bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of formic acid on the fermentation of ryegrass ensiled at different stages of growth and dry matter levels
Authors: HENDERSON A. R. , McDONALD P.
Published: April 2006

In the first experiment the buffering effect of Italian and perennial ryegrass to fonnic acid was determined with three varieties (Leda, S24 and Presto) cut at weekly intervals throughout the growth cycle. The buffer curves showed no significant differences between the three varieties at any one stage of growth and the results were combined to produce regression equations predicting pH values for the three ryegrasses cut at first ear emergence (e.e.), 50% e.e. and 100% e.e. after addition of formic acid.

In the second experiment Italian ryegrass was harvested at three stages of growth, wilted to four different DM contents and ensiled in laboratory silos with five levels of formic acid. The interaction of stage of growth, formic acid level and DM content on the water‐soluble carbohydrates, ethanol and volatile N contents of tbe resultant silages is discussed.
Nitrogen and Italian ryegrass. 3. Growth up to 14 weeks: yields, proportions, digestibilities and nitrogen contents of crop fractions, and tiller populations
Authors: WILMAN D. , OJUEDERIE B. M. , ASARE E. O.
Published: April 2006

The regrowth of Italian ryegrass following a cut in late April was studied at weekly intervals up to 14 weeks. There were four levels of applied N: 28, 84, 140 and 196 kg ha‐1. The proportion of green leaf blade declined from 80% of DM yield after 2 or 3 weeks of regrowth to 5% after 13–14 weeks. About three‐quarters of the increase in DM yield of total herbage from week 3 to week 11 was attributable to increased yield of ‘stem’. The level of applied N had little effect on the proportion of crop fractions except during the period immediately before and after the begiiming of ear emergence when the higher rates of N increased the proportion of ‘stem’ and reduced that of green leaf. The most digestible crop fractions were green leaf, inflorescence and immature ‘stem’. D‐value of ‘stem’ declined by about 20 units from week 1 to week 14, while D‐value of green and dead leaf declined at about half this rate and there was little or no decline in D‐value of inflorescence. The N content of green leaf was consistently higher than that of the other fractions. The N content of ‘stem’declined markedly to around 0.5% by week 12. The N content of dead leaf and inflorescence was intermediate between that of green leaf and mature ‘stem’. The N content of all fractions was increased by applying more N. The tiller population increased during the flrst 3 weeks of regrowth and declined during the next 4. Applying more N increased both tiller population and weight per tiller.
Removal of mineral nutrients by red clover varieties
Authors: HUNT I. V. , FRAME J. , HARKESS R. D.
Published: April 2006

K, P, Ca and Mg contents and uptakes are reported from total herbage of plots sown with six varieties of red clover harvested three times a year for 3 years.

K, P and Mg contents were above those reported as critical for growth; values for Ca were lower than quoted ranges which suggested that growth might have been affected by either deficiency of Ca or low pH. Hungaropoly was characterized by relatively low K and P and high Ca contents. Maximum uptakes in red clover total herbages over 3 years were 1198 kg ha−1 K (Hera), 112 kg ha−1 P (Hera), 494 kg ha−1 Ca (Hungaropoly) and 104 kg ha−1 Mg (Mars). Results were compared with those found for S101 perennial ryegrass, harvested on a similar system and receiving similar fertilization with uptakes of 759 kg ha−1 K, 100 kg ha−1 P, 200 kg ha−1 Ca and 46 kg ha−1 Mg, by expressing accumulating uptakes and inputs as linear regression equations. The better varieties of red clover, Hera, Hungaropoly, Mars and S123 show rates of DM accumulation similar to S101 perennial ryegrass and similar uptake rates of K and P but higher rates of uptake of Ca and Mg.

The levels of application of K and P used in the experiment seem to be more than adequate but attention to the Ca status may be required to sustain high‐yielding red clover swards.
Digestion in vitro of Italian and perennial ryegrasses, red clover, white clover and lucerne
Authors: WILMAN D. , KOOCHEKI A. , LWOGA A. B. , SAMAAN S. F.
Published: April 2006

Herbage at various stages of growth from three field experiments, one with Italian ryegrass, one with perennial ryegrass and one with white clover, red clover and lucerne, was incubated for 0, 24 or 48 h in rumen liquor followed by 48 h in acid‐pepsin.

The proportion of cell content OM in herbage (measured by pepsin) declined with advancing stage of growth more quickly in the legumes than in Italian ryegrass. At a high level of digestibility the legumes had a higher proportion of cell content OM than Italian ryegrass, but the position tended to be reversed at a low level of digestibility.

Decline in proportion of cell content and decline in digestibility of cell wall were both major contributors to the decline in digestibility of Italian ryegrass with advancing maturity, whereas in white clover the decline in proportion of cell content was entirely responsible for the decline in digestibility. Lucerne and red clover occupied intermediate positions.

At an early vegetative stage rate of digestion appeared to be higher in Italian than in perennial ryegrass. Rate of digestion was higher in the legumes than in the ryegrasses, the difference being largest at an advanced stage of growth.
Comparison of two in vitro procedures using rumen liquor‐pepsin or pepsin‐cellulase for prediction of forage digestibility
Authors: TERRY R. A. , MUNDELL D. C. , OSBOURN D. F.
Published: April 2006

Seventy‐three samples of grass and legume herbage of known in vivo digestibility were used to compare an in vitro procedure comprising incubation with pepsin followed by cellulase (Jones and Hayward, 1975) with the Tilley and Terry (1963) procedure using rumen liquor followed by pepsin. The results obtained using the pepsin‐cellulase method proved to be highly repeatable. On the basis of the residual standard deviation of the regression of in vivo dry matter digestibility (DMD) on dry matter digested in vitro (g/100 g DM), the pepsin‐cellulase method was shown to be only slightly less accurate than the rumen liquor‐pepsin method for combinations of both primary growth and regrowth of grasses (r.s.d. ±1.80 and ±1.46 respectively). However, the pepsin‐cellulase method was noticeably less accurate than the rumen liquor‐pepsin method when used on legume herbages (r.s.d. ±3.17 and ±1.91) or on grass and legume herbages combined (r.s.d. ±3.80 and ±1.60). For the rumen liquor‐pepsin method one regression equation predicting DMD having the form, Y= 1.02 X− 0.41, was permissible. For the pepsin‐cellulase method separate regression equations were necessary for grasses (species and growth stages combined) having the form, Y = 0.56 X+ 34.7, and for each legume species. It was concluded that the pepsin cellulase method was of value for grass samples, and, within species, for legumes because of its accuracy and precision and its speed and convenience relative to the rumen liquor‐pepsin procedure; however, for legume species combined, and presumably for grass‐legume mixtures, it was not sufficiently accurate.
The effect of propionic acid on the storage losses of hay
Authors: DAVIES M. H. , WARBOYS I. B.
Published: April 2006

Storage losses in moist hay treated with propionic acid were compared with those occurring in untreated moist hay in two experiments and with field‐cured hay in three experiments. Dry matter losses in treated hays ranged from 41 to 8.6% and from 1.7 to 12.6% in untreated hays. Digestible organic matter losses in both treated and untreated hays were generally greater than dry matter losses. Only in one experiment did propionic acid application significantly reduce nutrient losses in moist hays.

Nutrient losses, and water‐soluble carbohydrate losses in particular, were shown to be correlated with maximum and cumulative bale temperatures during storage in two of the experiments. The rise in hale temperatures during storage was reduced in all three experiments, to a greater or lesser extent, by application of the additive.

Loss of propionic acid from the hay during and after application was very large. In the three experiments 86.2, 85.3 and 85.6% of the acid applied was lost by the end of the storage period. Acid distribution studies indicated that variation in acid concentration within bales was as great as between bales. It was concluded that more research is needed into applicator design and position on the baler and into alternative application methods if the benefits of propionic acid as a moist hay preservative are to be fully exploited.
Further studies on palatability of grasses to horses
Authors: ARCHER MARYTAVY
Published: April 2006

The palatability of twelve grasses to horses was assessed by measuring the height of grass before and after grazing. The grasses were grazed on seven occasions between September 1974 and November 1975 by ponies, Thoroughbreds and hunters. There were significant differences (P < 0.001) between the palatahHity of the grasses, the most palatable being creeping red fescue (Festuea rubra) and tall fescue (Festuea arundinacea). The least palatable grasses were perennial ryegrass(Loliumperenne) and Meadow foxtail (Alopecurus pratensis). There was some evidence that the amount of grass consumed was negatively correlated with the calcium concentration in the herbage.
The effects of variation in sward characteristics upon the ingestive behaviour and herbage intake of calves and lambs under a continuous stocking management
Authors: JAMIESON W. S. , HODGSON J.
Published: April 2006

Groups of calves and lambs grazed on plots of S23 perennial ryegrass, in successive periods of 2, 2 and 3 weeks, at stocking rates which resulted in a slow change in herbage mass on each plot and measurements were made of ingestive behaviour (biting rate, bite size and grazing time) and herbage intake.

As the green herbage mass was progressively reduced from approx. 3000 to 1000 kg OM per ha between periods, biting rate and grazing time increased, but insufficiently to offset the rapid fall in bite size so that herbage intake declined by 24% and 39% for calves and lambs respectively. Patterns of response were similar in calves and lambs, though in all parameters except biting rate the lambs appeared to be more sensitive than the calves to changes in sward conditions and there was no evidence that lambs were better adapted to grazing on short swards than calves.

Intake increased in both calves and lambs up to levels of 2500–3000 kg green OM per ha, though this response may have been attributable in part to the reinforcing effects of increasing herbage mass and diet digestibility. Lambs consistently selected a more digestible diet than calves.

Both calves and lambs increased grazing time substantially in response to limiting sward conditions, in contrast to results in earlier strip‐grazing trials with calves, thus supporting the suggestion that the lack of response under strip‐grazing is a characteristic of the management imposed.
Effects of variation in herbage sodium levels and salt supplementation on the nutritive value of perennial ryegrass for sheep
Authors: MOSELEY G.
Published: April 2006

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.
The effects of nitrogen fertilizer applied in spring on swards of ryegrass sown with four cultivars of white clover
Authors: LAIDLAW A. S.
Published: April 2006

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.
Length of life of grass roots
Authors: TROUGHTON ARTHUR
Published: April 2006

The length of life of the root axes of a plant was taken as the interval between the prevention of the plant from producing any further axes and the death of the shoot. Of the cultivated species studied Lolium perenne had the shortest lived roots and Dactylis glomerata the longest with Phleum pratense, Festuca arundinacea, F. pratensis and F. rubra intermediate. Holcus lanatus and Nardus stricta had long lived roots comparable with Dactylis glomerata. The ranked order of species is in general agreement with the observations reported in the literature.
The effect of ammoniation using urea on the intake and nutritive value of chopped barley straw
Authors: HADJIPANAYIOTOU M.
Published: April 2006

Chopped barley straw was sprayed with a 10% urea solution at the rate of 400 ml kg‐1 straw and stored in sealed containers. Two experiments were conducted with this straw.

In experiment 1 the effect of ensiling periods of 1, 15, 30, 45, 60, 75 and 90 d on the in vitro digestibility, total N and free NH3‐N of straw were examined. In vitro digestibility reached a maximum 45 d post‐treatment and remained constant thereafter; the overall increase in digestibility of treated over untreated straw was 0·21 units. Forty‐four% of the added N was retained in the straw and free NH3‐N accounted for 31% of the total N. In experiment 2 when straw was given alone the voluntary intake and crude fibre (CF) and DM digestibilities of urea‐treated straw were increased by 47, 40 and 26% respectively over the untreated straw. The digestibilities of the diets were similar when either treated or untreated straw formed 20% of the diets. The CF digestibility of the two high‐concentrate diets was similar to that of the untreated straw. Treatment of straw with urea increased the digestible energy value of straw by up to 20%. Feeding urea‐treated straw resulted in a significant increase of ruminal NH3‐N concentration without any change of rumen pH.
Viable grass seeds in herbivore dung from a semi‐arid grassland
Authors: WICKLOW D. T. , ZAK J. C.
Published: April 2006

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.
Nitrogen studies in Lolium perenne grown for seed. IV. Response of amenity types and influence of a growth regulator
Authors: HAMPTON J. G. , CLEMENCE T. G. A. , HEBBLETHWAITE P. D.
Published: April 2006

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.
Use of pesticides to determine relative importance of pest and disease factors limiting establishment of sod‐seeded lucerne
Authors: DOWLING P. M. , LINSCOTT D. L.
Published: April 2006

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.
Silage and milk production: studies with diets containing white clover silage
Authors: CASTLE M. E. , REID D. , WATSON J. N.
Published: April 2006

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.
Variation in the epicuticular wax content of white and red clover leaves
Authors: MOSELEY G.
Published: April 2006

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.
The future of sainfoin in British agriculture: an economic assessment
Authors: DOYLE C. J. , THOMSON D. J. , SHEEHY J. E.
Published: April 2006

In view of the revived interest in sainfoin, an economic assessment of the prospects for an expansion of its area in Britain has been attempted. It is estimated that potentially it could be grown on 950 × 103 ha of the agricultural area of England and Wales, though it is unlikely in the near future that it would exceed 20 × 103 ha, even if economic conditions were favourable. Comparison of the energy and protein yields of sainfoin, red clover and lucerne under conservation management indicates that one of the attractions of sainfoin is its high protein content. However, an assessment of the costs of production and utilization of sainfoin indicate that, for it to be a more widely used legume, sustainable dry matter (DM) yields would need to be increased by 35% to about 11.5 × 103 kg DM ha−1. At the same time, although growing sainfoin as a mixture with grass appears to improve the economic attractiveness of the crop, silage production costs (kg DM)−1 are still about 15% lower on pure grass swards. However, trials in the UK, Canada and Rumania have shown that, compared to current UK levels, sainfoin yields can be significantly increased.
An investigation into the effect of cultures of lactic acid bacteria on fermentation in silage
Authors: WOOLFORD M. K. , SAWCZYC M. K.
Published: April 2006

Twenty‐one strains of lactic acid bacteria were subjected to a range of tests based on established criteria to ascertain their suitability for use as inoculants for silage. The tests included a monitor of their growth in the presence of representatives of the microflora of forage crops with which they might have to compete for substrate, and their ability to effect rapid acidification and achieve a low pH in conditions which simulate low and high ensiling potential. In addition, their ability to produce acid from sugars and their action against organic acids found in forage crops, together with their tolerance of acid, elevated temperatures and conditions of low moisture availability (e.g. in wilted material) and possible proteolytic and amylolytic activities were examined. None or these cultures satisfied all of these criteria. However, three strains (Streptococcus durans str. 1024, Lactobacillus acidophilus, str. 2356 and Lactobacillus plantarum str. 6) had a greater potential than the others.
An investigation into the effect of cultures of lactic acid bacteria on fermentation in silage
Authors: WOOLFORD M. K. , SAWCZYC M. K.
Published: April 2006

Forage‐harvested crops of perennial ryegrass (200 g DM kg−1) and red clover (163 g DM kg−1) were inoculated with cultures of Streptococcus durans str. 1024, Lactobacillus acidophilus sir. 2356 and Lactobacillus plantarum str. 6, and 1:1 mixtures of the Streptococcus and each of the lactobacilli, at rates of 106 and 106 (g fresh weight)−1 and ensiled in laboratory silos for up to 128 d. The possible influence of these bacteria on fermentation was examined in relation to formic acid at rates of application of 0 and 2.3 g(kg fresh weight)−1, None of the cultures or culture mixtures, either at the low or high rate of application, had any notable influence on microbial development, the rate of acidification or promotion of the homolactic fermentation; they tended to exacerbate loss of insoluble nitrogen and deamination. All silages were well‐preserved with no butyric acid being detected, in spite of pH increase during storage. Only formic acid had any consistent and desirable effect on preservation.
Silage and milk production: a comparison between supplements of barley and soybean meal offered with white clover silage
Authors: CASTLE M. E. , REID D. , WATSON J. N.
Published: April 2006

Silage made from Blanca white clover was offered ad libitum to four Friesian cows in a 12‐week changeover experiment. The silage contained 990 g white clover DM (kg DM)−1 with 254 g DM kg−1 and 243 g CP (kg DM)−1 The pH was 3.98 and the in vitro DOMD concentration 680 g kg−1. The silage was the sole feed in the control treatment; in the other three treatments it was supplemented with barley, soybean meal, and a mixture of these feeds supplying 8.1, 2.7 and 7.8 kg DM per cow respectively. The daily intakes of silage DM were 19.3, 13.5, 17.5 and 13.5 kg per cow, and the daily milk yields were 26.3, 28.0, 28.6 and 27.6 kg per cow on the control, barley, soybean and barley plus soybean treatments respectively. It is concluded that the white clover silage had an excellent fermentation and a large potential for milk production.
Quantifying the effect of nitrogen fertilizer applications in spring on white clover content in perennial ryegrass‐white clover swards
Authors: LAIDLAW A. S.
Published: April 2006

Data are presented for the fourth (1979) and fifth (1980) harvest years of a trial in which four levels of N fertilizer (0, 30, 60 and 90 kg N ha−1) were applied each spring to swards with grass (perennial ryegrass cv. Barlenna) and each one of four cultivars of while clover (Blanca, Sabeda, Olwen and S100) or grass alone. Results from the first three years have been published.

Dry matter (DM) harvested dropped from the fourth to fifth years over all swards by 1 −5 to 2 0 t ha−1 but response to N was maintained (17.4 and 24.4 kg DM (kgN)−l in response to 90 kg N ha−1 in 1979 and 1980 respectively) despite reductions in summer yields relative to unfertilized swards. Blanca swards produced significantly less DM harvested than all other cultivars in 1979 and all cultivars in 1980 except for Olwen. Clover DM harvested continued to fall from 1977, the mean for the unfertilized treatment in 1980 being 55% of that in 1979. Up to 1980 Sabeda swards produced more clover DM harvested than Blanca swards. Linear regressions between annual clover content at zero N and at each spring N level for each sward type over 5 harvest years were very highly significant. It is concluded that all cultivars used responded similarly to spring N. Further work to develop a method for predicting the effect of spring N on clover content of given swards is required.
The impact of low numbers of leatherjackets on grass yield
Authors: BLACKSHAW R. P.
Published: April 2006

Experiments were carried out on seven sites in Fermanagh to investigate the yield loss caused by leatherjackets in grassland. Populations on the sites ranged from 65,000 to 865,000 ha−1 and significant damage was recorded from all sites except the least populated. Greater yield increases were obtained by controlling leatherjackets in September when compared with control in March. Regression models were fitted and it was found that 125,000 leatherjackets ha−1 in March caused a yield loss of 50 kg herbage dry matter (DM) ha−1 by mid‐May. Based on these figures the average yield loss to leatherjackets in Northern Ireland, from 1965 to 1982, was 208 kg DM ha−1. Controlling leatherjackets in September, rather than March, increased the potential avoidable yield loss by a factor of 2.72. The average yield loss at first silage cut is therefore 566 kg DM ha−1. On average, 100,000 ha grassland in Northern Ireland may be suffering an annual loss of 1t herbage DM ha−1.
The influence of soil wetness on utilized output from grassland on commercial farms
Authors: MATKIN ELIZABETH A. , PEEL S. , THOMASSON A. J.
Published: April 2006

Records of grassland productivity have been used for 93 farms in 1975–76 (a dry year) and 117 farms in 1977–78 (a wetter year). The samples were selected to contrast well‐drained and poorly/ badly drained farms and were further subdivided into dairy and beef. The number of farms in each of the four subsamples for each year was between 19 and 32. In addition the number of days on which the soil was at meteorological field capacity (field capacity days) on each farm was calculated.

The mean utilized metabolizable energy (UME) output within the dairy sample was 45 GJ ha−1 on both well‐drained and poorly/badly drained farms. Within the beef sample the output was 41 GJ ha−1 on well‐drained farms and 37 GJ ha−1 on the poorly/badly drained farms.

The correlation between fertilizer N and UME output was stronger on well‐drained farms than on the poorly/badly drained farms in the wetter year (r = 0.69 v. 0.16 on dairy farms; r = 0.56 v.− 0.12 on beef farms). In the drier year the converse was found (r=0.15 v. 0.49 on dairy farms; 0.13 v. 0.44 on beef farms). The effect of field capacity days on output was inconsistent; only within the dairy sample in the wetter year did increased wetness appear to reduce output.

It is suggested that soil wetness may have only a small effect on utilized output from grassland on a whole‐farm basis because (i) most farms have at least some well‐drained land, (ii) much of the utilization damage occurs in relatively short periods in spring and autumn and (iii) despite having utilization problems, badly drained land is capable of growing large quantities of grass.
The winter hardiness of Festuca rubra, Holcus lanatus and Agrostis spp. in comparison with Lolium perenne
Authors: JONES P. K. , CHARLES A. H.
Published: April 2006

Preliminary experiments were conducted to assess the winter hardiness of representative cultivars or populations of Festuca rubra, Holcus lanatus and Agrostis spp. in comparison with a hardy (Premo) and a susceptible (Grasslands Ruanui) cultivar of Lolium perenne. Two controlled‐environment tests and a field experiment including two cutting and two fertilizer managements are reported.

Grasslands Ruanui andH lanatus suffered most damage in all tests. In the controlled‐environment experiments, Premo was at least as hardy as the F. rubra and Agrostis cultivars but in the field Premo was more susceptible. Spring growth of Premo was affected more by the cutting and fertilizer managements applied the previous summer and autumn than was spring growth of F. rubra or Agrostis spp.

It was concluded that, whereas use off. F. rubra or Agrostis spp. should not be limited by fears of winter damage, poor winter hardiness may limit the value of H. lanatus for hill and upland reseeding.
Nitrate in silage
Authors: SPOELSTRA S. F.
Published: April 2006

Due to intensive Fertilizer application most silage crops contain appreciable amounts of nitrate. During silage fermentation the nitrate is completely or partially degraded. End‐products are ammonia and nitrous oxide with nitrite and nitric oxide occurring as intermediates. Factors that influence nitrate degradation and the levels of end products and intermediates found in silages are reviewed. The role of plant nitrate reductase and of enterobacteria, Clostridia and lactobacilli in nitrate catabolism and the significance for silage quality are discussed. Attention is paid to silo‐filler's disease, an illness of farm workers that is caused by inhalation of oxides of nitrogen, and to the occurrence of nitrosamines in silages.
Comparative studies of the influence of sward conditions on the ingestive behaviour of cows and sheep
Authors: FORBES T. D. A. , HODGSON J.
Published: April 2006

Separate groups of non‐lactating cows and wether sheep grazed at similar herbage allowances for two successive 5‐d periods on swards that had previously been grazed frequently or infrequently with the intention of creating differences in canopy structure. Measurements were made of sward structure and composition, ingestive behaviour and diet composition. The preliminary treatments had little effect upon either sward conditions or animal behaviour.

Herbage mass was reduced from 4020 kg dry matter (DM) ha−1 to 3290 kg DM ha−1 on average over a 5‐d grazing period as a consequence of the relatively low grazing pressure imposed. This resulted in a mean decline in intake per bite of 28%, and the changes for cattle and sheep did not differ significantly. However, there was a marked difference in the other behavioural responses of the two species; in the sheep biting rate fell and grazing time increased with declining herbage mass, particularly in the sward previously grazed infrequently, whereas the changes in the cattle were small.

Differences in the botanical composition of the herbage eaten by cattle and sheep were minor, but there was a small but consistent advantage to the sheep in the digestibility of the herbage eaten.

In the first of the two periods the variation in surface height after grazing was substantially greater for sheep‐grazed than for cattle‐grazed swards, indicating more patchy grazing by the sheep.

Estimates of daily herbage organic matter (OM) intake calculated from ingestive behaviour variables were high (means 38 and 32 g (kg LW) −1 for cattle and sheep respectively) and usually declined substantially over a grazing period.
The use of a reflectance ratio meter to monitor grass establishment and herbicide damage
Authors: HAGGAR R. J. , ISAAC S. P.
Published: April 2006

A sensor which detects the presence of green vegetation against a brown background was used to monitor the establishment of plots of Lolium perenne and Poa trivialis, either hand weeded or unweeded. The spectral assessments obtained by the meter were very closely related to the proportion of ground cover, assessed photographically, and harvested dry weight of the two species, at least up to 100 days (approx. 50% ground cover) from sowing, Such spectral assessments therefore provide a rapid, non‐destructive method of monitoring changes in green‐leaf biomass of establishing grasses. In a complementary investigation the meter provided accurate and objective assessments of scorch damage to grasses caused by various herbicides.
Slot‐seeding investigations. 4. Effect of phosphate fertilizer and grass suppressant on the establishment and growth of white clover in permanent pasture
Authors: WILLIAMS E. D. , HAYES M. J. , HAGGAR R. J.
Published: April 2006

White clover (cv. Grasslands Huia) was slot‐seeded in April 1982 into plots of permanent pasture of differing botanical composition and reserves of soil phosphate. In one investigation the short‐term effects of placing different amounts of phosphate (P2O5) in different positions in relation to the slot were investigated. In another, emphasis was given to effects of a grass‐suppressing herbicide, propyzamide, on herbage growth and clover contributon during the second year.

Fewer seedlings established on plots with a high initial P status and abundant in Holcus lanatus and Alopecurus pratensis than on plots deficient in P2O5 and dominated by Agrostis capillaris and Festuca rubra. P2O5decreased numbers of establishing clover seedlings when applied in the slots but not when placed beneath them. Growth was increased most when placement was beneath the slot. Application of P2O5to plots previously supplied with it resulted in 7.2 g total above ground and 1.7 g stolon dry weight (m row)−1compared to 1.3 and 0.1 g respectively in plots with low reserves and DO applied P2O5.

Propyzamide greatly increased the yield and the contribution of clover in the presence of high initial P status and applied P2O5. Without propyzamide, clover made only a small contribution until July, averaging 7% for the whole season with little benefit from residual P. Clover growth in late summer was increased from 41 to 292 kg DM ha−1 where P2O5 was applied to P‐deficient plots sprayed with propyzamide in the previous autumn. The large increases in clover contribution following propyzamide application were accompanied by small decreases in total seasonal yield of grass. The proportions of H. lanatus and. F. rubra. were decreased and of A. capillaris, increased.

Spread of clover from the slots was slow during the first year but was encouraged by both P2O5 and propyzamide during the second year. Factors requiring further investigation are discussed.
South‐west England grassland survey 1983. 2. Trends in cropping pattern, reseeding and sward composition 1970–83
Authors: PEEL S. , MATKIN ELIZABETH A. , ELLIS JULIA A. , HOPKINS A.
Published: April 2006

Seventy‐eight farms in south‐west England, originally visited in 1970–72, were revisited in 1983 in order to identify changes in land use and re‐seeding over the c. 12‐year period; changes in sward composition were assessed on fifty‐nine of these farms. The results were also compared with Ministry of Agriculture, Fisheries and Food (MAFF) Census results and MAFF Seeds Branch data.

The proportion of tillage had declined from 29 to 24%. This was in agreement with census results for the south‐western counties, but contrasted with those for England and Wales as a whole, which showed an increase from 38.8 to 41.7% tillage. It is indicative of grass becoming more predominant in south‐west England as east England has become more dominated by tillage cropping.

There had also been a decline in the amount of short‐term grassland. In 1970–72 17% of the grassland was intended to last from 1 to 4 years; in 1983 the proportion was only 10%. That these intentions were being carried out was confirmed by the fact that in 1983 there was more grassland in each of the age categories 5·8,9·20 and over 20 years. The trend towards older grassland confirms that shown by regional and national census data, and the trend away from short‐term swards is in line with deliveries of herbage seed which indicate reduced use of Italian ryegrass (Lolium multiflorum).

Botanical composition had changed appreciably, with the proportion of Lolium perenne having increased in swards of all ages, e.g. from 35 to 51% in swards 5–8 years old and from 17 to 31% in those aged over 20 years. Other sown species, predominantly Dactylis glomerata and Phleum pratense, had declined markedly in swards over 4 years old. The proportions of Agrostis spp., Festuca spp. and Poa trivialis had fallen, but Holcus lanatus had increased slightly. There had been a marked reduction in infestations of perennial broad‐leaved weeds, particularly Ranunculus, but also Rumex and Cirsium spp.
The effect of system of silage harvesting and feeding on milk production
Authors: Gordon F. J.
Published: April 2006

Two silages were produced by harvesting grass either unwilted, using a direct cutting flail forage harvester (flail‐direct), or wilted following precut‐ting and being picked up using a meter‐chop harvester (precision‐wilted). Formic acid was applied at the rates of 2·45 and 2·9 1 t‐1 for the flail‐direct and precision‐wilted silages, respectively. Weather conditions were difficult, both before and during harvesting with a total of 27 mm rainfall falling on the wilted herbage before ensiling.

The in‐silo dry matter losses were 199 and 68 g kg‐1 for the flail‐direct and precision‐wilted silages, respectively. The resulting silages had mean particle lengths of 49 and 24 mm, dry matter contents of 186 and 276 g kg‐‐1 and D‐values of 068 and 062 for the flail‐direct and precision‐wilted silages, respectively.

During a 141‐day feeding period commencing on 19 November, the two silages were offered to 88 British Friesian cows with a mean calving date of 21 January and divided into four groups in a 2×2 factorial design experiment. The silos were divided longitudinally and two groups of cows were self‐fed the silages in situ, one for each silage type, while the other two groups were easy‐fed the same silages along a feed fence.

There were no significant interactions between system of silage harvesting and feeding on any of the measurements of animal performance. Animals on the flail‐direct silage consumed 16% less silage dry matter and produced 10% more milk per cow than those on the precision‐wilted silage treatment. The overall effect was a 12% greater milk output for each unit of grass dry matter ensiled with the flail‐direct than with the precision‐wilted harvesting system.

System of silage feeding did not significantly influence silage intake or milk output, with the mean milk yields during the final 21 days of the study being 234 and 236 kg d‐1 (±0.30) for the self‐ and easy‐feed systems, respectively.

The effects of the treatments on milk composition, liveweight change, body condition score and total ration digestibility are also reported.
Potential seed yield of white clover varieties
Authors: EVANS D. R. , WILLIAMS T. A. , DAVIES W. ELLIS
Published: April 2006

Fifteen varieties of white clover were sown in order to assess the seed yielding ability of new and potential varieties and to examine those plant factors which affect seed yield. Counts were made on number of inflorescences m‐2, proportion of ripe inflorescences and other inflorescence and seed characters. The data were used to compute potential seed yields.

Average potential seed yields were 276 and 76 kg ha‐1 in the first and second year, respectively. The decrease in the second year seed yields underlines the overriding effect of adverse weather conditions during the critical June to August period. The major effect was a reduction in the number of inflorescences produced, the number of florets per inflorescence and seeds per floret.

Some of the new listed varieties have a significantly higher seed potential than SI00, e.g. Menna (+ 38%) and Olwen (+28%), and this should facilitate the production of adequate seed supplies of British bred varieties.
Organic and inorganic fertilization compared in a natural Mediterranean grassland
Authors: LIACOS L. G. , PAPANASTASIS V. P.
Published: April 2006

The effect of goat slurry on species composition and herbage production as compared to inorganic fertilizer was studied in a natural grassland dominated by warm and cool season perennial grasses in Macedonia, Greece. Goat slurry was applied in early spring every 1 or 2 years at a rate of 40 t ha‐1 being equivalent to about 160 kg N ha‐1 and 100 kg, P2O5 ha‐1. Inorganic fertilizer was also broadcast in early spring at a rate of 80 kg N ha‐1 and 100 kg P2O5 ha‐1 every 2 years. Measurements of the basal cover of the dominant species or groups of species and herbage yields were taken for 6 years at the end of the growing period in June, while in the seventh year the experiment was grazed with goats. It was found that goat slurry improved species composition more than the inorganic fertilizer by depressing the less palatable warm season grasses and favouring the subdominant cool season grasses and legumes. Goat slurry significantly increased herbage yields in most of the years. It is suggested that the optimum rate of goat slurry is 40 t ha‐1 every 2 years as this encourages plants most preferred by goats.
Effect of cultivar and seed rate of perennial ryegrass and strategic fertilizer nitrogen on the productivity of grass/white clover swards
Authors: FRAME J. , BOYD A. G
Published: April 2006

Four cultivars of perennial ryegrass (intermediate diploid cv. Talbot and tetraploid cv. Barlatra, and late diploid cv. Parcour and tetraploid cv. Petra) were each sown at 10,20 and 30 kg ha‐1, all with 3 kg ha‐1 of white clover cv. Donna. Herbage productivity was measured over 3 harvest years, 1982–84. under two annual rates of fertilizer N (0 and 150 kg ha‐1); the 150 kg ha‐1 rate was split equally between March and August applications.

Fertilizer N increased total herbage DM production; the 3‐year means for the 0 and 150 kg ha‐1 N rates were 8·04 and 8·91 t ha‐1, respectively. In successive years, total herbage responses to N (kg DM (kg N applied)‐1) were 6·6, 35 and 72 (overall mean, 58). Mean white clover DM production over the 3 years was reduced from 4·48 t ha‐1 at nil N to 2·82 t ha‐1 at the 150 kg ha‐1 rate, a fall of 37%. Grass seed rate did not influence total herbage production or white clover performance. The two intermediate perennial ryegrass cultivars had a marginal advantage in total herbage production over the two late cultivars, but white clover content and production were higher with tetraploids than diploids.

It is concluded that the value of increased herbage production from strategic use of fertilizer N has to be weighed against its depressive effect on white clover performance; application of 75 kg ha ha‐1 N in both spring and autumn was excessively high if maintenance of a good white clover content in the sward is an objective. There is considerable flexibility in the grass: clover seed ratio in seeds mixtures. Modern highly‐productive perennial ryegrass varieties do not differ substantially in compatibility with white clover but tetraploids permit better clover performance than diploids.
Growth of naturally occurring Listeria spp. in silage: a comparative study of laboratory and farm ensiled grass
Authors: FENLON D. R.
Published: April 2006

A laboratory method for ensiling grass in bags, which simulates the aerobic deterioration found in big bale silage, is described. These conditions selectively encouraged the multiplication of naturally occurring listeria. All grasses ensiled in this way gave detectable numbers of listeria, usually L. monocytogenes, indicating that these bacteria are a normal part of the microflora of grass. The results from the laboratory silage were comparable to those found in the same grass ensiled in big bales on the farm.
The estimation of dry green biomass in hayfields from canopy spectroreflectance measurements
Authors: BÉDARD J. , LAPOINTE G.
Published: April 2006

Spectral reflectance measurements were found useful in estimating the dry green biomass (DGB) in hayfields in eastern Québec, Canada. The calibrated measurements of reflectance obtained in the 650 and 800 nm bands (respectively defined as the RED and NIR indices), the NIR/RED ratio, and the ratio (NIR‐RED)/(NIR + RED) were used to generate various regression models which explained between 74 and 90% of the variance in DGB. The proportion of legumes, grasses and herbs in the canopy had no apparent influence on the reflectance measurements or on the value of the models.