bluuebunny/crossref_metadata_2025 huggingface dataset:
Yield response of improved upland pasture to the control of leatherjackets under increasing rates of nitrogen
Authors: FRENCH N. , NICHOLS D. B. R. , WRIGHT A. J.
Published: April 2006

In each year from 1984‐5 to 1987‐8 the effect of leatherjackets on yield of improved upland pasture was assessed at Redesdale Experimental Husbandry Farm in Northumberland. Chlor‐pyrifos at 0.72 kg ha−1 was applied in November or December to half the plots; these and the untreated plots received one of four fertilizer rates (0, 40, 80, 120 kg N ha−1). All rates increased yield by a mean of about 24 kg DM kg N−1.

There was a significant correlation (Y (t DM ha−1) = 0‐21 + 0‐00168 ×, r = 0‐99 (P= 0.001)) between yield response to chlorpyrifos and leatherjacket numbers m−2 in November/ December. Treatment thresholds for leatherjacket numbers are given.
The influence of the carbohydrate fraction and additives on silage quality
Authors: PETTERSSON K. LUNDÉN , LINDGREN S.
Published: April 2006

Respiration losses, effect of sugar content, formic acid addition and inoculation were evaluated in relation to initial fermentation and silage quality in three experiments. Changes in the content of fermentable substrate during post–harvest respiration and initial fermentation were studied in the laboratory. Soluble carbohydrates were estimated as glucose, fructose, sucrose, fructans and starch by an enzymatic method.

About 70% of the sugars remained after 30 h of conventional wilting, as opposed to less than 50% in a chopped sample kept in the dark. During the first days of fermentation the metabolic activity was very intensive. Sugars, which accounted for 10% of the dry matter, were fermented within 4 d. There were indications, mainly in clover silages, that substances other than water‐soluble carbohydrates were used as energy sources.

Low‐sugar crops were obtained by shading the fields. After 3 d the sugar in the grass had decreased to half of the original content. This effect was less pronounced in clover. The amount of available substrate and dry matter (DM) content had a major influence on silage quality. In an unwilted crop at least 25 g of water‐soluble carbohydrate was needed per kg of fresh material to obtain an acceptable silage quality in the controls, while 20 g was sufficient in inoculated silage. Formic acid addition makes the fermentation less sensitive to water–soluble carbohydrate content. Inoculation of willed silage increased lactic acid production and decreased the pH. There was also less variation in silage quality.
The effects of contrasting cutting regimes on the components of clover and grass growth in microswards
Authors: GRANT SHEILA A. , BARTHRAM G. T.
Published: April 2006

Microswards of white clover and perennial ryegrass were subjected to one of four treatments: weekly cutting to 3·5 cm, weekly cutting incorporating a period of no cutting for 6 weeks starting 27 April (early rest), weekly cutting incorporating a period of no cutting for 6 weeks starting 8 June (late rest), or cutting every 3 weeks. Two sward types were used: a mixture of white clover cv. Milkanova with perennial ryegrass cv. Melle, and white clover cv. Kent with perennial ryegrass cv. Melle. Growth measurements (leaf appearance, branching/tillering and stolon internode length) were confined to the first three treatments with records collected during contiguous 21‐d measurement periods. Vertical height increments of clover and grass and red:far‐red light ratios at the sward bases were also recorded at frequent intervals. At the end of the experiment population densities and unit weights were recorded for all treatments.

Significant treatment effects on the rate processes were largely confined to the 21‐d period immediately after weekly cutting of rested swards had resumed. On previously rested compared with weekly cut swards, clover leaf appearance rates were increased by 40% and branching rates by 164%. During the same period, grass leaf appearance rates were reduced by 50% and net tillering changed from positive to negative values. Though the rate responses were transient, effects were still apparent at harvest in September, when population density and content (proportion by population density and weight) of clover were significantly higher in the late rest treatment. The variety Kent showed a consistent, though usually nonsignificant, higher leaf appearance and branching rate compared with Milkanova, and in September was characterized by a higher population (7400 m−2 compared to 3200 m−2) of smaller units (27 compared to 46 mg/apical meristem) than Milkanova.

The results are discussed in relation to defoliation effects and the role of light quantity and quality as they influence the component growth processes. Attention is drawn to the importance of canopy structure and the climatic and/or phenological differences in the relative seasonal behaviour of clover and grass, together with varietal variation within species in influencing responses to management manipulations.
The relationships between stolon characteristics, winter survival and annual yields in white clover (Trifolium repens L.)
Authors: COLLINS ROSEMARY P. , GLENDINING MARGARET J. , RHODES I.
Published: April 2006

Five white clover populations of Swiss origin and three bred varieties were grown in binary mixtures with two perennial ryegrass varieties, Aurora and S23. The seasonal yields of clover and grass plus clover were measured under a cutting regime during the second and third years after establishment. A series of destructive detailed sward measurements was made during the late autumn to spring period preceding each harvest year. In this way changes in the amounts of stolon, leaf plus petiole and numbers of growing points were monitored during the winter.

There were large differences in clover yield between populations in both years. These were evident from the first (spring) harvest in each year. Higher‐yielding clovers in spring tended to produce higher annual clover yields. No grass × clover interaction was evident at any harvest. Large differences between clovers were also apparent in the morphological characteristics measured, with the Swiss material generally having greater amounts of stolon, leaf plus petiole and numbers of growing points present in early spring. It is proposed that these factors contribute to the high spring yield in the Swiss populations. Loss of stolon length over each winter was less in the Swiss material, indicating that its good spring growth was not obtained at the expense of winter hardiness. Annual clover yield was found to be significantly positively correlated with the amount of stolon present in spring, exemplifying the importance of stolon survival over the winter.
Response to late season nitrogen of upland swards in Wales
Authors: SKINNER R. J. , ALLEN J. W.
Published: April 2006

During 1984 and 1985, trials at sixteen sites throughout Wales measured the yield response in upland swards from applying 40 and 80 kg N ha−1 at three dates, 20 August, 4 September and 18 September. All sites were between 230 m and 345 m above sea level. Grass yields were measured by cutting plots during October and November.

Nitrogen increased the herbage dry‐matter (DM) yield at all sites in both years. The yield response per kg N applied varied between sites. Mean yield response for the two years declined from 16·2 kg DM kg N−1 with 40 kg N ha−1 applied on 20 August to 8·9 kg DM kg N−1 with 80 kg N ha−1 applied on 18 September. In general there was a decline in response to N with increased rate and delay in time of application. The results indicate that responses above an optimum of 9 kg DM kg N−1 can be obtained well into September. A general rule that 1 kg N can be economically applied per 4 summed day degrees air temperature >6 °C remaining in the autumn up to 30 November is suggested.

Delay in application and increasing N rate increased crude protein in the herbage but had only small effects on modified acid detergent (MAD) fibre and sugar. Generally, grass quality was good. Sward density assessed during the spring after nitrogen had been applied appeared to have been unaffected by the treatments.
A model of aerobic fungal growth in silage.
Authors: PITT R. E. , MUCK R. E. , PICKERING N. B.
Published: April 2006

A simulation model of yeast and mould growth in aerobically deteriorating silage was tested and analysed. The model predictions of aerobic stability were compared with actual stability data from published experiments and were accurate when maize silage composition and initial yeast and mould counts were known. The time‐course of deterioration was simulated for various initial temperatures and yeast and mould concentrations and exhibited primary, secondary, and tertiary heating in some cases; however, the model was limited in its ability to predict temperature history during deterioration because of the simplified treatment of heat transfer. In simulations, the relative importance of yeasts and moulds depended mainly on initial fungal concentrations, whereas the relative importance of mesophiles and thermophiles depended primarily on initial temperature. The model predicted that the period of silage aerobic stability ends when fungal concentrations reach approximately 0·001 g g−1 silage. Temperature, water‐soluble carbohydrate concentration, fungal populations, and fermentation product concentrations in interaction with pH had the greatest direct effects on predicted aerobic stability. The model results suggest that aerobic stability is greatest when the pre‐ensiling forage is highly buffered, of low dry matter content, and contains sufficient water‐soluble carbohydrates to allow fermentation to the lowest possible pH with no residual water‐soluble carbohydrates.
Effect of winter grazing date on yield components of Lolium perenne (L.)/Trifolium repens (L.) hill pasture
Authors: Jaindl R. G. , Sharrow S. H. , Meyer H. H.
Published: April 2006

Perennial ryegrass/white clover pastures were grazed at different times in the winter to study the effect of time of grazing on subsequent plant growth. In 1983–84, 1984–85, and 1985–86, pastures were grazed to a residual of 400 kg dry matter ha‐1 by sheep once in early December (D), January (J), February (F), March (M), or April (A) and compared with an ungrazed control (C). Rates of herbage accumulation on C in the winter were low, averaging 6, ‐9, and 2 kg dry matter ha‐1 in December, January, and February, respectively. Little forage production occurred during the month immediately following winter grazing. Herbage accumulation rate then increased sufficiently to replace the forage removed from winter‐grazed paddocks by early spring. By May, herbage mass on grazed treatments was similar to C except for D and A which averaged 20 and 47% less forage than C, respectively (P<0·01). Herbage accumulation rates of D were unique among winter grazing treatments in never exceeding those of C. By May 1986, D yielded less perennial ryegrass compared with C (P<0·05). Grazing reduced the number of leaves per ryegrass tiller for 1 to 2 months following grazing. By May, J, F and M had numerically more tillers m‐2 and more leaves per tiller than C. Similar May yields of J, F, M, and C resulted from fewer but larger and slightly less leafy tillers of ungrazed compared with winter grazed plants.
The effect of glucose oxidase on the preservation of grass silage
Authors: Rauramaa A. L. , Setälä J. J. , Tommila A. E. A.
Published: April 2006

Five experiments were carried out to investigate the effects of glucose oxidase (GO) on the preservation of grass silage in the absence of micro‐organisms. In the first experiment, GO was tested in a 3% glucose solution. At the level of 1190 U GO l‐1 the pH value decreased to 3·94 in 1 h and to 3·02 in 24 h. At the level of 11·9 U l‐1 the pH decreased to 3·45 in 24 h.

The second experiment was performed by packing chopped grass into glass jars, sterilizing in an autoclave and adding GO. One day later the pH value had decreased to 4·65; 1·60% gluconic acid was found in the dry matter.

In the other three experiments grass was sealed in polythene bags and sterilized by gamma‐irradiation. GO was found to cause a faster decrease in pH. Removing air from the silage by compaction decreased the GO activity. The addition of cellulase delayed the GO functioning for one day. Lactobacillus inoculant had no effect. Evidence was obtained that GO may affect the profile or activity of the original microflora of grass silage.
Potential impacts of climate change on patterns of production and the role of drainage in grassland
Authors: ARMSTRONG A.C. , CASTLE D.A.
Published: April 2006

Grass production can be predicted using a simple model whose inputs include daily meteorological variables. Changes in both daily temperature and the soil water balance can be expected as a consequence of anthropogenic increases in the CO2 content of the atmosphere. Possible consequences of such changes for grass production are then predicted using the model. These indicate that, for the UK, patterns of grass production could be shifted significantly. Greater grass growth in the spring would follow from the increase in temperature, particularly on drained land where growth is not constrained by water logging. However, grass growth would be depressed by the mid‐season soil moisture deficit, and this again is more marked on drained land, it is concluded that, under a changed climate, the drainage of grassland to enable early season access to the land, together with sound management to optimize output, will be even more important than at present.
Factors affecting sonic sward stick measurements: the effect of different leaf characteristics and the area of sward sampled
Authors: HUTCHINGS N. J.
Published: April 2006

Laboratory experimentation found smooth and pubescent leaf surfaces to behave as specular (mirror‐like) reflectors of ultrasound, whilst ribbed leaves behaved as an array of reflectors. It was concluded that swards composed of species with smooth, erectophile leaves would reflect ultrasound poorly and that this may explain the low sward height measurements returned by the sonic sward stick in the field when compared with the HFRO sward stick. The likely effect of species with planophile leaves such as clover is discussed. The sward surface influencing a sonic sward stick measurement was calculated to subtend a solid angle of about 43° at the transducer, equivalent to an area of about 1000 cm2 with the transducer mounted at a height of 50 cm. However, measurements made over turves of varying sizes or over turves with cores of varying size removed found the sensitivity decreased very rapidly beyond an inner area subtending a solid angle of about 7° this is equivalent to an area of about 30 cm2.
Out‐of‐season management of grass/clover swards to manipulate clover content
Authors: LAIDLAW A. S. , TEUBER N. G. , WITHERS J. A.
Published: April 2006

Two experiments are described in which the effect of grazing or defoliating mixed swards at different times over winter and spring on clover content and development was investigated.

In the first experiment swards were grazed with sheep (to about 3 cm) for a short period in (a) November, (b) November, January and March, (c) March or (d) not at all, in three consecutive years. All swards were grazed intermittently during the grazing season with cattle and cut for silage once each year. Each plot received either 0 or 50 kg N ha−1 in March.

The effect of N fertilizer was to reduce clover content in each summer and clover growing point density in the third year.

In two of the three years, treatments involving grazing in March had lower subsequent net annual herbage accumulation compared with the other two treatments and higher clover content in summer of the third year. Reduction in growing point density in all plots during the grazing season was associated with cattle grazing when conditions were wet, suggesting that stolon burial was implicated. Grazing with sheep in November, January and March resulted in significantly more visible (when counted in situ) clover growing points in April in year 2 and more total growing points (counted after dissection of turves) in the third year than the November grazed and ungrazed treatments which had, on occasions, higher grass tiller density.

In a microplot experiment, high herbage mass standing over winter was associated with lower potential photosynthesis per unit clover lamina area and lower growing point density in March. Cutting herbage in March to 2‐3 cm resulted in higher clover content and higher growing point number per unit stolon length. The latter was significantly correlated with total irradiance and red: far red at the canopy base. Potential photosynthesis of clover was not affected by cutting in March.

It is concluded that growing point density can be increased by grazing or cutting during winter or spring. However, in order for these new stolons to contribute to clover yield during the summer, they have to be maintained until then by ensuring that competition from grass is minimized by keeping the sward short in winter and spring and avoiding the burial of stolons during grazing.
Growth and photosynthesis of tall and short cultivars of white clover with tall and short grasses
Authors: WOLEDGE JANE , DAVIDSON KERRY , DENNIS W. D.
Published: April 2006

A comparison was made of canopy structure, photosynthesis and dry weight production, during growth periods in spring and summer, of a large‐leaved and a small‐leaved cultivar of white clover (Blanca and S184), grown in mixtures with perennial ryegrass or tall fescue. Both clovers had leaves in the topmost, best‐lit layer of the canopies, even when sward surface height reached 40 cm in early June. Except early in the spring growth period, both clovers had a greater proportion of their leaf area near the top of the canopy than did their companion grass. Both clovers had a greater relative growth rate than the grass, increasing their percentage of the total crop dry weight during both spring and summer growth periods. Differences between clover cultivars were relatively minor and did not affect their dry weight in either measurement period. During the first growth period there was more clover dry weight with tall fescue than with ryegrass. There were no effects of clover cultivar on grass dry weights.
Some effects of herbage composition, as influenced by previous grazing management, on milk production by cows grazing on ryegrass/white clover pastures. 2. Milk production in late spring/summer: effects of grazing intensity during the preceding spring period
Authors: HOOGENDOORN C. J. , HOLMES C. W. , CHU A. C. P.
Published: April 2006

Three experiments (2a, 2b and 2c) were carried out to examine the effects of different grazing intensities imposed during spring on subsequent herbage composition and milk production measured in summer.

Increased intensity of grazing imposed during spring (including the period of reproductive development in ryegrasses) produced swards in early summer with lower pre‐grazing herbage masses, which contained higher concentrations of green leaf, clover and digestible nutrients, but lower concentrations of grass stem and senescent material.

In the first and second experiment cows were given a common daily allowance of total herbage dry matter (DM). The cows grazing on low‐mass swards in early summer produced larger daily yields of milk, fat and protein than those grazing on the high‐mass swards.

In the third experiment, cows were given a common daily allowance of green leaf DM from three swards which differed in pre‐grazing herbage mass and in herbage composition. The allowances of total DM required differed widely between the treatments. There were no significant differences in milk yields between the swards despite the large differences in herbage composition.

The practical implications of these results are discussed.
The effects of sward height and nitrogen fertilizer application on changes in sward composition, white clover growth and the stock carrying capacity of an upland perennial ryegrass/white clover sward grazed by sheep for four years
Authors: BARTHRAM G. T. , GRANT S. A. , ELSTON D. A.
Published: April 2006

Perennial ryegrass/white clover pastures grazed by sheep and receiving either no fertilizer N (No) or 120 kg N ha−1 year−1 (N0) were maintained with surface heights of 2·5, 3·5 and 5·0 cm for over four years. The treatments were replicated.

The white clover (WC) population was greatest in the N0treatment, and declined during the study. Between‐year variation in WC was negatively related to rainfall and positively related to temperature, WC as a proportion of the total plant population decreased during the summer in the Nl treatment. The perennial ryegrass (PRG) population was greater in the Nl treatment, declined during the study and both within and between years was positively related to temperature. The population density of the unsown grasses was highest in the N‐fertilized treatment and in the swards maintained at the lowest heights (these treatments also had the highest stocking rate); it increased during the study, within‐years being positively related to temperature and between‐years being positively related to rainfall.

The WC stolon extension rate was largely unaffected by N fertilizer application and was greatest in the taller swards. Leaf appearance rate was unaffected by N fertilizer application and sward height; it was positively related to temperature and negatively related to rainfall.

Branching rate was greater in the N0 treatment with significant sward height effects confined to a negative relationship with local sward height within treatment plots on one occasion; it was negatively related to rainfall. The ground level red:far red light ratio was negatively related to local sward height. The total live weight of sheep carried in the No treatments was 0·7 of that in the N1 treatments.

Expected photomorphogenic responses by we were confined to stolon extension. It was concluded that on the poorly drained clay‐loam soil used in this study the effects of sheep, in interaction with climatic factors, had an overriding effect on clover branching rate and the ultimate species composition.
Preliminary trials using a white clover (Trifolium repens L.) understorey to supply the nitrogen requirements of a cereal crop
Authors: JONES L.
Published: April 2006

A method of growing cereals with no input of N fertilizer was tested. Two experiments are reported in which white clover (Trifolium repens L.) was used to supply the nitrogen requirements of the cereal. Spring barley, spring oats and winter barley were direct drilled into an established clover crop and grown with the legume as an understorey. The yield of whole crop cereal, for ensilage, and yield of cereal grain were similar to those grown by traditional methods. In the first experiment, clover survived adequately to be used again, but in the second experiment it was killed by a very high slug population. A method of slug control by mob stocking with sheep is discussed. Where clover survived, no weed, insect or disease problems were encountered. The technique offers a possible method of reducing the environmental problems arising from the use of nitrogen fertilizers.
Effects of the type of additive and the type of supplement on the utilization of grass silage for milk production in dairy cows
Authors: CHAMBERLAIN D. G. , MARTIN P. A. , ROBERTSON S. , HUNTER E. A.
Published: April 2006

Four silages were prepared from grass treated with additives designed to produce different extents of fermentation in the silo. The additive treatments were: formic acid at 5 l t−1; a bacterial inoculant (Ecosyl, ICI plc); the inoculant plus molasses at 20 kg t−1; and a noadditive control. All silages were well preserved. Formic acid severely restricted the extent of fermentation, the concentration of lactic acid being only 50% of that seen for the other treatments, all of which were similar in lactic acid concentrations.

The silages were offered ad libitum, either as the sole component of the diet or together with three supplement treatments to 16 British Friesian cows, in four 4 treatment × 4 period Latin squares with periods of 28 d duration. The supplements were: a barley‐based mixture at 5 kg d−1 (B); a high‐fat, high‐protein product at 2 kg d−1 (FPI) and at 3 kg d −1 (FP2); both FP treatments were given with 1 kg d−1 of molassed sugarbeet pulp. A preliminary experiment, using three lactating, rumen‐cannulated cows in a 3×3 Latin square design with 28‐d periods, provided information on rumen digestion when the supplements were given with a separate, non‐experimental silage.

In the preliminary experiment, neither of the FP treatments influenced the molar proportion of the major rumen volatile fatty acids compared with treatment B; nor were there any depressive effects of the FP treatments on silage intake compared with treatment B.

In the main experiment, the intake of silage with the inoculant treatment was less than that with the other treatments, the effect being generally significant (at least P<0·05) for all three supplements. When the silages were given unsupplemented, there were differences in the concentration (P<0·001) and yield (P<0·01) of milk fat, both of which were lowest for the no‐additive control and highest for the formic acid silage. When supplement B was given, the concentration and yield of milk fat were lowest for the no‐additive control and the concentration and yield of milk protein were highest for the formic acid silage. For all silages both FP treatments tended to depress silage intake and reduce the concentration of fat and protein in milk compared with treatment B.

Although there were clear indications of differences in nutritional characteristics between the silages, there was little evidence that the differences between silages influenced the responses to changes in the composition of the supplements.
The growing and grazing season in the United Kingdom
Authors: BROAD H. J. , HOUGH M. N.
Published: April 2006

The definitions of the grass growing and grazing seasons as climatic parameters are investigated using a grass growth model. Taking a mean air temperature of 6°C to define the start and end of the growing season at nine UK stations, the model indicates the following: (1) dry matter growth rates at the start are 6 to 9 times greater than those at the end; (2) growth rates at the start of the growing season are higher in those areas where it begins late (i.e. late March/ early April) than in areas where it begins earlier (i.e. late February/ early March). When defining the grazing season in terms of a delay after the start of the growing season, the model indicates that (3) growth rates at the start of the grazing season are higher in upland areas and in areas where the growing season begins late than in lowland areas and in areas where the growing season begins early.

A definition of growing season in terms of growth rates shows that 5 and 8°C are more suitable temperatures to define the start and end than 6°C.

Grazing season was more adequately described using growth rates than in terms of a delay after the start of the growing season.
Sodium fertilizer application to pasture. 3. Rumen dynamics
Authors: CHIY P. C. , PHILLIPS C. J. C. , OMED H. M.
Published: April 2006

The objective of the present experiment was to examine the effects of 0 (Nil), 32 (Low), 66 (Medium) or 96 (High) kg sodium (Na) ha‐1 yr‐1, applied as fertilizer to zero‐grazed perennial ryegrass pasture, on rumen digestion and feed and water intake of steers. Herbage Na contents increased with increasing Na up to the Medium Na treatment and no further at the High. Dry matter (DM) contents were increased by Na fertilizer but not affected by the level. Herbage crude protein (CP), true protein (TP) and non‐protein nitrogen (NPN) fractions were not affected by treatment. Application of Na fertilizer increased the modified acid detergent fibre (MADF) and ash and total cation content of herbage, particularly at the Medium and High treatments. Faecal DM and TP contents were not affected by treatment, but the CP, NPN, MADF and ash and total cation contents were increased by Na fertilizer. Herbage DM intake increased in proportion to dietary Na content. Water intake increased with increasing Na fertilizer level. Rumen pH was increased by Na fertilizer but ammonia concentration was not affected. The rapidly (a), slowly (b) and potentially (a + b) soluble fractions of degradable DM and the effective degradability (P) of DM increased in direct proportion to amount of Na fertilizer applied up to the Medium level, above which b was reduced and a, a + b and P did not increase further. Solid and total outflow rates were not affected by treatment. Liquid outflow rates were greater in the Medium and High treatments than in the Nil and Low treatments. The immediately soluble fraction of MADF was increased in the Na‐applied treatments but the increase declined with each additional Na level. The degradability of MADF increased with increasing dietary Na, particularly in the High treatment. Na increased the proportion of small particles and those with a high specific gravity. It is suggested that the high dilution rates that accompanied the high water intakes and the increased rumen pH are essential factors enabling increased DM intake and rumen digestion when high Na herbages are fed to steers.
Some effects of added phosphorus on perennial ryegrass—white clover swards
Authors: ACUÑA P G. H. , WILMAN D.
Published: April 2006

The effect of applying 100kg P ha‐1 per year in the form of triple superphosphate to mixed swards of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) was examined on a soil of low P status.

The dry matter yield of total herbage was increased by 10′/i by added P. In the year of sowing the ryegrass benefited more than the clover from added P: in the subsequent four years the two species benefited equally. Both species responded 10 added P to a similar extent in terms of leaf size; the clover responded less well than the ryegrass in terms of rate of leaf emergence. However, clover responded positively to added P in terms of stolon internode length, length of stolon per m2 and number of growing points per m2. It is suggested that the application of P may promote the spread of white clover within an open sward, but that its application may not enhance the competitive power of white clover when growing with vigorous grasses.
The effect of agronomic factors on seed and forage production in perennial legumes sainfoin (Onobrychis viciifolia Scop.) and French honeysuckle (Hedysarum coronarium L.)
Authors: MARTINIELLO P. , CIOLA A.
Published: April 2006

Perennial legume varieties and ecotypes belonging to the species sainfoin (Onobrychis viciifolia Scop.) and French honeysuckle (Hedysarum coronarium L.) were investigated under different management treatments (two regimes of irrigation, cutting and seeding densities) at the Forage Crops Institute in Foggia, Italy (which has a typical Mediterranean environment) for two seasons, 1990 and 1991. Dry‐matter production, seed production and seed yield components were affected more by harvest year and irrigation than by seeding density. Mean increases due to irrigation were 2·8% and 60·6% respectively for dry‐matter and seed yield in sainfoin and 35·3% and 32·5% respectively in French honeysuckle. Under both cutting regimes, the higher seeding density was more suitable for sainfoin, increasing stems m−2 with irrigation and seed yield without irrigation. In French honeysuckle the lower seeding density was more suitable for production of inflorescences per tiller and for seed weight without irrigation. Higher seeding density positively influenced seed yield under irrigation. The seed yield components most influenced by irrigation were: 1000‐seed weight, seeds per inflorescence and inflorescence per stem. French honeysuckle genotypes were potentially more productive in dry matter and seed yield under both irrigation regimes than the sainfoin, which was more productive in seed yield when cut. The ecotypes of both legumes represent a genetic resource, particularly for seed yield after forage cutting, to be utilized in breeding programmes for developing varieties well adapted to Mediterranean environments.
The effect of oxygen concentration on changes in the microbial population, temperature and dry‐matter content in grass silage
Authors: WILLIAMS A. G. , LOWE J. F. , REES D. V. H.
Published: April 2006

The effects of transfusing cores of grass silage with mixtures of oxygen and nitrogen containing 0%, 0·2%, 2%, 5% and 20% oxygen were investigated. Changes in populations of yeasts, lactobacilli and streptococci were measured and the relationship between populations after 7 days' transfusion and oxygen concentration were tested against the predictions of two models, based on Monod and logistic growth functions. Yeasts were related to oxygen by the Monod model, while lactobacilli and streptococci were related by the logistic model. The differences were ascribed to yeasts initiating deterioration by growing aerobically, while lactobacilli and streptococci grew fermentatively once the environment had changed following yeast growth. Dry‐matter losses were related to oxygen by the Monod model. Changes in temperature were related to dry matter loss (through measurements of CO2 evolution) using a simple heat balance model.
Effects on milk production of feeding silage and sugar‐beet pulp as separate components, in a mixed ration or as an ensiled blend
Authors: FERRIS C. P. , MAYNE C. S.
Published: April 2006

Twenty early‐lactation British Friesian dairy cows were used in a five‐treatment, partially balanced change‐over design experiment, consisting of four periods each of 4 weeks' duration. Three treatments consisted of offering ensiled blends of silage and sugar‐beet pulp produced by mixing 40 (S40), 80 (S80) and 120 (S120)kg beet pulp t−1 herbage at ensiling. In two further treatments, an untreated silage was supplemented with 5 kg of beet pulp daily, either mixed with the silage prior to feeding (SM) or offered in two equal feeds each day (ST). Silage was offered ad libitum in all treatments, while in addition all cows received 1 kg d−1 of a concentrate supplement containing 470 g crude protein kg−1 fresh weight.

Dry‐matter intakes and milk fat + protein yields increased with increasing level of beet pulp inclusion in the diet, irrespective of whether it was offered in the form of an ensiled blend or as a supplement to an untreated silage. With the exception of D‐value (digestible organic matter in the dry matter), which was significantly higher with treatments SM and ST than with the ensiled blend treatment (S80), no significant differences were identified in total ration digestibility or in the efficiency of nitrogen or energy utilization between methods of beet pulp inclusion in the diet. However, offering beet pulp in the form of an ensiled blend reduced the acetate/propionate ratio in rumen fluid compared with offering best pulp as a supplement to an untreated silage. When account is taken of differences in the efficiency of recovery of edible silage dry matter between ensilage systems and of differences in dry‐matter intakes between treatments, total milk fat + protein outputs per 10000 kg herbage dry matter ensiled were 55 (s.e. 50·9) and 78 (s.e. 47·5) kg lower when equal quantities of beet pulp were offered as part of an ensiled blend rather than as a supplement to an untreated silage, as in treatments SM and ST respectively. However, these differences were non‐significant. Alternatively, in order to produce an equal milk output from ensiling a given quantity of herbage, 12·5 and 16·2% more beet pulp would have been required if the beet pulp had been mixed with the herbage at ensiling, rather than offered as a supplement, as in treatments SM and ST respectively.
Drying and physical characteristics of matted ryegrass
Authors: SAVOIE P. , BURGESS L. R. , KNIGHT A. C. , McGECHAN M. B.
Published: April 2006

Fresh ryegrass and lucerne were macerated and compressed into thin mats over a 4‐week period at two yield levels. The mats were left lo dry outside during the day. and inside overnight, and compared with unconditioned crops. Under a low swath yield of 4 t DM ha−1, mats required 0·7‐1·4 mm pan evaporation lo reach 70% moisture, suitable for wilted silage, compared with 1·8‐3·8 mm pan evaporation for unconditioned crops. On an average non‐rainy day. mats were ready to harvest as wilted silage after 2–5 h, whereas the unconditioned crop required between 6 h and 36 h of wilting. With a high swath yield of 8 t DM ha−1, mats required 1·4‐3·0 mm pan evaporation to reach 70% moisture compared with 2·4‐5·1 mm for unconditioned windrows. Low‐yield mats reached 20% moisture, suitable for hay, in 2 d of drying, after 4·5‐5·3 mm of pan evaporation. The thickness and cohesion of the mats were measured to assess their sensitivity to mechanical handling. The effect of controlled rainfall on mats was also investigated. Since mat making was most effective in low‐yield crops, it could become a useful complement to low‐input, extensive forage production. Mat making could eliminate most silage effluent losses; it could re introduce haymaking of ryegrass as a viable system under certain circumstances.
Effect of temperature and water variables on the juvenile growth of lucerne and red clover
Authors: KENDALL W. A. , SHAFFER J. A. , HILL R. R.
Published: April 2006

Plants of three cultivars of lucerne (Medicago sativa L.) and of red clover (Trifolium pratense L.) were grown at four levels each of water availability and temperature in all combinations to evaluate these factors as determinants of plant growth. Plants grew in conventional plant growth chambers from age 2 to 4 weeks with the roots held between layers of polyester cloths that held a volume of nutrient solution which was adjusted at 24‐h intervals by flushing and blotting the cloths. The experimental design consisted of two growth chamber runs at each of four temperatures. Within each run, water treatments and the species‐cultivar combination were arranged In four replicates of a split‐plot design with water treatment as whole plot and species‐cultivars as subplots.

Plant response variables over all treatments were significant (P < 0·05) for temperature and water for shoot weights, root weights, shoot/root ratios and number of roots. Cultivars within species had no significant difference in response lo the treatments, but species differences were significant for alt response variables except shoot/root ratio.
Ensiling of manured crops—effects on fermentation
Authors: RAMMER C. , ÖSTLING C. , LINGVALL P. , LINDGREN S.
Published: April 2006

The quality of silage from crops fertilized with cattle manure and an inorganic fertilizer was compared in experiments from 1985 to 1989. Manure was spread either as farmyard manure (FYM, 25t ha−1) or as slurry (20‐50t ha−1). Crops were direct cut (approximately 200 g DM kg−1) or wilted (approximately 300 g DM kg−1), precision chopped and ensiled in experimental silos. Silage was treated with 4 kg 85% fonnic acid t−1 fresh matter (FM), an inoculant or no additives. The use of manure, particularly FYM, resulted in more Bacillus spores on crops at harvest compared with fertilized crops. Clostridium spores increased as a result of manuring in 1989 only on FYM‐treated crops. Differences in the chemical composition of crops were usually small between fertilizer treatments. The quality of silage from slurry‐dressed crops, compared with that of silage from fertilized crops, varied between years. The FYM resulted in reduced silage quality, i.e. high pH values (> 4·5), high ammonia N (> 150 g kg−1 total N) and butyric acid (> 6·3 g kg−1 water) concentrations, and high numbers of Bacillus (105 g−1 FM) and Clostridium spores (105 g−1 FM). The concentration of lactic acid was low (≤ 12 g kg−1 water). Wilting and additives generally improved silage quality and reduced the differences between treatments. However, the efficiency of the inoculant on farmyard manured crops was limited.
Yield and compensatory growth of lucerne following simulated winter‐kill
Authors: STOUT D. G. , THOMPSON D. T.
Published: April 2006

Lucerne (Medicago sativa L.) sown at 2·8‐11·2 kg ha−1 in spring was thinned in the autumn by digging plants from alternate 15‐ or 30‐cm lengths of row. Both thinning treatments decreased the subsequent year stand density by 34%. Yields the following year were reduced by 24 and 17% for the 15‐ and 30‐cm treatments respectively, and the next year by 10% for both treatments. Thinning effects were similar at all sowing rates. During the year following thinning, plants did not grow larger in response to the thinning. Thus, development of compensatory growth by lucerne plants following sudden stand thinning is slow.
Effect of forage matting on rate of grass drying, rate of silage fermentation, silage intake and digestibility of silage by sheep
Authors: FROST J. P. , POOTS R. , KNIGHT A. , GORDON F.J. , LONG F.N.J.
Published: April 2006

The effects of forage matting on rate of grass drying and silage fermentation, digestibility, and intake were examined using perennial ryegrass swards. Treatments compared were: forage mats, where grass was processed through a laboratory scale macerator prior to matting and wilting to 228 g dry matter (DM) kg−1 (FM treatment); unconditioned grass which was direct ensiled at 163 g DM kg−1 (DE treatment); unconditioned grass which was wilted for the same period as FM to 213 g DM kg−1 (UC treatment); unconditioned grass which was wilted to 234 g DM kg−1 (UC25, treatment). All forages were dried on black plastic sheeting. For each treatment a total of approximately 80 kg grass DM was ensiled in seven 290 I plastic bins for 136 d prior to feeding to wether sheep. A further total of 14 kg grass DM from each treatment was ensiled in twenty‐one plastic pipes (152 mm diameter, 762 mm long) to give a total of 84 pipes. Rate of silage fermentation was determined by destructively sampling pipes following 1, 2, 4, 6, 13, 20 and 50 d of ensilage. Over the mean wilting period of 6·9 h, grass from the FM treatment dried significantly faster (P < 0·001) and required less solar energy per unit of moisture loss than unconditioned grass. The rate of grass drying was highly correlated with solar radiation. The FM treatment did not influence the rate or extent of silage fermentation. The intakes and digestibilities of FM, UC and UC25 were not significantly (P < 0·05) different from each other but were higher than for the DE treatment (P < 0·05 for digestibility and NS for intake). In Northern Ireland it is unlikely that there will be sufficient solar radiation to allow forage mats to be made, wilted to a level to prevent effluent production and harvested within one working day. Further work is required to optimize mat‐making technology for more rapid drying and to determine the effect of adverse weather on nutrient losses from mats.
The effect of surface height of swards continuously stocked with cattle on herbage production and clover content over four years
Authors: LAIDLAW A.S. , WITHERS J.A. , TOAL L.G.
Published: April 2006

The long‐term influence of sward height from April to July (Phase 1) and from July to early October (Phase 2) on total herbage and white clover production was measured over four years (1988–1991) as herbage accumulation. A subsidiary experiment to determine the influence of leaf area index (LAI) on gross canopy photosynthesis was conducted to aid interpretation of growth from herbage accumulation data. Target sward heights in 0·5 ha plots in two blocks were 5,7 or 9 cm in Phase 1 and 7 or 9 cm in Phase 2, although mean actual heights per phase were slightly higher. Net herbage accumulation (NHA) was measured within mobile exclosure areas over successive two‐week intervals. Gross photosynthesis was measured in circular turves removed from the trial area representing a range of LAIs with an at least reasonable clover content. Despite wide differences in mean sward height and herbage mass, NHA and net clover accumulation for a given phase were not generally affected by treatments. Positive effects of grazing at 5 cm in Phase 1 on NHA and clover accumulation later in the year, and of grazing at 7 cm in Phase 2 on NHA in the following spring were sometimes apparent. Gross canopy photosynthesis (g CO2 m−2 h−1) at 1500 μE m−2 s−1 and 18–21°C was linearly related to LAI described by 1·003 + 1·165 LAI over the LAI range 0·7 to 4·5. Total herbage and clover growth, interpreted from NHA by a previously described model, was predicted to be marginally lower in shorter swards. Similarity in NHA and clover accumulation between treatments was considered to be because of lower senescene and decomposition, and a higher proportion of new tissue being assigned to lamina growth, despite lower LAI and gross photosynthesis in the shorter swards. It was concluded that stocking intensity in swards continuously stocked with cattle did not have a strong influence on net total herbage and clover growth.
The effect of pattern and severity of cutting on the vigour of the soft rush (Juncus effusus L.)
Authors: MERCHANT M.
Published: April 2006

An experiment was conducted to examine the effect of the timing and severity of defoliation on the vigour of the soft rush (Juncus effusus). Three levels of defoliation (uncut, cut at half the current green stem height, and cut at ground level) were applied at each of two cutting dates (the end of June and the end of August) in a factorial design that gave nine cutting treatments. Treatments were imposed for two consecutive years and their effects on tussock size (rush herbage mass) and vigour, as determined by green stem height, peripheral green stem density, and the proportion of flowering green stems, were assessed in Year 3. Defoliation to half the current green stem height either once or twice annually had no effect on tussock mass or vigour. Defoliation to ground level reduced tussock mass and vigour but a large number of green, living stems remained on all treatments, indicating considerable potential for regeneration once the cutting treatments had ceased. There was no significant effect of number or timing of the cuts, but the results suggest that cutting rushes to ground level twice during the growing season is more effective at reducing rush vigour. Where only a single cut is possible, cutting in August after flowering is the best option.
Use of freshly cultured lactic acid bacteria as silage inoculants
Authors: MERRY R. J. , DHANOA M. S. , THEODOROU M. K.
Published: April 2006

The use of freshly cultured lactic acid bacteria in comparison with conventional freeze‐dried preparations as inoculants for grass silage was examined. Perennial ryegrass was ensiled in laboratory silos, either untreated or treated with formic acid, or a commercial freeze‐dried strain of Lactobacillus plantarum, or a fresh culture of the same strain of L. plantarum, or fresh cultures of Pediococcus pentosaceous, or Lactococcus lactis alone or in combination with L. plantarum. All inoculants were applied at a rate of 106 colony‐forming units g−1 fresh matter, with the mixtures containing a 1:l ratio of each species. Herbage treated with freshly cultured inoculants exhibited shorter lag times, in relation to the initiation of pH decline, than those associated with untreated or freeze‐dried inoculant‐treated herbages. Treatment of herbage with inoculants containing L. plantarum increased the initial speed of pH decline. In comparison with silages made with freeze‐dried L. plantarum, in measurements made during the initial 14 d of ensilage, those inoculated with fresh cultures bad significantly (P<0·05) higher lactic acid concentrations and significantly (P·0.05) lower pH values. Both P. pentosaceous and L. lactis initiated a rapid fermentation, but compared to L. plantarum alone, or mixtures of L. plantarum with P. pentosaceous or L. lactis, these cultures demonstrated intermediate rates of lactic acid production and pH decline. All mature (105 d) silages were of good quality with pH values of four or less, low ammonia‐N concentrations (<100gkg−1 total N) and no detectable levels of clostridia or butyric acid. Results suggested that the main advantage of freshly cultured inoculants over their freeze‐dried counterparts may lie in their metabolic state when added to herbage.