ALBERT

Notes: Measurements of rates of growth and senescence of leaf lamina per tiller and of changes in tiller population densities were made in three experiments designed to investigate the influence of sward slate on leaf turnover and net production under continuous stocking.In each experiment initially uniform swards were fenced to provide four plots on which animal numbers were adjusted twice weekly to give a series of swards maintained as nearly as possible in a steady state with respect to sward surface height (range 1.1–6.4 cm) and herbage mass (range 440–2690 kg OM ha−1). Two experiments were carried out in July–September on vegetative swards and one in May–June on a reproductive sward. Measurements were begun 3–7 weeks after treatments were started and were repeated weekly during 3–4 week measurement periods.In all three experiments the rate of lamina growth per tiller increased linearly with an increase in sward surface height and herbage mass. In the two experiments conducted in July–August this relationship was partially offset by a linear increase in the rate of senescence per tiller but net production per tiller also increased linearly in relation to sward height and mass. In the experiment conducted in May–June the rates of growth and senescence per tiller increased in parallel so that net production per tiller showed no relationship with sward condition.Tiller population densities in the July–August experiments were highest in swards maintained between 2 and 3 cm surface height and declined in swards maintained above and below this height. In the experiment in May–June tiller numbers were similar in all treatments prior to the summer solstice but diverged in a manner similar to the other experiments later in the year.The rate of lamina growth per unit area increased in a manner consistent with an asymptotic relationship and the rate of senescence increased linearly with increasing sward height and mass in all three experiments. Net production per unit area was reduced on swards below about 2.5 cm in height but was insensitive to variation in sward surface height between 2.5 and 6.0 cm (approximately 1000–2500 kg OM ha−1 herbage mass).The effectiveness of adjustments in tiller numbers and production per tiller and of changes in the balance between growth and senescence as mechanisms of sward homeostatis, together with their implications in the scope for manipulating herbage production by grazing management are discussed briefly.

Notes: There was a three-fold variation in epicuticular wax content between populations of white clover and a five-fold variation between populations of red clover. The mean for all populations of red clovers was twice that of white. There was also a two- to three-fold variation within each population.The epicuticular wax content of white and red clovers grown in the field showed an increase with age. Thin layer chromatography showed no qualitative differences in the epicuticular waxes extracted either between populations or with sampling date.The higher levels of epicuticular wax found in some clovers were considered to be of possible significance as a source of antifoaming compounds in bloat-inducing pastures.

Notes: Differences in ease of digestion of bundle sheath cell walls of leaf blades of Panicum spp. are shown to be associated with differences in bundle sheath cell wall structure, including the presence or absence of a suberized lamella. These structural differences are correlated with photo-synthetic type (viz. C3, intermediate C3/C4, and the C4 types, PCK, NADP-ME and NAD-ME), as are mesophyll: bundle sheath area ratios.

Notes: The 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.

Notes: The 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.

Notes: Laminae of Lolium perenne and Phleum pratense were tested mechanically and the results analysed using engineering composite theory and fracture mechanics. As the lamina dries the fibres double in stiffness. The intervening cells show a sevenfold increase in stiffness below 20% water content (based on dry weight). Work to fracture across the veins is almost independent of water content, but below 50% water content the mode of fracture changes. It is predicted that total fibre content will not affect hay shatter; total protein content may affect it by altering the water-binding properties.

Notes: Grass silages made from first-harvest perennial ryegrass in mid-May and early-June and termed high-D and low-D respectively had mean DOMD values of 694 and 633 g kg−1 and were offered ad libitum to twelve Ayrshire cows in a 16-week feeding experiment using a cyclic changeover design. The silages were supplemented with a concentrate containing 363g CP per kg DM at daily rates of 1.5, 3.0 and 4.5 kg per cow. The average daily intakes of silage DM were 12.6 and 11.1 kg per cow on the high- and low-D silage treatments respectively, and were not significantly different on the three concentrate treatments. The mean daily milk yields were 171, 18.6 and 21.0 kg per cow on the low-D silage treatments, and 19.6, 21.2 and 22.8 kg per cow on the high-D silage treatments at the 1.5, 3.0 and 4.5 kg rates of concentrate feeding respectively. Fat and lactose concentrations in the milk were not affected significantly by treatment, whereas the CP and SNF concentrations increased progressively and significantly as the rate of supplementary feeding increased. It is concluded that a high-protein concentrate supplement allows silage to make the maximum contribution in the diet, and gives a high response in terms of milk yield and composition.

Notes: Grass which had grown without interruption from late April was cut as for hay in early July in each of 2 years. Fifteen dates of removal of the cut herbage were compared ranging, at 1-d intervals, from the day of cutting to 14 d after cutting. Sward regrowth was studied.A delay of 5 d in removing cut herbage reduced herbage dry matter harvested during the remainder of the growing season by 9% and a delay of 10 d reduced yield by 16%. Delaying the removal of cut herbage reduced the density of grass tillers considerably in the short term, but the effect had worn off in 8 to 12 weeks. The presence of cut herbage reduced the rate of extension of leaf blades considerably. Delaying the removal of cut herbage reduced the area per leaf blade and the weight per unit area and these effects persisted for several weeks. Grass growing under cut herbage had a less negative leaf water potential and a rather cooler but much darker environment in which to grow than uncovered grass.

Notes: Book reviews in this article: Milk from Grass Edited by C. Thomas and J. W. O. Young Nitrogen Fixation in Legumes Edited by J. M. Vincent Herbage Intake Handbook Edited by J. D. Leaver Man's Proper Study By Richard J. Colyer Introduction to Sheep Fanning By R. G. Johnston

Notes: Information about the grazing behaviour and the return of dung to pasture by lactating dairy cows was collected from stocking rate experiments in northern Victoria. Grazing behaviour was observed for 24-h periods in mid-summer in two years. Grazing time increased as herbage allowance decreased to about 32 kg DM cow−1 d−1 but as herbage allowance decreased further grazing time also decreased. A herbage allowance of 32 kg DM cow−1 d−1 corresponded to a stocking rate of about 5.5 cows ha−1. This effect of herbage allowance on grazing time may have been confounded by herbage mass, however. Rumination time of the cows increased by 003 h for each kg increase in herbage allowance while resting time was not affected by treatment.The effects of stocking rate on some of the characteristics of faecal output were measured for a 3-d period in mid-summer. The number of pats deposited per cow daily declined by 0.66 for each unit increase in stocking rate. The fresh weight of dung also declined as stocking rate increased by 0.16 kg per unit of stocking rate. While the values for the amounts of dung deposited on the pasture by the cows at the lower stocking rates are similar to many of those reported in the literature, this study has quantified the way in which stocking rate may influence this in one instance. Furthermore, provided that some measure of herbage intake is made when measurements of dung excretion are performed, it is suggested that estimates of in vivo digestibility can be obtained.

Notes: Two red clover (Trifolium pratense) cultivars, Red Head (tetraploid) and Kuhn (diploid), were sown at a seed rate of 13 kg ha−1 either alone or in mixture with Italian ryegrass (Lolium multiflorum) cv. RvP sown at seed rates of 10, 15, 20 or 30 kg ha−1. RvP was also sown alone at a seed rate of 30 kg ha−1 and received nil or 300 kg ha−1 fertilizer a−1 fertilizer N. All plots were established using the barley cultivar Midas sown at a seed rate of 100 kg ha−1 as a nurse crop.Neither clover cultivar nor ryegrass seed rate significantly influenced either dry matter harvested or botanical composition over the 3 harvest years. On average over all years the grass-clover mixtures produced 75% of the yield of the N-fertilized RvP, 125% of the clover monocultures and 225% of the unfertilized RvP. The red clover contribution to the total dry matter harvested of the mixtures averaged 45–60%. The dry matter concentrations of the mixtures were considerably higher than those of the pure clover stands. In the third year yields were markedly reduced in comparison with those in the first and second years.It was concluded that Italian ryegrass can be a suitable companion grass for red clover. Its superior yielding capacity over other grasses such as perennial ryegrass or timothy under a conservation management can be coupled to advantage with red clover to give a sward which Is essentially stable, at least over a 2- to 3-year cropping period, although giving slightly reduced yields in the third year. Italian ryegrass-red clover mixtures, without the use of fertilizer N, can produce high DM yields of good quality herbage.

Notes: Red 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.

Notes: Two experiments were conducted to determine the effect of pre-harvest treatment by formic acid spray on the moisture concentration (MC) of perennial ryegrass (Lolium perenne) in vegetative growth. In Experiment 1 aqueous solutions containing 0.080, 0.148 and 0.259 kg formic acid per litre were applied to a perennial ryegrass sward (fresh matter yield 21.0 t ha−1) at a constant volume of 41.2 litres t−1to give active ingredient application rates of 3.5, 6.0 and 11.5 kg t−1 respectively. In Experiment 2 similar solutions were applied to a perennial ryegrass sward (fresh matter yield of 6.9 t ha−1) at 35.2, 19.0 and 10.9 litres t−1 respectively to give a constant formic acid application of 2.8 kg t−1. The changes in MC and chemical composition after treatment with acid were compared with those in untreated plotsIn both experiments treatment with acid significantly reduced the MC (P 〈 0.001) within 5 h of treatment from 4.4 to 3.0 kg per kg of dry matter (DM) in Experiment 1 and from 3.0 to 2.6 kg per kg DM in Experiment 2. There was no effect of level of acid applied in Experiment 1 or of the volume of water applied with the low level of acid in Experiment 2 on the changes in MC of acid-treated plots. There was however a significant (P 〈 0.00l) difference between the MC of plots treated with acid and those untreated which was maintained in Experiment I for up to 9 d even during rainfall.There were no differences between the chemical compositions of samples from acid-treated plots in either Experiment I or 2 or between untreated and acid-treated plots in Experiment 2. However there were significant differences between untreated and acid-treated plots in Experiment 1 for the content of nitrogen (N), water-soluble carbohydrate (WSC) and digestible organic matter (DOM). There were changes in the content of N, WSC and DOM with time in both experiments. In Experiment I there was an interaction between sampling time and treatment for both N and WSC but not for DOM. Compared with untreated plots, treatment with acid at all levels accelerated the loss of WSC and delayed the fall in N content. There were no such interactions in Experiment 2.

Notes: Over a 3-year period the productivity of perennial ryegrass (Lolium perenne L., cv. S24) swards as influenced by variations in the time of initial defoliation and close (2·5 cm) and lax (8 cm) defoliation was studied. Treatments with initial defoliations in the early vegetative stage, stem elongation and flowering stages of growth gave higher annual yields than treatments in which the initial defoliation was taken at an intermediate stage of growth when the majority of the stem apices had just been elevated above the height of defoliation. Initial defoliation treatments which removed a high proportion of apical meristems while the yield at the initial defoliation was still low produced the lowest annual yield. Consistent lax defoliation reduced yield by 14·5% compared with continual close defoliation. However, taking an initial lax defoliation followed by subsequent close defoliations produced a slight yield advantage of 4·8% over consistent close defoliation. The results are discussed in relation to other research findings and the practical implications commented upon.

Notes: 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.

Notes: In this contribution from the Imperial Bureau of Pastures and Field Crops, brief notes are given on a number of questions of current concern in countries where conditions and types of grassland resemble those in Great Britain. It is hoped to make this section a regular feature of this Journal. More complete extracts from the literature may be found in the abstracting journal of the Bureau, Herbage Abstracts. Items in this issue are provided by D. Brown (France), M. Hall (New Zealand), Louis Hedin (France), R. Peter Jones (Sweden), and G. M. Roseveare (Netherlands and Switzerland).

Notes: Awned seeds of four grasses were submitted to humidity changes on dry and damp soil to see how far the awns assisted in distribution and seed burial. The results indicate that awns on their own are probably of limited importance. In another study, seeds of seven species were soaked in water with high or low oxygen levels to determine whether dormancy could be induced. Waterlogging delayed germination briefly but did not induce dormancy except in Avena fatua. Oxygen level proved unimportant. The effect of temperature on germination and dormancy was examined in seeds of Agrostis capillars. Seeds of this species germinated best at fluctuating temperatures with a minimum difference of 10°C between day and night temperatures. Constant or slightly fluctuating temperatures over 20°C or under 10°C induced dormancy in a small percentage of seeds.

Notes: Changes in the population of stem-boring Dipterous larvae (including Oscinella frit) were examined weekly for a year on plots of perennial ryegrass (Lolium perenne cv. S24). The herbage net regrowth rate of these plots and of plots receiving the pesticide, phorate, was also monitored. Herbage net regrowth rates were greatest in April and October. At the same times the differences in net regrowth between treated and untreated plots were greatest, thus indicating the periods of the greatest loss of production due to pest damage to the sward.Populations of stem-boring larvae fell below 100 m−2 for only 4 weeks in the year and were maximal in autumn and early winter. Larval mortality exceeded 50% during the winter period. A correlation was found between larval activity and sward damage.

Notes: Swards 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.

Notes: A preliminary field experiment on a sward cut six times during 1978 indicated that total grass herbage harvested was negatively related to the number of Rumex obtusifolius plants present; densities of five to ten plants m−2 resulted in reductions of up to 30%, although the total quantity of herbage harvested (including Rumex) may have remained constant. However, R. obtusifolius densities did not significantly affect grass yield during the first half of the growing season. A negative relationship between R. obtusifolius ground cover and grass yield, particularly from late July onwards, was shown in a second field experiment during 1979 and 1980 using a 3-cut management. It was estimated that to produce a 20% reduction in grass growth in July-August and October, R. obtusifolius ground covers of 30% and 20% respectively were needed. Sixty per cent of the total herbage harvested in 1980 consisted of R. obtusifolius. These results indicate the damage that can be caused by this species and suggest that control measures should be taken before early summer.

Notes: A total of 104 cultivars of six agricultural grass species were compared under controlled conditions for their relative susceptibility to the common soil-borne fungus Fusarium culmorum (W.G.Sm.) Sacc. A number of the perennial ryegrass (Lolium perenne) cultivars showed a high degree of resistance, their emergence being little reduced under the stringent test conditions. The emergence of others was, however, severely affected. Italian ryegrass (L. multiflorum) cultivars generally had a high level of resistance, the outstanding exception being cv. Leda Daehnfeldt which proved very sensitive. None of the cultivars of cocksfoot (Dactylis glomerata), timothy (Phleum pratense), meadow fescue (Festuca pratensis) or tall fescue (F. arundinaceae) which were tested had more than a moderate level of resistance and most were highly susceptible.The vigour of ryegrass seedlings was, in most cases, closely correlated with percentage emergence but was less closely correlated in the more susceptible species. These often had a very low emergence but those seedlings which did establish were frequently of a size similar to that of healthy plants.Treatment of grass seed with a fungicide mixture of benomyl (15% a.i.) plus captan (60% a.i.) provided excellent protection against F. culmorum on even the most susceptible cultivars.Drazoxolon (40% a.i.) was, however, much less effective.

Notes: In field trials in 1979–81, perennial ryegrass cultivars Royal and Majestic (amenity) and Morenne (agricultural) produced maximum seed yields at levels of applied N ranging from 40 kg ha−1 to 160 kg ha−1. Available soil N levels were estimated at 55 kg ha−1; hence maximum seed yields were obtained at total nitrogen levels of 95–135 kg ha−1 in Royal, 95–215 kg ha−1 in Morenne, and 175–215 kg ha−1 in Majestic.Applied N at rates above 120 kg ha−1 either reduced or did not significantly increase seed yield, decreased seed numbers per unit area and decreased spikelets per tiller and seeds per spikelet.The use of a growth regulator increased seed yields by preventing lodging, but did so irrespective of nitrogen application rate. It is suggested that failure to increase seed yield at high N rates is a result not of poor pollination because of lodging, but seed abortion as a consequence of competition for assimilate supply by secondary vegetative tillers.

Notes: Swards were developed from plants of contrasting populations of Dactylis glomerata L. selected for high and low dry-matter (DM) production in monocultures and mixed cultures grown during 1970 and 1971. DM production of these mono-genotype swards was assessed during 1974. Those swards developed from the divergent selections from monocultures maintained a significant difference between the high and low selections, whereas those developed from selections out of mixed cultures showed no significant difference in yield. These results are consistent with earlier reports that there is no positive relationship between competitive ability in mixed cultures and vigour in pure stands. The implications of the physiological basis of these responses in terms of grass breeding are discussed.

Notes: Replicated 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.

Notes: This contribution form the Imperial Bureau of Pastures and Field Crops gives brief notes on questions of current concern in countries where conditions and types of grassland resemble those an great Britain. More complete extracts from the literature can be found in Herbage Abstracts. Items in this issue are provided by M. Hall (Beligum), R. Peter Jones (Sweden), G. M. Roseveare (Germany), and G. M. Howe (New Zealand).

Notes: The appearance of successive leaves on labelled tillers of S24 perennial ryegrass, and their subsequent death, were monitored for 1 year on cut plots on which four levels of N fertilizer were applied.A new leaf appeared about once every 15 d from the end of April until the beginning of September, and about once every 52 d from the end of October to the middle of February. Rate of appearance changed rapidly during September and October, and again from mid-February until the end of April. The response of leaf appearance rate to temperature changed early in the year; the effect of overwintering is discussed.Leaf lifespan was 50–60 d in summer and 120–140 d in autumn and early winter, and was influenced by conditions either during expansion of the leaf or shortly afterwards.The results are discussed in relation to the construction of a model to describe changes in the herbage available to animals grazing a grass sward.

Notes: A mathematical model which simulates the potential production and utilization of herbage on perennial ryegrass and grass-white clover swards in the context of an 18-month beef enterprise is described. Using the model the potential costs and benefits of replacing grass by grass-clover mixtures have been determined. Potentially grass-clover swards receiving no fertilizer N are shown to have annual DM yields equivalent to ryegrass swards receiving at least 300 kg N ha −1. Apart from the benefits of reduced fertilizer N usage there appear to be indirect benefits related to a lower concentrate requirement per head. In consequence, from an economic viewpoint grass-clover swards potentially compare very favourably with heavily fertilized grass swards, even if account is taken of the opportunity costs of lower stocking rates associated with grass-clover systems. However, this conclusion awaits experimental confirmation.

Notes: Earlier studies have concluded that for a dairy enterprise the most profitable conservation strategy, where cutting and grazing areas are separate, is generally associated with relatively low-digestibility silage. The aim of this study has been to investigate whether this conclusion remains true where cutting and grazing are integrated. A mathematical model of grass production and utilization by a dairy enterprise has been developed from information collected from a variety of experimental sources. It was found that cutting strategies aimed at making low-digestibility silage could not automatically be regarded as the most profitable. In good grass-growing conditions strategies resulting in low-digestibility silage did appear to offer the highest gross margins per unit area, but under average and poor growth conditions the greatest profits were associated with high-digestibility silage strategies. In particular, it was noted that the timing and frequency of conservation cuts influenced the efficiency with which grass could be utilized on the grazing areas and this fact rather than yield of conserved material influenced the comparative biological and economic efficiency of the different cutting strategies.

Notes: A study was conducted to determine the influence of herbage mass under continuous stocking management with sheep on rates of herbage growth (G), senescence (S) and net production of green herbage (NP) in a mixed-species sward of Lolium perenne. Poa annua and Trifolium repens. Plots were maintained in as nearly constant herbage mass as possible at 500, 700, 1000 and 1700 kg organic matter (OM) ha−1 by continuous but variable stocking with sheep for the period May to July inclusive. Estimates of G, S and NP were obtained for each species from repeated measurements over two 2-week periods on individually identified grass tillers or clover stolons. Estimates of species population densities enabled estimates of G. S and NP per unit area to be made.Rates of G were higher and of S were lower for Lolium tillers and Trifolium stolons than for Poa tillers. The laminae of Poa tillers occupied inferior positions in the canopy of the swards maintained at higher herbage masses and were less accessible to the grazing animals, so that Poa tissue was less well utilized.The total population densities of tillers and stolons declined at herbage masses both above and below 700 kg OM ha−1. The rate of G for the three species combined increased with herbage

Notes: The most likely reasons for seeding failures of sod-seeded lucerne (Medicago sativa L.) were determined from eight field experiments, where the effects of a range of pesticides on the establishment of and damage to lucerne were compared. The experiments were conducted during 1979–80 at four sites near Ithaca, N.Y., USA. Pesticides evaluated were: methyl bromide (MeBr), carbofuran, acylalanine (1979, 1980); fonofos, diazinon, methiocarb, metaldehyde and combinations of carbofuran with methiocarb or metaldehyde (1980). Seeded areas were pretreated with glyphosate for vegetation control.In 1979 seedling losses were decreased by carbofuran and methyl bromide whereas in 1980 seedling losses were decreased by methyl bromide at two sites and by methiocarb at all sites. Methiocarb was the only pesticide to reduce defoliation damage. The effect of combining methiocarb and metaldehyde each with carbofuran tended to be additive in terms of reducing seedling numbers and damage, and increasing yield. Treatment effects on lucerne yield were still apparent up to 12 months after seeding. Based on the consistent results of methiocarb, it was concluded that molluscs were probably the main factor limiting the establishment of sod-seeded lucerne but an arthropod component also appeared to be involved.

Notes: Book Reviews in this article: Silage in Milk Production By A. J. Corrall, H. D. St C. Neal and J. M. Wilkinson Sward Measurement Handbook Edited by J. Hodgson, R. D. Baker, Alison Davies, A. S. Laidlaw and J. D. Leaver Managing Agricultural Systems By G. E. Dalton

Notes: Faeces of cattle, pronghorn and rabbit were collected from the Central Plains Experimental Range, Colorado, 6, 18 and 30 months after being excreted. The faecal material was placed in moistened potting soil and seedling emergence observed. Bouteloua gracilis (blue grama grass) and Sporobolus cryptandrus (sand drop seed), emerged in abundance from cattle dung. Emergence of B. gracilis decreased with increasing period of exposure before collection, but emergence of S. cryptandrus increased with exposure. Forbs dominated the seedling populations in pronghorn dung, and few seedling populations of any species emerged from rabbit dung. The results are discussed in relation to the effect of large herbivores on the establishment of species from seed in rangeland.

Notes: The effect of temperature on the nutritive value of Macroptilium atropurpureum cv. Siratro and line 10–105 was determined in a controlled environment at day/night temperatures of 24/18, 30/24 and 36/30°C, and a 13-h daylength. Estimated dry matter digestibility, cell wall and lignin concentrations of leaf, stem and stubble were measured in two 5-week regrowth cuts.Siratro and line 10–105 were similar in digestibility and responded similarly to temperature with whole tops, stem and stubble decreasing by an average of 0.0023, 0.0026 and 0.0056 units of digestibility for each 1°C rise in growth temperature. These changes reflect the increase in cell wall and lignin concentrations with higher temperature.The digestibility of young, just-expanded leaves was increased by increased growth temperature. This effect may be explained by the faster rate of leaf expansion at high temperature which reduced cell wall and lignin concentrations at this stage of leaf development. However, for the bulk leaf fraction digestibility was unaffected by temperature. Leafiness declined at high temperatures.

Notes: This second paper concerned with effects of prolonged spring defoliations on two early perennial ryegrass varieties (Cropper and RvP Hay Pasture), an intermediate perennial ryegrass (Talbot) and an early cocksfoot (Roskilde) examines the effects of different closing dates on ear emergence, weekly DOMD (in vitro) and conservation yields. The grasses were mown fortnightly to simulate sheep grazing from January until three closing dates, 19 April, 3 May or 17 May, in 1978 and 1979. A set of plots was left undefoliated. All plots were sampled weekly from 2 or 3 weeks after 17 May until the end of June or early July.Prolonged mowing resulted in a small delaying effect on 50% ear emergence of the ryegrasses. The maximum delay was 3 d with the latest closing date. Under this treatment, ear emergence of the cocksfoot was delayed by an average of 12 d but by only 0–4 d under the earlier closing dates. Delay in date of closing caused a significant delay in the time to reach a given DOMD but the effect was largely confined to the latest closing date and was greatest for the cocksfoot. The time when 670 g kg−1 DOMD was reached was delayed in the ryegrasses by no more than 5 d, except for a 12-d delay in the intermediate ryegrass in 1978 following the late closing date. Under this treatment the delay for the cocksfoot was 8 d in both years. The early ryegrasses produced stemmy regrowths.

Notes: For the 2 years 1977 and 1978 Masham ewes grazed a perennial ryegrass (Lolium perenne cv. S24) pasture from the beginning of April until the end of September each year. Twelve ewes were allocated to each of the three stocking rate treatments, 12 (L), 16 (M) and 20 (H) ewes per ha. Each treatment was rotationally grazed around six paddocks with a forward creep for the lambs. Conservation cuts were taken from each treatment in late May and were generally sufficient to cover a 3-month winter feeding period for treatments L and M but were always insufficient for treatment H. Lambing took place at pasture during the second half of May. No concentrates were fed to the ewes during late pregnancy or lactation but lamb birth weights (4–8 kg) and lamb growth rates over the first 4 weeks (240 g d−l) were satisfactory. Organic matter intakes (OMI)of grass by the pregnant ewes(1816,1844 g OMI ewe−1) were not affected by the stocking rate. Intake of grass by the lactating ewes was affected by year and by stocking rate. The overall growth rate of lambs was higher on treatment L than either M or H but decreased on all treatments during the latter half of the grazing season, resulting in 43% of L and only 3% of M and H lambs being fit for slaughter by the end of September. The main features of this time of lambing are low costs and the production of predominantly store lambs.

Notes: A trial was carried out to investigate whether or not sheep grazing at stocking rates of 22 (low) and 44 (high) ha−1 select red clover from a red clover-perennial ryegrass sward, The distribution of botanical and morphological components was assessed in consecutive 5-cm layers through the canopy inside and outside exclosure cages moved every 2 weeks for 6 weeks. The difference between inside and outside cages for a given layer was an indication of the amount of each component consumed from that position in the sward, and the corresponding difference for clover content was considered an indication of selection.Evidence of selection was observed over the third and fourth weeks of grazing, especially in the high stocking rate treatment. Laminae of red clover were selected in preference to other plant parts and were grazed throughout the depth of the canopy in contrast to grass. The basal layer at the high stocking rate during weeks 5 and 6 was not grazed suggesting that the crown of red clover may be protected from severe overgrazing by accumulation of dead matter.It was concluded that the low herbage density of red clover-grass swards allowed the occurrence of selection which was most pronounced when the sward was being grazed down relatively quickly.

Notes: An attempt was made to determine monetary values for grass which might be used by researchers to assess the likely economic implications of their findings. It is shown that the value of extra grass production will vary considerably depending on the use made of it. At 1982 price levels, estimated values for grass in the field ranged from 1–4 to 10–6 pence kg−1 DM, with a modal value around 3–5 pence kg−1 DM. At the same time, the seasonal distribution of the extra grass production is important since the value of extra grass at different points in the growing season may vary markedly. The way in which these values for grass may be used is illustrated, using as an example weed control during sward establishment. Finally, the sensitivity of investment returns to changes in the value placed on grass is discussed. Extreme caution is necessary in drawing general conclusions about benefits and costs from an evaluation based on a specific value for grass.

Notes: In three separate feeding experiments using a total of twenty-six individually-housed Ayrshire cows, three wilted silages made from Blanca white clover were offered ad libitum with either different supplements or different proportions of grass silage. The clover silages contained 680 g white clover kg−1 on a DM basis, and had a mean DM concentration of 263 g kg−1 with 231 g CP kg−1 DM and 91 g ammonia-N kg−1 N. The pH values averaged 4·16 and the DOMD concentrations 611 g kg−1. In experiment 1 the daily intake of clover silage given alone was 15.2 kg DM per cow, i.e. 30·1 g kg−1 live weight, and decreased by 0·76 kg DM kg−1 barley DM and by 0·66 kg DM kg−1barley plus soybean meal DM when these feeds were offered as supplements. Milk yield and fat concentration were higher on the supplement treatments than on the clover silage-only treatment. In experiments 2 and 3 the intakes of silage and total DM increased as the weight of clover in the diet increased from 0 to 700 g kg−1 with parallel increases in milk yield. The effects on milk composition were small and generally non-significant. Although white clover silages with excellent fermentations were made, it is concluded that the main role of white clover in a silage system will be in mixed swards with grass to reduce the input of fertilizer N and to increase the voluntary intake of silage.

Notes: Results 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.

Notes: 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.

Notes: Nitrogen fertilizer was applied at 0, 30,60 and 90 kg N ha-1 in March 1976, 1977 and 1978 to plots containing perennial ryegrass cv. Barlenna sown either alone or with white clover cv. Blanca, Sabeda, Olwen and S100 in four replicated blocks.Dry matter (DM) yield of all swards responded positively to N with the response being highest in the no-clover swards in two of the three years. Annual DM yields were lower in the no-clover than in the mixed swards at any given N level. The higher levels of N reduced DM yield in mixed swards at some harvests in midsummer.Swards of S100 were consistently among the lower yielding mixed swards, whereas the other three clover cultivars varied in their relative yields. There were no N x cultivar interactions for white clover yields; irrespective of cultivar, N application reduced annual white clover yield by similar amounts.It is concluded that it is beneficial to apply moderate amounts of N fertilizer to mixed swards in spring and that under these conditions the yield differences between swards including medium-large and smaller leaved white clover cultivars are similar to differences between the inherent yield potential of these cultivars in mixed swards receiving no N.

Notes: In order to assess the relative effects of protein content and acid on intake, grass silage was given ad libitum to twelve entire male calves, initially 4 months of age and 117 kg liveweight (LW), either alone or supplemented with fishmeal at 50 g dry matter (DM) per kg silage DM. These two diets were offered alone or with additions of lactic acid at 50 g per kg silage DM in a partial changeover design in which lactic acid levels only were reversed between two 28-d measurement periods.In the absence of lactic acid, fishmeal significantly increased absolute intake but not intake relative to LW. There was a significant interaction between treatments in that the addition of lactic acid depressed DM intake in the absence of fishmeal (23·9 vs 21·1 g kg-1 LW) but not in its presence (23·2 vs 23·1 g kg-1 LW). Addition of fishmeal increased the digestibility of DM from a mean of 0·708 to 0·744 (P 〈 0·05), of gross energy from 0·646 to 0·694 (P 〈 0·01) and of N from 0·422 to 0·592 (P 〈 0·001) but had no significant effect on the digestibility of cellulose (0·766 vs 0·788 for treatments without and with fishmeal respectively). Lactic acid addition had no effect on the digestibility of plant components and, further, interaction effects between treatments were not significant. Supplementation with fishmeal reduced the total time spent eating and ruminating (Ro value) from a mean of 284 to 240 min kg-1 DM (P 〈 0·01) and increased urine pH from 8·34 to 8·50. Lactic acid influenced neither Ro value nor urine pH and the interaction effect did not reach significance for these two parameters.The results indicate that the addition of fishmeal can overcome a depressant effect of lactic acid on intake and it is suggested that the responses to treatment were mediated via changes in the ratio of energy to protein supply rather than as a result of treatment effects on digestive efficiency or acid-base balance.

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

Notes: Two early perennial ryegrass varieties (Cropper and RvP Hay Pasture), an intermediate perennial ryegrass (Talbot) and an early cocksfoot (Roskilde) were grazed fortnightly by sheep, mown to simulate grazing or left undefoliated from January to May. The effects of spring management on ear emergence, D-value (in vitro) and conservation yields were assessed in each of the 2 years 1976 and 1977. Grazing and mowing had a similar effect on date of first (5%) and 50% ear emergence of the ryegrass varieties; the effect was an average delay of 2 d in both stages of growth over the 2 years. Defoliations significantly (P〈0·001) delayed the fall in D-value with no significant differences between grazing and mowing in the ryegrass varieties, nor in cocksfoot in 1977. The occurrence of a D-value of 67 was delayed by between 3 and 8 d for the ryegrasses and 9 and 11 d for the cocksfoot. The early ryegrasses produced stemmy regrowths and fell to 67 D-value about 4 weeks after the final defoliations in 1976 and after 5–6 weeks in 1977. The fall in D-value took 7–14 d longer in the intermediate ryegrass. Yields were significantly (P 〈 0·001) reduced by grazing and mowing, particularly in 1976. The DM yield reductions in mid June averaged 25% for the ryegrasses and 41% for the cocksfoot.The results indicate that either first or 50% ear emergence may be used to indicate times when a D-value of 67 will be reached in grazed or ungrazed swards but further work is required to determine the effect of weather conditions on the accuracy of this prediction. An early fall in D-value of early perennials after spring grazing, and a marked reduction in yield of cocksfoot, suggests that these grasses should be used sparingly where spring grazing of fields set aside for conservation is a feature of the farming system.

Notes: 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.

Notes: Small-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.

Notes: Book review in this article Turfgrass Management By A. J. Turgeon; illustrated by F. A. Giles Feeding Strategy for the High Yielding Dairy Cow Edited by W. H. Broster and H. Swan Seed production Proceedings of the 28th Easter School in Agricultural Science, University of Nottingham, 1978 Edited by P. D. Hebblethwaite

Notes: 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.

Notes: Several different techniques for the non-destructive estimation of pasture or range biomass are critically reviewed and compared to remote sensing methods. Similarities and differences between the visual estimation procedure, β-attentuation, capacitance meters, weighted disc, and spectral methods are discussed in terms of accuracy, time, ease of operation, operational constraints and calibration procedures. No one technique has been shown to be superior across the board to the other techniques reviewed for ground-based biomass estimation. A discussion of the strengths and weaknesses of each non-destructive method allows for the selection of the technique most suited to a particular application.

Notes: A comparison was made of the effect of a cereal supplement during early lactation on the performance and intake of ewes suckling two lambs while rotationally grazing pasture at stocking rates of 20, 17 or 14 ewes per ha. Supplement (S) at the high (H) and medium (M) stocking rates resulted in higher organic matter (OM) intakes (grass + supplement) of 2040 and 2500 g d-1 respectively, compared with the herbage OM intakes of unsupplemented (U) ewes of 1750 and 2040 g d-1 respectively. At the low (L) stocking rate the total OM intake of supplemented ewes and the herbage OM intake of unsupplemented ewes was similar at 2250 and 2210 g d-1 respectively.Lamb growth rate (g d-1) to 12 weeks of age was significantly lower on treatment UH (229) compared with those on UM (253) and UL (262). Growth rates on S treatments were similar (SH 248; SM 261; SL 272) and there were no significant differences between S and U within stocking rates. Unsupplemented ewes lost significantly more weight during the period of intake measurement than those receiving supplement. The speed of rotation was faster where supplement was not fed at the medium and high stocking rates and herbage accumulation under UH was less than under SH. Only at the high stocking rate did feeding a supplement give a higher financial output.

Notes: Calibration of an earth-plate forage capacitance meter was conducted on pure stands of Festuca arundinacea Schreb., Medicago sativa L., Cynodon dactylon (L.) Pers. and Trifolium repens L. and a mixture of Trifolium repens and Dactylis glomerata L. Dry weight (DW) prediction equations were developed using the instrument capacitance reading modified by visual estimates of height, stand density and species percentage. In general, meter readings (MR) correlated better with DW than with fresh weight or weight of water and especially when the area harvested exceeded 0·537 m2. Correlation between MR and DW improved with increasing top plate area and with decreasing distance between the top plate (suspended sheet of aluminium) and the earth-plate ground. The use of a plastic shield to suppress the forage to a uniform height caused a reduction in the correlation between MR and DW.The use of MR to predict DW from selected settings, their linear and curvilinear relationships and several auxiliary observations gave results with R2 values ranging from 0·94 to 0·99, depending on species and mixture.

Notes: The response of marsh birdsfoot trefoil (Lotus uliginosus) to inoculation with appropriate Rhizobium spp. was compared over 2 years. Inoculated and uninoculated seed was sown at 5 kg ha-1 on three soil types, brown earth, peaty podsol and deep peat. Perennial ryegrass cv. Perma was sown at 20 kg ha-1 as a companion species. Plots received either no N or a light starter dressing of 30 kg ha-1 N. Significant benefits from inoculation were recorded for Lotus germination and nodulation, Lotus and non-Lotus herbage DM harvested and Lotus cover on the deep peat, and to a lesser extent on the other soil-types. Due to particularly uneven early establishment, work on the peaty-podsol site was discontinued at an early stage. There was a trend towards depression of Lotus where N had been applied to inoculated plots.

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

Notes: 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.

Notes: 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.

Notes: 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.

Notes: Italian ryegrass, Lolium multiflorum Lam., cv. RvP., was broadcast in spring on to fine and coarse seedbeds at seed rates of either 2 or 20 kg ha-1. Each of the four combinations of sowing condition was either left untreated or treated with fungicide or insecticide. The establishment of the sown species and of weeds under each regime was measured and their relative contribution to dry matter assessed in four cuts during the sowing year. Seed rate affected weed invasion and yield more than seedbed condition. Insecticide treatment increased the establishment and yield of ryegrass and its contribution to total herbage yield under all four sowing conditions. The fungicide treatment had no effect. The improvements caused by insecticide treatment were associated with a reduction in the level of infestation by shoot flies, Oscinella spp. (Diptera: Chloropidae): the effect of a single treatment in April was still detectable in October.

Notes: Book review in this article The Response of Perennial Ryegrass to Fertilizer Nitrogen in Relation to Climate and Soil Report of the Joint ADAS/GRI Grassland Manuring Trial—GM20 Technical Report No. 27, Grassland Research Institute By J. Morrison, M. V. Jackson and P. E. Sparrow Recognition and Control of Pests and Diseases of Farm Crops (2nd edition) By Ernst Gram An Introduction to Practical Animal Breeding By Clive Dalton Planned Beef Production By David Allen

Notes: An improved electronic capacitance pasture meter is described, and data on its calibration and use in a grazing trial are presented. The instrument is light (1·4 kg) and portable, and uses integrated circuits to record the readings from a number of sampled sites. It has a digital display and can be constructed for a modest cost. The meter is mainly responsive to the surface area of the herbage and hence it is less sensitive to variations in moisture content of the pasture than previous meters. Thus it can be calibrated to measure the mass of herbage dry matter to ground level and reduces the need to collect and dry herbage samples for frequent recalibration of the instrument.

Notes: 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.

Notes: Dactylis glomerata and Lolium perenne were grown in single-species stands and in mixed-species stands in boxes for 1 year. Plants were grown in paired rows in each box with full competition below ground, but aerial partitions prevented shoot competition. The rows were cut either frequently (six cuts) or infrequently (three cuts).In single-species stands, frequent defoliation reduced the root competitive ability of D. glomerata plants, when growing with infrequently defoliated plants, though this occurred only if no N fertilizer was applied. Frequent defoliation did not affect the root competitive ability of L. perenne plants, in single-species stands, whether or not N fertilizer was applied.In mixed-species stands, the root competitive ability of D. glomerata was always greater than that of L. perenne, though N fertilizer applications and frequent cutting both reduced the root competitive ability of D. glomerata relative to L. perenne.Mixtures of frequently cut and infrequently cut plants, in unfertilized single-species stands, always yielded more than the mean of the uniformly treated stands (frequently or infrequently cut); they usually yielded more than the highest-yielding uniformly treated stand. Mixtures of frequently and infrequently cut plants, in fertilized single-species stands, always yielded less than the mean of uniformly treated stands.Mixed-species stands usually yielded more than the mean yield of the component species, and sometimes yielded significantly more than the highest yielding component. This effect generally increased with time.Relative yield totals (RYT) were consistently greater than 1·0, in both single-species and mixed-species stands, when no N fertilizer was applied. RYT were greatest (1·2–1·6) when neither N nor P fertilizer was applied, and generally increased with time.The results are discussed in relation to the effects of cutting on root competition and the probable value of mixed-species stands.

Notes: 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.

Notes: Six groups of five 18-month-old wether sheep received a diet of dried grass ad libitum with a pelleted ground barley/oat supplement containing various levels of salt for 30 d. The first group received grass of high Na concentration (7·3 g per kg DM) with no added salt in the supplement, a second group received low sodium grass (4·2 g per kg DM) with no salt additions, and the other four groups received the low sodium grass with varying levels of salt added to the supplement to provide a final dietary Na concentration ranging from 7·0 to 18·0 g per kg DM.Dry matter (DM) and organic matter (OM) intakes were significantly reduced for groups receiving salt supplementation. The digestibilities of DM and OM were reduced for all groups on the low sodium grass diets compared with the high sodium grass diet, but were not affected by salt supplementation.No consistent changes were observed in the molar proportions of volatile fatty acids in rumen fluid, but N availability and retention were higher for the animals on the high sodium grass diet.The high sodium grass diet gave a better apparent availability and retention of minerals than the low sodium grass diets and, while addition of salt tended to improve the availability of minerals, the urinary loss of minerals increased with salt addition to the diet.There were no changes in plasma Na levels, and plasma K changes were inconsistent. However, plasma Ca concentration was reduced significantly for salt-supplemented diets with a Na concentration above 7·0 g per kg DM, and plasma Mg was significantly depressed at dietary Na concentrations above 15·0 g per kg DM.

Notes: An 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.

Notes: Two 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: Book review in this article Ecology and Utilization of Desert Shrub Rangelands in Iraq By D. C. P. Thalen Population Biology of Plants By J. L. Harper How Grasses Grow By R. H. M. Langer Plant Strategies and Vegetation Processes By J. P. Grime Proceedings of the 36th Southern Pasture and Forage Crop Improvement Conference, 1979. Beltsville, Maryland, USA. Tropical Pasture Seed Production By L. R. Humphreys

Notes: The 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.

Notes: Studies have been carried out to measure the response to selection for canopy characters, as measured on young spaced plants, and the associated changes in sward yield in Lolium. In addition certain of the selection lines were compared with and found to be more productive than several existing bred varieties, indicating the considerable scope for improvement of dry matter yield through breeding.The canopy characters which were associated with high yield are compared with those which confer high yielding ability on a spaced plant and an individual in a community. The plant breeding implications of the results are briefly discussed.

Notes: A 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.

Notes: Thousand-seed weight, germination and seedling dry weight were measured in some tetraploid hybrid ryegrasses to study variations in seed quality. In cv. Sabrina, seed from spaced plants had a higher 1000-seed weight and seedling dry weight, and a slower germination rate than seed from narrow drills. Seed from later emerging groups of inflorescences had a low 1000-seed weight and seedling dry weight, but a high germination rate. Seeds of cv. Sabrina, Leri and Augusta harvested at between 10 and 25 d after peak anthesis had low 1000-seed weights, low germination rates and low seedling dry weights. Air temperatures between inflorescence emergence and seed maturity also affected seed quality; an increase in temperature from a 15°/10°C regime to a constant 25°C environment reduced 1000-seed weight and seedling dry weight, but increased germination rate. It is concluded that year-to-year variation in seed characters will occur because of temperature and other climatic changes, but seed quality can also be influenced by the time at which the seed is harvested. If combine harvesting is carried out at a moisture concentration of about 400 g kg-1 (≡40%) then maximum yields of seed of a high quality should be obtained.

Notes: This contribution from the Imperial Bureau of Pastures and Field Crops gives brief notes on questions of current concern in countries where conditions and types of grassland resemble those in Great Britain. More complete extract from the literature can be found in Herbage Abstract. Items in this issue are provided by R. Peter Jones (Sweden), Louis Hedin (France), and M. Hall (New Zealand).