Establishment and production of common sainfoin (Onobrychis viciifolia Scop.) in the UK. 1. Effects of sowing date and autumn management on establishment and yield

The effects of sowing date and autumn management of sainfoin ( Onobrychis viciifolia Scop.) were investigated over 3 years in the UK. Replicated plots were sown between April and September in 2003 and 2004. Autumn management treatments were early and late cutting carried out in the establishment year and in subsequent years. Dry matter (DM) yields were measured over 3 years. One harvest was taken from April to July sowings in the establishment year and three harvests in each of the following years. DM yields from sowings in April and May were 2·8 and 3·3 t DM ha⁻¹, respectively, in the establishment year, which were higher ( P  <   0·001) than from sowings in June and July. Sowings from April to July yielded 10·9–12·5 t DM ha⁻¹ in the first full-harvest year, and 9·5–11·5 t DM ha⁻¹ in the following year. Sowings in August and September only gave 5 t DM ha⁻¹ year⁻¹. Early-autumn cutting of an established sward reduced yields of sainfoin at the second harvest in the first and second full-harvest years. Sowing in May had the lowest proportion of weed species (0·06) in the establishment year, and sowing in July had the highest (0·53). Crude protein concentration increased as the seasons progressed from 149·8 to 230·1 g kg⁻¹ DM.     

Survival of plants of common sainfoin (Onobrychis viciifolia Scop.) in competition with two companion grass species

A 2-year experiment on competition between sainfoin ( Onobrychis viciifolia Scop.), meadow fescue ( Festuca pratensis ) and tetraploid perennial ryegrass ( Lolium perenne ) was conducted using plants grown in plastic containers outdoors. Root and shoot systems of sainfoin and the grasses were separated in order to investigate full and no competition of root and shoots, at two planting ratios (0·33 grass:0·66 sainfoin and 0·66 grass:0·33 sainfoin). Survival of sainfoin plants was lower at the higher grass:sainfoin ratio. More sainfoin plants died in the winter than during the growing season. Root competition had no effect on survival of sainfoin plants, but shoot competition reduced survival of sainfoin plants during one growing season. Companion grass species had no effect on survival of sainfoin plants, except in the first winter, when fewer sainfoin plants survived when grown with meadow fescue than perennial ryegrass.     

Dry-matter yield and herbage quality of a perennial ryegrass/white clover sward in a rotational grazing and cutting system

The expected reduction in the use of fertilizer nitrogen (N) on grassland in the Netherlands has led to renewed interest in white clover. Therefore, the performance of a newly sown perennial ryegrass/white clover sward on clay soil was assessed during 4 consecutive years. The experiment consisted of all combinations of two defoliation systems, i.e. one or two silage cuts per year (S1, S2), spring N application rate, i.e. 0 or 50 kg ha⁻¹ year⁻¹ (N₀, N₅₀), and the management system, i.e. rotational grazing and cutting, or cutting only (RGC, CO). The overall mean white clover cover was 30%. All treatments affected white clover cover, which was 8% higher with S2 than with S1, 6% higher with N₀ than with N₅₀ and 12% higher with CO than with RGC. The overall mean annual dry-matter (DM) yield (13·1 t ha⁻¹ year⁻¹) was significantly affected only by the management system: in two relatively wetter years, the annual DM yield was 1·19 t ha⁻¹ higher with RGC than with CO, whereas there was no difference in two relatively drier years. Nitrogen application increased the DM yield in the first cut by 7·0 kg kg⁻¹ N applied, but had no significant effect on the annual DM yield. Herbage quality was not affected by the experimental treatments. The average in vitro organic matter digestibility was 0.801, and the average crude protein content was 193 g kg⁻¹ DM. With the expected reduction in the use of fertilizer N, perennial ryegrass/white clover swards should be seriously considered as an alternative option to perennial ryegrass swards on these clay soils.     

Concentration of ergot alkaloids in Czech ecotypes of Lolium perenne and Festuca pratensis

The content of ergot alkaloids (ergovaline and chanoclavine), and their production in October 1996 and during the period May–September 1997, were investigated in seventeen ecotypes of perennial ryegrass ( Lolium perenne L.) and in nineteen ecotypes of meadow fescue ( Festuca pratensis Huds.), naturally infected with Neotyphodium spp. The ecotypes were collected in the north-eastern part of the Czech Republic. In 1996 the content of ergovaline in the ecotypes of perennial ryegrass ranged from 0·00 to 2·73 μg g^–1 dry matter (DM) (one cut), and in 1997 from 0·00 to 4·65 μg g^–1 DM (five cuts). In meadow fescue the content of ergovaline varied from 0·00 to 0·61 μg g^–1 DM (one cut) in 1996, and in 1997 from 0·00 to 2·31 μg g^–1 DM (five cuts). The content of chanoclavine (investigated in 1997 in four cuts only) in perennial ryegrass ranged between 0·00 and 3·39 μg g^–1 DM, and in meadow fescue between 0·00 and 2·26 μg g^–1 DM. Most ecotypes of L. perenne reacted to the high temperature and heavy rainfall in June and July of 1997 with an enhanced production of ergovaline, whereas the content of chanoclavine was not changed. Such reaction to stress conditions was not observed in the ecotypes of F. pratensis. Large differences in the production of both ergot alkaloids between different ecotypes of both plant species were observed.     

Herbage productivity of a range of grass species in association with white clover

Red fescue ( Festuca rubra L.) cvs Reptans, Dawson and Ruby, perennial ryegrass ( Lolium perenne L.) cvs Perma and Sprinter, crested dogstail ( Cynosurus cristatus L.) cv. Southlands, smooth meadow-grass ( Poa pratensis L.) cvs Parade and Arena, Yorkshire fog ( Holcus lanatus L.) commercial types I and II, creeping bent ( Agrostis stolonifera L.) cv. Penncross and rough meadow-grass ( Poa trivialis L.) cvs Omega Øtofte, Dasas and Sabre were each sown with white clover ( Trifolium repens L.) cv. Donna and the productivity of the fourteen mixtures assessed under simulated grazing (six harvests per year) for 3 years. A single fertilizer-N rate (50 kg ha⁻¹) in early spring was applied to all treatments each year.
Over the 3 years, mean annual dry matter (DM) production of the swards ranged from 5·25 t ha⁻¹ (creeping bent) to 8·71 t ha⁻¹ (red fescue cv. Reptans), with the species ranking order of: red fescue > perennial ryegrass > crested dogstail > smooth meadow-grass > Yorkshire fog > creeping bent. Rough meadow-grass only persisted over the first harvest year. Mean annual organic matter digestibility (OMD) values of the swards ranged from 0·712 (creeping bent) to 0·782 (ryegrass cv. Sprinter). Mixtures with the lowest proportion of grass (crested dogstail and smooth meadow-grass) generally gave the highest proportions of white clover. The creeping bent mixture had exceptionally low production of both components.
Red fescue, crested dogstail and smooth meadow-grass showed compatibility with clover and, therefore, have potential for use in grass/clover swards. Yorkshire fog had lower compatability with clover. Some breeding effort to improve selected characteristics of promising species, e.g. improvement of low OMD in red fescue, seems warranted.     

A plate meter inadequately estimated herbage mass in a semi-arid grassland

A resting plate meter was tested in the laboratory and on a field site to determine its effectiveness for estimating peak herbage mass on semi-arid grasslands. In laboratory tests, data from the plate meter closely predicted the herbage mass of four perennial bunch grasses (thirteen of sixteen tests with r ² ≥ 0·90) but the closeness of the prediction varied with the pressure of the plate. Field tests took place on a southern Arizona, USA semi-arid grassland in 2005, 2006, 2007 and 2008. Twenty teams of two or three people sampled the site; five teams in each year measured eight to thirteen plate heights and clipped the vegetation beneath. Consistent with a need for yearly calibration, a significantly different ( P  <   0·05) linear relationship was detected between 3 of the 4 years which was associated with differences in average herbage mass of dry matter (DM) (1525 kg ha⁻¹ for 2005, 2093 kg ha⁻¹ for 2006, 1338 kg ha⁻¹ for 2007 and 1370 kg ha⁻¹ for 2008). Plate height poorly predicted herbage mass within years ( r ²  = 0·21, 0·51, 0·49 and 0·41 respectively) with plate heights explaining half or less of the variability in field herbage mass and having a mean prediction error of 466 kg DM ha⁻¹. The plate meter technique had limited potential for estimating peak herbage mass in semi-arid grasslands.     

The liveweight gain of Limousin × Friesian heifers grazing perennial ryegrass/white clover swards of different clover content and the effects of their grazing on sward botanical composition

An experiment was carried out in 1992 and 1993 to examine the effect of white clover content of perennial ryegrass/white clover swards on the performance of Limousin × Friesian heifers. Swards with low (L), medium (M) and high (H) white clover contents were established and managed by continuous variable stocking. A compressed sward height of 5·5 cm was maintained using a buffer fence to vary plot areas, with herbage surplus to grazing requirements cut, removed and yields measured. The mean white clover proportions for treatments L, M and H were 0·02, 0·19 and 0·18 in 1992 and 0·13, 0·16 and 0·31 in 1993 respectively. White clover contents of the swards reached a maximum in August and September, and differences between treatments diminished. There was no significant difference between treatments in the content of white clover in the swards in autumn 1993.
Liveweight gains of heifers increased asymptotically with increasing white clover content of the sward. Below a white clover herbage mass of 300 kg DM ha^–1, there was little effect on liveweight gain, which was 0·70 kg day^–1 over the grazing season. Between 400 and 450 kg DM ha^–1 white clover, liveweight gains were 0·85–0·90 kg day^–1. While clover content of the sward did not significantly affect utilized metabolizable energy output; the mean output over the grazing season in the two years from liveweight gain and herbage yield was 78 GJ ha^–1. It is suggested that, using this grazing system, white clover reached an equilibrium with a mean herbage mass of about 400 kg DM ha^–1 over the grazing season.     

Long-term responses in the yield of Eastern Gamagrass [Tripsacum dactyloides (L.) L.] to nitrogen fertilizer under two harvest regimes in the United States

Eastern Gamagrass [ Tripsacum dactyloides (L.) L.] is a perennial C₄ grass with potentially high productivity. Intensive management through the application of nitrogen (N) fertilizer and frequency of cutting, however, may be required to maximize its potential for forage production. This study determined the long-term and residual responses of Eastern Gamagrass in terms of dry matter (DM) yield and tiller density to three annual application rates (0, 50 or 100 kg ha⁻¹) of a N-fertilizer solution applied by broadcasting or knife placement for 5 out of the 10 years of the study, and harvested using one-cut or two-cut regimes. Application of N-fertilizer increased total DM yield in the 5 years of N applications by 0·44 with the first increment of 50 kg N ha⁻¹, and by an additional 0·15 with the next increment of 50 kg N ha⁻¹. In the first year that directly followed N-fertilizer applications, DM yield was 0·175 higher than the no fertilizer treatment when 50 kg ha⁻¹ had been previously applied and a further 0·16 higher when 100 kg ha⁻¹ had been previously applied. Dry matter yields were greater from the one-cut than the two-cut regime only in years when no N-fertilizer was applied. Knife placement of N-fertilizer increased total DM yield only at 100 kg N ha⁻¹. Tiller densities were generally higher under the one-cut than the two-cut regime, particularly when N-fertilizer was broadcast. The application of N-fertilizer increased herbage production, especially when responses in the year subsequent to application are considered.     

Productivity of mixtures of Italian ryegrass and red clover

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.     

Effect of long-term changes in relative resource availability on dietary preference of grazing sheep for perennial ryegrass and white clover

Three replicate paddocks, each of 0·235 ha, containing adjacent monocultures of perennial ryegrass or white clover [50:50 by ground area, 6 cm sward surface height (SSH) at start of experiment] were continuously stocked with three yearling and four mature non-lactating, non-pregnant Scottish halfbred ewes for 12 weeks. Herbage intake, grazing behaviour and dietary selection were measured on seven occasions. Clover SSH declined rapidly over the first 5 weeks then stabilized at 1·2–1·6 cm, whereas perennial ryegrass SSH rose slightly initially, then declined gradually. Animals initially included proportionately c . 0·6 white clover in their diet but, by the end of the experiment, this had fallen to 0·3. Total daily herbage intake declined over the 12 weeks from 1·8 kg dry matter (DM) day^–1 at the start to 1·0 kg DM day^–1. Total grazing time increased from 561 min day^–1 to 649 min day^–1 at the end of the experiment. The results suggest that, despite overall herbage depletion and a greater depletion of white clover than perennial ryegrass as a result of the initial partial preference for white clover, the animals traded-off a reduced total intake and an increased grazing time in an attempt to maintain their initial preferred dietary composition.     

The utilization of N fertilizer, applied to perennial ryegrass/white clover pasture growing on a humus iron podzol in N.E. Scotland

Applications of N fertilizer (0.40, 80, 120 and 240 kg N ha⁻¹ year⁻¹ in dressings of 40 or 80 kg N ha⁻¹) were made to a perennial ryegrass/white clover ( Lolium perenne L. Trifolium repens L.) pasture growing on a humus iron podzol reclaimed from heather ( Calluna vulgaris L.) moor in 1982 and 1983. Where no N was applied, estimates of Ni fixation and mineralization were almost equal, being approximately 50 kg N ha⁻¹ year⁻¹ from each source. Apparent efficiencies of fertilizer use were generally low; for each dressing they ranged between –0·7 and 25·5 kg dry matter (DM)kgN⁻¹. Also, responses to N fertilizer were affected by previous dressings. The net N recovery in harvested herbage from application of 120 kg N ha⁻¹ year⁻¹ was 30 kg N ha⁻¹ year⁻¹.     

Effects of different rates and timing of application of nitrogen as slurry and mineral fertilizer on yield of herbage and nitrate-leaching potential of a maize/Italian ryegrass cropping system in north-west Portugal

Efficient use of cattle-slurry to avoid nitrogen (N) leaching and other losses is important in designing intensive dairy systems to minimize pollution of air and water. The response in dry-matter (DM) yield of herbage and nitrate-leaching potential to different rates and timing of application of N as cattle slurry and/or mineral fertilizer in a double-cropping system producing maize ( Zea mays L.) silage and Italian ryegrass ( Lolium multiflorum Lam.) was investigated in north-west Portugal. Nine treatments with different rates and combinations of cattle slurry, and with or without mineral-N fertilizer, applied at sowing and as a top-dressing to both crops, were tested and measurements were made of DM yield of herbage, N concentration of herbage, uptake of N by herbage and amounts of residual soil nitrate-N to a depth of 1 m, in a 3-year experiment. Regression analysis showed that the application of 150 and 100 kg of available N ha⁻¹ to maize and Italian ryegrass, respectively, resulted in 0·95 of maximum DM yields of herbage and 0·90 of maximum N uptake by herbage. Residual amounts of nitrate-N in soil after maize ranged from 48 to 278 kg N ha⁻¹ with an exponential increase in response to the amount of N applied; there were higher values of nitrate-leaching potential when mineral-N fertilizer was applied. The results suggest that it is possible in highly productive maize/Italian ryegrass systems to obtain high DM yields of herbage for maize silage and Italian ryegrass herbage with minimal leaching losses by using slurry exclusively at annual rates of up to 250 kg available N ha⁻¹ (equivalent to 480 kg total N ha⁻¹) in three applications.     

Milk-production potential of different sward types in a temperate southern Australian environment

The milk-production potential of different sward types was measured in each of the four seasons of the year in a replicated experiment in south-west Victoria, Australia. Dairy cows were offered ad libitum allowances of a 'short-term winter' sward, based on Italian ryegrass (treatment STW), a 'long-term winter' sward, based on a winter-active tall fescue (treatment LTW), a 'long-term summer' sward, based on a summer-active tall fescue (treatment LTS) and a Control sward (perennial ryegrass) in four seasons (days in milk in parentheses): spring (November dairy cows, 124), summer (February, 227), autumn (May, 234) and winter (August, sixty-four). A 'short-term summer' sward, based on chicory and white clover (treatment STS), was also included in summer. There was a significant season × treatment interaction caused by a more gradual decline in milk yield from peak for cows grazing treatment LTS compared to the Control treatment in the transition period from spring to summer. In summer, cows grazing treatment STS produced more milk (1·41 kg fat plus protein per cow d⁻¹) than cows grazing all other treatments (0·92 kg per cow d⁻¹) because of the superior nutritive value of herbage of pre-grazing pasture and higher apparent dry-matter intakes. Swards based on alternative species to perennial ryegrass are capable of supporting milk production that is at least comparable over an annual cycle.     

Growth of prairie grass (Bromus willdenowii) and tall fescue × perennial ryegrass (Festuca arundinacea×Lolium perenne) on the Appalachian Plateau of southern West Virginia, USA

The productivity and persistence of prairie grass ( Bromus willdenowii Kunth) cv. Grasslands Matua were compared with a similarly managed endophyte-free tall fescue × perennial ryegrass hybrid ( Festuca arundinacea Schreb. × Lolium perenne L.) cv. Johnstone. A field study was conducted on the Appalachian Plateau of southern West Virginia, USA (81°W, longitude; 38°N, latitude; 850m above sea level) for three consecutive years. Nitrogen totalling 0, 168, and 336 kg N ha⁻¹ year⁻¹ was applied to stands managed as hay. Annual herbage yields were similar for both species in year 1 (1989), but by year 3 (1991) Matua sown-grass yield was about 35% of first-year yields. Total herbage yield for Matua plots in the third year was similar to first-year yields owing to encroachment by non-seeded grasses and white clover ( Trifolium repens L.). Matua was susceptible to powdery mildew [ Blumeria graminis (DC) E. O. Speer] in this environment, and was similar in productivity (first year only) and nutritive quality to tall fescue × perennial ryegrass hybrid. Matua use may be limited to areas where low-temperature stress and resultant winter damage is unlikely to occur.     

Cell wall degrading enzymes for silage. 1. The fermentation of enzyme-treated ryegrass in laboratory silos

The effects of two commercial cellulase/hemicellulase enzymes derived from Trichoderma reesei on silage fermentation were investigated in three laboratory-scale experiments. In Experiment 1, perennial ryegrass ( Lolium perenne ) was treated with enzyme A at the rates of 0, 0·125, 0·250, 0·500 and 0·750 cm³ kg^-1. In Experiment 2, Italian ryegrass ( Lolium multiflorum ) was treated with the same enzyme at the rates of 0, 0·250 and 0·500 cm³ kg^-1 and with 85% formic acid (3·5 cm³ kg^-1). In Experiment 3, perennial ryegrass was ensiled untreated, with enzyme A (0·250 and 0·500 cm³ kg^-1) and with 0·200 and 0·400 cm³ kg^-1 enzyme B which also contained glucose oxidase. All silages were well preserved. In general enzyme treatment reduced pH and the contents of ammonia nitrogen, neutral detergent fibre and acid detergent fibre, whereas the contents of water-soluble carbohydrates, acetic acid, lactic acid and ethanol were increased.     

Effect of fertilizer nitrogen on six-year-old red clover/perennial grass swards

Three diploid red clover cultivars—Sabtoron, Violetta and Essex—and three tetraploid, Hungaropoly, Teroba and Red Head, were sown separately in pure culture and with each of three companion grasses: timothy (Aberystwyth S48), tall fescue (Aberystwyth S170) and perennial ryegrass (Aberystwyth S24).
The effects of fertilizer N on yield and on clover/grass ratio over a 2-year period (seventh and eighth harvest years) subsequent to 6 harvest years during which no N fertilizer was applied were investigated. The data for productivity and persistence have already been published (McBratney, 1981; 1984).
Application of fertilizer N increased DM yields in the eighth year. In this year, the highest yield, 11·9t ha^-1, averaged over the six clover cultivars, was given in association with tall fescue. Tall fescue contributed 90% of this yield. Clover content continued to decrease in all swards but the decrease was greatest in the swards receiving fertilizer N. The yield of clover DM averaged over the six cultivars under N treatment declined from 5·6t ha^-1 in the seventh year to only 0·4t ha^-1 in the eighth year.
The results from this trial demonstrate the potential of red clover sown either pure or in mixture with a suitable perennial grass, to maintain high output of quality herbage over a 6-year period without the aid of fertilizer N. They further demonstrate that following decline in red clover content, both herbage yield and quality may be restored by the application of N fertilizer, particularly where the clover was seeded with a highly productive companion grass.     

The effect of nitrogen in cattle slurry and mineral fertilizers on nitrogen fixation by white clover

The influence of N in slurry or in mineral fertilizers on herbage yield and nitrogen fixation by white clover grown in mixed swards was investigated. Two levels of N in cattle slurry were compared with a range of mineral N fertilization. The percentage of N derived from symbiosis (% Nsym) was measured by the ¹⁵N-isotope dilution method. The measurements were made in spring 1987 in two 4-year-old field trials, and included two out of five harvests.
The % N_sym was approximately 90% without N fertilization. It decreased in response to both mineral N and N in slurry but did not fall below 63%. The sum of two harvests revealed that 51·2 kg N ha⁻¹ were fixed in the absence of N fertilization. With 75 kg mineral N ha⁻¹ or 50 m³ cattle slurry ha⁻¹, the yield of fixed N decreased to 17·2 and 24·9 kg ha⁻¹, respectively. When compared on the basis of the fertilizer effect on dry matter yield and N concentration of perennial ryegrass, the decrease in yield of N fixed due to treatment with cattle slurry was less than that due to mineral N fertilizer. This was owing to the smaller extent of the depression in the proportion of white clover in the sward when the same amount of N was applied in cattle slurry, as compared with mineral fertilizer, although % N_sym responded similarly to both types of N fertilization.     

Seasonal changes in the crude protein concentration of mixed swards of white clover/perennial ryegrass grown without fertilizer N in an organic farming system in the United Kingdom

Changes in the crude protein (CP) concentration of white clover and perennial ryegrass herbage from a mixed sward were determined on six sampling dates from May to October in each of 2 years. The swards were grown without fertilizer N in an organic farming system and continuously grazed by dairy cows during the grazing season. The annual mean contents of white clover in the dry matter (DM) of the sward were 272·3 and 307·0 g kg⁻¹ in Years 1 and 2. The mean CP concentrations of the white clover and perennial ryegrass herbage were 251·6 and 151·9 g kg⁻¹ DM in Year 1 and 271·9 and 174·0 g kg⁻¹ DM in Year 2 respectively. The CP concentration of the white clover increased significantly during the grazing season from 220·0 to 284·1 g kg⁻¹ DM in Year 1 and from 269·0 to 315·5 g kg⁻¹ DM in Year 2. In the perennial ryegrass herbage the CP concentration increased from 112·2 to 172·6 g kg⁻¹ DM in Year 1 and from 142·7 to 239·5 g kg⁻¹ DM in Year 2. The rate of increase during the season in the CP concentration of the perennial ryegrass herbage was similar to the rate of increase recorded in the white clover herbage.     

Cell wall degrading enzymes for silage. 2. Aerobic stability of enzyme-treated laboratory silages

The effects of two commercial cellulase/hemicellulase enzymes derived from Trichoderma reesei on silage fermentation and aerobic stability were investigated in three laboratory-scale experiments. In Experiment 1, perennial ryegrass ( Lolium perenne ) was treated with enzyme A at the rates of 0. 0·125, 0·250, 0·500 and 0·750 cm³ kg^-1. In Experiment 2, Italian ryegrass ( Lolium multiflorum ) was treated with the same enzyme at the rates of 0, 0·250 and 0·500 cm³ kg^-1 and with 85% formic acid (3·5 cm³ kg^-1). In Experiment 3, perennial ryegrass was ensiled untreated, with enzyme A (0·250 and 0·500 cm³ kg^-1) and with 0·200 and 0·400 cm³ kg^-1 enzyme B which also contained glucose oxidase. All silages were well preserved. Aerobic deterioration was related to numbers of lactate assimilating yeasts. In Experiment 1, all silages were stable over a 4-day period. In Experiment 2, enzyme A treatment delayed the temperature rise compared with the untreated control ( P <0·05), whereas the formic acid-treated silage was stable. In Experiment 3, the temperature rise in the silage treated with the higher level of enzyme B occurred one day later than in the other silages ( P <0·05).     

Herbage productivity of a range of grass species under a silage cutting regime with high fertilizer nitrogen application

The productivity of fourteen grasses was measured under a silage cutting regime of four harvests per year for 3 years (1984-86) with an annual fertilizer N rate of 360 kg ha⁻¹, applied at 120, 100, 80 and 60 kg ha⁻¹ for successive harvests. The grasses were: red fescue (Festuca rubra) cvs Reptans, Dawson and Ruby, perennial ryegrass (Lolium perenne) cvs Perma and Sprinter, Yorkshire Fog (Holcus lanatus) commercial types I and II, smooth meadow-grass (Poa pratensis) cvs Parade and Arena, creeping bentgrass {Agrostis stolonifera) cv. Penncross, crested dogstail {Cynosurus cristatus) cv. Southlands and rough meadow-grass (Poa trivialis) cvs Dasas, Omega Øtofte and Sabre.
Red fescue gave the highest dry-matter (DM) production over the 3 years but because of low organic matter digestibility (OMD), its production of digestible organic matter (DOM) was lower than that of perennial ryegrass. Rough meadow-grass was relatively low yielding in the first year and did not persist thereafter. Three-year mean DM production ranged from 9-22 kg ha"'(crested dogstail) to 14-37 kg ha-1 (red fescue cv. Reptans), while mean annual OMD values ranged from 0-660 (smooth meadow grass cv. Arena) to 0766 (ryegrass cv. Sprinter). The mineral composition (P, K, Ca and Mg) differed among species; creeping bentgrass, crested dogstail, perennial ryegrass and Yorkshire fog had moderate to high mineral concentrations while smooth meadow-grass had low concentrations. Mean two-year (1985-86) mineral composition (g kgDM⁻¹) ranged from 3-1 to 40 (P), 234 to 31-0 (K), 3-8 to 6-0 (Ca) and 1-6 to 2-6 (Mg),
It was concluded that while red fescue and Yorkshire fog showed considerable potential for silage DM production, there is scope for breeding red fescue cultivars with improved digestibility and more winterhardy Yorkshire fog; characterization of their ensiling qualities would also be useful.