bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EFFECT OF THE ADDITION OF ARACHIS OIL ON THE CONSERVATION OF HEAVILY–WILTED HERBAGE SEALED IN POLYTHENE FILM
Authors: Jackson N. , Brown W. O.
Published: April 2006

A conservation experiment is described in which arachis oil was used to improve the energy content of heavily‐wilted herbage of approximately 46% dry matter. The 2 oil‐treated herbages and 2 control silages were enclosed in polythene film. The DM losses from all 4 silos were high compared with losses normally encountered in completely sealed silos. This is attributed to secondary fermentation which occurred after the silos were opened. The oil had a depressing effect on the digestibility of the mineral matter of both grass and silage. The metabolizable energy values of the silages are reported and discussed.
COMPARISONS OF LIQUEFIED (ANHYDROUS) AMMONIA AND AMMONIUM NITRATE AS NITROGENOUS FERTILIZERS FOR GRASSLAND
Authors: Jeater R. S. L.
Published: April 2006

Three trials were conducted to compare liquefied ammonia and ammonium nitrate as nitrogenous fertilizers for grassland. One was at Jealott's Hill and the other two at Henley Manor, Crewkerne, Somerset. At neither centre was the response to liquefied ammonia as great as that from equivalent rates of ammonium nitrate applied in a number of split dressings throughout the season.

Split applications of liquefied ammonia were more efficient than single large dressings, but even these were not as efficient as ammonium nitrate.

The response from a single large application of liquefied ammonia in spring was superior to that from an autumn application, especially under the high‐rainfall conditions at Henley Manor.

The pattern of response from split applications of ammonium nitrate was more uniform than that from a single application of liquefied ammonia. In general, the latter gave a large mid‐summer cut, but fell away badly at the end of the season. These data confirm earlier findings, which also showed that liquefied ammonia was not as efficient as ammonium nitrate applied in the normal way as a nitrogenous fertilizer for grass.
THE INFLUENCE OF NITROGEN ON A PASTURE TREATED WITH DALAPON FOR THE SELECTIVE SUPPRESSION OF AGROSTIS STOLONIFERA AND HOLCUS LANATUS IN PERENNIAL RYEGRASS
Authors: Allen G. P.
Published: April 2006

This experiment confirmed earlier experience that dalapon applied at doses between 2 and 5 lb a.e./ac (2.242 and 5.605 kg/ha) in early July can suppress Agrostis stolonifera and Holcus lanatus growing in perennial ryegrass pasture. The long‐term control of Poa trivialis was not achieved, partly because of a widespread emergence of seedlings shortly after spraying. Dalapon caused a reduction in the total herbage harvested diuring the 14 weeks after spraying, but the yield subsequently increased above that of the unsprayed sward. A substantial increase in the yield of ryegrass occurred. Nitrogen caused a general increase in the yield of herbage and the proportion of ryegrass, but neither N nor dalapon used alone was as efficient in improving yield as their use in combination. Treatment with dalapon resulted in an increase in the number of ryegrass tillers per unit area in the April following spraying, as well as in the yield and ground cover of this species.
THE FREQUENCY AND SEVERITY OF DEFOLIATION OF INDIVIDUAL TILLERS IN SET‐STOCKED SWARDS
Authors: Hodgson J. , Ollerenshaw J. H.
Published: April 2006

Individual tillers of S23 ryegrass, in three paddocks set‐stocked with sheep at widely differing grazing pressures, were marked and studied from 11 July to 19 August, 1966, and observations were made on the frequency and severity of grazing.

The uprooting of tillers, and the destruction of others, were major sources of loss of records. It was found that an acceptable measure of the frequency of defoliation could be made by recording three times a week. In a subsidiary experiment it was shown that repeated handling did not affect the DM yield, the number of tillers or the length of green leaf (G.L.L.) of single plants.

Despite the extreme differences in grazing pressure, there were no significant differences between paddocks in the daily increase in the G.L.L. of tillers which were not grazed during a short period of intensive recording. In all three paddocks the sheep tended to graze the tillers with the greatest G.L.L. at any one time, and there was evidence of patchy grazing only at the lowest grazing pressure.

An increase in grazing pressure resulted in increases in both the frequency and severity of defoliation. Comparisons were made between the product of the frequency X severity of defoliation of individual tillers, and the stocking rate, grazing pressure and herbage consumption on the three paddocks.
NET PHOTOSYNTHESIS AND LEAF AREA INDEX RELATIONSHIPS IN SWARDS OF DACTYLIS GLOMERATA UNDER CONTRASTING DEFOLIATION REGIMES
Authors: Vickery P. J. , Brink V. C. , Ormrod D. P.
Published: April 2006

Net photosynthesis per unit area of ground surface was determined at saturating light energy levels in Dactylis glonwrata swards over a wide range of leaf area indices (LAI). The relationship between net photosynthesis and LAI was influenced by the particular defoliation regime to which the sward was subjected. In most instances net photosynthesis and LAI were linearly related, with defoliation regime influencing both the slope and intercept of the regression. However, a defoliation regime which left leaves below 3 inches (7.5 cm) resulted in a curvilinear relation. The net photosynthesis‐LAI relationships were compared with the DM production of the swards on which they were obtained. Differences in these relationships did not entirely explain the differences in sward yield. The significance of these findings is discussed with reference to the theories of light interception and pasture growth.
FAECES COLLECTION IN YOUNG MALE LAMBS AND WETHER SHEEP
Authors: Ingleton JeanW.
Published: April 2006

The construction and use of a lightweight plastic harness for total faecal collection from young male lambs and wethers is described. The presence of this harness does not appear to interfere with growth and normal behaviour; it is therefore suitable for indoor‐ and‐field experiments.
THE SIGNIFICANCE AND CONTROL OF POA TRIVIALIS IN RYEGRASS PASTURES
Authors: Haggar R. J.
Published: April 2006

A review of published information on the growth and productivity of Poa trivialis in relationship with perennial ryegrass is presented. The available evidence indicates that P. trivialis is usually out‐yielded by ryegrass, particularly under drought and infertile soil conditions. In addition, the quality and seasonal distribution of the yield is often of questionable value. It would therefore appear that P. trivialis can be considered an undesirable species in most intensively managed ryegrass pastures. Preliminary results from competition studies between F. trivialis and S23 perennial ryegrass confirm that the replacement of ryegrass by P. trivialis leads to a lowering of productivity. The latest control measures for preventing the invasion and/or removal of P. trivialis from ryegrass pastures are given, based largely on the use of selective herbicides.
THE ERROR IN PREDICTING PASTURE DRY–MATTER DIGESTIBILITY FROM FOUR DIFFERENT METHODS OF ANALYSIS FOR LIGNIN
Authors: McLeod M. N. , Minson D. J.
Published: April 2006

The lignin content of 50 samples of five grasses of known in vivo digestibility were determined by the methods of Armitage, van Soest and two modifications of the van Soest technique. The error in predicting DM digestibility varied from ±3.1 for tbe Armitage metbod to ±5.0 for the van Soest method. This error compares nnfavourably witb ±2.1 previonsly obtained on tbe same samples with the in vitro technique of Tilley and Terry.
THE ENSILAGE OF AUTUMN‐SOWN RYE
Authors: Wilson R. F. , Wilkins R. J.
Published: April 2006

Autumn‐sown rye was cut on five dates in spring and ensiled in laboratory silos. On two of the dates forage‐harvested material was ensiled in PVC silos (containing about 1 t of fresh crop) as well as in laboratory silos. Ensiling was carried out with and without the addition of formic acid or glucose solution. After 96 days in laboratory silos, rye cut before ear‐emergence and ensiled without additives gave silages of high pH value and high ammonia content. After ear‐emergence satisfactory silage was produced without an additive, but the addition of formic acid always resulted in silages having lower pH values and lower ammonia contents. The addition of glucose resulted in silages with only slightly lower pH values and ammonia contents which were closely similar to those made without addition. Silages made in PVC silos were all well preserved, as indicated by low contents of acetic and butyric acids, but the addition of formic acid resulted in pH values and ammonia contents lower than those found in other treatments.
THE DECOMPOSITION OF CATTLE DUNG AND ITS EFFECT ON PASTURE
Authors: Castle M. E. , MacDaid Elizabeth
Published: April 2006

A total of 228 separate dung pats voided by lactating dairy cows between May and October on a ryegrass/dover sward were studied for 2 years. The pats were on grazed swards receiving, on average, either 440 or 110 lb N/ac (492 or 123 kg/ha) per year. The mean area of the pats was 0.62 ft2 (0.058 m2) with no difference in area between the pats on the two N treatments. On average, the pats on the high‐ and the low‐N treatments crumbled in 63 and 55 days, respectively, and disappeared in 115 and 113 days, respectively. Pats deposited in July disappeared significantly quicker than pats deposited in May. The average area of rejected herbage around the pats was 2.63 and 084 ft2 (0.244 and 0.078 m2), respectively, 1–2 months, and 1 year after they were voided; but after 2 years the affected areas were recolonized with ryegrass and clover and were grazed normally. It is concluded that the levels of N fertilizer applied had no differential effects on the breakdown of the dung and on the subsequent recolonization of the affected areas by pasture plants.
EFFECT OF STRENGTH, TILTH AND HETEROGENEITY OF THE SOIL SURFACE ON RADICLE‐ENTRY OF SURFACE‐SOWN SEEDS
Authors: Campbell M. H. , Swain F. G.
Published: April 2006

Seeds of Medicago sativa, Trifolium subterraneum, Lolium perenne and Phalaris tuberosa were sown on different soil surfaces and the effects of strength, tilth and heterogeneity of the surface on the entry of the radicle into the soil were noted.

On a level, finely structured soil surface prepared in the laboratory slight increases in soil strength markedly reduced percentage radicle‐entry. At constant soil strength, radicle‐entry was greater on coarse than on fine tilth; which helped to explain the higher percentage radicle‐entry on heterogeneous soil surfaces taken from the field compared with the level, finely structured surface, prepared in the laboratory despite the lower soil strength of the latter.

As conditions for radicle‐entry hecame less favourable (stronger, smoother surface) the rate of radicle‐entry became slower and there was a greater use of radicle‐entry methods in which the radicle was more exposed to desiccation.

The radicle‐entry ability of the four species declined in the order: perennial ryegrass < phalaris < lucerne and subterranean clover. Factors considered to account for the superior radicle‐entry of the grasses were better anchorage of the seedling, better angle of entry of the radicle and smaller radicle diameter.
WHOLE‐CROP VICIA FABA FOR CONSERVATION. A COMPARISON BETWEEN WINTER‐, HORSE‐, TICK‐, AND BROAD‐BEAN CULTIVARS
Authors: Toynbee‐Clarke Gillian
Published: April 2006

A trial containing cultivars of Vicia faba var. equina, minor and major was harvested as a whole‐crop in 1971. The aim was to estahlish the DM yield obtainahle from a selection of spring‐hean cultivars and evaluate this in relation to previously reported yields from winter heans. DM yields ranged from 48 to 86 hkg/ha over the three cutting dates. Significant differences were found hetween cv. in digesdhiUty, the range being 54 to 71%, and one hroad‐hean cv. was shown to have a high digestihility at all cuts. Crude‐protein contents of 13 to 19% were recorded. Percentage DM rose from 16 to 18% at the first cut to 23 to 45% at the third, hroad‐hean cv. rising more slowly than horse‐ and dck‐hean cv. Spring‐bean cv. had a lower DM yield than winter cv. Horse hean was superior to tick bean in DM yield, percentage DM, and D‐value. Broad‐bean cv. proved difficult to dry and therefore may be more suitable for ensilage than dehydradon.
THE SPECIES PREFERENCES OF GRAZING HORSES
Authors: Archer Marytavy
Published: April 2006

Palatability studies of 29 species of grasses, legumes and herbs, and two seeds mixtures, were conducted using three replicates of each species. Crossbred ponies and a few Thoroughbreds were obserred and timed for a total of 260 hours grazing. The results were analysed and sbowed small statistical differences between replicates, between tbe 2 years observed and between horses; and highly significant differences (P<0.001) between certain species. The most palatable was a clover‐rich mixture. Tbe pasture varieties of perennial ryegrass were significantly more palatable tban S24, and as palatable as timothy and cocksfoot Alta tall fescue, crested dogs tail and wild white clover were palatable. Some herbs, red clover, brown top, red fescue and meadow foxtail were tbe least palatable. Dandelion, ribgrass and yarrow were palatable herbs.
THE RELATIONSHIP BETWEEN THE DM CONTENT OF HERBAGE FOR SILAGE MAKING AND EFFLUENT PRODUCTION
Authors: Castle M. E. , Watson J. N.
Published: April 2006

A study of 16 silages made at the Hannah Research Institute and 22 silages made at the Grassland Research Institute showed highly significant positive relationships hetween the DM percentages of the material ensiled and the resultant silage. Using regression equations derived from this data, and from a record of the presence or absence of effluent, it was calculated that the average minimum DM content of herbage for ensiling which would produce no effluent was 22.9%. To ensure a margin of safety against production of effluent, a minimum DM content of 24.7% in the herbage was calculated from the confidence limits. To obtain this DM content, herhage will normally require wilting; effluent production should then be negligible.
THE MANAGEMENT OF LONG GRASS AS A BIRD REPELLENT ON AIRFIELDS
Authors: Mead H. , Carter A. W.
Published: April 2006

Authorities responsible for the safety of aircraft have for a number of years been very concerned with the dangers and the damage caused by aircraft striking birds while in flight, particular since the introduction of the jet engine. Methods of reducing this risk have been sought, which have brought about the method of grass management described in this paper.
POTENTIAL PASTURE PRODUCTION IN THE UPLANDS OF WALES
Authors: Munro J. M. M. , Davies D. A. , Thomas T. A.
Published: April 2006

Detailed soil and vegetation analysis at Pant‐y‐dwr Hill Centre illustrated the main physical, chemical and biological factors involved in low output from rough grazing on 5 soil series, ranging from acid brown earth to undifferentiated peat, which are representative of most of upland mid‐Wales. While all the soils, derived from Silurian shale, had low pH and base saturation status and high lime, phosphate and potash requirements, the principal restraint on the productivity of resown grassland, particularly on the wet peaty gleys, was low available N status.
THE ESTABLISHMENT OF GRASS AND FODDER CROPS AFTER SWARD DESTRUCTION BY HERBICIDES
Authors: Squires N. R. W. , Elliott J. G.
Published: April 2006

A series of 9 experiments carried out on an alluvial soil at two levels of fertility during the period 1971–3 showed that cultivation of the mineral soil was unnecessary for the satisfactory germination, emergence and establishment of a wide range of forage crops. With small‐seeded crops (grasses and clover) non‐cultivation gave improved establish ment and early growth compared with crops from soil which had been disturbed.

A second series of 6 experiments investigated the effects of surface plant material on the establishment of a smaller range of forage crops sown without cultivation. The presence of this mat or trash was associated with a reduction in establishment of seedlings, but not with subsequent growth of the plants that became established. Treatments which processed or partially removed the organic matter were associated with increased emergence. Crops with small seeds were more susceptible to the effects of organic matter than those with larger seeds.
SEED PRODUCTION STUDIES ON PERENNIAL RYEGRASS, TIMOTHY AND PRAIRIE GRASS
Authors: Hill M. J. , Watkin B. R.
Published: April 2006

A study over two years involving tiller identifica tion according to month of origin enabled the contribution of individual tillers of perennial rye grass Grasslands Ruanui, timothy Grasslands Kathu and a local New Zealand strain of prairie grass (Bromus unioloides) to be determined at seed harvest. In addition, the distribution of seed‐heads in different arbitrary emergence groups was detemined so as to allow analysis of individual seedhead components within each group.

In all species, tillers formed during the first 4 months following an autumn sowing in the first year, and also in the immediate post‐harvest period and through the autumn in the second year, made a major contribution to seedhead numbers and seed yield at harvest. These tillers had a lower vegetative mortality rate than those formed in the spring.

Primary tillers formed after sowing were highly persistent and became almost exclusively repro ductive. Many vegetative tillers died before har vest, behaving as annual tillers.

Spring‐formed tillers made a major contribution to the vegetative growth of the plant over the summer and early autumn. These tillers generally died before the following winter. Tillers formed in winter and early spring by ryegrass and prairie grass showed a high mortality, particularly in the second year. In timothy, mortality was highest amongst tillers formed in late spring. The reduced contribution of spring‐formed tillers to the seed head population occurred as a result of fewer heads numerically compared with older tillers.

In all species, most seedhead components varied according to time of ear emergence. Early emerged heads were generally longer, bore more spikelets and more florets per head and had a greater culm length than late‐emerged heads.

The major trend in all species was a general depression in head length, spikelet and floret number and culm length with grazing. These effects were in most cases partly or completely overcome by N application. The major effect of applied N was to increase floret number per head.
Effects of fertilizers on the sulphur content of herbage
Authors: McLAREN R.G.
Published: April 2006

The sulphur concentrations in herbage samples from the plots of a long‐term fertilizer experiment have been examined in relation to levels of fertilizers applied. Sulphur applied as superphosphate increased herbage sulphiir concentrations whereas reduction in concentrations were observed with applications of nitrogen as ‘Nitro‐chalk’ and potassium as potassium chloride. Reduction in sulphur concentration occurred most likely as a result of increased dry matter production brought about by the added nitrogen and potassium, effectively diluting the sulphur content of the plant material. Potassium chloride may also have exerted an anion‐antagonistic effect on sulphate uptake by the plants. Levels of soil extractable sulphate were low in plots receiving no sulphur as fertilizer and high levels of nitrogen applied to these plots resulted in wide nitrogen: sulphur ratios in the herbage. Most of the sulphur applied to the soil in the spring was leached out of the topsoil by the end of the growing season.

In some areas of Britain it seems possible that optimum utilization of applied nitrogen may only be obtained where sulphur is also added to the soil.
The effect of variety and fertilizer nitrogen level on red clover production
Authors: FRAME J. , HARKESS R. D. , HUNT I. V.
Published: April 2006

Established swards of two diploid and two tetraploid red clover varieties sown pure received 0, 75, 150, 225 or 300 kg ha−1 N fertilizer and were cut three times in June, August and October 1971. The total yields of herbage DM for red clover varieties ranged from 8.01 to 11.32 t ha−1; swards sown with tetraploids Hungaropoly and Hera Pajbjerg were superior by 25% in DM yield and 23% in CP yield. The red clover contribution to these total yields of DM ranged from 6.05 to 10.69 t ha−1; tetraploid clovers outyielded diploids by 42% in DM yield and 39% in CP yield.

The mean effect of N level on yield and on compositional attributes was slight. Total yields of herbage DM, averaged over all varieties, ranged from 9.50 to 10.22 t ha−1 and of total herbage CP from 1.76 to 1.91 t ha−1. The influence of N level on the red clover contribution was negligible. DM yields ranged from 8.54 to 8.72 t ha−1 and CP yields from 1.60 to 1.64 t ha−1.

Superiority of tetraploid clovers over diploids was again confirmed. Red clover swards sown pure can give high yields without the application of fertilizer N.
The effect of a short‐persistence systemic insecticide on the yield of perennial ryegrass
Authors: HENDERSON I. F. , CLEMENTS R. O.
Published: April 2006

The insecticide dimethoate was applied to a sward of S23 perennial ryegrass over a period of 2 years at three dose rates and at five frequencies of application. Annual DM yield was increased by up to 5% in the first year and by up to 17% in the second. The value of the additional yield is compared with the cost of obtaining it.
Estimation of herbage consumption by grazing cattle using measurements of eating behaviour
Authors: CHACON E. , STOBBS T. H. , SANDLAND R. L.
Published: April 2006

Feed consumption (I). of a group of eight non‐lactating Jersey cows strip‐grazing oats at three stages of growth was estimated from number of eating bites (N) and bite size (5) measurements using the expression, I= N × S. N was measured with four non‐fistulated animals while S was determined independently with four oesophageal fistulated animals. These estimates were compared with herhage consumption estimates using a cutting technique (fourteen samples of both herbage offered and refused).

Eating behaviour estimates of intake based on N and S were 29% higher than cutting estimates due to fistulated animals having a high number of mastication bites with the head up during sampling and a large diurnal variation in bite size. After allowing for these sources of error eating behaviour estimates were only 2% higher than cutting estimates.

Sampling variability was similar for both cutting and eating behaviour techniques; on an individual plot basis the percentage coefficients of variation were 11.2 and 10.1 for cutting and eating behaviour techniques, respectively. Methods of reducing sample variability are discussed and tables of numbers of animals required to detect true differences in intake at various levels of precision are presented.

It is concluded that herbage consumption by grazing ariimals can be obtained from measurements of eating behaviour.
The seasonal productivity, quality and response to nitrogen of four indigenous grasses compared with Lolium perenne
Authors: HAGGAR R. J.
Published: April 2006

To rectify the lack of comparative data on the productivity of some commonly occurring indigenous grasses, seasonal growth curves were obtained during the first year of a 3‐year study by harvesting monoculture plots of Holcus lanatus, Agrostis stolonifera, Festuca rubra, Poa trivialis and Lolium perenne (cv. S23) at monthly intervals in a staggered sequence. Under conditions of high soil fertility (40 kg ha−1 N per defoliation and frequent irrigation) the daily production of dry matter by P. trivialis followed the familiar two‐peaked pattern of L. perenne, albeit at a lower level after flowering. By comparison, F. rubra and A. stolonifera grew more uniformly throughout the year; H. lanatus, like F. rubra, was noticeable for its high productivity after midsummer. With monthly cutting all four indigenous grasses had a higher mean nitrogen content compared with L. perenne; mean digestibilities were also comparable with the exception of F. rubra.

During the second year, when inputs of nitrogen and moisture were lower, primary spring growth was most rapid with H, lanatus and F. rubra but the high digestibility of L. perenne meant that harvesting could be delayed to obtain the most forage of a given D‐value. Regrowth, measured from cuts taken in early August and September, was greatest with A. stolonifera and F. rubra respectively.

Dry‐matter responses to a total of 60 and 180 kg ha−1 N, applied in three applications on a split‐plot basis, were recorded during the last year. Apart from the early nitrogen application, the indigenous grasses responded well, except for A. stolonifera, especially after flowering. Though the response of L. perenne was consistently high throughout the summer, at least 20 kg DM per kg N, it yielded least of all the grasses at the low nitrogen level.

The agricultural significance of these results are discussed. It is concluded that whereas L. perenne performs well at high levels of nitrogen and moisture, the other species do better than L. perenne, especially during mid‐season, when these factors are limiting.
The effect of cutting frequency and applied nitrogen on production and digestibility of perennial ryegrass
Authors: CHESTNUTT D. M. B. , MURDOCH J. C. , HARRINGTON F. J. , BINNIE R. C.
Published: April 2006

Grass swards were cut at intervals of 2, 3, 4, 5, 6 and 8 weeks and received 336 or 673 kg ha−1 nitrogen the higher level being applied as a single or as split dressings. Reducing cutting interval from 8 to 2 weeks reduced mean DM yield by 37% from 14·2 to 9·0 t ha−1 and digestible DM yield by 24% from 9·4 to 7·2 t ha−1. The response to the extra N at the highest level of application was greatest under the most frequent cutting regimes. Application of N did not affect the digestibility of DM. Results are discussed in relation to the comparative effects of frequency of cutting at different seasons of the year and at different levels of N.
Nitrogen studies in Lolium perenne grown for seed I. Level of application
Authors: HEBBLETHWAITE P. D. , IVINS J. D.
Published: April 2006

In field trials in 1971–73, perennial ryegrass cv. S23 and S24 were given up to 200 kg ha−1 nitrogen (N) and dry weight, seed yields and seed yield components measured. Optimum levels of applied N ranged from 80 kg ha−1, where livestock had grazed the crop in the establishment year or where residual N levels were about 70 kg ha−1, to 120 kg ha−1 where residual N was low. Application of more than 120 kg ha−1 did not increase yields further because of increased lodging and increased production of vegetative tillers. Seed set was 37–55% in S24 and 25–29% in S23 and was decreased by lodging.
The effect of silage chop length on the voluntary intake and rumination behaviour of sheep
Authors: DESWYSEN A. , VANBELLE M. , FOCANT M.
Published: April 2006

Two experiments were conducted with sheep to investigate the effect of silage chop length on voluntary intake and eating and ruminating behaviour. The silages, made from Italian rye‐grass, either received no additive or formic acid at a rate of 4 g kg−1 and were chopped to lengths of 5.3 cm (long), 1.8 cm (short) before ensiling or 1.8 cm (long/short) before feeding. The addition of the additive and short chopping improved the fermentation characteristics of the silage. Voluntary intake of silage dry matter and organic matter was higher with the short than with the long silage. Differences in silage digestibilities and cellulolytic activity did not explain the increase in silage intake. Sheep on the long silage had a lower rate of intake and a shorter ruminating time than on short silage, and thus the effective breakdown of the silage in the rumen was delayed, i.e. an increased latency time. Pseudo‐rumination was significantly higher on the long than on the short silage.
Seed development and seed shedding in North Italian ecotypes of Lolium multiflorum
Authors: HARUN R. M. RAJA , BEAN E. W.
Published: April 2006

Seed development and seed shedding were studied in seven populations of Lolium multiflorum. Five of these populations were from the North Italian Plains, two from the Piedmont area and three from the Lombardy region. The remaining populations were Delecta, a variety derived from ecotypes from the Lombardy Plain, and RvP Lemtal. Seed shedding was greatest in the three ecotypes from the Lombardy Plain and lowest in RvP Lemtal. The two ecotypes from the Piedmont Plain, and Delecta, gave intermediate values. Moisture loss during ripening was greatest in the Lombardy ecotypes but there were no differences in the time taken to reach maximum 1000‐seed weight. Germination values had reached a maximum 27 d after anthesis in all populations. It is suggested that the North Italian ecotypes, or varieties derived from them, should be harvested by direct combining at a moisture concentration of 450 g kg‐1 (≡45%) to obtain the maximum weight of germinable seed.
Effects of defoliation and fertilizers on root competition between Dactylis glomerata and Lolium perenne
Authors: REMISON S. U. , SNAYDON R. W.
Published: April 2006

Dactylis glomerata and Lolium perenne were grown in single‐species stands and in mixed‐species stands in boxes for 1 year. Plants were grown in paired rows in each box with full competition below ground, but aerial partitions prevented shoot competition. The rows were cut either frequently (six cuts) or infrequently (three cuts).

In single‐species stands, frequent defoliation reduced the root competitive ability of D. glomerata plants, when growing with infrequently defoliated plants, though this occurred only if no N fertilizer was applied. Frequent defoliation did not affect the root competitive ability of L. perenne plants, in single‐species stands, whether or not N fertilizer was applied.

In mixed‐species stands, the root competitive ability of D. glomerata was always greater than that of L. perenne, though N fertilizer applications and frequent cutting both reduced the root competitive ability of D. glomerata relative to L. perenne.

Mixtures of frequently cut and infrequently cut plants, in unfertilized single‐species stands, always yielded more than the mean of the uniformly treated stands (frequently or infrequently cut); they usually yielded more than the highest‐yielding uniformly treated stand. Mixtures of frequently and infrequently cut plants, in fertilized single‐species stands, always yielded less than the mean of uniformly treated stands.

Mixed‐species stands usually yielded more than the mean yield of the component species, and sometimes yielded significantly more than the highest yielding component. This effect generally increased with time.

Relative yield totals (RYT) were consistently greater than 1·0, in both single‐species and mixed‐species stands, when no N fertilizer was applied. RYT were greatest (1·2–1·6) when neither N nor P fertilizer was applied, and generally increased with time.

The results are discussed in relation to the effects of cutting on root competition and the probable value of mixed‐species stands.
A critical review of remote sensing and other methods for non‐destructive estimation of standing crop biomass
Authors: TUCKER COMPTON J.
Published: April 2006

Several different techniques for the non‐destructive estimation of pasture or range biomass are critically reviewed and compared to remote sensing methods. Similarities and differences between the visual estimation procedure, β‐attentuation, capacitance meters, weighted disc, and spectral methods are discussed in terms of accuracy, time, ease of operation, operational constraints and calibration procedures. No one technique has been shown to be superior across the board to the other techniques reviewed for ground‐based biomass estimation. A discussion of the strengths and weaknesses of each non‐destructive method allows for the selection of the technique most suited to a particular application.
Grass production studies in the uplands of north‐east Scotland 2. The effects of fertilizer treatment
Authors: RILEY H. C. F. , MACLEOD D. A.
Published: April 2006

The effects of fertilizer treatment were studied over two seasons on a 2 × 2 factorial arrangement of altitude and major soil group. The soil groups were brown earths and podzols and the altitudinal zones were 260–320 m and 380–440 m. Major responses were found to N only and these were generally linear in terms of overall dry matter yield up to the highest treatment level of 176 kg ha‐1. Productivity on brown earths was significantly higher than on podzols and differences between soil groups were not removed by increasing fertilizer input. In most instances 88–132 kg ha‐1N would have to be added to podzols to achieve the same yields as on brown earths with no N input. Apparent fertilizer recoveries and responses per unit of fertilizer input did not, however, differ markedly between soil groups. Overall yields were comparable with those from lowland situations at similar levels of N input, but the growing season was short and 60–80% of production was obtained by early July.
Components of regrowth in grazed and cut Lolium perenne swards
Authors: GRANT SHEILA A. , BARTHRAM G.T. , TORVELL LYNNE
Published: April 2006

Growth measurements were made on Lolium perenne‐dominant vegetative swards during 4‐week regrowth periods following grazing or cutting.

In the grazing study, the ryegrass (Lolium perenne) swards were grazed for 12‐d periods with stock numbers set according to initial herbage allowances per animal of 16, 32 and 64 kg organic matter per sheep. One area was grazed in summer and another area in the autumn.

In the cutting experiment four ryegrass swards growing in boxes were prepared by cutting to either 2 or 6 cm at either 14‐ or 28‐d intervals. The swards were cut back in autumn to 2 or 6 cm. During the regrowth period half the boxes were retained in full light and half shaded to 48% of incident light.

Herbage weight, rates of leaf extension, senescence, leaf appearance and tillering, water soluble carbohydrate reserve levels in tiller bases and, in the cutting experiment, sheath tube lengths and lamina lengths of leaves which had grown through the sheath tube were measured at intervals during the regrowth period.

Final herbage weights reflected management history but net herbage accumulation over the four‐week regrowth period, though affected by season, pretreatment and light level, was similar on swards subjected to different grazing or cutting treatments.

This result was partially explained by changes in the balance between growth and senescence per tiller as herbage weight increased with time during regrowth, and partially by the reduced production per tiller in harder‐grazed swards being offset by a rapid increase in tiller numbers.

There was a positive curvilinear relationship between lamina length and the length of the sheath tubes through which the laminae emerged.

Carbohydrate reserve levels declined rapidly after grazing or cutting, the extent of the decline being related lo the severity of the defoliation. Recovery commenced after four days in summer and was complete within 3 weeks but reserve levels remained low in plants grazed or cut in autumn.

The need is discussed for more detailed descriptions of sward states in management studies and for more information on component processes of growth, the factors affecting them and how these interact with different kinds of management systems.
Presence ofDrechsleraspecies in certified ryegrass seed‐lots
Authors: LAM A.
Published: April 2006

Samples of 39 perennial ryegrass (Lolium perenneL.) and 24 Italian ryegrass (Lolium multiflorumLam.) commercial seed‐lots used at the Grassland Research Institute between 1974 and 1978 were examined for the presence of seed‐borneDrechsleraspecies. The five species ofDrechsleraisolated from the seeds wereD. andersenii, D. siccans, D. nobleae, D. sorokinianaand an unidentifiedDrechslerasp.

A high proportion of the seed‐lots were infected but levels of infection were low except in the perennial ryegrass cv. S24. Infection was located more commonly inside the caryopses than externally on the lemmas and paleae, and about 12% of the seedlings growing from infected seeds were infected. The species recovered in the seedlings were the same as those observed on the seeds.

There was no relationship between level of seed infection and level of damage observed in the field in the autumn of the first harvest year.
Effects of formic acid on silage fermentation, digestibility, intake and performance of young cattle
Authors: PARKER J. W. G. , CRAWSHAW R.
Published: April 2006

Data from twenty‐two comparisons carried out at ADAS Experimental Husbandary Farms are used to compare untreated and formic acid‐treated silages. Additive treatment led to an improved fermentation in some crops, particularly those of low DM concentration (<262 g kg‐1). Where this occurred there were associated benefits in silage digestibility (+0·234 units), intake (+16%) and the growth rate of young cattle (+0·28 kg d‐1). Where the fermentation of the untreated silage was good, both digestibility and animal performance associated with treated and untreated silages were similar. It is suggested that the justification for using formic acid in a commercial situation is thus restricted to occasions where the untreated crop would be liable to develop a clostridial fermentation. These may be when crops contain less than 35 g water‐soluble carbohydrate kg‐1.
The effects of degree of chopping grass for silage and method of concentrate allocation on the performance of dairy cows
Authors: GORDON F. J.
Published: April 2006

Three silages were produced from the same swards by harvesting grass using either a double‐chop harvester (DC) or a precision‐chop harvester adjusted to produce a long staple length (PL) or a short staple length (PS). The mean particle lengths were 47, 52 and 14 mm respectively.

Of each material 250 t was ensiled unwilted and with formic acid additive at the mean rate of 2‐4 litres t‐1 of grass. All three silages were well preserved and degree of chopping had no effect on fermentation as indicated by either pH, ammonia N or organic acid concentration.

The silages were offered ad libitum to seventy‐two British Friesian cows with a mean calving date of 28 January which were in their second or later lactation, in a randomized‐block experiment from day 8 of lactation until 12 April. In addition twelve animals on each silage received a uniform daily concentrate allowance of 7·2 kg while twelve were offered concentrates according to their individual milk yields but with a mean concentrate allowance over the twelve cows of 7·2 kg d‐1. Degree of chopping had no significant effect on either silage dry matter intake or milk yield with mean intakes during the final 21 d of the experimental period of 9·2, 9·2 and 9·2 kg d‐1 and mean milk yields of 25·2, 25·2 and 25·2 kg d‐1 for the DC, PL and PS silages respectively. Method of concentrate allocation did not affect either the total yield of milk during the experimental period, 1717 and 1697 kg, or the total lactation yield, 5635 and 5711 kg, for the uniform and yield‐related allocation methods respectively. The butterfat and protein concentrations of the milk were not significantly affected by either the degree of silage chopping or the method of concentrate allocation.
The fertility of heifers consuming red clover silage
Authors: AUSTIN A. R. , ASTON K. , DRANE HILARY M. , SABA N.
Published: April 2006

The fertility of forty‐two heifers offered either red clover silage or grass silage prior to and during the period of insemination was compared. Pregnancy rate to first service was significantly higher (P < 0·25) on red clover silage at 76% compared with 43% on grass silage. Pregnancy rates from a mating period covering three oestrus cycles were similar on the two silage diets. The ratio of services to pregnancies was lower on red clover silage (1·2) than on grass silage (2·2). In a subsidiary trial with twenty‐three heifers, pregnancy rate to first service on red clover silage was 78%.

There was no evidence to indicate that herd fertility is depressed by red clover silage.
Effects of the field drying of herbage on sward regrowth
Authors: OWEN I. G. , WILMAN D.
Published: April 2006

Grass which had grown without interruption from late April was cut as for hay in early July in each of 2 years. Fifteen dates of removal of the cut herbage were compared ranging, at 1‐d intervals, from the day of cutting to 14 d after cutting. Sward regrowth was studied.

A delay of 5 d in removing cut herbage reduced herbage dry matter harvested during the remainder of the growing season by 9% and a delay of 10 d reduced yield by 16%. Delaying the removal of cut herbage reduced the density of grass tillers considerably in the short term, but the effect had worn off in 8 to 12 weeks. The presence of cut herbage reduced the rate of extension of leaf blades considerably. Delaying the removal of cut herbage reduced the area per leaf blade and the weight per unit area and these effects persisted for several weeks. Grass growing under cut herbage had a less negative leaf water potential and a rather cooler but much darker environment in which to grow than uncovered grass.
The susceptibility of agricultural grasses to pre‐emergence damage caused by Fusarium culmorum and its control by fungicidal seed treatment
Authors: HOLMES S. J. I.
Published: April 2006

A total of 104 cultivars of six agricultural grass species were compared under controlled conditions for their relative susceptibility to the common soil‐borne fungus Fusarium culmorum (W.G.Sm.) Sacc. A number of the perennial ryegrass (Lolium perenne) cultivars showed a high degree of resistance, their emergence being little reduced under the stringent test conditions. The emergence of others was, however, severely affected. Italian ryegrass (L. multiflorum) cultivars generally had a high level of resistance, the outstanding exception being cv. Leda Daehnfeldt which proved very sensitive. None of the cultivars of cocksfoot (Dactylis glomerata), timothy (Phleum pratense), meadow fescue (Festuca pratensis) or tall fescue (F. arundinaceae) which were tested had more than a moderate level of resistance and most were highly susceptible.

The vigour of ryegrass seedlings was, in most cases, closely correlated with percentage emergence but was less closely correlated in the more susceptible species. These often had a very low emergence but those seedlings which did establish were frequently of a size similar to that of healthy plants.

Treatment of grass seed with a fungicide mixture of benomyl (15% a.i.) plus captan (60% a.i.) provided excellent protection against F. culmorum on even the most susceptible cultivars.

Drazoxolon (40% a.i.) was, however, much less effective.
In vitro digestion of bundle sheath cells in rumen fluid and its relation to the suberized lamella and C4 photosynthetic type in Panicum species
Authors: WILSON J. R. , HATTERSLEY P. W.
Published: April 2006

Differences in ease of digestion of bundle sheath cell walls of leaf blades of Panicum spp. are shown to be associated with differences in bundle sheath cell wall structure, including the presence or absence of a suberized lamella. These structural differences are correlated with photo‐synthetic type (viz. C3, intermediate C3/C4, and the C4 types, PCK, NADP‐ME and NAD‐ME), as are mesophyll: bundle sheath area ratios.
The influence of sward condition on rates of herbage growth and senescence in mixed swards under continuous stocking management
Authors: BIRCHAM J. S. , HODGSON J.
Published: April 2006

A study was conducted to determine the influence of herbage mass under continuous stocking management with sheep on rates of herbage growth (G), senescence (S) and net production of green herbage (NP) in a mixed‐species sward of Lolium perenne. Poa annua and Trifolium repens. Plots were maintained in as nearly constant herbage mass as possible at 500, 700, 1000 and 1700 kg organic matter (OM) ha−1 by continuous but variable stocking with sheep for the period May to July inclusive. Estimates of G, S and NP were obtained for each species from repeated measurements over two 2‐week periods on individually identified grass tillers or clover stolons. Estimates of species population densities enabled estimates of G. S and NP per unit area to be made.

Rates of G were higher and of S were lower for Lolium tillers and Trifolium stolons than for Poa tillers. The laminae of Poa tillers occupied inferior positions in the canopy of the swards maintained at higher herbage masses and were less accessible to the grazing animals, so that Poa tissue was less well utilized.

The total population densities of tillers and stolons declined at herbage masses both above and below 700 kg OM ha−1. The rate of G for the three species combined increased with herbage
Sward management, lamina turnover and tiller population density in continuously stocked Lolium perenne‐dominated swards
Authors: GRANT S. A. , BARTHRAM G. T. , TORVELL L. , KING J. , SMITH H. K.
Published: April 2006

Measurements of rates of growth and senescence of leaf lamina per tiller and of changes in tiller population densities were made in three experiments designed to investigate the influence of sward slate on leaf turnover and net production under continuous stocking.

In each experiment initially uniform swards were fenced to provide four plots on which animal numbers were adjusted twice weekly to give a series of swards maintained as nearly as possible in a steady state with respect to sward surface height (range 1.1–6.4 cm) and herbage mass (range 440–2690 kg OM ha−1). Two experiments were carried out in July–September on vegetative swards and one in May–June on a reproductive sward. Measurements were begun 3–7 weeks after treatments were started and were repeated weekly during 3–4 week measurement periods.

In all three experiments the rate of lamina growth per tiller increased linearly with an increase in sward surface height and herbage mass. In the two experiments conducted in July–August this relationship was partially offset by a linear increase in the rate of senescence per tiller but net production per tiller also increased linearly in relation to sward height and mass. In the experiment conducted in May–June the rates of growth and senescence per tiller increased in parallel so that net production per tiller showed no relationship with sward condition.

Tiller population densities in the July–August experiments were highest in swards maintained between 2 and 3 cm surface height and declined in swards maintained above and below this height. In the experiment in May–June tiller numbers were similar in all treatments prior to the summer solstice but diverged in a manner similar to the other experiments later in the year.

The rate of lamina growth per unit area increased in a manner consistent with an asymptotic relationship and the rate of senescence increased linearly with increasing sward height and mass in all three experiments. Net production per unit area was reduced on swards below about 2.5 cm in height but was insensitive to variation in sward surface height between 2.5 and 6.0 cm (approximately 1000–2500 kg OM ha−1 herbage mass).

The effectiveness of adjustments in tiller numbers and production per tiller and of changes in the balance between growth and senescence as mechanisms of sward homeostatis, together with their implications in the scope for manipulating herbage production by grazing management are discussed briefly.