bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvements to the dry‐weight‐rank method for measuring botanical composition
Authors: JONES R. M. , HARGREAVES J. N. G. 
Published: April 2006

AbstractTwo modifications have been made to the dry‐weight‐rank (DWR) method for measuring botanical composition. One previous limitation of the method has been that it gives biased results in pastures where there is a consistent relation between quadrat dry matter yield and the order in which species are ranked for yield. A weighting factor, applied to the DWR multipliers and based on pasture yield in quadrats estimated for dry weight rank, can correct for this bias. In routine pasture sampling quadrat yields are often visually estimated in the same quadrats in which composition is assessed by DWR. These estimated quadrat yields can then be used as weighting factors to improve the accuracy of DWR as well as to estimate pasture yield. Dry weight rank has also been unsuited to pastures which are heavily dominated by one species but this problem can be lessened by assigning more than one rank to the dominant species, a method referred to as ‘cumulative ranking’.Both these modifications were found to give a more accurate estimate of composition using data from a wide range of tropical and temperate pastures. On the other hand, creation of new DWR multipliers for particular cases was inadvisable. All data made available for this study and the original data ('t Mannetje and Haydock, 1963) were used to derive new multipliers: 0·705, 0·238 and 0·057. The overall benefits from using the new multipliers will, however, only be slight.
Herbage intake and milk production by grazing dairy cows 1. The effects of variation in herbage mass and daily herbage allowance in a short‐term trial
Authors: COMBELLAS J. , HODGSON J. 
Published: April 2006

AbstractTwenty‐four British Friesian cows were allocated between six grazing treatments (two levels of herbage mass x three levels of daily herbage allowance) in a balanced change‐over design with four periods of 12 d each at monthly intervals. Herbage OM mass ranged from 3790 to 5770 kg ha‐1 measured to ground level and daily herbage DM allowances were 30, 60 and 90 g per kg animal live weight. Herbage OM intake was lower at high than at low herbage mass (24·6 vs 26·3 g per kg LW), and was 26·9, 26·6 and 22·9 g per kg LW respectively at daily herbage DM allowances of 90, 60 and 30 g per kg LW. Milk yield was not affected by herbage mass but was depressed at the low herbage allowance.
Nitrogen studies in Lolium perenne grown for seed III. The effect of nitrogen and water stress
Authors: HEBBLETHWAITE P. D. , McLAREN J. S. 
Published: April 2006

AbstractThe effects of water and nitrogen (N) availabilities and their possible interactions on the seed yield and yield components of S23 perennial ryegrass grown in pots in the glasshouse were investigated. Increasing the N fertilizer from 0 to 5 g per pot more than doubled the seed yield but no further increase in seed yield was found by increasing N fertilizer from 5 to 10 g per pot. The main effect of increasing water availability was to increase both seed and straw yield. When N had been applied, accumulated evapotranspiration was linearly related to seed and straw yield. The component of yield having the greatest effect on yield was the number of fertile tillers and, although both N and water availability affected this component, N had the larger effect. Implications of these responses are discussed in relation to the potential yield of the crop and to the field situation.
Herbage intake and milk production by grazing dairy cows 2. The effects of level of winter feeding and daily herbage allowance
Authors: LE DU Y. L. P. , COMBELLAS J. , HODGSON J. , BAKER R. D. 
Published: April 2006

AbstractTwo experiments are described in which two levels of winter feeding and three levels of herbage allowance during the grazing season were imposed upon March/April calving British Friesian dairy cows. The winter treatments resulted in differences in live weight and milk yield at turnout of 35 and 53 kg and 3·4 and 3·2 kg d‐1 for the two trials. Subsequently, when grazed at generous herbage allowances, the cows were able to compensate for much of this difference but when herbage was restricted the milk yield differences were accentuated.Groups of cows from each winter treatment were offered 25, 50 or 75 (Experiment 1) and 30, 50 or 70 (Experiment 2) g herbage DM per kg LW daily during the grazing season. Daily herbage intakes on the three allowances in each trial were 14·1, 13·3, 10·7 and 12·5, 12·1, 11·5 kg OM and milk yields were 16·0, 15·3, 12·5 and 15·2, 14·3, 11·8 kg SCM respectively. Both intake and milk production were depressed once the cows were forced to consume more than 50% of herbage on offer or to graze the sward down to a mean height of less than 8–10 cm. Grazing behaviour observations indicated that under rotational managements the cows did not compensate for restrictions in available herbage by grazing longer. Highest levels of milk production per unit area were observed in both trials when production per cow was depressed by 20–25%.
Herbage measurement in situ by electronics. 1. The multiple‐probe‐type capacitance meter: a brief review
Authors: ANGELONE ALFONSO , TOLEDO JOSE M. , BURNS J C. 
Published: April 2006

AbstractThe history and development of the multiple‐probe capacitance meter used for in situ, non‐destructive estimations of herbage mass is reviewed. An elementary, semi‐theoretical electric‐field analysis focuses attention on the inherent difficulties associated with the multiple‐probe approach. This report establishes the background for the introduction of an ‘earth‐plate’ capacitancemeter.
The influence of sowing date, harvest date and seed rate on the yield of forage peas
Authors: POTTS MICHAEL J. 
Published: April 2006

AbstractA series of preliminary trials is described to assess the potential and some of the cultural requirements of new cultivars of forage peas grown as pure stands in the west of Scotland. Optimum sowing date was late March for harvesting 15 weeks later to leave sufficient of the growing season for a catch crop or the establishment of a grass sward. Yield of dry matter (DM) at harvest was approximately 6 t ha‐1 but DM concentration varied greatly with season. The digestibility of the organic matter was of the order of 0·700 and the crude protein concentration in the DM 170 g kg‐1. DM yield increased with increasing seed rate up to 200 kg ha‐1 the maximum rate tested.
Growth and carbon economy of nodulated white clover in the presence and absence of combined nitrogen
Authors: HAYSTEAD A. , KING J. , LAMB W. I. C. , MARRIOTT C. 
Published: April 2006

AbstractAn investigation of the carbon economy of single S184 white clover plants nodulated with an effective strain of Rhizobium trifolii growing on N‐free nutrient solution and supplied with 150 parts/106 N as NH4NO3 has shown that 10% more of the C fixed per day is available for growth in the plants supplied with combined N. The difference between the two groups of plants is a result of higher respiratory activity in the roots of plants growing exclusively on N2. In terms of shoot growth, however, the difference in growth rate is likely to be less than 10%, because the rate of root growth is greater in the plants supplied with a moderate level of combined N. There is no evidence that NO‐3 and CO2 compete for photosynthetically produced reductant in the leaves of plants grown on N2+NH4NO3, since no reduction in net photosynthesis was observed in plants assimilating combined N.An experiment carried out on detached leaflets of white clover grown on N2 and on N2+ NH4NO3 has shown that NO‐3 ‐reducing activity is present in the leaflets of plants grown on N2+ NH4NO3 but not in plants grown on N2 and that the activity is light‐dependent. Measurements of 14CO2 respired in the light and dark by leaflets previously allowed to photosynthesize 14CO2 showed that the ratio of 14CO2 output in the light to 14CO2 output in the dark was no higher in plants grown on N2+ NH4NO3 than in plants grown on N2. This observation is consistent with the finding that N source does not affect net photosynthesis in whole plants.
Influence of initial cutting date and cutting frequency on yield and quality of star, elephant and Guinea grasses
Authors: OMALIKO C. P. E. 
Published: April 2006

AbstractTwo experiments were conducted to estimate the influence of initial cutting dates in March and April and of cutting frequencies on Guinea grass, elephant grass and star grass productivity. Increasing delay in date of first cut in the season resulted in a progressive increase in dry‐matter yield. 72–81% of the tiller population at any cut were vegetative and this helped to maintain good aftermath yield for each date of first cut. Early April cuts gave the highest dry‐matter yield and early March the least.Harvesting frequencies affected the sward productivity such that the annual dry matter yield increased with increasing harvesting interval from 6800 kg ha‐1 for a 3‐week interval to 13,000 kg ha‐1 for a 10‐week interval. The proportion of green leaf in the dry matter dropped from 57·7% at 3‐week intervals to 32·0% at 10‐week intervals. Seasonal effects showed that potential yield was reduced by a short interval between harvests early in the season but not late in the season. Species differences in quality and in the harvesting interval that gave the maximum yields were noted. These results are discussed in relation to management of the sward throughout the growing season.
A comparison of root competition and shoot competition between Dactylis glomerata and Holcus lanatus
Authors: REMISON S. U. , SNAYDON R. W. 
Published: April 2006

Abstract Dactylis glomerata and Holcus lanatus were grown together in boxes with either full competition, root competition only, shoot competition only or no competition between them. The boxes were either fertilized (150 kg ha‐1N, 100 kg ha‐1 K, 80 kg ha‐1 P) or not fertilized. The experiment was continued for 13 months, and a total of six cuts were taken. H. lanatus was more competitive than D. glomerata throughout the experiment, though the effect declined after flowering during the second growing season. The effects of root competition were generally much greater than those of shoot competition and tended to increase during the first year. However, the effects of root competition declined, relative to shoot competition, after flowering in the second growing season.Fertilizer applications slightly increased the root competitive ability of H. lanatus relative to D. glomerata but slightly reduced its shoot competitive ability.
The effect of companion perennial ryegrass cultivars on red clover productivity when timing of the first cut is varied
Authors: LAIDLAW A. S. , McBRATNEY JUNE M. 
Published: April 2006

AbstractReplicated plots of Hungaropoly red clover were sown on a sterilized area in May 1975 alone (seed rate 11 kg ha‐1) or with one of six cultivars of perennial ryegrass (seed rate 3·5 kg ha‐1) viz. Cropper and S24 (early heading), Barlenna and Hora (medium heading) and Melle and Perma (late heading). In 1976 and 1977 primary growth was cut at one of four dates ranging from mid‐May to mid‐June and thereafter plots were harvested twice each year.Varying the time of first cut did not have a significant effect on total dry matter (DM) yield in either year despite differences in means of cutting treatments on annual red clover yields of the order of 6–9%.In some companion grass treatments total DM yield in 1976 was increased and total red clover yield and percentage red clover contribution were reduced relative to swards sown only with red clover. In 1977 a similar but non‐significant trend was found. Swards containing early ryegrasses had higher total herbage DM yields but lower red clover yields and contents than all other swards at the first harvest in both years.Delay in date of taking the first harvest in 1976 reduced DM digestibility in the first cut and increased it in the second in both years.It is suggested that by cutting early and increasing the number of harvests from three to four per year, differences in the content of red clover between the first and second cut might be reduced, and it is concluded that more benefit is derived from red clover when medium or late heading ryegrasses are used as companion grasses.
The interaction of perennial ryegrass and timothy in mixtures and their reaction to clover and nitrogen in cut swards
Authors: CHESTNUTT D. M. B. , BARTHOLOMEW P. W. , BINNIE R. C. 
Published: April 2006

AbstractResults of experiments where timothy, perennial ryegrass and mixtures of these two in the presence and absence of white clover and receiving various nitrogen treatments were compared, have been considered in the light of previous related experiments. There is evidence that under certain conditions greater yields of sown grass can be achieved from mixed seedings than from either of the two grasses on its own. No yield advantage was gained from mixtures of species when cut infrequently after a late first cut. Inclusion of white clover changed the balance of species in favour of perennial ryegrass and no yield advantage occurred with mixtures in the presence of clover. Yield advantage may be related to seasonal changes in the order of dominance of the two grass species in mixed seedings.
Initial evaluation of lupin for forage
Authors: SHELDRICK R. D. , TAYLER R. S. , MAINGU Z. , PONGKAO S. 
Published: April 2006

AbstractSmall‐plot trials with Lupinus albus cv. Kievskij Mutant (sweet) and L. angustifolius cv. Kubesa (bitter) and Uniwhite (sweet) were sown in April 1977. Sequential whole‐crop samples of the above ground dry matter (DM) were taken to assess the interaction of DM yield and forage quality during crop growth. Both species had similar DM yields, exceeding 11 t DM ha1 in August. L. albus displayed superior whole‐crop in vitro digestibility from late July, due to the large contribution to total DM yield from this time from its succulent, highly digestible pod shells. L. angustifolius showed higher N contents in June and early July, but N concentrations fell below those of L. albus from early August. The steady decline in digestibility of forage from L. angustifolius suggests this species should be harvested rather earlier than L. albus. Harvested in mid‐August, L. albus should yield 11 t DM ha‐1, ata D‐value of 64 and 23·5 g N per kg DM, whereas L. angustifolius harvested 10–14 d earlier should give the same DM yield, but at a D‐value of 58 and 22·0 g N per kg DM. Lupins can thus be regarded as having good potential forage yields, but providing material of only moderate quality.
Silage and milk production: a comparison between grass silages of different chop lengths and digestibilities
Authors: CASTLE M. E. , GILL M. S. , WATSON J. N. 
Published: April 2006

AbstractFour grass silages of two chop lengths and two D‐values were made from S23 perennial ryegrass, and compared in a feeding experiment with lactating cows and in an eating‐behaviour study with non‐lactating cows. The median chop lengths were 11·6 and 11·5 mm in the short silages and 18·2 and 19·5 mm in the medium silages. Chop length had negligible effects on D‐value and on pH with values of 3·81 and 3·94 on the short and medium silages respectively.Silage DM intakes were higher on the short than on the medium‐chop silages in both experiments except where the high D‐value silage was supplemented with concentrates. Milk yields were not affected significantly by chop length with daily values of 19·3 and 19·7 kg per cow on the short and medium treatments respectively with the high D‐value silage, and 18·2 and 18·3 kg per cow with the low D‐value silage. Chop length had only small and non‐significant effects on milk composition.Eating times expressed as min per kg DM were significantly lower on the short than on the medium‐chop silages.It is concluded that the small differences between the short‐ and the medium‐chop silages were of no economic importance.
Silage and milk production: a comparison between long, chopped and ground hays as supplements to silage of high digestibility
Authors: CASTLE M. E. , GILL M. S. , WATSON J. N. 
Published: April 2006

AbstractGrass silage made in May from S24 perennial ryegrass had a DM concentration of 262 g kg‐1 and an in vitro D‐value of 0·698, and was given ad libitum to twelve Ayrshire cows in a 16‐week feeding experiment. In addition supplements of hay with a mean in vitro D‐value of 0·603 were offered in one of three forms—long, chopped (12·1 mm) or ground (0·80 modulus of fineness) and cubed—and of concentrates given at either 2 or 4 kg per 10 kg milk. Hay averaged 18·2% of total forage DM intake with mean daily intakes of 1·28, 1·22 and 2·26 kg DM per cow in the long, short and ground forms respectively. The highest daily intakes of forage, i.e. silage plus hay, occurred on the ground hay treatments, with values of 10·24 and 9·25 kg DM per cow on the 2 and 4 kg concentrate treatments respectively. The mean daily milk yields were 18·2,18·2 and 19·2 kg per cow on the long, short and ground hay treatments respectively but the increase in yield with the ground hay was only significant at the low level of concentrate intake. The hay treatments had small and non‐significant effects on milk composition. It is concluded that ground hay was superior to either long or chopped hay as a supplement for silage, but the small advantages depended on the level of concentrate intake.
The influence of light and temperature during winter on growth and death in simulated swards of Lolium perenne
Authors: THOMAS HENRY , NORRIS IAN B. 
Published: April 2006

AbstractTwo growth experiments were carried out in January‐March 1978 in which simulated swards of perennial ryegrass were (1) heated by soil warming cables to give soil surface temperatures of approx. 7·5‐9·C above ambient temperature, (2) shaded with netting to reduce light levels by approx. 50%, or (3) both heated and shaded.Heating alone increased leaf appearance, death, extension, lamina size, leaf area index (LAI), tillering (month 1)and whole plant weight (month 2) and reduced stubble water‐soluble carbohydrates and specific leaf weight (SLW).Shading alone increased leaf extension, lamina size and LAI but to a lesser extent than did heating. Shading decreased SLW, leaf death rate, tillering (month 2), stubble carbohydrates and whole plant weight, but not herbage weight.The effects of heating plus shading were similar to those of heating alone, except that the increases in leaf size, extension and LAI were even greater, and shoot bases and roots had low or negative growth rates.In general the heating treatments caused a rapid turnover of leaf material, but net herbage growth was relatively insensitive. It is concluded that (1) temperature rather than light was limiting whole plant growth, especially from mid‐February to mid‐March and (2) mild, dull weather in winter is likely to induce tiller death associated with reduced investment in carbohydrate reserves.
Effect of defoliation on flower initiation in white clover in summer
Authors: THOMAS R. G. 
Published: April 2006

AbstractFlowering behaviour of plants of six cultivars of Trifolium repens (Kent Wild White, Grasslands Huia, S100, Blanca, Olwen and Milkanova) growing in field plots at the Grassland Research Institute, Hurley, was recorded in mid‐July. Half of each plot had been defoliated in early May, the other half in mid‐June. In all cultivars defoliated in May, inflorescence initiation had stopped even though the natural photoperiod at that time was well above the critical daylength for initiation Defoliation in mid‐June had led to a renewal of inflorescence initiation in all cultivars.The results confirm that the stimulatory effect of defoliation on inflorescence initiation in plants that have stopped initiation in long days, which has previously been observed in Grasslands Huia in controlled environments, also occurs in the field and in other cultivars.
Cattle slurry as a source of nutrients for red clover: herbage production and clover contribution
Authors: GRACEY H. I. 
Published: April 2006

AbstractAn established sward of red clover cv. Hungaropoly sown pure received approx. 30 kg P ha‐1 and 200 kg K ha‐1 each year for 3 successive years. The P and K were applied either as cattle slurry, inorganic fertilizer or combinations of these. Treatments were applied either in spring or after the first harvest. There were a total of six treatments and these were harvested three times each year. The average yields of total herbage DM over all the treatments in the first, second and third years were 15·2, 14·2 and 14·2 t ha‐1 respectively and the various treatments had no significant effect on the overall yields.Treatments had a significnt effect on red clover DM yields and percentage red clover in one harvest in each of the first 2 years and all three in the third year. Yields of red clover were lower and grass higher in treatments receiving cattle slurry only. On this treatment there was a total yield of 23·2 t ha‐1 red clover DM in the 3 years compared with 30·2 t ha‐1 on the inorganic fertilizer treatments. However, by applying P and K fertilizer in the spring, followed by cattle slurry after the first harvest, it was possible to maintain a high proportion of red clover in the sward and to produce yields of red clover DM similar to those on the inorganic fertilizer treatments.
A comparison of a hybrid stubble turnip (cv. Appin) with other cruciferous catch crops for lamb fattening. 2. Animal performance and toxicological evaluation
Authors: YOUNG N. E. , AUSTIN A. R. , ORR R. J. , NEWTON J. E. , TAYLOR R. J. 
Published: April 2006

AbstractForage brassica catch crops can provide a valuable source of additional feed in the autumn when supplies of other feed are limited. Weaned lambs grazed either (A) a novel hybrid crop, stubble turnip cv. Appin, or (B) a sequence of crops consisting of fodder radish cv. Nerys, followed by forage rape cv. Canard. Forty, 60 or 80 g of crop DM per kg current live weight (LW) were allowed daily and the performance, intake and carcass yield of the lambs were monitored. Lamb LW gains were lower on treatment A (45, 65 and 72 g d‐1) than on B (78, 111 and 117 g d‐1) at the 40‐, 60‐ and 80‐g DM d‐1 allowances respectively. Intakes of forage crops, however, did not differ significantly, probably because the estimates of intake were made in the middle of each 14‐d allocation period of the crops. The intake values are thus an indication of the potential intake when a relatively plentiful supply of food is available; they were 19·2, 17·2 and 18·2 g OM kg‐1 LW for treatment A and 16·2, 19·2 and 19·2 g OM kg‐1 LW treatment B at the 40‐, 60‐ and 80‐g DM d‐1 allowances respectively.Mild anaemia occurred in lambs feeding on both crops. Anaemia was more marked on treatment B, which was consistent with the higher concentrations of S‐methyl cysteine sulphoxide (SMCO) but as the performance of animals was superior on treatment B, SMCO intake and anaemia are not thought to be the first or the most important factors in limiting animal performance. Goitrogenic changes in thyroid glands occurred on both crops. Mean weights of paired thyroid glands were 3·22, 4·28 and 4·21 g on treatment A and 3·29, 5·27 and 5·21 g on B at the 40‐, 60‐ and 80‐g DM d‐1 allowances respectively; the effects of both treatment and allowance were significant (P <0·21). Thiocyanate concentrations were higher on treatment A than B, indicating differing glucosinolate concentrations. While this was consistent with animal performance, it was not consistent with the weight of thyroid glands. However, the goitrogenic responses may have been complicated by the ingestion of soil iodine because very high faecal ash values were recorded. Thus, glucosinolates appear not to have affected lamb growth rate by their goitrogenic effect but the possibility remains that they may have influenced performance by other means.