bluuebunny/crossref_metadata_2025_split huggingface dataset:
STUDIES OF RESPONSE TO FERTILIZER NITROGEN
Authors: Hunt I. V. 
Published: April 2006

ABSTRACTThe effects of 59, 118 or 177 kg N/ha were measured on 7 occasions from 8 to 57 days after application to a perennial ryegrass sward in terms of changes in composition.The first increase Dt of N significantly raised percentages of CP, non‐protein N, K, P, Ca, Na and Mg and significantly depressed percentages of DM, OM and OM digestihility. The second increment of N resulted in a further rise in the percentages of CP, true protein, non‐protein N, K, P, Ca, Na and Mg; the percentages of DM and OM were further depressed but OM digestihility was not significantly depressed. Percentages of P and Na showed increased responses for the more mature herbage; while percentage non‐protein N showed a more marked response in younger herbage. As herbage matured percentages of OM and Na rose, the latter only from days 16 to 45. All other attributes showed falling percentages to levels which could be inadequate for a 500 kg dairy cow yielding 15 kg milk. CP percentage reached this critical level (1.4% N) at days 37, 45 or 56 given 59, 118 or 177 kg N/ha; P percentage became critically low (< 0.36%) at days 27, 35 or 38, respectively; Mg percentage fell to the critical level (0.12%) at days 23, 35 and 46. Na percentage showed the reverse trend, being deficient (< 0.13%) in the earliest samples and becoming satisfactory from days 23 or 27 at 118 and 177 kg N/ha but it remained inadequate at 59 kg N/ba.
PREDICTING ORGANIC‐MATTER DIGESTIBILITY FROM IN VIVO AND IN VITRO DETERMINATIONS OF DRY‐MATTER DIGESTIBILITY
Authors: Mcleod M. N. , Minson D. J. 
Published: April 2006

ABSTRACTThe DM digestibility (DMD) and organic matter digestibility (OMD) of 36 tropical grass samples were determined both in vivo and in vitro. Regressions relating OMD to DMD were calculated. In vivo OMD=1·02 in vivo DMD+ 0·1, r=0·99. In vitro OMD=1·05 in vitro DMD—4·7, r=0.99. At the same DMD, the in vitro method predicted OMD 2·8 to 3·4 percentage units lower than the in vivo method. This difference was caused by the difference in mean apparent digestibility of the ash, in vitro 71%, in vivo 47%. In vivo DMD was correlated (r=0·92, P<0·01) with in vitro DMD and the regression relating these two factors had a residual standard deviation of ±1·42 digestibility units. This deviation was reduced to ±1·9 digestibility units when OMD was determined. For both DMD and OMD significant differences were found between grass species in the relation between in vivo and in vitro digestibility.To overcome biased estimates of OMD it was suggested that conversion equations should be avoided, and that the in vitro method be standardized with samples of known in vivo OMD as similar as possible to those being tested.
Relationship between digestibility and faecal nitrogen in sheep and cows offered herbage ad libitum
Authors: THOMAS S. , CAMPLING R. C. 
Published: April 2006

AbstractA comparison was made of the digestibility, voluntary intake and concentration of N in faecal organic matter in castrated male sheep and non‐lactating cows offered herbage ad libitum. The sheep ate 22% more herbage DM per kg liveweight than the cows. In general, the sheep and cows digested the organic matter of the herbage to the same extent, although on two occasions significantly higher digestibilities were observed in cows than in sheep. Similar concentrations of N in faecal organic matter in sheep and cows were matched by similar digestibilities of herbage organic matter. Regression equations relating herbage organic matter digestibility to faecal N concentration were not significantly different between sheep and cattle.
The physiology of tiller death in grasses.
Authors: ONG C. K. 
Published: April 2006

AbstractA reproducible method of causing tiller death on individual ryegrass (Lolium perenne L., cv. S23) plants is described. This was achieved by subjecting whole plants grown previously for 7 weeks in full light (100%) and full nutrient (100%) to either light stress (17.5% or 2.5%) or nutrient stress (10% or 0%) or various combinations of light and nutrient stress. Detailed records were made of tiller appearance, position and weight, and the probability of tiller death was calculated. Analysis of each plant indicated that the smallest tiller, which was often, but not always the youngest, was the most vulnerable when the whole plant was stressed. Tiller position was relatively unimportant in determining survival. The results are discussed in relation to tiller mortality in natural populations and crop communities.
The effect of herbage allowance upon the herbage intake and performance of suckler cows and calves
Authors: BAKER R. D. , ALVAREZ F. , LEDU Y. L. P. 
Published: April 2006

AbstractTwenty‐four Hereford × Friesian cows and their South Devon cross calves were allocated to three herbage allowances allotted daily for three periods of 8 weeks in a Latin square design. The daily allowances were 17, 34 and 51 g dry matter per kg cow plus calf live weight. Milk production was depressed by 0·2 and 1·2 kg d‐1 at the medium and low allowances. The corresponding falls in liveweight gain were for cows 0·26 and 0·25, and for calves 0·27 and 0·24 kg d‐1. Residual sward height after grazing gave a better indication of the animals' reaction to sward conditions and the management imposed than actual herbage allowance. The quantity per unit area and the composition of material present were important factors influencing intake. Calves were unable to compete with their dams to maintain herbage intake at the lower allowances and therefore are likely to benefit from additional feeding or creep grazing when residual sward height falls below 6cm for periods in excess of 1–2 weeks.
Silage and milk production: a comparison between barley and dried sugar‐beet pulp as silage supplements
Authors: CASTLE M. E. , GILL M. S. , WATSON J. N. 
Published: April 2006

AbstractTwo grass silages made from perennial ryegrass, and with D‐values of 0·216 and 0·255, were offered ad libitum to 18 Ayrshire cows in two feeding experiments. On the control treatment the silages were supplemented with soybean meal only, and on the other two treatments with equal weights of DM from either barley or dried molassed sugar‐beet pulp plus the same weight of soya as on the control treatment. The daily intakes of silage DM were not significantly different on the barley and beet‐pulp treatments, and, on average, the intake of silage DM was reduced by 0·24 and 0·20 kg by feeding 1 kg barley and beet pulp DM respectively.The daily milk yields were not significantly different on the barley and beet‐pulp treatments with mean values of 19·2 and 19·2 kg per cow respectively compared with 17·2 kg on the control treatment. On the barley and beet‐pulp treatments the fat, SNF, CP and lactose concentrations in the milk and the live weights of the cows were not significantly different. It is concluded that the barley and beet pulp had similar feeding values and replacement rates when used as supplements with grass silage, and that the two feeds were interchangeable on an equal DM basis.
Pest damage to white clover and perennial ryegrass seedlings after reseeding with a slot‐seeder
Authors: CLEMENTS R. O. , BENTLEY B. R. , SQUIRES N.R.W. 
Published: April 2006

AbstractA high risk of pest damage to seedlings of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) was shown to exist after reseeding with a slot‐seeder. Damage varied between years and sites; white clover appeared to be more affected than perennial ryegrass. Insecticides of feasible commercial use (chlorpyrifos granules and γ‐HCH seed treatment) were found to prevent damage. There was no evidence of phytotoxicity from any of the pesticides studied at the dose rates used in the field.
Value of a rising‐plate meter for estimating herbage mass of grazed perennial ryegrass‐white clover swards
Authors: MICHELL P. 
Published: April 2006

AbstractA rising‐plate meter was used in a double sampling technique to measure the herbage mass of rotationally grazed perennial ryegrass‐white clover swards over a period of 2 years. The meter was calibrated by developing a linear regression between meter reading and herbage dry matter mass as measured by cutting 0·2‐m2 quadrats to ground level.There was a strong relationship between meter reading and herbage mass, and correlation coefficients were consistently 0·2 or above. The calibration regression was normally constant for extended periods, especially over the winter and spring. The relationship was more variable over the summer but appeared to follow a pattern that was to some extent repeatable between years. The slope of the regression (kg DM ha‐1 cm‐1) was 312 and 267 in the two winters and reached values of 800 and 452 in the two summers. The calibration relationship was adequately described by a linear model over the winter and spring but there was a tendency for a curved relationship in mid‐to late summer.The standard pooled regression found with winter ryegrass‐clover swards was not applicable to the more erect prairie grass, and the standard regression overestimated slightly the yield of heavily grazed swards. There was no evidence of a difference in relationship between irrigated and non‐irrigated swards over the summer.The individual meter readings could be used to develop a useful diagrammatic picture of the changes that occurred in sward structure as the pastures were subjected to different managements and this could be used to illustrate problem areas in pasture management.The meter was useful in overcoming the problem of variability of herbage mass within paddocks and could give precise estimates of herbage mass, especially when it was possible to use a pooled regression encompassing a large number of calibration cuts. In these cases the meter could be used to detect differences of about 8%.
The effects of temperature and fertilizer nitrogen on the spring growth of tall fescue and cocksfoot
Authors: LEMAIRE G. , SALETTE J. 
Published: April 2006

AbstractA detailed study of the spring growth curves of two forage grasses, tall fescue and cocksfoot, over three successive years showed a large variability of growth over the vegetative phase. This variability was evident at levels of fertilizer N which were considered to be non‐limiting (60 kg N ha‐1 in autumn plus 120 kg N ha‐1 in February).At this level of N there was a relationship between yield in the vegetative phase and accumulated temperatures from the last cut in the autumn which was described by a regression common to the three years. The slope of this regression represents the potential growth of a variety. At a lower level of N a separate regression was needed in each year to relate growth to accumulated temperature.Variation in spring growth was not related to accumulated net radiation. Growth in the reproductive phase was related to accumulated temperature and accumulated net radiation from the 10‐cm ear stage.
Slot‐seeding investigations
Authors: Haggar R. J. , Koch D. W. 
Published: April 2006

AbstractRed clover cv. Hungaropoly was slot‐seeded into a perennial ryegrass‐dominant sward in April 1979. Glyphosate and paraquat were applied separately as bandsprays each at two doses and at two band widths. Control plots were either slot‐seeded without a herbicide bandspray or received ±150 kg N ha−1 a−1. Red clover establishment was assessed and amounts of dry matter (DM) and total N accumulated were measured at two harvests in 1979 and three harvests in 1980. Bandspraying increased seedling vigour and development and resulted in the eventual replacement of 1 t grass DM ha−1 by an equivalent amount of red clover. Of the treatment variables investigated, bandspray width had the greatest influence on red clover establishment and productivity. The slot‐seeded area, meaned for all treatments, produced a total of 6.40 and 13.16 t DM ha−1 in 1979 and 1980. This was estimated to be equivalent to the all‐grass sward receiving 112 kg N ha−1 a−1 during the second year of the experiment or 238 kg N ha−1 over the 2 years when measured in terms of N yield. Slot‐seeding overcomes several of the problems associated with conventional establishment of red clover.
The production and persistency of different grass species cut at different heights
Authors: JONES E. L. 
Published: April 2006

AbstractThe effect of two heights of cutting (5 and 8 cm) on the dry matter harvested and persistency of a range of different grass species and varieties were monitored over a 3‐year period (1976 to 1978). Dry matter harvested was measured in the second and third harvest year and persistence of sown grass was assessed at the end of the first and third harvest year. The grasses were managed under a frequent cutting system, i.e. simulated grazing. Results showed that at the low cutting height tetraploid hybrid ryegrasses and diploid Italian ryegrasses in the third harvest year gave lower annual dry matter harvests of sown grass and were less persistent than at the high cutting height, whilst, in contrast, perennial ryegrasses gave higher annual harvests of sown grass but persistency was unaffected. In general at the low cutting height varieties of cocksfoot, meadow fescue and tall fescue gave comparatively higher annual harvests of sown grass in the second harvest year but lower yields of sown grass in the third harvest year. A notable exception was Cambria cocksfoot which in the second harvest year gave higher yields of sown grass and was more persistent at the low cutting height.However, at 5 cm cutting height, the proportions of weed grasses (mainly Poa spp.) in swards sown to tetraploid hybrid ryegrasses and diploid Italian ryegrasses were generally greater, particularly in mid‐season.
A technique to record automatically some aspects of grazing and ruminating behaviour in sheep
Authors: PENNING P. D. 
Published: April 2006

AbstractThe construction of a transducer and the use of a recording system to measure jaw movements of grazing sheep is described, The time spent grazing, ruminating and idling may be measured by this equipment and the data produced automatically processed using a microprocessor which determines each minute whether the animal is grazing, ruminating or idling and also summarizes these data to give total times. The accuracy of this technique in relation to manual observation is discussed.
Defoliation and productivity of a phalaris‐subterranean clover sward, and the influence of grazing experience on sheep intake
Authors: CURLL M. L. , DAVIDSON J. L. 
Published: April 2006

AbstractSwards of Phalaris aquatica‐Trifolium subterraneum were subjected to four defoliation treatments—zero, low (11 sheep ha−1) and high (22 sheep ha−1) stocking rates, and weekly cutting. At high stocking rate the annual grass Hordeum leporinum dominated while clover was dominant at low and zero stocking rates. Weekly cutting suppressed species other than clover and so failed to simulate grazing.There were similarities in net herbage production between zero and lightly grazed swards and between heavily grazed and repeatedly cut swards. Net herbage production decreased in the order undisturbed sward < lightly grazed sward < heavily grazed sward < repeatedly cut sward.When sheep grazed swards where herbage mass was low their daily consumption of herbage, and therefore liveweight change, depended on their recent grazing experience. Sheep accustomed to swards where herbage mass was low ate more because they grazed for much longer each day than unaccustomed sheep, although they selected a diet of similar digestibility.
The estimation of herbage mass of perennial ryegrass swards: a comparative evaluation of a rising‐plate meter and a single‐probe capacitance meter calibrated at and above ground level
Authors: MICHELL P. , LARGE R. V. 
Published: April 2006

AbstractA rising‐plate meter and a single‐probe capacitance meter were calibrated on perennial ryegrass swards (cultivars S23, Endura, Melle) over the spring and summer (13 March to 14 September 1981). The swards were rotationally grazed by cattle and from mid‐June onwards they were irrigated and cut at 5 cm after grazing to remove rejected herbage. Linear regressions were calculated relating meter readings to herbage dry matter mass as measured by cutting 0–2 m2 quadrats to either 18 mm above ground or to ground level.The regression for the rising‐plate meter was constant over the spring (slope 275 kg DM ha−1 cm−1) and again over the summer (slope 385 kg DM ha−1 cm−1). The regression for the capacitance meter changed slightly over the spring (slope 11.2 to 14.0 kg DM ha−1 unit reading−1) and was also constant over the summer (slope 20.3 kg DM ha−1 unit reading −1). Correlation coefficients were always above 09 and residual standard deviations ranged from 258–525 in Spring up to 636–918 kg DM ha−1 in summer. Residual standard deviations were lower with the plate meter than with the capacitance meter and were lower with the above‐ground cutting height. Neither meter was able to give accurate results with tall rejected herbage containing a build‐up of senescent material.Herbage mass below 18 mm was greater on summer than spring swards. When compared with a ground level cut. cutting above ground underestimated herbage mass on summer relative to spring swards; there was also a tendency to underestimate herbage mass on tall pastures relative to short pastures.There was no evidence of a curved relationship between herbage mass and meter reading with either meter and both meters gave readings related to herbage dry matter mass rather than mass of green herbage or water.
Changes in the structure and physiology of a perennial ryegrass sward when released from a continuous stocking management: implications for the use of exclusion cages in continuously stocked swards
Authors: PARSONS A. J. , COLLETT B. , LEWIS JANINE 
Published: April 2006

AbstractA perennial ryegrass sward was managed by continuous stocking with sheep (April–September) for 4 successive years after sowing. The sward was grazed to maintain a leaf (lamina) area index (LAI) close to 1.0. Areas of the sward were released from grazing on three occasions: once during summer in the third year after sowing, and twice during spring and summer in the fourth year after sowing. There were marked changes in the structure and physiology of the continuously stocked sward following release from grazing. After several successive years of continuous stocking, the sward comprised a large population of small tillers and the small LAI resulted in consistently low rates of photosynthesis. Following release from grazing, photosynthesis increased markedly as the LAI increased but this change was associated with the loss of a large proportion of the population of tillers. There were seasonal differences in the pattern of changes in photosynthesis and tiller numbers following release from grazing which were not apparent under continuous stocking. The changes in the structure and physiology of the sward following release from grazing suggest that the net accumulation of herbage in areas of sward from which the animals are excluded, for instance using cages, may be an unreliable estimate of production under continuous stocking.
Effect of pH and added ammonium hydroxide on in vitro digestibility of roughages of different origin treated with sodium hydroxide and ammonia*
Authors: LESHEM Y. , GOLDMAN A. , YULZARI A. 
Published: April 2006

AbstractAmmonia and sodium hydroxide (NaOH) have been used to improve the dry matter (DM) digestibility of roughages or to conserve them. These treatments have had incidental effects on pH alone or both the pH and nitrogen contents of the roughages. in the present study, the effects of pH and NH4OH on the in vitro dry‐matter digestibility (IVDMD) of eight roughages—four legumes and four grasses—were investigated. The pH levels of approximately 5, 7, 9 and 12 were achieved by adding appropriate amounts of NH4OH or NaOH and H2SO4. Nitrogen levels of approximately 20, 30, 40 and 50 g kg−1 on a DM basis were obtained by adding NH4OH. Results of a multiple regression showed that increasing the pH caused a linear increment in IVDMD and that the added NH4OH reduced the increment of IVDMD. The effects of both pH and N on IVDMD were found to be specific to the individual roughage; the response of grasses to both pH and NH3 was greater than that of legumes
The influence of the epidermis on the drying rates of red clover leaf petioles and stems and of Italian ryegrass stems at low water contents
Authors: HARRIS C. E. , DHANOA M. S. 
Published: April 2006

AbstractPrevious results with red clover (Trifolium pratense) leaflets, leaf petioles and stems indicated that the epidermis continued to impose a barrier to water loss at low water contents. Further experiments with red clover leaf petioles and stems suggest that cuticular wax is the epidermal component concerned and that treatments which remove or merely modify this will also increase drying rate. However, when treatments to reduce epidermal resistance were applied to pseudostems and flowering stems of Italian ryegrass (Lolium multiflorum) the initial increase in drying rate produced was not sustained at low water contents. The pseudostems consisted of three layers of leaf material rolled one within the other and the true flowering stems were surrounded by one leaf sheath. Their pattern of response to treatments suggested that these affected only the outer sheath, which produced an initial acceleration in drying rate, but that this was not sustained after the outer sheath was dry because the lower untreated layers dried in a similar way to untreated controls.The results suggest the possibility of devising practical treatments to increase drying rate at low water contents with crops containing a high proportion of leaf or stem not surrounded by leaf sheath. Devising such treatments for crops with a high proportion of grass pseudostem or flowering stem surrounded by leaf sheath will be considerably more difficult.
Potential pasture production in the uplands of Wales
Authors: DAVIES D. A. , MUNRO J. M. M. , MORGAN T. E. H. 
Published: April 2006

AbstractOnly a very limited number of species, including red fescue (Festuca rubra), perennial ryegrass (Lolium perenne), timothy (Phleum protense) and white clover (Trifolium repens) are considered as suitable for wet hill land. Detailed comparison of red fescue, perennial ryegrass and timothy on contrasting acid brown earth and stagnogley soils from 1966 to 1969 at Pant‐y‐dŵr Hill Centre (305 m OD) highlighted the advantages of red fescue in annual DM production and its more even distribution over a longer growing season but also indicated drawbacks of slow initial establishment and lower feed quality. In vitro DOMD of red fescue averaged 645 g kg−1 over the year compared with 690 g kg−1 for perennial ryegrass and timothy. Assessment of a narrow range of species under surface seeding conditions on a stagnogley soil from 1971 to 1975 confirmed the value of red fescue in DM production and persistence. The results are discussed in relation to the characteristics required in herbage species for hill land improvement.