bluuebunny/crossref_metadata_2025 huggingface dataset:
The incidence of vims‐like symptoms and ryegrass mosaic virus in perennial ryegrass pastures in the West of Scotland
Authors: HOLMES S. J. I. , CHANNON A. G.
Published: April 2006

In 1972 and 1973 fields of perennial ryegrass in the West of Scotland were surveyed for ryegrass mosaic virus (RMV). Visual determinations of foliar symptoms were made in the field and leaf samples were collected for diagnosis of the virus by electron microscopy and by sap transmission to S22 Italian ryegrass.

In 1972, ninety‐eight fields were surveyed and virus‐like symptoms were observed in 59%, but tests showed that only 21% were infected with RMV. In the more extensive 1973 survey, 201 fields selected on a stratified random basis were examined and whilst 45% had virus‐like symptoms only 5% proved to be infected with RMV.

Symptoms were most readily seen in fields which had a high percentage of long, lush perennial ryegrass. Analysis of data collected in 1973 on management practices did not reveal any obvious association between the incidence of virus‐like symptoms and the cutting and grazing regimes, the grazing animal used or the level of nitrogen applied.
The value of timothy (Phleum pratense L.) in ryegrass — timothy mixtures managed to simulate intensive grazing
Authors: SWIFT G.
Published: April 2006

The performance of timothy in mixtures with perennial ryegrass was assessed under a simulated intensive grazing management over two harvest years in 1974–75. Three seed rates of S23 perennial ryegrass were factorially combined with three rates of Scots timothy and compared with pure stands of each grass. All were sown with Huia white clover. When cut six times at monthly intervals and with an annual N input of 350 kg ha−1, there were no significant differences in total DM production in either year. The 2‐year mean DM yield for the nine mixtures and six pure swards was 9·77 t ha−1 (range 9·34–10·16). Compared with the pure ryegrass swards, in both years the ryegrass‐timothy mixtures produced earlier spring growth but were significantly lower yielding at the second cut. Over the first five cuts the proptortion of timothy in the three mixtures with 22·4 kg ha−1 ryegrass seed averaged 26% in the first year and 37% in the second. Corresponding calculated mean DM yields of timothy were 2·75 and 3·00 t ha−1.

It is concluded that an early timothy variety is capable of competing with a late‐heading perennial ryegrass in frequently cut swards managed to simulate intensive grazing. The strong development of timothy in the dry summer of 1975 suggests that in mixtures of late perennial ryegrass varieties, an early variety of timothy should be beneficial for its spring growth in grazed swards.
The effects of rates of application and sources of nitrogen on nitrate concentration in oat forage
Authors: JOSHI B. S. , PRASAD RAJENDRA
Published: April 2006

A field experiment was conducted during the winter seasons of 1972–73 and 1973–74 to study the effects of rates of application (0, 100, 200 kg ha−1) and sources of nitrogen (ammonium sulphate, calcium ammonium nitrate, urea, sulphur‐coated urea and sulpha‐thiazole‐treated urea) on nitrate‐N concentration in oat (Avena sativa L.) forage. N application increased the nitrate‐N concentration, the effects being more marked when the rate was increased from 100 to 200 kg ha−1 than when it was raised from 0 to 100 kg ha−1. The highest nitrate‐N concentration in the dry matter (> 0·16%) was obtained when calcium ammonium nitrate was applied at 200 kg ha−1 N. Sulphur‐coated urea gave the lowest nitrate‐N concentration. In one year treatment of urea with sulphathiazole reduced nitrate‐N concentration in oats forage.
Temperature effects in determinations of leaf relative water content
Authors: SHEPHERD W.
Published: April 2006

Differences between field temperature and floating temperature during determination offect apparent leof relative water content (RWC). When floating temperature was lower or higher than field temperature, RWC appeared higher or lower, respectively, than when the temperatures were the same. Discrepancies averaged 0·24% RWC per TC temperature difference for wheat and perennial ryegrass, and 0·33% for the less xeromorphic white clover and potato. These averages might reasonably be used in future for correcting values obtained with these or similar species.
Dalapon resistance in Lolium perenne populations
Authors: CHARLES A. H. , JONES J. L. , RYAN P. J.
Published: April 2006

The resistance often early, ten medium late and ten late flowering ryegrass populations to two rates of dalapon (2.8 and 5.6 kg ha‐1 acid equivalent) was measured in a box experiment. There was no difference in the mean effect of dalapon on the maturity groups at the time of greatest yield reduction, but the recovery of the late flowering population was, on average, better than that of the medium late group. There was a range of reaction to herbicide within all three maturity groups and, in general, the high yielding populations without dalapon were the most resistant, but there were exceptions. Assessment at 2.8 kg ha‐1 acid equivalent gave a similar ranking order to that using twice the amount of dalapon. The results of the current box experiment with seedlings were consistent with those obtained in the field at another location (Faulkner, 1974) for the eleven cultivars common to both trials. The resistance of a permanent pasture population was much lower than that of some cuttivars.
Winter hardiness in Lolium multiflorum Lam. I. The effect of nitrogen fertilizer and autumn cutting managements in the field
Authors: HIDES D. H.
Published: April 2006

Four Italian ryegrass varieties of different origins and winter hardiness were grown as spaced plants at a lowland and an upland site and subjected to ten managements comprising two nitrogen levels and five autumn cutting treatments. Tiller mortality after the winter of 1971–72 was measured in March and subsequent spring recovery from winter damage in April.

Although the winter was not severe, there was considerable winter kill, particularly at the upland site where the most severe treatment combinations killed up to 90% of the plants of the more susceptible varieties. In general, winter kill was increased by raising the level of nitrogen fertilizer and by late or frequent autumn defoliations, and significant interactions between locations and the two treatment factors emphasized the importance of the siting of the experiment.

The varieties difFered in their overall winter hardiness, with Bb 1430 and RvP suffering less tiller mortality than S22 and Grasslands Paroa in all the treatment combinations, but significant interactions of varieties with locations and cutting treatments revealed that the magnitude of the difference between varieties varied with location and cutting management. Regression analysis of these interactions, however, showed that the tiller mortality of all four varieties increased linearly with the increasing stresses applied by the location × management combinations. There was no differential variety recovery from winter kill, the spring yields being entirely related to the level of tiller mortality experienced.

These results are discussed in relation to the breeding of winter hardy varieties, the choice of variety and autumn management practice.
The effects of nutrient supply on flowering and seed production in Poa annua
Authors: ONG L. CHIN K. , MARSHALL C. , SAGAR G. R.
Published: April 2006

The effect of nutrient concentration on the reproductive development and seed yield of Poa annua was examined in a sand culture experiment. The nutrient concentration during the initial vegetative stage did not affect the time taken for double ridge formation by the main shoot but did influence the subsequent development of the inflorescence as did the post‐initiation level of nutrients. At low nutrient levels flowering was inhibited in some individuals but at the higher concentrations inflorescence emergence was hastened, inflorescence size was increased and, in particular, the number of spikelets and hence the number of seeds per inflorescence was greatly increased. The mean weight of 100 seeds was unaffected by the nutrient concentration. The number of reproductive tillers per plant was increased by high nutrient supply but the proportion of dry weight allocated to root development was reduced.
The influence of vernalization on response to nitrogen of perennial ryegrass
Authors: BARTHOLOMEW P. W. , CHESTNUTT D. M. B.
Published: April 2006

Vernalized and unvernalized perennial ryegrass (Lolium perenne cv. Gremie) tillers planted in microplots in a glasshouse in April 1974 and 1975 were exposed to natural daylength thus inducing vernalized plants to produce reproductive, and unvernalized plants vegetative growth. Nitrogen was applied at 0–30 g m−2 (to 24 g m−2 in 1975) to both types of herbage. At the first defoliation in each year yields from vernalized grass were greater than those from unvernalized grass; subsequently differences were minimal or reversed. Vernalization had no significant effect (P > 0.05) on total yields over four defoliations in either year.

Apart from the first cut in 1974 nitrogen application increased dry matter yields of both types of herbage. Tiller numbers were usually increased by the lowest level of nitrogen application but at higher levels the effect was variable.

There was no evidence of an interaction effect of level of nitrogen application and vernalization on dry matter yields.
Nitrogen studies in Lolium perenne grown for seed. II. Timing of nitrogen application
Authors: HEBBLETHWAITE P. D. , IVINS J. D.
Published: April 2006

The effects of applying nitrogen at different growth stages to S24 and S23 perennial ryegrass grown for seed were investigated in a series of field experiments from 1971 to 1976. These varieties of ryegrass were found to be insensitive to timing of nitrogen application from apex initiation to the stage when ears first emerged. However, if nitrogen application was delayed until about 30% or more of the ears had emerged, yields were lower compared with earlier applications, this effect being significant when nitrogen was delayed until 70–80% ear emergence because of a decrease in both numbers of fertile tillers and number of seeds per unit area. No advantages were found for splitting nitrogen applications between apex initiation and ear emergence.
Winter hardiness in Lolium multiflorum Lam. II. The effect of defoliation and nitrogen application as assessed by low temperature response in a controlled environment
Authors: HIDES D. H.
Published: April 2006

The effect of defoliation and nitrogen application on the cold tolerance of four varieties of Italian ryegrass was assessed using controlled environment chambers. Both defoliation and nitrogen fertilizer markedly reduced overall cold tolerance and this closely matched changes in winter hardiness induced by similar treatments applied to the same varieties in a field experiment. However, the relative response of individual varieties differed from that found under field conditions. Thus, RvP showed high levels of tolerance to low temperatures in the controlled environments and was also winter‐hardy under field tests; by contrast Bb 1430, although previously shown to be winter hardy in the field, exhibited low tolerance of cold stress in growth chambers. Thus, results obtained in controlled environment tests cannot be entirely equated to winter hardiness in the field.

Water‐soluble carbohydrate (WSC) levels were reduced by both defoliation and nitrogen application and there were significant overall differences between varieties. It was not possible, however, to detect any clear relationship between these differences in WSC levels and cold tolerance.

The significance of these results in relation to the use of controlled environment chambers for selecting for improved winter hardiness is discussed.
The physiology of tiller death in grasses. 2. Causes of tiller death in a grass sward
Authors: ONG C. K. , MARSHALL C. , SAOAR G. R.
Published: April 2006

The causes of tiller death in a 2‐year‐old perennial ryegrass sward were examined between April and August 1977. Physiological causes accounted for most tiller deaths and grazing by slugs and rodents was more important than the damage caused by stem‐boring larvae. Tillers which died were mainly small and vegetative, although some flowering tillers died prematurely. Low nutrient status delayed but did not prevent tiller death.

Using 14CO2 it was shown that small tillers fixed relatively less radiocarbon than did larger tillers and they did not receive much support for their carbon economy. Selective defoliation showed that in April defoliated tillers imported radiocarbon from undefoliated tillers but that in July at anthesis an undefoliated reproductive tiller retained most of the carbon it fixed, despite its vascular association with defoliated tillers. It appears that much of the tiller death during the period April‐August is due to the failure of the more favourably placed tillers to support other tillers which are heavily shaded.
Nitrogen and Italian ryegrass 5. Growth up to 14 weeks: residual effects
Authors: WILMAN D.
Published: April 2006

In a field experiment with Italian ryegrass residual effects of N applied in late April at four rates, 28, 84, 140 and 196 kg ha−1, and of different dates of first harvest ranging from 1 to 14 weeks after N application, were studied. The harvests after the first added about 10 kg dry matter yield and about 0.16 kg N yield for each extra kg N applied in April. Residual response was similar for each increment of applied N. A positive residual response to N was obtained in May of the year following N application despite high winter rainfall. N content of herbage during part of the summer was reduced by extra N applied in April although N yield was increased. The reduction in N content was accompanied by a reduction in P and K content, these latter elements having been applied only once and at a uniform rate on all plots. Loss of N, P and K from the crop, when a period of more than about 9 weeks regrowth was allowed prior to the first harvest, was not recouped at subsequent harvests. Residual marginal recovery of N in Aberystwyth was no higher than in comparable experiments in Cambridge although marginal recovery of N at the first harvest had been appreciably lower in Aberystwyth than in Cambridge.
Selection for resistance to ryegrass mosaic virus and crown rust (Puccinia coronata Corda) in Italian ryegrass populations
Authors: HIDES D. H. , WILKINS P. W.
Published: April 2006

Inoculation in the glasshouse revealed marked differences in resistance to both ryegrass mosaic virus (RMV) and crown rust (Puccinia coronata Corda) among eight unselected populations of Italian ryegrass (Lolium multiflorum Lam.). Two generations of selection for crown rust resistance led to a significant improvement in all eight populations, while one generation of selection for RMV gave a more variable response. Frequency distributions of individual genotype scores suggested that much of the resistance to crown rust was under the control of one or two genes with major effects, while resistance to RMV appeared to be controlled by a large number of genes each having a small effect.

In the field, resistance to RMV meeisured after 20 months was strongly correlated with that obtained in the glasshouse. Natural infection by crown rust in the field was too low to reveal any differences between populations, although three populations from the Po Valley region of Northern Italy became heavily infected with Puccinia recondita.

Selection for disease resistance significantly reduced the persistency of three populations, but that of four others was unaffected and one showed a significant improvement. Selection reduced water‐soluble carbohydrate (WSC) levels in spring slightly but significantly from 27.6 to 25.8% WSC overall. These results emphasize that agronomic performance must be monitored during selection for disease resistance.
Production of perennial ryegrass cultivars of different maturity types when grown as pure swards and in certain combinations
Authors: McBRATNEY JUNE M.
Published: April 2006

A field investigation was carried out over 3 years to determine if there was a synergistic effect on total or seasonal yield when cultivars of perennial ryegrass were grown in combination.

The three cultivars used were Stormont Zephyr, Hora and Perma, representing respectively early, medium late and late maturing groups. Each cultivar was grown as a pure stand and also as a 50:50 mixture with each of the other two cultivars. Each of these swards was maintained under two rates of nitrogen fertilization (300 and 600 kg per ha per annum) and under two harvesting treatments (4 and 8 harvests per annum).

Mixture yield did not exceed significantly the pure sward yieid of the highest yielding component. Occasional yield improvements were detected for the mixtures averaged as a group over monocultures averaged as a group. There was a tendency, especially under frequent cutting, for the yield response to nitrogen to be greater from mixed than from pure swards.
Evaluation of a sward sampling technique for estimating herbage intake by grazing sheep
Authors: WALTERS R. J. K. , EVANS E. M.
Published: April 2006

A sampling procedure for estimating herbage intake by the ‘Difference’ method over short grazing periods using an electrically powered sheep‐shearing head to cut long narrow sample strips, was compared with several indirect animal techniques on single‐variety grass swards. The method provided intake estimates in good general agreement with those obtained by animal methods but discrepancies arose when used on a semi‐prostrate variety due, probably, to incomplete recovery of sampled herbage cut from post‐grazing residues.

It was concluded that the method might be usefully adopted for the preliminary assessment of the intake characteristics of herbage varieties in routine evaluation programmes, provided that care is taken to ensure the efficient collection of herbage sampled post‐grazing and that a reduction in the land requirement can be achieved without undue loss of accuracy or precision. Confirmation of results should be sought using animal methods when possible.
Silage and milk production: a comparison between soya, groundnut and single‐cell protein as silage supplements
Authors: CASTLE M. E. , WATSON J. N.
Published: April 2006

Grass silage made in May from S24 perennial ryegrass was offered ad libitum to twelve Ayrshire cows in a 12‐week feeding experiment. The silage had a DM concentration of 217 g kg ‐1, contained 147 g crude protein per kg DM and had a D‐value of 64·6. In addition each cow consumed 1 kg hay per d plus concentrate supplements of dried sugar‐beet pulp with (A) soya bean meal, (B)‘Pruteen’, a single‐cell protein (C) groundnut cake. The three concentrate supplements each contained 250 g crude protein per kg DM and were offered at the rate of 2·9 kg per 10 kg milk. The daily intakes of silage DM were 8·38, 7·94 and 7·49 kg on treatments A, B and C, respectively, with the extreme values being significantly different. The mean daily yields of milk on treatments A and B were both 16·2 kg per cow, and were significantly higher than the yield of 15·2 kg per cow on treatment C. The fat and lactose contents of the milk on the three treatments were not significantly different, but the CP content on treatment C was significantly lower than that on the other treatments. It is concluded that soya bean meal and‘Pruteen’were superior to groundnut cake as a protein supplement in a silage‐based ration.
The effect of date of primary growth harvest and levels of nitrogen and potassium fertilizers on the dry matter production of timothy (Phleum pratense)
Authors: HUNT I. V. , FRAME J. , HARKESS R. D.
Published: April 2006

Scots timothy was harvested three times a year for 3 years under four harvesting patterns and at all combinations of three levels of application of nitrogen and four of potassium. Harvesting patterns, H1, H2, H3 and H4, comprised cutting primary growth on 27–29 May or 14, 28 or 42 d later followed by cutting a first regrowth 8 weeks afterwards and a second regrowth on 15–16 October. N treatments, N0, N1 and N2, involved annual totals of 0,108 and 216 kg ha‐1 N in three equal doses. K treatments, K0, K1, K2 and K4, involved annual totals of 0, 54, 108 and 216 kg ha‐1 K also in three equal doses.

Mean herbage DM yields in successive years were 8·90, 9·54 and 9·61 t ha‐1 containing92·4%, 93·1% and 94·5% timothy, respectively. Systems H3 and H4 had 24% higher yields than H1 and H2. The superiority of the late systems derived from higher yields of primary growth. Mean response to 108 kg ha‐1 N at 36·7 kg DM per kg N was significantly higher than the response to an additional 108 kg ha‐1 N. Response in primary growth to successive increments of 36 kg ha‐1 N averaged 53·9 and 27·5 kg DM per kg N. The first regrowth gave linear responses up to 72 kg ha‐1 N. The possibility is discussed of more effective use of N by increasing the proportion applied to regrowth. Response to K was low except in the third year when there was a marked response at N2. It was calculated that to maintain soil potash it is necessary to apply 23·9, 47·7 and 86·6 kg ha‐1 fertilizer K for each harvest at N0, N1 and N2 respectively.
The effect of stage of growth on the rate of drying of cut grass at 20°C
Authors: JONES LEWIS
Published: April 2006

The drying of Italian ryegrass (RvP) tillers under controlled conditions at three stages of growth is described. The rate of water loss was dependent on tiller morphology as well as on water content. Leaf laminae dried faster than stems and also aided the loss of water from stems. Drying time was shortest for vegetative tillers despite their high water content, and longest for reproductive tillers shortly before ear emergence. The practical implications in relation to haymaking are discussed.
Amino acid composition of sainfoin forage
Authors: KALDY M. S. , HANNA M. R. , SMOLIAK S.
Published: April 2006

The crude protein concentration, amino acid composition and protein quality of sainfoin (Onobrychis viciifolia) forage was compared to that of lucerne (Medicago sativa). The amino acid analyses showed that sainfoin contained higher amounts of lysine, histidine, proline, cystine, glycine, alanine, valine, leucine, tyrosine, phenylalanine and tryptophan than lucerne, whereas lucerne contained more aspartic acid, methionine and isoleucine than sainfoin; the limiting amino acid in both legumes was methionine. The protein score, an estimation of protein quality for nonruminants, was 68 for sainfoin forage and 71 for lucerne forage compared to 100 for an ‘ideal protein’. The similarity of protein quality of sainfoin forage to that of lucerne indicates that, where conditions permit, sainfoin could be grown for the production of protein as an alternative to other crops.
Supplementary feeding of grazing beef cattle
Authors: VADIVELOO J. , HOLMES W.
Published: April 2006

The effects of cereal and protein supplements on feed intake and liveweight gain were studied. In 1975, steers were continuously stocked on autumn pasture and fed no supplement or 8 g dry matter (DM) per kg liveweight (LW) per d as rolled barley (crude protein (CP) concentration 120 g kg‐1), lucerne cobs (CP concentration 190 g kg‐1) or a mixed concentrate (CP concentration 300 g kg‐1). In 1976, steers were continuously stocked or rotationally grazed in summer and fed no supplement or 7 g DM per kg LW per d as either rolled barley (CP concentration 130 g kg‐1) or a mixture of rolled barley and groundnut meal (CP concentration 210 g kg‐1). Herbage organic matter (OM) intakes in 1975 and 1976 were depressed on average by 22 and 15% respectively with supplementation, but total OM intakes were increased by 9 and 15% respectively. Daily liveweight gain was not significantly increased by supplementation in 1975 when herbage allowance was ample but was significantly increased in 1976 when herbage allowance was limited and herbage digestibility was lower. Protein concentration of the concentrate did not significantly affect daily gain in either year nor was there any difference in gain between rotational grazing and continuous stocking.
A comparison between barley and groundnut as supplements for dairy cows at pasture
Authors: CASTLE M. E. , WATSON J. N. , LEAVER J. D.
Published: April 2006

In two 12‐week grazing experiments using twelve and eighteen spring‐calved cows in 1976 and 1977 respectively, the effects of feeding either a barley or a groundnut concentrate supplement were investigated. The mean yield of herbage DM on offer was 2330 and 2030 kg ha‐1, with crude protein concentrations of 192 and 193 g per kg DM in 1976 and 1977 respectively. Grazed herbage was the sole feed in the control treatment. In the other two treatments the herbage was supplemented with 3 kg per cow per d of a concentrate containing either 82·2% barley or groundnut with mean crude protein concentrations of 109 and 409 g per kg DM respectively. Similar results were obtained in both experiments with average daily milk yields of 18·3, 19·8 and 19·9 kg per cow on the control, barley and groundnut treatments respectively. The supplements had no significant effects on either milk composition or liveweight change. It is concluded, that with an ample supply of herbage of high crude protein concentration, a supplement of groundnut had no advantages over one of barley.
A comparison between supplements to silage of high digestibility offered to dairy cows
Authors: ADAMSON A. H. , NEWELL D. W. , CASTLE M. E.
Published: April 2006

Grass silage containing 180 g crude protein and 660g digestible organic matter per kg DM was offered to forty‐two dairy cows for 20 weeks in a self‐feeding system. In addition, supplements of either mineralized barley (130 g crude protein per kg DM) or barley plus groundnut (180 g crude protein per kg DM) were offered. The mean daily milk yields were 18·5 and 19·4 kg per cow respectively.
The quality of‘brown midrib‐3’mutant maize grown for forage under field conditions in southern England
Authors: SHELDRICK R. D.
Published: April 2006

A field trial with maize (Zea mays) was sown in two successive years at Hurley to examine whether the advantages in terms of low lignin concentration and high digestibility demonstrated in USA and France for the‘brown mid‐rib‐3’(bm3) mutant over its otherwise isogenic counterpart would still be manifest in a cool maritime climate. Plants of the bm3 mutant and the normal counterpart (cv. Troyer Reid) together with a locally adapted earlier maturing variety (cv. Caldera 535) were grown in 1976 and 1977 and sampled on three occasions. Despite considerable contrast in the two growing seasons, 1976 being unusually hot, differences of 4 to 8 units in whole‐crop D‐value and 6 to 10 units in stover D‐value were demonstrated in favour of the mutant form, together with significantly lower lignin concentrations (1976, normal 22 g per kg DM, mutant 14; 1977, normal 25 g per kg DM, mutant 16). The results give strong support to the case for introducing the bm3 gene into forage maize breeding programmes in Britain.
Prevention of damage to grass swards from applications of silage effluent by neutralization or dilution of effluent acids
Authors: STEWART T. A.
Published: April 2006

Estimates of the total acidity of silage effluent from a range of first‐cut silages varied from 1025 to 21,125 mg Ca CO3 per l with a weighted mean of 8817 mg l‐1. Quick‐lime (CaO), hydrated lime [Ca(OH)2] or caustic soda (NaOH) were found to be effective neutralizing agents when thoroughly mixed with the effluent. Results from seven field‐plot experiments carried out between 1973 and 1977 involving application of silage effluent to grass swards are reported. Leaf scorch occurred when silage effluent with a total acidity equivalent to more than 6000 mg CaCO3 per l was applied at rates exceeding 50 m3 ha‐1 to swards with several weeks regrowth. Scorch was most severe when applications were made during periods of dry sunny weather and to mechanically damaged swards. In these conditions reducing the total acidity to below 2000 mg CaCO3 per l by neutralization or dilution allowed rates of over 100 m3 ha‐1 to be applied without harmful effects.

Acid neutralization was found to be unnecessary when silage effluent was applied to recently cut swards. Here rates of up to 150 m3 ha‐1 were applied without adverse effects and generally resulted in increased grass growth.
Herbage measurement in situ by electronics 2. Theory and design of an earth‐plate capacitance meter for estimating forage dry matter
Authors: ANGELONE ALFONSO , TOLEDO JOSE M. , BURNS J. C.
Published: April 2006

A forage capacitance‐measuring scheme is presented which uses the earth and plants growing in it as one plate of a two‐plate capacitor. Low frequency analogue circuitry is coupled with digital circuitry to sense and read out digitally the capacitance as a function of the forage under the sensing head. The circuitry is linear, reasonably stable and offers the opportunity for electrically confining the sensed area. The apparatus behaviour is characterized by a mathematical describing function.
Grass production studies in the uplands of north‐east Scotland 1. The effects of soil parent material, altitude and soil major group
Authors: RILEY H. C. F. , MACLEOD D. A.
Published: April 2006

Sites were established on good quality grass swards in areas representative of three of the most extensive soil parent materials in north‐east Scotland and covering an altitudinal range of 260–460 m. Overall yields of herbage dry matter in 1975 were high, ranging from 6280 kg ha‐1 with no fertilizer to 9190 kg ha‐1 with an application of 100, 26 and 50 kg ha‐1 N, P and K respectively. Differences in production between parent material and altitude groupings were found to be associated with differences in major soils group and past land use, with long‐enclosed brown earths outyielding podzols recently reclaimed from heather moorland by about 30% overall. Increasing inputs of fertilizer appeared to reduce the effects of soil and climatic conditions. Brown earths showed higher apparent recoveries of N fertilizer than did podzols.
Regulating the content of white clover in mixed swards using grass‐suppressing herbicides
Authors: HAGGAR R. J. , BASTIAN C. J.
Published: April 2006

A preliminary investigation evaluated six grass‐suppressing herbicides applied on two occasions in late winter to a predominantly ryegrass ley containing only 15% ground cover of white clover. Substantial increases in clover growth, estimated visually, and flower head numbers per unit area were recorded in the first summer after treatment with 2·8 kg ha‐1 carbetamide, 0·8 kg ha‐1 propyzamide and 0·6 kg ha‐1 paraquat. To achieve these increases, visual estimates suggested that spring growth of grass was reduced by 40–80%. However, grass growth recovered fully by mid‐summer on the majority of the treatments.

The following year five of the herbicides were compared in a field experiment. Dry matter (DM) and nitrogen (N) assessments of the grass and legume components were made at three harvests in the first growing season and a single harvest in the second year. Carbetamide, paraquat and, especially, propyzamide increased the proportion of clover in the DM (to 89% in the case of 1·2 kg ha‐1 propyzamide); in general, using herbicides to raise clover contents above 20% lead to reductions in spring grass growth of about 70%. However, such reduction was offset by subsequent increased growth so that total annual yields were largely unaffected. The increased legume content resulted in an increased N concentration in both grass and legume components, measured in the second summer. At this time, the greatest increase in total N yield (up to 35%) was recorded from 0·6 kg ha‐1 propyzamide. Potential uses to achieve legume dominance by grass‐suppression are suggested and the needs for further research are outlined.
Sowing date, harvest date and the yield of forage brassica crops
Authors: HARPER F. , COMPTON I. J.
Published: April 2006

The effect of sowing date, within the period from late May to mid‐August, on the DM yield of five leafy forage brassica crops sown to a stand was examined over the period 1976–78. Kale was the crop most sensitive to variation in sowing date and yields declined progressively with later sowings. There was no yield benefit from sowing rapes or stubble turnips earlier than mid‐ to late‐June. Raphanobrassica produced yields as good as rape when sown in June. In 1978, DM yields of rape, kale and Raphanobrassica increased from September to early November, largely as a result of stem growth; kale was slower to accumulate DM than rape in late summer but continued growing longer into the autumn. The DM concentrations of all crops increased from September to December. Rape had a higher DM concentration than stubble turnip. Raphanobrassica was 10–25 g kg‐1 lower in DM concentration than rape or kale. Raphanobrassica produced 23–59% flowering plants from late‐May to early‐June sowing. Harvest date affected DM yield and concentration, leaf: stem ratio and flowering percentage. The effects of sowing dale on DM concentration were small.
Sclerotinia trifoliorum Erikss. on white clover (Trifolium repens L.)
Authors: SCOTT S. W. , EVANS D. R.
Published: April 2006

Herbage dry‐matter yields of sown plots of white clover were greatly reduced by a natural infection of clover rot (Sclerotinia trifoliorum), the extent of the reduction being related to the level of infection. Examination of seasonal yield patterns suggested that although the plants apparently recovered from the disease it re‐exerted its influence later in the season. No effects on seed yield could be detected but effects on the development of inflorescences and the proportion of ripe heads surviving to harvest were noted. Marked differences between varietal types existed for some of the characters examined.
A simple method of extracting stem nematodes, Ditylenchus dipsaci (Kühn) Filipjev, from lucerne
Authors: CAPITAIN P.
Published: April 2006

A simple technique for extracting stem nematodes from air‐dried samples of lucerne is described. The technique was found to be suitable for use in a breeding programme to improve resistance to stem nematodes in lucerne.
Silage and milk production: a comparison between three grass silages of different digestibilities
Authors: CASTLE M. E. , RETTER W. C. , WATSON J. N.
Published: April 2006

Three first‐harvest grass silages made from S23 perennial ryegrass cut on 25 May, 13 June and 25 June, and termed early, medium and late silages respectively, were compared in a 16‐week feeding experiment with fourteen Ayrshire cows. The early, medium and late silages had D‐values of 71·2, 65·0 and 62·5 respectively. The early silage was offered alone, whereas the medium and late silages were supplemented with a concentrate containing 208 g crude protein per kg DM at rates of 2, 3 and 4 kg per 10 kg milk. Silage DM intake was 12·8 kg per cow per d on the early silage treatment, and decreased progressively as concentrate intake increased on the other silage treatments. The mean daily milk yields were 16·0 kg per cow in the early silage treatment, 17·0, 18·4 and 20·4 kg per cow in the medium silage treatments, and 16·8, 18·1 and 20·2 kg per cow in the late silage treatments on the 2‐, 3‐ and 4‐kg concentrate treatments respectively. Fat concentration in the milk was not affected significantly by treatment, whereas the CP and SNF concentrations increased progressively and significantly as supplementary feeding increased. From the relationship between milk yield and concentrate intake it was calculated that the medium and late silages required a daily concentrate supplement of 2·1 kg DM per cow to give the same daily milk yields as the early silage.
The effect of defoliation upon yield, flowering and vegetative spread of Holcus lanatus growing with and without Lolium perenne
Authors: WATT TRUDY A. , HAGGAR R. J.
Published: April 2006

Plants of Holcus lanatus L. and Lolium perenne L. were grown in monocultures and in 50:50 mixtures and cut at three heights and at three frequencies during 24 weeks. The higher the H. lanatus plants were cut the greater was their harvested yield but height of cutting did not affect the yield of L. perenne. Reduction in the frequency of cutting increased the total harvested yield of both species in monoculture. In mixture, H. lanatus dominated L. perenne, especially with high and infrequent cutting. Stubble yields generally followed harvested yields.

In a second experiment, H. lanatus plants were cut sequentially in spring; plants cut in early June produced very few panicles in the regrowth.

In a third experiment the growth of decumbent tillers in late summer on spaced plants of H. lanatus produced a stoloniferous growth habit. The production of lateral shoots and roots on these stolons was measured in spring on plants undergoing various types of defoliation. Regular cutting of the parent plant increased the production of lateral shoots on stolons but did not affect the production of lateral roots.

The significance of these results is discussed in relation to the manipulation of swards containing these two species.
Influence of nitrogen and sewage sludge on botanical composition of an old hay field†
Authors: MAGDOFF F. R. , AMADON J. F. , WOOD G. M.
Published: April 2006

Applications of either sewage sludge or N as ammonium nitrate were made to a 15‐year‐old hayfield over a 2‐year period. The original seeding mixture was unknown but was believed to be timothy (Phleum pratense L.) and red clover (Trifolium pratense L.). During the second year, botanical separations indicated that applications of both N and sewage sludge resulted in reduced proportions of red and volunteer white clover (Trifolium repens L.) as well as volunteer Kentucky bluegrass (Poa pratensis L.). During the growing season a decline in proportion of timothy (Phleum pratense L.) was observed for the control as well as for the N and sludge treatments. In contrast, quackgrass (Agropyron repens (L.) Beauv.) was markedly stimulated by the treatments and the proportion of it in the hay increased during the growing season.
Changes in the lignin and hemicellulose concentrations of ten varieties of temperate grasses with increasing maturity
Authors: MORRISON I. M.
Published: April 2006

The lignin and total hemicellulose concentrations of ten varieties of temperate grasses (five species) were determined with increasing maturity. A strong correlation existed between the lignin and hemicellulose concentrations. Lignin and hemicellulose concentrations tended to be higher in cocksfoot and timothy than in perennial ryegrass and diploid varieties also had higher lignin and hemicellulose concentrations than their tetraploid counterparts. The hemicellulose fractions were further separated into their linear and branched components whose compositions were determined. The varieties with higher lignin concentrations showed a higher linear:branched ratio and the ‘linear’ components also had higher xylose: arabinose ratios. These findings were consistent for both leaf and stem tissue although the effects from stem tissue were more marked.
The effects of paraquat and glyphosate residues in sprayed herbage on the development of seedlings of a normal and a paraquat‐tolerant variety of Lolium perenne
Authors: FAULKNER J. S.
Published: April 2006

Paraquat and glyphosate were sprayed on to simulated swards in a glasshouse experiment. Residues of these herbicides depressed emergence, growth and survival of Lolium perenne seedlings sown after spraying.

Residues of paraquat applied at a rate (1·5 kg ha‐1) within the range normally used for sward destruction killed nearly all seedlings of a normal L. perenne variety, Barlenna, but had much less effect on the paraquat‐tolerant variety, Causeway. It was estimated that Causeway was almost nine times as tolerant of paraquat residues as Barlenna. Sowing at a depth of 20 mm gave some protection against paraquat residues. A delay of 10 d between spraying and sowing had equivocal effects. It was concluded that residues of paraquat used for killing swards before direct drilling may hinder the establishment of normal L. perenne varieties but not of paraquat‐tolerant varieties.

Residues of glyphosate had equal effects on the two varieties and the effects were severest on seedlings sown on the soil surface immediately after spraying. It is thought to be unlikely that glyphosate residues in sprayed herbage would be a problem in direct drilling.
The development of response to fertilizer nitrogen in the first regrowth of perennial ryegrass
Authors: HUNT I. V. , FRAME J. , HARKESS R. D.
Published: April 2006

The experiment was undertaken to examine the interactions between yield responses to secondary applications of fertilizer N and length of regrowth interval following three levels of primary N. A sward of S24 perennial ryegrass received all combinations of three fertilizer treatments, nil, 50, and 100 kg ha‐1 N for primary growth harvested on 21 May and four treatments, nil, 33, 66 and 100 kg ha‐1 N for the second growth harvested 2, 3, 4, 5, 6 or 7 weeks later.

Cubic equations of growth were derived from the yields of dry matter and both the direct response to secondary N and the residual responses to primary N increased as regrowths developed. A positive residual effect to increasing primary N was obtained at the three lower levels of secondary N for weeks 4–7 but a negative response was obtained with the highest level of secondary N. The implications are discussed in terms of target responses and yields and the growth interval required to attain these targets.
The rate of water loss from cut grass of different species dried at 20°C
Authors: JONES LEWIS , PRICKETT JULIA
Published: April 2006

The water loss from tall fescue cv. S170, perennial ryegrass cv. S24, Italian ryegrass cv. RvP and timothy cv. S352 when dried as a thin layer under controlled conditions at 20°C and r.h. 50% is described. Comparisons were made on six occasions between mid‐April and mid‐June. Tall fescue dried faster than the other species and the time to reach a water concentration of 0·2 g water per g dry matter varied little between the six harvests. In contrast, the drying time for the ryegrasses and timothy increased to maximal values in mid‐May and then fell. Drying time was dependent on the initial water concentration of the grass, the ratio of leaf to stem and on the amount of true stem exposed to the drying environment. The practical implications in relation to haymaking are discussed.
Variations in the surface characteristics of the sward and the short‐term rate of herbage intake by calves and lambs
Authors: HODGSON J.
Published: April 2006

The results are reported of an examination of detailed measurements on the ingestive behaviour of calves and lambs in response to variations in the surface characteristics of swards under strip‐grazing and continuous stocking managements. It is shown that intake per bite and the short‐term rate of herbage intake were both sensitive to the height of the surface horizon above ground level but, at least under strip‐grazing management, not to variations in herbage density in the grazed horizon. The rate of biting was less sensitive to variations in sward conditions, particularly under strip‐grazing.

Both intake per bite and rate of intake were more sensitive to variations in grazing height under strip‐grazing, where sward changes were rapid, than under continuous stocking, where they were slow. Under continuous stocking, ingestive behaviour was more sensitive to changes in sward conditions in lambs than in calves.
Effect of plant density and removal of ears on the quality and quantity of forage maize in a temperate climate
Authors: LESHEM Y. , WERMKE M.
Published: April 2006

The present study was aimed at testing the hypothesis that a dense maize stand (320–720·203 plants ha‐1) will produce more dry matter of acceptable quality than a stand sown at the density generally advocated (105 plants ha‐1). It was also aimed at proving that grain is not essential in order to obtain a high yield of good‐quality forage maize.

It was found that dry matter yield increased with density, especially at the early stages of growth. When ear‐formation was depressed by increasing plant density, the resulting reduction of ear yield and its quality due to the absence of ear was partly compensated for by the increased yield and quality of the stem.
The effect of drying and processing red clover on the digestion of the energy and nitrogen moieties in the alimentary tract of sheep
Authors: BEEVER D. E. , THOMSON D. J.
Published: April 2006

The effect of artificial dehydration and processing of red clover on nutrient digestion and absorption has been studied with sheep. A total of three diets were fed, each at an intake of 900 g DM d‐1; comprising frozen (to represent fresh control), wafered and pelleted red clover.

Dehydration caused small depressions in energy and N digestibility. Grinding and pelleting had no further effect, although both treatments reduced the amount of energy digestion occurring in the rumen, frozen 63, dried 60, pelleted 48 MJ per 100 MJ digestible energy. Digestion of energy in the caecum and colon was increased on both dried diets, and in the small intestine on the pelleted diet.

Almost 40% of the extra duodenal energy on the pelleted diet was due to increased cellulose flow, with only 79% of digestible cellulose being digested in the rumen compared with 96% on the other two diets. There was an associated decrease in ruminal volatile fatty acid production of approx. 20%. Approximately half of the extra energy was due to an elevated flow of protein on the pelleted diet, but this increase was not reflected in amino acid absorption due to a reduced efficiency with the dried diets (frozen 72%, dried diets 54%).

The results demonstrate that dehydration and processing of red clover can markedly influence nutrient digestion and supply and thus offer attractive means of improving the nutritive value.
Economics of irrigating grassland in the United Kingdom
Authors: DOYLE C. J.
Published: April 2006

A mathematical model which simulates the response of grass to irrigation over a range of rainfall and soil conditions is described. Using the model the probable costs and benefits from investing in irrigation facilities for intensive beef and dairy production have been determined. Irrigation only appears to show a reasonable return on investment where the mean summer rainfall is less than 350 mm or the water‐retaining capacity of the soil is low. Furthermore, investment in irrigation is only likely to be logical where the rate of fertilizer N applied is greater than 300 kg N ha‐1. It also appears that a strategy of partial irrigation is unlikely to yield the maximum financial gain. Overall the indications are that for the foreseeable future only a small percentage of the total grassland area in the UK can be irrigated profitably.