bluuebunny/crossref_metadata_2025 huggingface dataset:
Early needle senescence and thinning of the crown structure of Picea abies as induced by chronic SO2pollution. I. Model deduction and analysis
Authors: SLOVIK STEFAN
Published: April 2006

Regarding time ranges of years, a rationale has been developed which is capable of explaining observed ‘spruce decline’ symptoms observed when spruce is exposed to air containing ambient levels of SO2. It integrates and interrelates (i) ecophysiological data (tree morphology, assimilate partitioning, canopy turnover, senescence physiology, stomatal conductance, canopy throughfall, sulphur metabolism, tonoplast symport), (ii) pedological data (soil leaching, cation recycling, litter decomposition, forest nutrition), and (iii) meteorological data (site elevation, length of the annual trunk growth period, SO2‐pollution). Furthermore, it can explain field observations at numerous sites of spruce decline in central Europe where SO2 is implicated as a factor of forest decline: (i) thinning of the canopy structure; (ii) early needle senescence; (iii) cation deficiency; (iv) low SO2 tolerance at sites with depleted soils in the mountains; (v) synergism of SO2pollution and acidic precipitation; (vi) recovery after liming, fertilization and after decreasing SO2 pollution; and (vii) higher SO2 tolerances of deciduous angiosperms. Different SO2tolerance strategies are identified that are employed by more SO2‐tolerant tree species. Ecophysiological SO2tolerance factors interact in a complex synergistic or antagonistic manner. It is concluded that chronic SO2 pollution at ambient concentrations predisposes mainly evergreen gymnosperms to suffer under synergistic environmental stresses (frost, drought, pathogens, etc.). Thinning of the crown structure is massive at extreme sites, where several stresses act simultaneously on the trees (depleted soils, high SO2 pollution, acidic rain, etc.). Mathematical formulations allow precise definitions of terms such as cooperativity, synergism, antagonism, vitality, predisposition, latency, etc. This universal rationale, which is applicable to all tree species, is exemplified here for Norway spruce (Picea abies [L.] Karst.). Integration of parameters yields an ordinary differential equation, which can be solved analytically. It predicts reversible dynamics of crown structures and gives an ecophysiological background to‘damage’.
THE COMPOSITION OF A SHEEP'S NATURAL DIET
Authors: Tribe D. E.
Published: April 2006

Summary

Tbe protein, carbohydrate, fat, vitamin and mineral contents of plants are known to differ at different stages of growth and between species; for this reason it is plainly important for the husbandman to know what plants and parts of plants bis animals prefer. Tbis paper reviews available information concerning the composition of a sheep's natural diet and discusses the experimental difficulties involved in its collection.
STUDIES ON THE PRODUCTIVITY OF FIRST YEAR LEY GRASS WHEN CUT AT DIFFERENT STAGES OF GROWTH, ENSILED AND FED TO BEEF CATTLE
Authors: Dodsworth T. L. , McK. Campbell W. H.
Published: April 2006

A number of feeding trials, designed to determine the fattening value of grass silage for beef cattle, have been carried out during the last four years in Aberdeenshire. A general account of these trials has been published, (3, 4) and a detailed account of some of the results of Trial No. 9 is in the press (5). The chemical analysis required in Trial 9 was performed by Dr. A. J. G. Bamett, Department of Biological Chemistry, Univeristy of Aberdeen. Some aspects of these analytical results have already been published (1, 2).

During two of these trials, carried out on the Duthie Craibstone Farm, data was eollected during the silage making periods as well as for the actual feeding trials. It was therefore possible to relate the liveweight increase obtained in the feeding trials to the acreage of grass cut. This has been done and the results obtained are now presented.

Both trials were designed to determine the fattening value of silage made from grass cut at three different stages of maturity. In both cases the acreage of grass available had to be cut a number of times in order to obtain the tonnage of silage required for the feeding trials. The results obtained therefore represent the full seasonal yields per acre of grass, grass eilage and liveweight increase which can be obtained when first year ley grass is cut at difFerent stages of growth, and when different cutting frequencies are practised. In both trials a control group of cattle was fed on swedes and oat straw. A comparison can then be made of the stock carrying and fattening capacities of swedes and silage.
THE RENOVATION OF DOWNLAND PERMANENT PASTURE
Authors: Norman M. J. T. , Green J. O.
Published: April 2006

An experiment involving surface cultivations and seeding of poor downland permanent pasture, followed by controlled sheep grazing at two levels of nitrogen manuring, was conducted at Hurley, between 1951 and 1955.

Two series of sowings were made. In 1952, establishment of spring‐sown perennial ryegrass was more successful than that of summer‐sown ryegrass, while in 1955 the reverse was true. Differences in establishment were attributed to the degree of competition from the original herbage and to soil moisture conditions. In spite of a relatively low establishment, development of perennial ryegrass on plots which received 5 cwt. Nitro‐Chalk per acre annually following the 1952 spring and summer sowings was satisfactory. Development of white clover was satisfactory only after spring sowing without nitrogen. Cocksfoot, timothy and meadow fescue failed to establish. On the area treated in 1952, first‐class pasture species (perennial ryegrass, cocksfoot and white clover) contributed, by 1955, nearly 60 per cent to sown plots receiving nitrogen, and approximately 40 per cent to sown plots without nitrogen. Without cultivations and sowing, the proportion of first‐class species was approximately 30 per cent at both levels of nitrogen. The mean increase in dry matter yield due to cultivations and sowing two and three years after treatment was 11 per cent, while the mean increase due to nitrogen was 30 per cent. Both nitrogen manuring and sowing increased the nitrogen content of the herbage and the proportion of total annual yield recorded in spring and autumn.
STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS
Authors: Baker H. K.
Published: April 2006

The effects of cutting on the root, stubble and herbage growth of perennial ryegrass during establishment was studied under sward conditions.

Although a few weeks after a cutting treatment there was a smaller root weight on the cut than on the uncut swards, this difference eventually disappeared.

By the autumn the frequently cut swards had considerably more plants and tillers per unit area than the uncut plots. As a result of these changes in plant density the root weight per unit area of the sward was not decreased by increasing the cutting frequency during establishment. However, the root weight per plant (and per tiller) was decreased by increases in the cutting frequency.

The root and stubble weights increased during the spring, summer and early autumn of the first year and decreased during the winter. In the second season the root weight increased to a maximum in December whilst the stubble weight rose during the spring and summer and decreased after September.

Although the percentage of total soluble carbohydrate was consistently higher in the stubble than the roots or herbage the quantity was similar in both roots and stubble, and in these organs the major soluble carbohydrate was fructosan.

During the winter both the percentage and the total quantify of soluble carbohydrate in the stubble and roots decreased considerably.

Herbage growth in February and March was not correlated with the root weight per unit area in the previous autumn but was positively correlated with the root weight per plant. The highest herbage yield in the early spring came from plots which were leniently treated in the previous autumn: these plots had a low plant and tiller density but the root weight per plant or per tiller was relatively high.

In April the rate of herbage growth tended to be positively correlated with the sward density. In May and June the highest herbage yields came from the open swards. It was suggested that during this latter period moisture, and/or nitrogen, may have been the limiting factor, so that the open sward benefited from less interplant competition.
THE EFFECT OF DUNG AND URINE AND ITS INTERACTIONS WITH APPLIED NITROGEN, PHOSPHORUS AND POTASSIUM ON THE CHEMICAL COMPOSITION OF PASTURE
Authors: Watkin B. R.
Published: April 2006

The importance of the grass/clover balance of a pasture in determining the effects of manurial returns and fertiliser applications on the chemical composition of the sward is shown.

The response to applied nitrogen was very dependent on the presence or absence of the animal excrements. For example, the N recovery from an application of 18 cwt. per acre of nitro‐chalk was only 2% in the absence but 68% in the presence of the grazing animal.

Urine caused a marked increase in the N and K content and the yield of pasture, particularly when returned in quantity to a high‐producing grass‐dominant sward, and at the same time tended to depress the Ca, P and Mg content. Urine K was superior to fertiliser K, per pound of K returned or applied, in raising the K content of the pasture.

By comparison, dung had little direct effect on chemical content; even when returned in large amounts it affected the Ca and K content of the pasture to a relatively small extent. The P returned in the dung had little effect on the P content of the pasture and was inferior to superphosphate in this respect.

Together, as in normal grazing, dung and urine tended to counter or enhance their individual effects.

There was a positive correlation between the Mg and P content of the pasture and a negative correlation between Mg and K. Brief mention is made of the possible importance of the nutrient balance in pasture as a factor in animal health.
SPACED‐PLANT TRIALS AT EAST CRAIGS
Authors:   V. Strains of timothy, Phleum pratense L., and perennial ryegrass, Lolium perenne L., 1955, Thomson J. R. , Keppie J. L.
Published: April 2006

Four strains of Phleum pratense L., and one strain of Lolium perenne L., all of foreign origin, are classified by comparison with established strains on the basis of their performance in a spaced‐plant trial in Scotland in 1955.
EAR‐BEARING CAPACITY OF TILLERS ARISING AT DIFFERENT TIMES IN HERBAGE GRASSES GROWN FOR SEED
Authors: Langer R. H. M. , Lambert D. A.
Published: April 2006

Three experiments are described, two with S215 meadow fescue and one with S37 cocksfoot, all grown for seed, during which all new tillers, soon after their appearance, were labelled at intervals of a month—a total of nearly 12,000 tillers. Whatever the first date of observation, the earliest tillers were always found to have contributed the largest proportion of the ears present at harvest. In one experiment applied nitrogen caused an increase in the number of tillers and ears, without however affecting the percentage contribution of the earliest tillers to the final crop of ears. The importance of the autumn period of tillering is stressed.
THE STABILITY OF S23 PERENNIAL RYEGRASS DURING SEED MULTIPLICATION
Authors: Cooper J. P.
Published: April 2006

In outbreeding species, such as perennial ryegrass, most plants are heterozygous for genes controlling agronomic characters and varieties must usually be based on more than one plant to avoid inbreeding depression. This leads to the possibility of change under the selective action of seed multiplication.

Several stocks of S23 perennial ryegrass were examined to see whether such a change occurred; Irish, Kent and Hunsballe were grown for comparison.

The characters recorded were date of ear emergence, winter requirement before heading, and leaf size, rate of leaf appearance, tillering and dry‐weight production in the young seedling.

A slight shift towards earliness of heading occurred during seed multiplication, but no regular change in the other characters could be detected. The S23 stocks could readily be distinguished from Hunsballe and, less easily, from Irish, as early as the sixth leaf stage.

It is concluded that although considerable genetic variation for all these characters exists within the S23 stocks, changes during seed multiplication are not inevitable but depend on the management of the crop.
THE PERSISTENCE OF WHITE CLOVER UNDER POULTRY GRAZING
Authors: Cowlishaw S. J.
Published: April 2006

An experiment was carried out in two parts to investigate lack of persistency of white clover in a meadow fescue/white clover sward when grazed by poultry. It was found that poultry manure was responsible for a considerable part of this depressing effect. Grazing by poultry in the autumn and winter was nearly as effective in reducing the clover conlent of the sward as grazing for the whole year, autumn grazing being particularly harmful. Autumn and winter grazing alone increased the number of sown grass tillers and reduced Poa tririalis tillers in comparison wilh all‐the‐year‐round grazing. Range and fold grazing at a high stocking rate (312 per acre in the first winter) both had the same effect on the sward. The effects of drought and continual close mowing on white clover persistence are discussed. Fertilizers containing calcium, potassium and phosphorus might counteract the depressing effect of poultry grazing and manure on white clover.
LEAFINESS, CHEMICAL COMPOSITION AND YIELD OF SOME LUCERNE VARIETIES
Authors: Zaleski A. , Dent J. W.
Published: April 2006

The leaf: stem ratio on green and dry weights, chemical composition and yield of dry‐matter and protein per acre were determined for ten varieties of lucerne at the National Institute of Agricultural Botany during 1955–8. The first cut was taken when about 20% of the flowers were open and the subsequent cuts when 10–15% were open.

The mean leaf: stem ratio, based on green weights, showed no significant difference between varieties. The early varieties, however, contained a higher proportion of dry‐matter in the leaf and a lower proportion in the stem than did the mid‐season and late types. As a result, the early types tended to show a higher leaf: stem ratio based on dry‐matter than the mid‐season and late types.

The early types also contained a significantly higher percentage of protein than the mid‐season and late types, and had a lower crude fibre content for the whole plant.

Highly significant differences were established between varieties and types in the total yields of dry‐matter and protein from three cuts in each of three seasons, when all were cut at similar stages of maturity. The heaviest yields of dry‐matter and protein were secured from Eynsford, Chartrain‐villiers and Du Puits, the lowest from certified Provence and Grimm, both of which came from an environment vastly different from that of Cambridge. Gamma, an early variety, had the highest percentage of crude protein at each cut during the three year period, but it was similar to FD 100 and Marais in total dry matter yield.
DETERMINATION OF THE DRY WEIGHT OF HERBAGE BY DRYING METHODS
Authors: Greenhill W. L.
Published: April 2006

An investigation has been made with the object of establishing a satisfactory drying method for use in determining the dry weight of air‐dry herbage. In one experiment, drying was carried out at various temperatures over P2O5 and also at a sustained high vacuum: in a second experiment, oven drying was carried out at atmospheric pressure at various temperatures and for various periods.

Decomposition has been found to occur at comparatively low temperatures while, on the other hand, the intensity with which some of the moisture is held suggests that it may not all be removed at “safe” temperatures, even at very low vapour pressures.

The best technique that can be suggested at the present time is drying over P2O5 at 40°C. For less accurate results oven‐drying at atmospheric pressure at 80°C for 16 hours is proposed.
THE GRASSLANDS OF YORKSHIRE'S WEST RIDING
Authors: Jones John
Published: April 2006

In the West Riding of Yorkshire there is great variation in farm practice as well as in the character and productivity of the grasslands.

Such natural Features as the weather and the form and type of the land coupled with man's influence help to explain why most of the grass and rough grazings occupy the western areas whereas arable crops are concentrated in the east.

The distribution of grass as a percentage of total crops and of grass (excluding rough grazings) of cattle and of sheep are each illustrated in a diagram.

In describing the Riding's grassland pattern the county is divided into two main regions—the Pennines and the lowlands.

Sub‐divisions of these areas have been used to simplify this account of grassland husbandry.
CLOVER NITROGEN AND SWARD PRODUCTIVITY
Authors: Herriott J. B. D. , Wells D.
Published: April 2006

Under mowing conditions in the absence of the animal, ultra‐simple swards based either on ryegrass or cocksfoot gave large increases in yield of dry matter and nitrogen from the inclusion of white clover in the seeds mixture. Raising the clover seed rate from 1 to 3 lb./acre gave a further response in yield.

As the swards aged, the continuing effect of increased clover seed rate was dependent on applied nitrogen.

The rate of transference of nitrogen from clover to the soil depended upon the species of the associated grass, the clover seed rate, the age of the sward and the degree of reduction of the clover in the sward.

Suppression of clover led to an increase in soil nitrogen, particularly with high seed rates of clover.

Dry matter response to applied nitrogen (69 lb./acre/annum) was greater in cocksfoot than in ryegrass. Fertilizer nitrogen had little effect on the yield of nitrogen from the sward except where the high seed rate of clover had been used.
SOME FACTORS AFFECTING THE OUTPUT OF STARCH EQUIVALENT FROM GRAZING LAND ON UPLAND DAIRY FARMS
Authors: Wynne A. J.
Published: April 2006

Grazing records and cost records have been analysed from 19 dairy farms, all situated at least 400 feet above sea level, in order to determine the effect of height and of increased expenditure on the level of output of starch equivalent, and to investigate whether these farms have special problems not met with on lowland farms. The analysis shows a very marked influence of height on output and a low, statistically non‐significant, correlation between costs and yields. The low correlation between costs and yields is reviewed and reasons are suggested why a higher correlation was not found. Finally the fall in output with increasing height of farm is related to costs in order to quantify the economic disability of the upland dairy farm.
AGRONOMIC CHARACTERISTICS OF RYEGRASS PLANTS OBTAINED FROM AN ELEVEN YEAR OLD SWARD
Authors: Gardner A. L.
Published: April 2006

The investigation compared the agronomic characteristics of Irish and S 23 perennial ryegrass plants grazed for 11 years with newly propagated Irish and S 23.

The sample drawn from the surviving Irish population displayed the following characters relative to the newly propagated plants: the date of ear emergence was 2 days later, the growth habit at emergence was similar, the aftermath was more leafy.

The S 23 subjected to the same management as the Irish was identical with newly propagated S 23, apart from earlier ear emergence. The possible reason for this and the consequent limitations of the results are discussed.
THE PRODUCTION OF EARLY SPRING GRASS
Authors: Baker H. K.
Published: April 2006

Spring nitrogen significantly increased the yields of early spring grass. The response per lb. of nitrogen applied in the early spring ranged from 9 to 28 lb. of dry matter, depending upon the weather. Autumn nitrogen significantly increased herbage yields during the autumn. The increase per lb. of nitrogen ranged from 12 to 22 lb. of dry matter.

Autumn nitrogen caused significant increases in the yield of early spring grass in 1956, but these increases were very small and not of practical importance.

The effects of autumn grazing on spring yields were not consistent and were small when compared with the effects of spring nitrogen. Both autumn grazing and autumn nitrogen tended to reduce the percentage of soluble carbohydrates in the stubble and roots of grasses in November.
STUDIES OF THE GROWTH OF A HYP ARRHENIA‐DOMINANT GRASSLAND IN NORTHERN RHODESIA
Authors: Brockington N. R.
Published: April 2006

The results of studies preliminary to management trials on this type of grassland are reported. The annual growth cycle of the community is described in terms of herbage yields and chemical composition. It is shown that repeated cutting at an early growth stage will prevent the rapid deterioration in quality of the herbage which is evident in the uninterrupted growth cycle. Changes in the sward with repeated cutting are described.

The second phase of growth, after the main flush has flowered and set seed, may be enhanced by cutting in the second half of the wet season; it is suggested that this aftermath growth might be used for grazing in the first part of the dry season.

The annual growth cycles cf six component species of the community grown as pure stands are described, together with the yields and chemical composition of the herbage obtained from them with repeated cutting.

The results of fertilizer trials on this type of grassland are given, and it is shown that substantial increases in yield of dry matter and percentage crude protein may be obtained with the application of sulphate of ammonia. Responses to dressings of superphosphate are largely conditional on alleviating the nitrogen deficiency, and there is a significant nitrogen/phosphorus interaction. Both marinate of potash and agricultural lime have little effect on growth and production at the levels tested.

Investigation of the practice of burning the grassland in the late dry season, after resting from grazing in the previous wet season, confirms that this is an effective means of checking the encroachment of woody species, but the flush of new grass growth induced by the fire is of such small bulk as to be of no importance in grazing management.
THE EFFECT OF NITROGENOUS FERTILIZER ON AN ESTABLISHED WHITE CLOVER SWARD
Authors: Cowling D. W.
Published: April 2006

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.
STUDIES IN THE DIGESTIBILITY OF HERBAGE
Authors: Minson D. J. , Kemp C. D.
Published: April 2006

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.
MAGNESIUM, POTASSIUM, SODTUM AND CALCIUM CONTENTS OF HERBAGE AS INFLUENCED BY FERTILIZER TREATMENTS OVER A THREE‐YEAR PERIOD
Authors: Hemingway R. G.
Published: April 2006

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.
THE PROBLEM OF NARDUS AND ITS PRODUCTIVITY IN RELATION TO SHEEP GRAZING AT MOOR HOUSE, WESTMORLAND
Authors: Rawes M.
Published: April 2006

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.
POPULATION‐DENSITY STUDIES ON COOL‐SEASON TURFGRASSES GROWN IN A SUBTROPICAL CLIMATE
Authors: Younger Victor B.
Published: April 2006

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.
THE PRODUCTION AND USE OF COCKSFOOT FOGGAGE FOR WINTER GRAZING IN SOUTH‐WEST SCOTLAND
Authors: Castle M. E. , Watson J. N.
Published: April 2006

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.
COMPARISONS OF GRASS VARIETIES FOR SURFACE SEEDING UPLAND PASTURE TYPES
Authors: Hughes R. , Nicholson I. A.
Published: April 2006

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.
GRAZING MANAGEMENT FOR DAIRY CATTLE
Authors: Holmes W.
Published: April 2006

Many studies in recent years have stressed that grassland provides the greater part of the feed requirements of ruminant livestock in temperate lands, that a large proportion of this is supplied as grazing (83, 122) and that in this form it is the cheapest source of feed for ruminants (25, 38, 40). Several authors have contrasted the production estimated to be available from pasture with the much lower proportion—about 50% (74, 116)—harvested by the animal. For these reasons the efficiency of grass utilization under grazing conditions has received intensive study in the past 20 years and many of the principles of grazing management have been elucidated. Consideration of grazing management involves a study of the needs of the animals to be catered for, the sequence of grass crops which may be grown over the season, including the influence of special‐purpose pastures and of fertilizer treatment on the yield and seasonal distribution of production, and the effective conservation of surplus herbage. In this review, however, attention is concentrated on the problems concerned in grazing management for the dairy cow during the main growing period of the year. The object of grazing management may be defined as ‘to ensure a large supply of nutritious grazing over the growing season at a low cost and to utilize it in such a manner that physical waste of herbage and inefficient utilization by the animal are minimized and the productive capacity of the sward is maintained’. It is a complex subject, involving many interrelated factors including botanical, animal and per‐acre considerations. These are briefly outlined before the available experimental data in grazing management practices are considered.
THE INFLUENCE OF SEVERAL FACTORS IN DETERMINING THE GRAZING BEHAVIOUR OF BORDER LEICESTER × MERINO SHEEP
Authors: Arnold G. W.
Published: April 2006

Over a period of 20 months twenty continuous, 24‐hour, observations were made on the grazing behaviour of Border Leicester × Merino sheep. Distinct seasonal changes were found in the pattern of grazing. Grazing usually began during the dawn period and decreased at dusk. In spring and summer there were two peaks of grazing, but there was only one peak in autumn and winter. The percentage of grazing taking place between 6 a.m. and 6 p.m. varied with season, and was highest in spring and early summer. These seasonal changes in the pattern of grazing appeared to be independent of grazing pressure, or of the nutritional requirements of the sheep.

The mean grazing time, for all observations, was 8·2 hours with a standard deviation of 0·97. Decreasing pasture availability increased grazing time, as shown by an increased intensity of grazing.

Ruminating times were found to be considerably lower than have been reported for cattle. There was a significant negative correlation between ruminating time and the nitrogen content of available pasture.

There was no clear evidence that the number of lambs carried before parturition, or suckled after parturition, had any effect on grazing time.

There was no evidence that the behaviour of one sheep influenced that of another, even of a twin, grazing nearby.

Consistent differences between sheep were found for ruminating time. The variation in grazing time between sheep, at any one time, was considerably greater than previously reported and differences between sheep were not consistent.

Variation in grazing time appeared to be less in flocks of less than 6 sheep than in flocks of 6 to 12 sheep.
THE EFFECT OF STOCKING DENSITY ON THE PRODUCTIVITY OF YEARLING FEMALE SHEEP
Authors: Cowlishaw S. J.
Published: April 2006

The effect of stocking density on the productivity of yearling female sheep was studied over the 1960 grazing season. The cumulative effect on pasture productivity of previous differences in grazing pressure was eliminated by re‐randomization of the pasture after each grazing cycle. Stocking densities from 12 to 30 sheep/acre/unit of time were imposed from March to September, followed by 7 months on a common treatment to measure subsequent effects on animal fertility. Correlations were found between stocking density and (a) liveweight gains, (b) loss of weight in fasting, (c) quality and quantity of herbage residues at the end of the last grazing cycle. Subsequent animal fertility was not measurably affected.
COMPARISONS OF GRASS VARIETIES FOR SURFACE SEEDING UPLAND PASTURE TYPES
Authors: Hughes R. , Nicholson I. A.
Published: April 2006

A study was made of the agronomic behaviour of 18 grass varieties, surface sown, after burning an upland heath community dominated by Calluna vulgaris. Complete exposure of the soil surface, the absence of competition and favourable moisture conditions provided excellent conditions for establishment. Despite this, sward development was slower than at any other site studied, and 18 months elapsed before satisfactory sward densities, and consequently a reasonable level of production, were achieved. In contrast, white clover developed vigorously from the outset. The red fescues, cocksfoots and S170 were the most promising, while the performance of most varieties was affected by one or more hazards such as frost‐heaving and summer drought. The latter aggravated the tendency of some of the varieties to produce a profusion of flowering stems and, with few exceptions, considerably reduced the colour and vigour of the herbage.
DEVELOPMENTS IN METHODS OF BARN HAY DRYING*
Authors: Culpin C.
Published: April 2006

The development of barn hay drying techniques is briefly reviewed and modem systems of drying in the bale are classified. Some results of an investigation of hay drying on commercial farms in 1961 are given. Causes of unsatisfactory operation, including uneven bale density, insufficient field drying, inadequate air flow and incomplete drying are discussed. Typical total drying costs range from about £2 to £5 10s. 0d. per ton. Benefits in experiments at Drayton Experimental Husbandry Farm have consistently included an increased yield of dry matter conserved, equivalent to £2–3 per acre. Likely developments include drying and handling of hay in the form of wafers or large cubes.
THE ‘MAT’ OF HILL SWARDS
Authors: Troughton Arthur
Published: April 2006

The application of lime reduced the weight of mat. The original botanical composition of the sward, the method of utilization of the herbage, and the application of manures other than lime had little effect upon this weight.
THE USE OF NITROGEN ON GRASS/WHITE‐CLOVER SWARDS*
Authors: Brockman J. S. , Wolton K. M.
Published: April 2006

The problem of combining clover and fertilizer nitrogen was studied in the presence and in the absence of the grazing animal. Results from mown experiments confirmed those of other workers and indicated that the large variation in response of a grass/white‐clover sward was related to level of clover production. Grazing, by recirculating nitrogen, raised the nitrogen status of all swards and increased the response to applied nitrogen. On grazed swards there was generally less clover than on mown swards, but grazing increased the nitrogen transfer from clover to grass. Grazed grass/white‐clover swards responded consistently to applied nitrogen and, at each nitrogen level (up to the 120 lb tested), out‐yielded the grass swards. A single spring nitrogen application to grass/white‐clover swards increased yield early in the season but on occasions reduced mid‐season production. A succession of applications—in early and late spring and summer—gave increased spring growth, stimulated yield in mid‐season and also accentuated the autumn flush. Applied nitrogen decreased clover population but did not impair the ability of the clover that remained to fix nitrogen and transfer it to associated grass. Practical suggestions for the use of clover and fertilizer nitrogen are given.
THE EFFECT OF PELLETING AND WAFERING ON THE FEEDING VALUE OF ROUGHAGE—A REVIEW*
Authors: Minson D. J.
Published: April 2006

Experiments to study the effect of pelleting and wafering on the feeding value of rations containing 50% or more roughage are reviewed. Although pelleting often depresses the dry‐matter digestibility of the ration, there appears to be no evidence of an alteration in the net energy value. The increased meat production and food‐conversion efficiency observed with pelleted rations is caused by an increased food intake. The extent of the improvement achieved by pelleting depends on the quality of the unpelleted ration. Milk production is sometimes changed by pelleting and milk‐fat percentage is depressed where finely‐ground hay has been used. Wafering does not appear to change the feeding value of hay.
THE PALATABILITY OF HERBAGE PLANTS*
Authors: Garner Frank H.
Published: April 2006

The survey of literature shows that palatability is a very complex subject which has not attracted the attention it deserves. Grasses and clovers are most readily consumed when they are making rapid growth and so contain a good percentage of carbohydrates, provided that they do not contain too much water and are not lacking in fibre. Palatability may be influenced by species, strains, manuring and management of cutting and grazing. Palatability varies with the kinds of animals, their ages and condition. Since there are so many deficiencies in knowledge of palatability it is recommended that this subject should receive more attention from research workers in plant breeding, chemistry and crop and animal husbandry.
CERTAIN ASPECTS OF THE INTENSIVE PRODUCTION OF FAT LAMB FROM GRASS
Authors: Thorpe E. F.
Published: April 2006

The effects of breed, rate of stocking and the creep feeding of concentrates to lambs have been studied when using intensive creep‐grazing techniques for the production of lamb fat from the ewe. With the right type of ewe and appropriate management, high rates of stocking, giving high outputs of lamb per acre, need not result in failure to market lambs fat by weaning.
THE EFFECT OF THE RATE AND TIMING OF NITROGEN APPLICATIONS ON THE SEED YIELD AND COMPONENTS OF YIELD IN S48 TIMOTHY (PHLEUM PRATENSE L.)
Authors: Lambert D. A.
Published: April 2006

An experiment on the effect of the rate and timing of N applications on the seed yield of S48 timothy is described. Some benefits were obtained from the use of nitrogen, but the results were variable, probably because of the effect of the fertilizer on root size interacting with the currently prevailing climatic conditions. It is suggested that the adverse effect of dry weather during ear initiation and development might be alleviated by the use of irrigation.
WILD WHITE CLOVER SEED PRODUCTION
Authors: Haggar R. J. , Holmes W.
Published: April 2006

A survey, covering some 140 fields, totalling 1540 acres, in Kent was conducted in 1961 on the effect of different methods of management on yields of perennial ryegrass and white clover seed. The main results were: (a) the majority of seed growers harvested seed from short‐term leys and only a limited acreage of permanent pasture was used for producing seed. Yields of both ryegrass and clover seed were considerably higher on the younger leys; (b) the highest seed yields in 1961 were obtained from fields where sheep grazing was stopped on 24 May. However, a large number of growers continued sheep grazing well after this date: (c) mechanical defoliation, especially when used to supplement sheep grazing, proved an effective method for producing high yields of clover seed; (d) honey bees are important in increasing seed yields, particularly on recently sown leys; (e) combine harvesting from the swath was the most common method of harvesting and no instance of the use of tripods was reported. Seed yields from baling methods were generally low, but direct combining produced a high average yield of clover seed. From these results it was concluded that there was much scope for raising the general level of clover seed yields, especially by giving greater attention to details of management.
THE NUTRITIVE VALUE AND AGRONOMIC ASPECTS OF SOME FODDERS IN NORTHERN NIGERIA
Authors: Miller T. B. , Rains A. Blair , Thorpe R. J.
Published: April 2006

The results are presented of digestibility trials on silage samples made from the following materials: Andropogon gay anus, Chloris gayana (Rhodes grass), Hyparrhenia rufa (Jaragua grass), Panicum maximum (Guinea grass), Pennisetum pedicellatum, P. purpureum (Elephant grass). Sorghum vulgare (sorghum), Acanthospermum hispidum, Helianthus annuus (sunflower), Stizolobium sp. (velvet bean), Zea mays (maize) and mixtures of A. gayanus/P. pedicellatum, Arachis hypogoea (groundnut haulms)/P, pedicellatum. Sorghum vtdgare/Stizolobium sp., Z. mays/Vigna sinensis (cowpea). The results obtained, also the agronomic aspects of the subject and the use of the materials as fodder for cattle during the dry season are discussed.
THE EFFECT OF HISTAMINE ON SILAGE DRY‐MATTER INTAKE
Authors: McDonald P. , Macpherson H. T. , Watt J. A.
Published: April 2006

The oral introduction of 0·5 g histamine as the diphosphate into the rumen of sheep produced no effect on the physiological condition of the animals. The feeding of histamine, as the dihydrochloride, in levels up to 1 g/day to sheep on silage diets did not affect the dry‐matter intake.
THE USE OF GRAZING CONTROL FOR INTENSIVE FAT‐LAMB PRODUCTION
Authors: Broadbent P. J.
Published: April 2006

A comparison of 3 systems of creep grazing, at a stocking rate of 6 ewes and 12 lambs per acre, indicated that lambs on a set‐stocking management with a lateral creep area grew at a significantly (P < 0·05) slower rate than lambs folded with a lateral creep area or those rotationally grazed with a forward creep area. A similar difference was apparent in the ability of the managements to maintain the ewes liveweights. However, it is suggested that these results were not the direct outcome of the applied treatments per se. Parasite burdens in the lambs were low on all the treatments and there were no significant differences between them.
INTER‐VARIETAL COMPETITION IN PERENNIAL RYEGRASS SWARDS
Authors: Gardner A. L. , Hunt I. V.
Published: April 2006

Pure cultures and mixtures of equal numbers of plants of Irish. New Zealand and S23 perennial ryegrass were grown in artificially constructed swards under field conditions. They were cut every time they reached grazing height for three successive years. Counts of plant numbers and tiller numbers per plant made each November show that S23 suppressed both plant number and tiller number per plant of Irish ryegrass and to a lesser extent of New Zealand perennial ryegrass. Its own plant number and tiller number per plant were improved in these combinations. New Zealand perennial ryegrass suppressed plant and tiller numbers of Irish perennial ryegrass.

Varying the method of cutting to match the growth of each variety resulted in improved plant survival and tiller number per unit area of Irish perennial ryegrass when cut according to the growth of S23, i.e. late in the spring. The importance of the effect of experimental technique is discussed.
THE CRUDE PROTEIN AND NITRATE NITROGEN RELATIONSHIP IN S22 IN RESPONSE TO NITROGEN AND POTASH FERTILIZER TREATMENTS
Authors: Kershaw E. S.
Published: April 2006

A field experiment to consider the effects of sulphate of ammonia and calcium nitrate at two levels of potash showed that there was little difference between the two forms of applied N in regard to percentage and yield of crude protein. High potash tended to depress both values, where calcium nitrate was the form of N applied.

Calcium nitrate generally gave higher nitrate‐N percentages in the herbage, especially at the lower percentage crude protein values; levels of applied N and season also affect nitrate‐N percentage in herbage.
A COMPARATIVE STUDY OF PAPER AND OIL AS CARRIERS OF CHROMIUM SESQUIOXIDE ADMINISTERED TO GRAZING STEERS TO DETERMINE THEIR FAECAL OUTPUT
Authors: Cowlishaw S. J. , Alder F. E.
Published: April 2006

Two steers excreting similar quantities of organic matter daily were grazed at pasture during the summer of 1961. The four experiments each involved a preliminary period of five days dosing with Cr2O3 to reach a fairly constant excretion. The steers received a daily dose of Cr2O3 either in oil suspension or in shredded paper. The carriers and steers were interchanged for each trial. For two of the trials each steer in turn was harnessed every other day and all its dung collected in a bag. Total faecal excretion of organic matter was measured from the bagged steer and estimated from the Cr2O3 concentration in a composite sample made up from all dung pats voided during the ten‐day collection period. In the other two trials the steers were not harnessed and each dung pat was separately sampled and analysed for Cr2O3 in the organic matter. The average recovery of Cr2O3 in the first two trials was 99·1 (oil) or 94·4% (paper). Calculating the faecal organic matter excretion from the concentration of Cr2O3 in the faeces and the quantity given daily overestimated it by 3·5 to 8·0%. There was no significant difference between shredded paper and oil as carriers of Cr2O3 for estimating the quantity of organic matter excreted. There were 37% and 22% less variation between dung pats in Cr2O3 concentration when this was administered in shredded paper than when given in oil suspension.
PLANT JUICES IN RELATION TO SILAGE FERMENTATION
Authors: Greenhill W. L.
Published: April 2006

Using ryegrass and lucerne silages, investigations were made into the relationship between plant‐cell breakdown, as evidenced by a collapse of the silage mass and by an increase in its electrical conductivity, and the initiation of lactic‐acid production. Changes in the water activity of the juices available as a medium for the silage bacteria were also examined. It has been shown that cell breakdown and the resultant release of the plant juices Is a necessary pre‐requisite for the production of significant amounts of lactic acid during ensilage. The investigation also confirms that the complete exclusion of fresh air from the silage mass can usually be expected to result in cell breakdown within a few hours.
PANICLE DEVELOPMENT AND PLANT VIGOUR IN DACTYLIS GLOMERATA L. IN RELATION TO DATE OF SOWING AND PLANTING
Authors: Beddows A. R.
Published: April 2006

Cocksfoot sown late in summer or early in autumn to provide a seed crop the following year generally produces a disappointing yield. The experiments described were set up to study this problem. Seeds of four varieties, American, Danish and two British cocksfoots, were sown at fortnightly intervals during the spring and summer of 1956. The sowings were repeated in 1957 with the addition of Potomac, a bred variety from USA, and an ecotype from Israel.

Plants sown after mid‐May showed a diminishing capacity to produce panicles the following summer. The last sowing in 1957 caused the weight of green hay per plant in 1958 to be at least 50% below that of the spring‐sown plants, and panicle number to drop 60–80%. Sowing after mid‐May affected panicle development in the autumn and in the following hay crop. Date of sowing had no effect on mean date of panicle emergence in the following summer. In the populations as a whole, neither the presence nor the number of panicles in the first autumn was related to productivity in the hay stand.