bluuebunny/crossref_metadata_2025 huggingface dataset:
INTERACTIONS BETWEEN FIRST AND SECOND APPLICATIONS OF FERTILIZER NITROGEN AND IMPLICATIONS IN EFFICIENCY OF NITROGEN USE
Authors: Hunt I. V. , Frame J. , Harkess W R. D.
Published: April 2006

DM yield and N uptake data are presented from primary growth and two successive regrowths of perennial ryegrass treated with combinations of three N treatments for the primary growth viz. 0, 50 and 100 kg N/ha (PN) and four N treatments applied for the second growths, viz. 0, 33, 66 and 100 kg N/ha (SN). Primary growth gave a response of 24·2 kg DM/kg applied N to PN50 with only a further l±0 kg DM/kg applied N from the second PN increment. A significant interaction between PN and SN treatments was shown in second growth. The residual DM response to PN was highest at SN0 and reduced as the level of SN was raised. Substantially greater residual responses to PN treatments were shown in the third growth. Third growth DM responses to SN treatments were high. High apparent recovery of fertilizer N reached 111% of primary N where SN66 followed PN50.

High available soil N is partly responsible for both high apparent recovery of N and high DM response. The latter appears to be associated with inclusion of growths given no fertilizer N so that the full residual effects of fertilizer N and ‘priming’ of available soil N can be realised.
ESTIMATION OF THE BOTANICAL COMPOSITION OF OESOPHAGEAL EXTRUSA SAMPLES. 2. A COMPARISON OF MANUAL SEPARATION AND A MICROSCOPE POINT TECHNIQUE
Authors: Hall D. G. , Hamilton B. A.
Published: April 2006

The botanical composition of extrusa collected from oesophageally fistulated sheep fed diets of known proportions of a legume and a grass was estimated by manual separation and a microscope point technique. The microscope hits were adjusted for the weight per unit area of each plant component in order to estimate composition by weight. The microscope point technique was more accurate than manual separation. The deviations between the actual lucerne percentages and percentages estimated by manual separation were explained by higher losses of organic matter prior to separation from the legume than the grass and by the presence of unidentifiable particles that resulted in only a portion of the samples being separated. After adjustments for these sources of error the estimates determined by manual separation were similar to the actual botanical composition of the ingesta.
POWER CORE SAMPLING OF FRESH FORAGE IN SMALL PLOT EXPERIMENTATION
Authors: Alexander R. H. , McGowan Mary , Whyte J. S. C.
Published: April 2006

A power‐driven corer, designed to collect internally samples cored from small plot forage cuts of about 5–15 kg, is described. Sampling errors for percentage DM are shown to be lower than those associated with conventional practices; smaller than usual sample weights (200 g) which are less demanding on oven space are shown to be feasible, and the tedium of the sampling procedure is alleviated.
THE EFFECT OF STOCKING RATE ON ANIMAL PRODUCTION FROM CONTINUOUS AND ROTATIONAL GRAZING SYSTEMS
Authors: Robinson G. G. , Simpson I. H.
Published: April 2006

Liveweight and wool production data are presented from a grazing management experiment in which continuous stocking was compared with a four‐paddock rotational system at three stocking rates on a sown pasture. Significant differences were recorded in liveweight and wool production between stocking rates. The overall effect of management was non‐significant but its interaction with stocking rate and year were both significant.

At the intermediate stocking rate (8 wethers/ac, 20 wethers/ha) increases in both liveweight and wool production were recorded for the rotational management system; in this treatment there was also less need for supplementary feeding. Greater wool production was recorded from the continuously grazed treatments at both the high and the low stocking rates but there was little effect on liveweight or the need for supplementary feeding.
The effect on young beef cattle of supplementing hay with dried grass or concentrates
Authors: McCULLOUGH T. A.
Published: April 2006

Forty‐eight Friesian steers with an average live‐weight of 168 kg were given hay ad libitum supplemented with 0, 0.6, 1.2, 1.8, 2.4 and 30 kg artifically dried grass or concentrates. In vitro dry matter digestibility of hay was 55%. Liveweight gain increased with each successive increase in the level of supplementation. The intake of hay decreased but the total DM was greatest at the higher level of supplementation. The results suggest that dried grass pellets combine well with hay and may be used to replace concentrates. It was shown that 1 kg of either dried grass or concentrates given as a supplement to hay fed ad libitum, will increase the live‐weight gain by 0.16 kg d−1 and decrease hay intake by 0.25 kg d−1.
The effects on ewes and lambs of grazing pasture containing differing levels of nitrate‐nitrogen
Authors: DICKSON I. A. , MACPHERSON A.
Published: April 2006

Perennial ryegrass (Lolium perenne) swards were given annual applications in six equal instalments at 21‐day intervals of either 100, 400 or 700 kg ha−1 N in 1973 and 1974. Ewes with twin lambs were rotationally grazed on these areas. The nitrate‐N content of the grass was measured immediately before grazing. Blood samples were taken at regular intervals from the ewes and lambs to estimate blood methaemoglobin and certain plasma mineral concentrations. A maximum nitrate‐N concentration of of 0.67% in the herbage dry matter was recorded but no adverse effect of N fertilizer was found in terms of the blood constituents or growth of the sheep, or in the carcase quality of the lambs.
A simple disc instrument for estimating herbage yield
Authors: CASTLE M. E.
Published: April 2006

A simple instrument for estimating the yield of herbage from measurements of height has been tested in cutting and grazing experiments. The instrument consists of a verticle graduated shaft and two linked aluminium discs which settle on the herbage. The height of the discs from the ground is recorded. Highly significant relationships were established between the yield and the height of herbage. Linear regressions explained 80–90% of the variation in the cutting experiments, and 39–62% in the grazing experiments. The errors attached to the estimated yields were high, but, because of the simple construction, low cost and rapid operation of the instrument, it is concluded that it has many useful functions in grassland research and management.
Silage and milk production. A comparision between barley and groundnut cake as supplements to silage of high digestibility
Authors: CASTLE M. E. , WATSON J. N.
Published: April 2006

Grass silage of hjgh digestibility made in late May from S23 perennial ryegrass was offered to twelve Ayrshire cows in a 16‐week winter‐feeding experiment. The silage had a DM content of 27.2% and contained 147% crude protein and 70.3% digestible organic matter in the DM. The silage was fed ad libitum and was the sole feed in the control treatment. In the other three treatments the silage was supplemented with barley, groundnut cake or a mixture of barley and groundnut supplying 4.7, 1.5 and 4.7 kg DM per cow per day respectively. The daily intakes of silage DM were 10.8 kg per cow in the control treatment and 8.6, 11.1 and 9.3 kg per cow in the barley, groundnut and barley plus groundnut treatments, respectively. The daily yields of milk were 14.6 kg per cow in the control, and 16.1, 17.6 and 17.9 kg per cow in the three supplement treatments, respectively. The fat content of the milk was highest in the barley treatment, whereas the SNF and CP contents were highest in the barley plus groundnut treatment. It is concluded that with a high digestibility silage, a supplement of groundnut cake was superior to barley for milk production.
Non‐symbiotic nitrogen fixation in some soils of England and Wales
Authors: LOCKYER D. R. , COWLING D. W.
Published: April 2006

The acetylene‐reduction method was used to estimate the fixation of atmospheric nitrogen by non‐symbiotic micro‐organisms in soils from England and Wales. Significant fixation was found only in the surface horizon of the soil (0–1 cm) and was much higher in the light than in the dark. The highest rates were found with samples having a well‐developed surface film of blue‐green algae and were from 6 to 10 g ha−1 N per h. Generally, rates were very much lower. The addition of fertilizer nitrogen at 100 kg ha−1 markedly reduced N fixation by blue‐green algae.
Qualitative effects of asulam and glyphosate on swards dominated by bracken (Pteridium aquilinum (L.) Kuhn)
Authors: WILLIAMS GARETH H.
Published: April 2006

The initial effect on the underlying sward of spraying bracken with 4.5 kg ha−1 a.i. asulam or 2.0 kg ha−1 a.i. glyphosate was to cause some damage which was greater if glyphosate was used rather than asulam or if treatment was carried out in August rather than in July. Agrostis species were especially susceptible while Festuca species were resistant. The recolonization of areas of bare ground after spraying was primarily by Holcus moliis, Anthoxanthum odoratum, Galium hercynicum and Potentilla erecta, but the population of the latter two species decreased as Agrostis became reestablished. If Digitalis purpurea, Urtica dioica or Cirsium arvense were present originally, heavy infestations developed following the use of asulam, with a smaller increase after glyphosate spraying. In all cases, by the end of three years after treatment, grasses occupied a greater area of the sward in treated than in control plots.
Voluntary feed intake and metabolism of sheep when lactic acid is administered in the feed or intraruminally
Authors: MORGAN D. J. , L'ESTRANGE J. L.
Published: April 2006

Four sheep in a 4 × 4 Latin Square experiment were offered ad libitum grass meal pellets alone or supplemented with lactic acid at 600, 800 or 1000 mmol per kg dry matter (DM) intake, either mixed into the feed or continuously infused intraruminally for 6‐d periods. When added to the feed lactic acid did not significantly affect DM intake but when infused intraruminally it significantly reduced DM intake especially at the highest rate of infusion.

In a second 4 × 4 Latin Square experiment, four sheep were offered ad libitum grass meal pellets alone or supplemented with lactic acid mixed into the pellets at 900, 1200 and 1500 mmol per kg DM for 15‐d periods. There was a small reduction in intake on the three lactic acid treatments but this was not significant.

In a third experiment the effects of intraruminal infusion with lactic acid was studied further with four sheep which received infusions of lactic acid at a fixed daily rate of 40 mmol per kg W−0·75 per d or of an equal volume of distilled water for 3‐d periods while being offered grass meal pellets ad libitum. Infusion with lactic acid resulted in reduced DM intake but the effect was less consistent than in Experiment 1.

In all three experiments lactic acid supplementation had little effect on the pH and total volatile fatty acid concentration of rumen
Optimum time of combine harvesting for amenity grasses grown for seed
Authors: HEBBLETHWAITE P. D. , AHMED M. el H.
Published: April 2006

The relationships between, and changes in moisture content, 1000‐seed weight, germination percentage and seed yield were determined from anthesis onwards in ten amenity grasses in 1975. These relationships were used to indicate the optimum date for combine harvesting and to give some indication of the consequences which follow if harvest was not carried out at this stage.

In all species seed moisture content declined, and 1000‐seed weight and germination increased to a maximum value, during ripening.
Effect of partial and complete defoliation on regrowth of white clover plants
Authors: KING J. , LAMB W. I. C. , McGREGOR MARY T.
Published: April 2006

Single plants of white clover (Trifolium repens) were subjected either to two intensities of overall defoliation or to severe defoliation of different parts of the plant. Measurements were made of growth in terms of leaf size, petiole length, internode length and other parameters, and compared with those of undefoliated plants. The results show that, while growth of all parts of the plant was reduced by severe overall defoliation, partial defoliation affected various parts of the plant differently according to which leaves were removed. The results are interpreted in terms of the acropetal movement of assimilates from alternative sources in response to defoliation.

The probable effects of this on yield and its relevance to grazing management of newly seeded clover are discussed.
A comparison of continuous grazing systems for milk production
Authors: CASTLE M. E. , WATSON J. N.
Published: April 2006

In two experiments conducted with Ayrshire dairy cows in 1974 and 1975 on swards of S23 perennial ryegrass, four systems of continuous grazing were investigated. The leys received 345 and 370 kg ha‐1 fertilizer nitrogen in 1974 and 1975 respectively and were stocked at the rate of five cows per ha. In 1974, a comparison was made between two systems which either integrated silage making with, or separated it from, the continuous grazing. The provision of a silage aftermath in late July increased milk yield after that time, but had no significant effect on milk yield over the 19‐week experimental period. In 1975, a comparison between weekly and monthly applications of fertilizer N showed no significant differences between milk yields in a 20‐week period. The feeding of supplementary concentrates from late July onwards significantly increased milk yield. The treatments in both years had only small and mainly non‐significant effects on milk composition. On average, excluding the concentrate treatment, the annual output of milk was 10,800 kg ha‐1 using spring‐calved cows.
Antimicrobial effects of mineral acids, organic acids, salts and sterilizing agents in relation to their potential as silage additives
Authors: WOOLFORD M. K.
Published: April 2006

Mineral acids, organic acids, salts and sterilizing agents were tested against a range of microorganisms at pH 4, 5 and 6. The antimicrobial spectra obtained revealed that hydrochloric, orthophosphoric, sulphuric and glycollic acids have no specific antimicrobial properties and merely function as acidifying agents. Acrylic acid, sulphamic acid and sodium formaldehyde bisulphite would apparently encourage a lactic acid‐type fermentation by suppressing the growth of butyric acid‐producing microorganisms. Chlorine dioxide and sodium metabisulphite are both antibacterial and of potential value for restricting silage fermentation Ammonium isobutyrate might find application in the production of a conventional fermented silage which is stable on exposure to air; it would appear particularly suited to silage made from wilted material. Sodium chloride apparently had no potential as a silage additive.
Seasonal variation in in vitro digestibility and structural carbohydrate content of some commonly grazed plants of blanket bog
Authors: GRANT SHEILA A. , CAMPBELL D. R.
Published: April 2006

Oven‐ and freeze‐dried samples of the separated green material of Trichophorum caespitosum, Molinia caerulea, Eriophorum vaginatum, Erio‐phorum angustifolium, Juncus acutiflorus and J. squarrosus collected in May, July and September were analysed for dry matter digestibility (DMD) using an in vitro procedure and for structural carbohydrate content.

Results were affected by method of drying, oven‐dried (45°C) samples in general giving lower estimates of quality than freeze‐dried samples. Low DMD values were obtained for J. squarrosus for all sampling dates. The remaining species had DMD values above 60 in May; some maintained these levels until July but all had low values by September.

A comparison was made between in vitro DMD and predicted DMD using the data from the structural carbohydrate analyses and the summative equation of Van Soest (1965a). Two species, J. acutiflorus and J. squarrosus, showed poor agreement between values obtained by the two methods. The other species showed good agreement between values in May and July but poor agreement in September.

The data are discussed in relation to the quality and seasonal patterns of growth of species of hill vegetation.
The effect of nitrogen and length of primary growth period on yield of leaf and stem components of perennial ryegrass
Authors: BARTHOLOMEW P. W. , CHESTNUTT D. M. B.
Published: April 2006

The influence of length of first growth period of the season and level of nitrogen application on yields of leaf and stem components of perennial ryegrass was estimated. Three primary growth periods of 21, 42 and 70 d were used in combination with nitrogen treatments allowing 0, 1.43, 2.86 and 429 kg N per ha per d of growth applied as a single dressing at the beginning of the growth period. Increases in level of nitrogen application and in growth time produced higher yields of both components, but particularly of stem. Mean leaf yield per tiller reached a maximum with a 42‐d growth period.

Whilst the ratio of leaf: stem was altered markedly by longer growth periods it was apparently unaffected by nitrogen application.
The assessment of persistence and its application to the evaluation of mid‐season and late perennial ryegrass cultivars
Authors: CAMLIN M. S. , STEWART R. H.
Published: April 2006

Persistence assessments on eight mid‐season and ten late cultivars of perennial ryegrass were made at the end of the second, third and fourth years after sowing. Botanical analyses were carried out on the herbage from plots cut in the fourth year and these results related lo the different persistence assessments. It was found that persistence assessments carried out at the end of the second year enabled predictions to be made about botanical composition of cuitivars in the fourth year. Little extra precision was gained by delaying assessment until the third or fourth years as the ranking order of cultivars with respect to persistence remained largely unchanged. All persistence assessments were positively correlated with yields of sown cultivars and negatively correlated with yields of unsown herbage species in the fourth year. However, only low correlation coefficients were obtained between persistence assessments and the total yield of sown cultivar and unsown species in the fourth year, due to yield substitution between these two components.

In swards sown as monocultures low persistence in a cultivar is considered to be a lack of perenniality and tiller regeneration rather than poor competitive ability against volunteer species though in mixed swards competitive ability per se will have considerable influence upon the changes in botanical composition under different managements. Persistence and yield capacity are seen, however, as distinct characteristics of a cuitivar and long‐term yield potential is a joint function of these characteristics.
Effects of season and level of grazing on the utilization of heather by sheep 1. Responses of the sward
Authors: GRANT SHEILA A. , BARTHRAM G. T. , LAMB W. I. C. , MILNE J. A.
Published: April 2006

The effects of sheep grazing on the development and production of heather swards were studied over a period of 3 years in an experiment in which sheep numbers were adjusted to remove 0, 40% or 80% by weight of the current season's shoots in summer and in autumn.

The number of shoots grazed increased with the level of grazing but not in direct proportion. The length of shoot grazed was greater at the 80% level of grazing. Heavy autumn grazing was associated with frequent uprooting and breaking off of shoots and with a high incidence of shoots grazed down to the previous season's wood. The siting of new season's shoots was influenced by the amount of shoot length grazed in the previous season. Grazing behaviour of sheep within a plot was affected by variation in heather cover with the sheep showing a tendency to graze near bare areas.

After 3 years of grazing, standing crop was reduced by both levels of grazing whether in summer or autumn. New shoot production was unaffected on plots which had had the 40% level of shoot removal but was reduced by half on plots which had had the 80% level of shoot removal whether in summer or autumn.

A clipping experiment was also carried out where 0, 40% or 80% of the length of current shoots was removed in May, early July and Septeinber. Standing crop was unaffected by May clipping but was reduced on plants with a history of 80% shoot removal in July or September. New shoot production was only reduced on clipped plants which had been subjected to 80% removal in September.

The role of overwintering green shoots and carbohydrate reserves in the support of new shoot growth was considered.

The implications of the results in relation to heather management are discussed.
A comparison of methods of recovering oesophageal extrusa from grazing sheep
Authors: HAMILTON B. A. , DENNEY G. D.
Published: April 2006

Extrusa samples were collected from two groups of oesophageally fistulated sheep grazing together. One group had foam plastic oesophageal plugs fitted below the fistula to assist in the complete collection of extrusa; the second group grazed without plugs. The extrusa were collected in four periods chosen to cover as wide a range of herbage conditions as possible varying from herbage with a high proportion of green leaves to predominantly dry material with a high proportion of dead leaves and stems. The plant components of the extrusa were determined and there was no evidence that stems or any other plant component preferentially by‐pass the fistula in grazing sheep. It was concluded that it is not necessary to insert foam plastic plugs in the oesophagus of grazing sheep to obtain representative samples of ingested herbage.
Effects of season and level of grazing on the utilization of heather by sheep. 2. Diet selection and intake
Authors: MILNE J. A. , BAGLEY L. , GRANT SHEILA A.
Published: April 2006

The effect of level of removal of current season's shoots of heather (0,40 and 80% of the dry matter of the shoots) in the summer and autumn on the intake and diet selection by grazing Scottish Blackface wether sheep was examined in an experiment conducted over two years in which all combinations of level and season of grazing were provided. The treatment plots were grazed for 5 weeks at any one time and measurements made of intake and diet selection in weeks 2 and 5.

In both the summer and autumn grazing periods level of removal in week 2 had little effect on the quality of the diet selected. In week 5, digestibility of organic matter was higher for the 40% than the 80% level of removal in the summer (0·543 vs 0·508) and particularly in the autumn (0·503 vs 0·449). Digestibility of the diet selected was higher in week 2 than in week 5 in both the summer (0·555 vs 0·525) and in the autumn (0·511 vs 0·476). Mechanisms of diet selection are discussed.

In the summer grazing period only small differences existed in intake of organic matter between levels of removal but in the autumn intakes were higher at the 40% than the 80% level of removal. In a clipping experiment in which 0, 40 or 80% of the length of current season's shoots was removed in May, July and September in 3 consecutive years the nitrogen content of clippings in May and July was higher and the cell wall constituent lower at the 40% level in comparison to the 80% level of removal. Higher levels of removal at the previous clipping increased the nitrogen content of the clippings in May, July and September and reduced the cell wall constituent content in September.
The influence of climatic factors on physiological development in perennial ryegrass
Authors: KEATINGE J. D. H , CAMLIN M. S. , STEWART R. H.
Published: April 2006

Dates of initiation of reproductive development and of ear emergence were determined for four cultivars of perennial ryegrass (Lolium perenne) representing a range in maturity from early to late in a single trial in 1977. The influence of climatic factors upon the reproductive development was investigated and it was found that, while day‐length largely influenced the dates of initiation, subsequent growth and development towards ear emergence was influenced mainly by temperature. The data indicated that cultivars may have similar requirements in terms of accumulated temperature between the physiological growth stage of initiation and the agronomically significant growth stage of ear emergence. The possibility of achieving greater accuracy in forecasting ear emergence dates by relating meteorological data to the physiological development of the individual cultivars is suggested.
Regrowth of ryegrass swards subject to different cutting regimes and stocking densities
Authors: KING J. , LAMB W. I. C. , McGregor M. T.
Published: April 2006

A cutting experiment was carried out on a sward of S23 perennial ryegrass to study the effect of different defoliation regimes on regrowth and the factors affecting regrowth. The defoliation frequencies and intensities encompassed the range commonly found on continuously stocked pastures. The defoliation regimes produced swards of contrasting growth form with regrowth characteristics which differed in respect of senescence loss, fall in water‐soluble carbohydrate concentration, residual leaf area index, photosynthesis per unit leaf area index and photosynthesis per unit area of land. Regrowth was most closely related to the latter. These results were used to interpret data for net canopy photosynthesis of continuously grazed pastures.
Effects of grazing by lambs in autumn on a red clover‐perennial ryegrass sward
Authors: LAIDLAW A. S.
Published: April 2006

In 1976, 1977 and 1978 a red clover‐perennial ryegrass sward was cut twice for silage, and in the autumn of 1976 and 1977 it was either grazed at low and high stocking rates, i.e. seventeen and thirty‐four lambs per ha respectively, or was cut with a forage harvester. The effects of grazing on yield in the following year were examined.

Herbage growth in the grazing period was slow and did not differ significantly between the treatments. The yield of silage dry matter taken in May and July was highest in ungrazed plots (9·8 and 8·1 t ha‐1 in 1977 and 1978 respectively) and lowest in plots stocked at the high rate (5·9 and 5·7 t ha‐1 in 1977 and 1978 respectively). The aftermath yield for grazing in 1977 was slightly but significantly greater on treatments grazed in the previous year compared with ungrazed treatments.

Red clover content decreased markedly during grazing, the high stocking rate treatment containing 2·4% clover and the ungrazed treatment 57·3% clover. The high stocking rate treatment also had the lowest red clover content in the first silage cut. Red clover content in grazed plots increased to a level similar to that in ungrazed plots by the start of the grazing period in the subsequent harvest year.

Animal performance was higher at the low than at the high stocking rate but herbage consumption per head did not differ significantly between the two grazing treatments.

Possible reasons for the adverse effect of grazing on the red clover are defoliation and treading. It is concluded that such experiments can form the basis of an economic assessment of red clover and help the farmer decide whether or not he should integrate the crop into his system.
The effect of some pre‐treatments on proteolysis during the ensiling of herbage
Authors: CARPINTERO C. M. , HENDERSON A. R. , McDONALD P.
Published: April 2006

Two experiments were carried out to examine the nitrogenous changes occurring in herbage during harvesting and ensiling. In the first, ryegrass‐clover was wilted rapidly in the laboratory (6 h) and in the field under good (48 h) and poor (48 h and 144 h) weather conditions. Protein breakdown and ammonia formation were negligible in herbage wilted rapidly and it was only when the crop was exposed to a prolonged wilt in humid conditions that appreciable proteolysis occurred. In the second experiment ryegrass‐clover was ensiled in laboratory silos after treatment with varying levels of formic and sulphuric acids. An additional treatment included herbage inoculated with a mixture of lactic acid bacteria and glucose. The silos were opened after 4 and 50 d and samples were analysed for protein‐N, ammonia‐N, water‐soluble carbohydrates and organic acids. There was a high negative correlation between level of addition of either acid and the degree of proteolysis and deamination. Even at the highest levels of formic acid (7·7 g per kg) and sulphuric acid (4·0 g per kg) additions, however, about 45% of the original herbage protein was degraded after 50 d in the silo. The inoculum treatment was also effective in reducing proteolysis, the effect after 50 d being comparable with formic acid applied at a rate of 4·1 g per kg.
The effects of density, date of inflorescence emergence, date of harvesting and temperature upon seed quality in tetraploid hybrid ryegrasses
Authors: AKPAN E. E. J. , BEAN E. W.
Published: April 2006

Thousand‐seed weight, germination and seedling dry weight were measured in some tetraploid hybrid ryegrasses to study variations in seed quality. In cv. Sabrina, seed from spaced plants had a higher 1000‐seed weight and seedling dry weight, and a slower germination rate than seed from narrow drills. Seed from later emerging groups of inflorescences had a low 1000‐seed weight and seedling dry weight, but a high germination rate. Seeds of cv. Sabrina, Leri and Augusta harvested at between 10 and 25 d after peak anthesis had low 1000‐seed weights, low germination rates and low seedling dry weights. Air temperatures between inflorescence emergence and seed maturity also affected seed quality; an increase in temperature from a 15°/10°C regime to a constant 25°C environment reduced 1000‐seed weight and seedling dry weight, but increased germination rate. It is concluded that year‐to‐year variation in seed characters will occur because of temperature and other climatic changes, but seed quality can also be influenced by the time at which the seed is harvested. If combine harvesting is carried out at a moisture concentration of about 400 g kg‐1 (≡40%) then maximum yields of seed of a high quality should be obtained.
Herbage measurement in situ by electronics. 3. Calibration, characterization and field application of the earth‐plate forage capacitance meter: a prototype
Authors: TOLEDO J. M. , BURNS J. C. , LUCAS H. L. , ANGELONE A.
Published: April 2006

Calibration of an earth‐plate forage capacitance meter was conducted on pure stands of Festuca arundinacea Schreb., Medicago sativa L., Cynodon dactylon (L.) Pers. and Trifolium repens L. and a mixture of Trifolium repens and Dactylis glomerata L. Dry weight (DW) prediction equations were developed using the instrument capacitance reading modified by visual estimates of height, stand density and species percentage. In general, meter readings (MR) correlated better with DW than with fresh weight or weight of water and especially when the area harvested exceeded 0·537 m2. Correlation between MR and DW improved with increasing top plate area and with decreasing distance between the top plate (suspended sheet of aluminium) and the earth‐plate ground. The use of a plastic shield to suppress the forage to a uniform height caused a reduction in the correlation between MR and DW.

The use of MR to predict DW from selected settings, their linear and curvilinear relationships and several auxiliary observations gave results with R2 values ranging from 0·94 to 0·99, depending on species and mixture.
The effect of a cereal supplement during early lactation on the performance and intake of ewes grazing perennial ryegrass at three stocking rates
Authors: YOUNG N. E. , NEWTON J. E. , ORR R. J.
Published: April 2006

A comparison was made of the effect of a cereal supplement during early lactation on the performance and intake of ewes suckling two lambs while rotationally grazing pasture at stocking rates of 20, 17 or 14 ewes per ha. Supplement (S) at the high (H) and medium (M) stocking rates resulted in higher organic matter (OM) intakes (grass + supplement) of 2040 and 2500 g d‐1 respectively, compared with the herbage OM intakes of unsupplemented (U) ewes of 1750 and 2040 g d‐1 respectively. At the low (L) stocking rate the total OM intake of supplemented ewes and the herbage OM intake of unsupplemented ewes was similar at 2250 and 2210 g d‐1 respectively.

Lamb growth rate (g d‐1) to 12 weeks of age was significantly lower on treatment UH (229) compared with those on UM (253) and UL (262). Growth rates on S treatments were similar (SH 248; SM 261; SL 272) and there were no significant differences between S and U within stocking rates. Unsupplemented ewes lost significantly more weight during the period of intake measurement than those receiving supplement. The speed of rotation was faster where supplement was not fed at the medium and high stocking rates and herbage accumulation under UH was less than under SH. Only at the high stocking rate did feeding a supplement give a higher financial output.
An improved electronic capacitance meter for estimating herbage mass
Authors: VICKERY P. J. , BENNETT I. L. , NICOL G. R.
Published: April 2006

An improved electronic capacitance pasture meter is described, and data on its calibration and use in a grazing trial are presented. The instrument is light (1·4 kg) and portable, and uses integrated circuits to record the readings from a number of sampled sites. It has a digital display and can be constructed for a modest cost. The meter is mainly responsive to the surface area of the herbage and hence it is less sensitive to variations in moisture content of the pasture than previous meters. Thus it can be calibrated to measure the mass of herbage dry matter to ground level and reduces the need to collect and dry herbage samples for frequent recalibration of the instrument.
Effect of spring grazing on the yield and quality of perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata) cut for conservation
Authors: SWIFT G. , EDWARDS R. A.
Published: April 2006

Two early perennial ryegrass varieties (Cropper and RvP Hay Pasture), an intermediate perennial ryegrass (Talbot) and an early cocksfoot (Roskilde) were grazed fortnightly by sheep, mown to simulate grazing or left undefoliated from January to May. The effects of spring management on ear emergence, D‐value (in vitro) and conservation yields were assessed in each of the 2 years 1976 and 1977. Grazing and mowing had a similar effect on date of first (5%) and 50% ear emergence of the ryegrass varieties; the effect was an average delay of 2 d in both stages of growth over the 2 years. Defoliations significantly (P<0·001) delayed the fall in D‐value with no significant differences between grazing and mowing in the ryegrass varieties, nor in cocksfoot in 1977. The occurrence of a D‐value of 67 was delayed by between 3 and 8 d for the ryegrasses and 9 and 11 d for the cocksfoot. The early ryegrasses produced stemmy regrowths and fell to 67 D‐value about 4 weeks after the final defoliations in 1976 and after 5–6 weeks in 1977. The fall in D‐value took 7–14 d longer in the intermediate ryegrass. Yields were significantly (P < 0·001) reduced by grazing and mowing, particularly in 1976. The DM yield reductions in mid June averaged 25% for the ryegrasses and 41% for the cocksfoot.

The results indicate that either first or 50% ear emergence may be used to indicate times when a D‐value of 67 will be reached in grazed or ungrazed swards but further work is required to determine the effect of weather conditions on the accuracy of this prediction. An early fall in D‐value of early perennials after spring grazing, and a marked reduction in yield of cocksfoot, suggests that these grasses should be used sparingly where spring grazing of fields set aside for conservation is a feature of the farming system.
Further experiences of beef production on permanent pasture in 1976–78
Authors: ELLIOTT J. G. , DALE R. J.
Published: April 2006

Between 1976 and 1978 a further 154 beef animals were grazed in separate groups on Alberts and Far field at Begbroke Hill, the former being a paddock system and the latter being set‐stocked. Each year part of Alberts received complete fertilizer (147–180 kg ha‐1 N) and part did not. All of Far field received complete fertilizer (140–190 kg ha‐1 N). Drought caused a reduction in output in 1976, but in 1977 and 1978 total production of live weight was 9·07 and 8·74 t respectively from 11·65 ha grassland. Calculations of corrected outputs show that maxima of 829 kg ha‐1 in Alberts and 908 kg ha‐1 in Far field were achieved from fertilized grass. The highest output in Alberts represented 929 livestock unit grazing days per ha or 87·9 GJ ha‐1 in 1978.
Copper and other minerals in herbage species and varieties on copper‐deficient soils
Authors: FORBES J. C. , GELMAN A. L.
Published: April 2006

The mineral composition of Lolium perenne, Dactylis glomerata, Trifolium repens, Lotus corniculatus and six non‐leguminous broadleaved herbs was determined at two sites on copper‐deficient soils with and without soil‐applied copper sulphate at 2 kg Cu ha‐1. D. glomerata was richer than Lolium perenne in P, Mn and Cu, and T. repens was richer than either grass species in Ca, P, Mg and Cu. D. glomerata cultivars differed in Ca, P, Na and Mg concentrations, and L. perenne cultivars in Ca concentration. Lotus corniculatus contained less Ca, P, Na and Mn but more Zn than T. repens. Achillea millefolium was rich in K, Cichorium intybus in K, Mg and Zn, Petroselinum crispum in Na and Zn, Rumex acetosa in K, P, Mg and Zn and Taraxacum officinale in Na, Mg and Zn. Rumex was low in Na and Plantago lanceolata in Na and Mn. None of these herbs was richer than T. repens in Cu. Copper sulphate application raised the Cu concentration of the herbage only slightly, species or varieties differing little in their response to applied Cu. It is concluded that adjustment of botanical composition, with or without copper sulphate application, will not help to prevent hypocupraemia in grazing stock.
Herbicides and seed production by two perennial ryegrass cultivars grown in weed‐free conditions
Authors: OSWALD A. K.
Published: April 2006

The effects of five herbicides on seed yield and viability of perennial ryegrass cv. S24 were tested at two sites. Benzoylprop‐ethyl, chlorfenpropmethyl, difenzoquat, ethofumesate and flam‐prop‐isopropyl were safe to use at doses recommended for use in other crops. When applied at three times the recommended dose, only difenzoquat reduced the yield and germination of seed and benzoylprop‐ethyl reduced seed germination. The recommended doses of difenzoquat and ethofumesate were safe when applied on cv. Barlenna at different growth stages. Difenzoquat reduced seed yield only after three times the recommended dose was applied to tillered plants. Ethofumesate, even at three times the recommended dose, did not affect seed yield but plant numbers were reduced by early treatment. The results suggest that the herbicides tested may be safe to use in perennial ryegrass seed crops at the recommended doses but more work is needed on the safety of difenzoquat in relation to crop growth stage.
Varying the time of spraying with paraquat or glyphosate before direct drilling of grass and clover seeds with and without calcium peroxide
Authors: DAVIES W. I. C. , DAVIES J.
Published: April 2006

The practise of sward desiccation using glyphosate or paraquat followed by direct drilling of seed gave an environment which increasingly inhibited germination and establishment when the interval between spraying and drilling was decreased from 21 days to nil. Burning or removal of old sward improved establishment. Calcium peroxide used as a seed dressing improved seedling establishment in most treatments.
A comparison of methods of establishing perennial and Italian ryegrasses
Authors: BARTHOLOMEW P. W. , EASSON D. L. , CHESTNUTT D. M. B.
Published: April 2006

An experiment extending over a 2½‐year period from June 1976 to October 1978 assessed the effect on herbage yield of method of establishment, species and level of N application.

Perennial ryegrass cv. Gremie and Italian ryegrass cv. RvP were established by broadcasting or drilling into cultivated ground or by direct‐drilling, using a Howard Rotaseeder, into paraquat‐sprayed but uncultivated ground. These treatments were combined with annual rates of N application of 0, 120, 240 or 360 kg ha‐1.

Over the experiment drilling into cultivated ground gave the highest yield—3·6 and 4·8% higher than the broadcast and direct‐drilled treatments, respectively. Italian ryegrass consistently outyielded perennial ryegrass, with an overall mean dry matter yield advantage of 23·7%. There was no significant interaction between sowing method and species; direct‐drilled Italian ryegrass produced a mean yield 17·3% higher than that of drilled perennial ryegrass.
The development and use of equipment for the automatic recording of ingestive behaviour in sheep and cattle
Authors: CHAMBERS A. R. M. , HODGSON J. , MILNE J. A.
Published: April 2006

A description is given of equipment designed to be fitted to either sheep or cattle, and to record automatically information on the jaw movements associated with both grazing and ruminating, movements of the head in plucking mouthfuls of herbage, and the time spent in grazing. The equipment has been successfully tested against alternative visual and mechanical methods of measuring grazing behaviour.

The use of modified equipment in detailed studies has shown (a) that the maximum acceleration of the head in a longitudinal plane when plucking mouthfuls of herbage was twice as great in sheep as in cattle and in the sheep, but not in the cow, increased as sward height decreased; and (b) that the ratio of jaw movements to head movements was always greater than unity in both sheep and cattle, and was greater on tall than on short swards in two out of three comparisons. The rate of biting was significantly lower on tall than on short swards.
Observations on the effect of post‐emergence application of ethofumesate on the shoot growth of Poa annua and Lolium perenne seedlings†
Authors: JUKES A.M. , GOODE P.M.
Published: April 2006

Swards of L. perenne and P. annua were treated at the 2–3 leaf stage with recommended rates of ethofumesate (5 and 10 kg a.i. ha‐1). P. annua ceased normal growth, became swollen at the shoot base and eventually showed signs of senescence. L. perenne showed no visible defects, treated swards being more vigorous than untreated. Scanning electron micrographs showed that the developing leaf primordia of P. annua had been affected by the ethofumesate. In both grass species, ethofumesate induced abnormalities in cell division. These abnormalities caused irreversible damage to P. annua but only slight distortion of L. perenne which later recovered and resumed normal growth. More detailed biochemical studies are required to determine the specific effects of ethofumesate on cell growth.
Herbage intake and milk production by grazing dairy cows. 3. The effect of grazing severity under continuous stocking
Authors: LE DU Y. L. P. , BAKER R. D. , NEWBERRY R. D.
Published: April 2006

The effects of severity of grazing on the herbage intake and milk production of continuously stocked British Friesian cows calving in February–March were examined in three experiments conducted in the years 1976–78 (experiments 1–3 respectively) using a put‐and‐take technique. In experiment 1 four grazing severities were imposed by maintaining swards with different herbage masses (2500, 3000, 3500, 4000 kg OM ha‐1); in experiments 2 and 3 there were two severities of grazing maintained by keeping swards canopies at constant heights of 5 and 7 cm (experiment 2) and 5 and 7·2 cm (experiment 3). Cows were reallocated to treatment every 8 weeks in experiments 1 and 2 and there were three periods, whereas they all grazed throughout a 23‐week period on the same treatment in the final trial.

A decrease in the quantity of herbage on offer or in sward height reduced herbage intake and milk production in all experiments. Mean daily herbage OM intakes were 11·2, 12·2, 12·2 and 12·2 kg respectively in experiment 1, 12·2 and 13·2 kg respectively in experiment 2 and 12·2 and 152 kg respectively in experiment 3. Mean daily solids–corrected milk yields were 14·2, 15·2, 15·2 and 16·2 kg respectively in experiment 1, 14·2 and 16·2 kg respectively in experiment 2 and 12·2 and 17·2 kg respectively in experiment 3. It was apparent from the data obtained in the first two trials that grazing at a sward canopy height of 7 rather than 9 cm had little effect, but that at 5 cm there were significant depressions in both herbage intake and milk production. Milk yield was depressed to a greater extent when cows were kept on the same treatment for the whole season.
The effects of clover variety, cutting interval and nitrogen application on herbage yields, proportions and heights in perennial ryegrass‐white clover swards
Authors: WILMAN D. , ASIEGBU J. E.
Published: April 2006

Six varieties of white clover, each grown with perennial ryegrass, four intervals between cuts and two levels of applied nitrogen in all combinations, were compared in a field experiment during the first 27 months after sowing.

Increasing the interval between harvests from 3 or 4 to 8–12 weeks increased the yield of white clover and generally did not reduce the proportion of clover in total herbage. Increasing the interval between harvests reduced the number of grass tillers but increased grass yield and the size of grass leaves and increased grass height more than clover height; it also increased the proportion of petiole relative to leaflet in the clover. Differences between varieties in response to interval between harvests were small but supported the view that medium large‐leaved varieties can with advantage be defoliated rather less frequently than small‐leaved ones. The adverse effect of applied N on clover appeared almost equally great with all four intervals between harvests and further research on this topic is suggested. Applied N increased grass height more than clover height and increased the number of grass tillers, the size of grass leaves and grass yield. The medium large‐leaved varieties seemed more tolerant of applied N than the smaller varieties.
The effects of pesticide application on upland permanent pasture
Authors: CLEMENTS R. O. , HENDERSON I. F. , BENTLEY B. R.
Published: April 2006

An estimate of the level of pest damage on enclosed upland permanent pasture in England and Wales was made by reducing invertebrate populations with insecticides at thirteen well‐distributed sites and measuring the effect on herbage growth over a 3‐year period. Potential pests were fewer in number than on lowland pastures and there was a wide range in herbage yield between sites. Insecticide treatment significantly increased annual yields at only three of the sites, and significantly decreased yield at two of the sites. Insect damage to grassland appears to be much less important in upland than in lowland areas: this may be due to the relative scarcity of frit‐fly in these areas, but this could change if its preferred host, ryegrass, were encouraged by intensification of sward management in the uplands. At all but one of the sites insecticide treatment led to considerable soil compaction, probably as a consequence of suppressing earthworm populations.