silage. The cost of this type of silo and of the ancillary equipment required is prohibitive, and it remains to be seen whether a relatively cheap form of gas-tight silo can be evolved.In future it is likely that the recommendation to allow a temperature rise to 90–100°F in silage will be ignored, as results from a number of trials clearly show that there is no advantage in doing this. Continuous filling of the silo, rather than filling in layers and allowing the mass to heat up, will allow a greater quantity of herbage to be ensiled in a given time, thus making it easier to ensile the herbage at the correct stage of growth.In the past when an additive was used it was applied by hand, a very inefficient method of distribution. Silage-making has become highly mechanized, and it is likely that mechanical application of additives will become much more popular.The importance of the dry-matter content of the herbage being ensiled will be more generally recognized. There are many benefits in pre-wilting herbage before it is ensiled, and this treatment is well worth consideration. It is obviously undesirable to have a prolonged wilting period, and one technique which may be of some interest is cutting the crop with a flail-harvester, allowing it to wilt and then picking up with a harvester. Cutting with a harvester gives a very much increased drying rate of the herbage, and the double lacerating action of the harvester in cutting and picking up results in short material which is easily handled and consolidated.

Notes: The practice of‘early bite’ was surveyed on sixty dairy farms in Wales during the period 1958–60. Assessment in a financial sense was made of the pros and cons of this practice. It was obvious that‘early bite’ was wasted or misused on many farms.

Notes: A laboratory apparatus has been constructed which makes use of a commercial compressor-type refrigeration unit and enables fresh or previously-frozen herbage samples to be freeze-dried in trays. During drying the moisture content and temperature of the herbage have been determined and shown to be closely related.

Notes: Tilley et al. (1) have clearly demonstrated that their rumen liquor and pepsin procedure for the determination of digestibility of herbage is useful and precise. The method has, however, the disadvantage that the equipment required for the centrifugation stages is relatively expensive and, moreover, when using one centrifuge only the procedure is somewhat tedious. The method outlined below completely eliminates centrifugation; the rumen-liquor stage is terminated by acidification and the residues from the pepsin stage is recovered by filtration, using a filter aid. Digestible dry matter or digestible organic matter may be determined; results for the former estimation on thirteen samples already examined at Hurley have given satisfactory results.

Notes: In controlled environment cabinets, root growth relative to shoot growth varied directly with the temperature within the range 50·–80·F. Increasing the photoperiod from 6 to 12 hours increased the root growth relative to shoot growth; additional hours of light had no further influence on this ratio. These results are discussed in relation to the maintenance of a balance between photosynthesis and the absorption of water and minerals.

Notes: Three-year leys of cocksfoot/white clover and cocksfoot alone were dressed with 0, 35, 105 and 210 lb. N per acre every year to provide information on the effect of clover and N on annual production.White clover contributed 40% of the dry-matter yield but its presence was responsible for 77% of this yield where no N was used: it was responsible for less than 8%, and contributed 5%, where 210 lb. N per acre was applied annually, lt was estimated that grass alone receiving 160 lb. N per acre would yield as much dry matter as a mixed sward receiving none.Clover had the indirect effect of raising yield of nitrogen in the companion grass by 60 lb. per acre per year. A maximum of l06 lb. was recorded in 1958.The response of the tnixed sward averaged 10 lb. of dry matter per lb. N. Prevailing economic circumstances will determine if this level is satisfactory in practice.The recovery of N by grass alone varied from 54% at the lowest level of N to 80% at the highest. On mixed swards apparent recovery was negative or low: N was to a large extent only replacing the effect of clover which was suppressed by its use.Factors influencing response and the difference between that obtained under experimental and practical conditions are discussed.The use of N to produce out-of-season grass may give good response, but may cause a reduction in clover contribution.

Notes: Book reviews in this article:M.A.F.F., Bulletin No. 154. Grassland Management

Notes: Two deep peal deposits, one in a high-rainfall area, were surface seeded with a number of grass varieties. Their sward development and general agronomy are described. Differences in performance are associated with moisture supply and severity of winter conditions. Tall fescue, red fescue and timothy gave good results at both centres.

Notes: The importance of leaf area as a determinant of yield in herbage crops is now widely realized. Selection for a rapid increase in leaf area might therefore be a useful approach to the problem of breeding for yield.The present paper describes the seasonal changes in two important components of leaf area, rate of leaf and tiller production, in contrasting varieties of ryegrass, timothy and meadow fescue. The regular seasonal variation in these components in the glasshouse is shown to be determined primarily by available light energy, the species and varieties differing in their response to changes in light energy. The possibilities of selection for these components of leaf area are discussed, but it is pointed out that individual leaf size must also be considered.

Notes: The performance of livestock, on winter grass was studied at eighteen sites in England and Wales from 1957 to 1960.Beef cattle generally gained weight while grazing winter grass. They invariably did better than similar animals overwintered on the normal feeding regime of the farms concerned.At 8 centres winter grass was utilized by dairy cows. Calculations indicated that the grass provided a valuable portion of their feed.The general condition and health of livestock grazing winter grass were satisfactory at all centres.Damage caused by poaching was largely prevented by controlled grazing.The production and utilization of winter grass had no adverse effects on sward recovery in the subsequent spring.

Notes: Attention is drawn to the increase of the unpalatable and unproductive grass, Nardus stricia, on hill grazings. This increase is considered to be related to a decline in soil fertility, which is being hastened by present-day management.An experiment to measure the production of a typical Nardus-dominated sward at 1700 feet O.D. on the northern Pennies is described. The results sliow that there was no increase in dry matter during the growing season. There was however an increase in some mineral elements. A manurial treatment showed poor response, but when the sward was cut and the herbage removed in spring, subsequent manuring gave spectacular yields.

Notes: The effects of management on the production of winter grass wen studied of 47 site England and Wales from 1954 to 1958.Cocksfoot swards provided better grazing during December and January than perennial ryegrass. The best treatment for winter-grass production from cockfoot swards was to rest from mid-August, giving un application of 52 lb of nitrogen per acre at this time.Perennial ryegrass produced relatively high yields if rested from early September, but the herbage should be grazed before the end of November because of the risk of it rotting.Cocksfoot herbage in normal swards lost more weight from December to January than cocksfoot sown in wide drills.Local Factors, such as aspect, altitude and sward vigour, were generally more important than latitude in determining level of yield in December. but there were greater lovsess of dry matter from December to January in the north than in the south.

Notes: Although it has been widely established that increased crop yields follow leys sown on arable land, the relative importance of the many causative factors which may be involved is obseure. An attempt has been made to evaluate the influence of 3- to 4-year leys on the organic matter in an arable soil and to distinguish also the relative importance of the resultant change in moisture-holding capacity, crumb stability and the nitrogen status of the soil as factors in the yield of winter wheat.An increase of about 4 tons per acre in total soil organic matter was recorded after 3 years under grazed swards. Moisture-holding capacity increased by an amount equivalent to the evapo-trans-piration loss from a full plant cover on one summer day. An increase in crumb stability was largely confined to the top inch of soil, which is effectively buried when leys are ploughed.The influence of variation in soil nitrogen status and in crumb stability on the yield of winter wheat after leys was examined by multiple regression analysis of data obtained over a number of yean from field experiments. After allowing for the effect of variation in the nitrogen status of the soil, the influence of variation in crumb stability was insignificant Conversely variation in the nitrogen status of soils, sampled under leys before ploughing, was closely correlated (r =+0.93***) with wheat yield.

Notes: The design is given of a wagon box that has 2 compartments: one serves as a self-feeding bunk for 8 cows, the other tan he emptied into a stationary bunk to feed a like number of cows. Facilities for automatic sampling of forage from 2 fields and procedures for efficient harvesting and weighing arc described.

Notes: Five cool-season turf grass mixtures were grown under two culling heights and two nitrogen levels. Turfs were sampled for population density each spring and fall for a three-year period, using the core-sampling method. Densities of all declined steadily throughout the period in all treatments. With one exception, populations of any one species were at the same low level at the end of the study, regardless of the treatment.

Notes: A series of experiments was laid down in 1957 on different upland vegetation types in Scotland to provide a basis of critical information on the performance of 18 herbage varieties. The present paper deals with results on areas dominated originally by Molinia and Nardus at Sourhope farm, Roxburghshire. Data obtained between 1957 and 1954 are discussal in relation to sward development, competition with remnants of native herbage and seasonal productivity.

Notes: With modern machinery and modem techniques of grass production, mechanical-or zero-grazing offers a means of utilizing the crop to perfection. Whether this results in enhanced profits depends largely upon the farm and the specific circumstances. It may, it may not. What is evident is that the health of the cows is not affected by an unnatural manner of summer feeding; the sward, per se, may be improved by the regular and uniform defoliation; and under conditions of intensive production and the vital need to use profitably every blade of grass, as for instance on small, highly-rented farms, the practice of zero-grazing merits the most careful consideration. It cannot lightly be dismissed as merely a new fad.

Notes: The effects of variety, date of cutting flush growth and level of nitrogenous manuring on the crude-protein content of Italian ryegrass were studied on plots cut five times in 1958.Raising the level of nitrogenous fertilizer from 174 lb. to 348 1b. N/acre reduced the percentage of dry matter from 0·5 to 2·0 and increased the percentage of crude protein in the dry matter from 0·9 to 5·1, with net increases in crude protein/fresh material of from 0·06 to 0·57%. Varieties showed consistent differences, the three Westcrwolth types, New Zealand H.I and New Zealand Italian being higher in percentage crude protein than Ayrshire, Irish, Danish and S22.Culling the flush growth earlier resulted in an increased percentage of crude protein for that particular cut, but no overall increase in mean crude-protein percentage.

Notes: Considerable plant-to-plant variation has been observed in ten varieties of Rhodes grass in Kenya, Progenies of single plants of one diploid and two tetraploid varieties showed similar variations, thus suggesting sexual xenogamous reproduction.

Notes: Book reviews in this article:GRASSLAND RESEARCH INSTITUTE. 1961. Research techniques in use at the Grassland Research Institute, Hurley.M.A.F.F. Silage making and feeding.RATTRAY, J. M. The grass cover of Africa.RUSSELL, E. W. Soil conditions and plant growth.

Notes: A study was made of the effect of sheep urine and some of its components on herbage production. The return of urine to the sward increased production from the grass species; the clover content of the sward was reduced.The application of nitrogen or potassium fertilizer equivalent to the normal return of nitrogen and potassium in urine increased production, but not as much as urine. The return of nitrogen and potassium fertilizer together increased production and altered botanical composition in much the same way as did urine.On a grass-dominant urine-treated sward the application of nitrogen fertilizer increased the “efficiency” of urine.The effect of urine on a grass/clover sward was almost entirely due to its nitrogen and potassium content. The water and indole acetic acid content of urine had no effect on pasture production or composition.

Notes: Results are given showing the effects of applying nitrogen, phosphorus, potassium, sodium and magnesium on the yield and mitieral composition of herbage cut repeatedly at the silage stage over a 3-year period. Grasses and clovers were separated before analysis. A combination of nitrogen and potassium was essential for the maintenance of high yields. Superphosphate did not increase dry-matter yields. 4 cwt. of common salt was ineffective, even under conditions of acute potassium deficiency; it reduced responses to potash and decreased yields when given with potash.Ammonium sulphate and common salt greatly increased sodium uptakes and muriate of potash depressed them. Potassium contents were greatly reduced by repeated nitrogen applications and muriate of potash gave consistent and significant increases. Potassium-deficient grasses contained more sodium than potassium.Ammonium sulphate increased magnesium contents and muriate of potash reduced them. There was a marked tendency for both effects to be more significant in late-season cuts. In late May the effects were small. 22 and 44 Ib. Mg/acre as magnesium sulphate had variable effects on herbage magnesium. These changes are discussed in relation to hypomagnesaemia.None of the fertilizer treatments altered the calcium contents of either grass or clover.

Notes: Range research and its application in the United States have been primarily in the area of ecology. The guiding principle developed is that the natural plant communities (the climax vegetation) provide the best guides to forage production potential.A careful study of man's history from the Ice Ages to the present reveals the fact that man has progressed by modifying his environment. In fact, the ability to do so is one of the significant differences between man and other animals. During the last 10,000 years man has been in turn a collector and hunter, a cultivator and domesticator, and finally an industrial agriculturist. The transition has been a slow, laborious process.The mixed-oak forests of the Mediterranean and Europe were cleared by felling and burning the trees and cultivating the cleared ground by crude flint hoes. In his migrations man learned of differences in soils and adaptations of cultivated plants. He learned to work with nature, but he also learned how to overcome some of nature's limitations.Agriculture, then, is man's attempts to overcome nature's limitations so that a desired crop can be grown and harvested. By this modification of the environment the crop supersedes the pattern of natural vegetation. There is no intrinsic difference between range and intensive agriculture, since both involve factors inherent in climate, soil, plants and harvesting.Ecologists working in the field of range management must be willing to accept ideas and principles that have put more science in the “science and art” of farming, if the “science and art” of range management is to progress suffiientiy to make possible the realization of the vast potential of our ranges and wild lands.

Notes: A study was made of the responses of four upland soil- and vegetation-types to applied lime and phosphate in the north of Scotland. Light and heavy dressings were used, the former at a rate which might be economically considered for aircraft application. Two experiments were laid down on graminaceous communities and two on contrasting types of Callunetum. The low rate of lime produced little measurable soil response, whereas the high rate induced marked and persistent effects. In terms of botanical response, however, the high rate of liming showed little advantage over the low rate in the presence of phosphate at the two grassland sites. Only very minor vegetation effects were observed at the Calluna centres, particularly where the community was in the mature stage. The results emphasize the importance of an ecological approach to upland pasture improvement, involving a knowledge of the specific responses of different plant communities to fertilizer application, combined with an appropriate measure of stock control.

Notes: It has been found for pasture purposes that the numerous varieties belonging to the species Eragrostis curvula can be grouped into types for which the names curvula, robusta blue, robusta green, robusta intermediate and chloromelas are proposed.The relative palatability of 20 varieties of E. curvula, and 1 variety of E. plana, Chloris gayana and Digitaria smutsii were compared with one another. Chloris and Digitaria were found to be the most palatable. Of the Eragrostis varieties studied, the robusta green, robusta intermediate and robusta blue were the most palatable, chloromelas varieties and E. plana being intermediate and the curvula varieties the least palatable.The grasses with the highest phosphate and potash contents were also those most acceptable to livestock. Results obtained from analyses suggested that crude fibre had little bearing on palatability.The more acceptable grasses were also the more succulent.No relationship between leaf structure and livestock preference could be demonstrated.

Notes: The effects of autumn management and nitrogenous manuring on the production of early spring grass were studied from 1954 to 1957 on farms throughout England and Wales.The most important management factor influencing spring yields was the application of spring nitrogen. In the early spring 6 to 10 lb. of dry matter were produced per lb. of nitrogen applied. Autumn nitrogen increased herbage yields in the auttimn by 8 to 17 lb. of dry matter per lb. of nitrogen applied.Italian and perennial ryegrass responded well to autumn nitrogen but it was important to graze off the extra growth fairly quickly to prevent the sward becoming too open. The yield of ryegrass swards which received spring nitrogen were very much higher if they were grazed during the previous September and October than if they had been rested during those months.In two years neither the autumn management nor alumni fertilizer appeared to influence the spring yields of cocksfoot, timothy or meadow fescue swards, in one year, however, when autumn growth was poor, autumn nitrogen and resting resulted in slightly better yields on these swards in the following spring.It is suggested that resting swards during September and October to build up “reserves” is relatively unimportant in relation to the yields of grass in the following spring.

Notes: The response of single plants of Aberystwyth S48 timothy (Phleum pratense L.) to increasing rates of ammonium nitrate applied in the spring and autumn is described.All spring treatments markedly increased the number of heads, as well as the total head-length per plant, but autumn dressings had no significant effect. Percentage head-length distribution was also greatly influenced by applications of nitrogenous fertilizer in the spring. Each higher rate of application gave a proportionate increase in the number of heads over 9 cm. in length, and a corresponding reduction in the frequency of those of 4 cm. or less. There was a positive correlation between head-length and number of florets per unit length.The results are discussed in terms of their relationship to current practices in managing timothy crops for seed.

Notes: Book reviews in this article:WATSON, S. J. and NASH, M. J. The conservation of grass and forage crops.BOR, N. L. The grasses of Burma, Ceylon, India and Pakistan (excluding Banibuseae).DAVIES, W. The grass crop, its development, use and maintenance.ELWELL, F. R. Science and the farmer.EDDOWES, M. and HARRIS, R. Measuring output from grassland in terms of amimal production.

Notes: The effect of four grasses, and four methods of utilizing the herbage, on the root weight, the proportion of organic matter in the soil and the water-stability of the soil aggregates was measured over a period of three years. The grass species in the sward had a greater effect upon the measurements than had the methods of management. Of the grass species, Lolium perenne produced the greatest root weight and highest percentage of organic matter in the soil.

Notes: It is commonly said that‘resistance to change’ is a basic factor preventing farmers from adopting new techniques, but such a statement depends on an external judgement as to the suitability of the technique studied for the farmer. In a recent survey, farmers were asked to give their reasons for not taking up recommended techniques for grassland farming, and these reasons are examined. In some cases it is clear that the farmer has no good reason for not using the technique except that he dislikes it, and differences between techniques in this respect are discussed.

Notes: Calves born in late September to early October in 1956, 1957 and 1958 were reared at pasture. They were fed milk substitute, supplemented in some cases with concentrate feeding-stuffs.The losses due to outdoor rearing were low, and calves made satisfactory gains in weight. By rearing at pasture, a considerable saving was effected in the weight of concentrates and hay consumed, while no marked response to the feeding of these supplements before weaning was found. Animals born in the autumn of 1957 and reared on this system reached 10 cwt. in less than 24 months.

Notes: The characters in 25 varieties of Rhodes grass introduced from Africa have been studied with a view to improving on Australian Commercial. Only the diploid Katambora and a tetraploid variety from Kenya appeared to possess a higher yield potential than Commercial. Sixty per cent of the varieties are tetraploid, the rest diploid. A degree of association occurred between the level of ploidy and some Rhodes grass characters.Although Rhodes grass appears to be xenogamous, all the critical evidence points to an apodictic form of reproduction. Viable caryopses were extracted from harvested “seed” and the percentage of florets setting caryopses was low. Rhodes grass caryopses germinate fairly well and have a higher resistance than usual to irradiation by gamma rays.

Notes: Three leafy grass varieties, S215 meadow fescue, S37 cocksfoot and S51 timothy. were subjected to four dril spacings of 6, 15, 24 and 36 in. under two levels of nitrogen application. Over three harvest years, meadow fescue gave better seed yields with 6- and 15-in, drill spacings. Cocksfoot gave very similar yields from 1.5, 24- and 36-in, drills but a signincantly reduced yield from 6-in, spaced drills. Timothy produced significantly higher yields at the 24 in spacing.The three varieties showed a significant response to nitrogen application.Aphids seriously affected the vegetative growth of meadow fescue and timothy at the wider spacings, but the 6-in. drills m boths species remained relatively free of aphid attack, as also did the cocksfoot block.

Notes: To estimate the proportion of the total dry matter of a herbage sample which arises either from dead or from green herbage, four methods have been compared. One of the methods, the pigmentation method, is described.

Notes: During the years 1957 to 1959 a number of trials carried out at various centres throughout the country showed that the yield of Irish pastures could be greatly increased through the application of fertilizers. Phosphorus increased both yield and the protein content of herbage. The increase in yield was a linear function of the initial P status of the herbage. For the series as a whole, phosphorus increased the yield by approximately 20%, potassium by 7% and phosphorus and nitrogen by 45%. The national and sociological implications of these results are discussed.

Notes: The effect of nitrogenous fertilizer on a white clover sward was studied to obtain information to be used in the evaluation of white clover in grassland. There was no evidence of a yield response. The weight of nodules was depressed by the addition of fertilizer.Where management is adjusted to maintain white clover in swards receiving large quantities of nitrogenous fertilizer the clover may use part of this fertilizer at the expense of symbiotic fixation.The relation of the results obtained to the assessment of the benefit derived from white clover in mixed swards is briefly discussed.

Notes: A study of plant establishment showed that a considerable depletion in the size of the grass poptilation occurred during the first few months after sowing. In this experiment, two months after reseeding, the surviving grass seedlings amounted to about 20% of the viable seed sown; this figure was further reduced to about 10% before the swards were twelve months old.In swards based on several cultivars within a species the casualty rate varied from cultivar to cultivar, and may be further modifted by manuring and management.Evidence from older swards indicated that within a period of six years one cultivar could suppress another almost completely.The data suggest that not only is there a strong selection pressure within a sward during its early life, but also that the environment (produced in this case by manuring and management) eternities the relative persistency and aggressiveness of the individual cultivars. This illustrates how a sward originally composed of several plant types eventually settles to a narrow range, provided the management is not varied.

Notes: Data from 291 digestion trials have been used to derive regression equations relating the organic-matter digestibility of herbage to the nitrogen percentage of its dry matter and to the nitrogen percentage in the organic matter of the resulting faces.The residual errors are very high and it is shown that the deviations from the lines are not randomly distributed but have a seasonal trend. The seasonal biases have been calculated, and the inclusion of month of cutting as a factor is found to improve the two regressions to some extent. Monthly regressions have also been calculated. Even with these, however, the errors are still too high for many practical purposes.

Notes: Book reviews in this article:WHYTE, R. O. Crop production and environment.IVINS, J. D. [Editor]. The measurement of grassland productivity.VOISIN, A. Better grassland sward.MOORE, I. Winter keep on the farm.