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1.
T. A. WATT 《Grass and Forage Science》1987,42(1):43-48
This work examined whether or not Holcus lanatus, cv. Massey Basyn, is an improvement on plants from German Commercial seed of this species and whether either could outyield Lolium perenne cv. Aberystwyth S23. The three grasses were sown in monoculture in a field near Oxford and received a total of either 250 or 500 kg N ha-1 over two years. They were also sown with Tri-folium repens cv. Blanca. The plots were cut 11 times over the 2-year period at a height of 50 mm from ground level.
At the high rate of nitrogen Lolium perenne always gave the highest yields of DM and DOM. In the second year, both types of H. lanatus gave higher yields than L. perenne at the low level of N. The L. perenne and T. repens mixture yielded more than that with H. lanatus and T. repens. H. lanatus depressed the yield of T. repens more than did L. perenne. H. lanatus h lanatus; Massey Basyn was affected less by rust infection than was German Commercial H. lanatus. At the final harvest, plots with r. repens contained more unsown grass than did N-fertilized plots sown to grasses only. 相似文献
At the high rate of nitrogen Lolium perenne always gave the highest yields of DM and DOM. In the second year, both types of H. lanatus gave higher yields than L. perenne at the low level of N. The L. perenne and T. repens mixture yielded more than that with H. lanatus and T. repens. H. lanatus depressed the yield of T. repens more than did L. perenne. H. lanatus h lanatus; Massey Basyn was affected less by rust infection than was German Commercial H. lanatus. At the final harvest, plots with r. repens contained more unsown grass than did N-fertilized plots sown to grasses only. 相似文献
2.
A. H. Charles 《Grass and Forage Science》1969,24(2):111-118
The annual yield of tall fescue was higher than that of Italian ryegrass in the third year after sowing, but the total yield of herbage from grass plus clover swards was similar.
In both the second and third year after sowing, the yield of herbage in the spring grazing was higher when fescue was used as the sown grass. The method of establishment of both tall fescue and Italian ryegrass affected the total and seasonal yield in the second and third year after sowing, but the magnitude of these effects was not nearly as marked as it was earlier in the life of the leys. In the second year after sowing, swards of both Italian ryegrass and tall fescue had a higher yield of total herbage and of white clover, and a lower ingress of unsown species, when established without a cover crop and grazed frequently in the year of sowing.
The inclusion of red clover did not increase total yield of DM in the second and third year after sowing, and it slightly decreased the yield of the tall fescue mixture in the third year following sowing when N was applied. S170 tall fescue was readily grazed by sheep in spring and autumn.
The apparent recovery of applied N varied with the mixture sown, and the management given during establishment. 相似文献
In both the second and third year after sowing, the yield of herbage in the spring grazing was higher when fescue was used as the sown grass. The method of establishment of both tall fescue and Italian ryegrass affected the total and seasonal yield in the second and third year after sowing, but the magnitude of these effects was not nearly as marked as it was earlier in the life of the leys. In the second year after sowing, swards of both Italian ryegrass and tall fescue had a higher yield of total herbage and of white clover, and a lower ingress of unsown species, when established without a cover crop and grazed frequently in the year of sowing.
The inclusion of red clover did not increase total yield of DM in the second and third year after sowing, and it slightly decreased the yield of the tall fescue mixture in the third year following sowing when N was applied. S170 tall fescue was readily grazed by sheep in spring and autumn.
The apparent recovery of applied N varied with the mixture sown, and the management given during establishment. 相似文献
3.
J. FRAME 《Grass and Forage Science》1990,45(1):57-64
Red fescue ( Festuca rubra L.) cvs Reptans, Dawson and Ruby, perennial ryegrass ( Lolium perenne L.) cvs Perma and Sprinter, crested dogstail ( Cynosurus cristatus L.) cv. Southlands, smooth meadow-grass ( Poa pratensis L.) cvs Parade and Arena, Yorkshire fog ( Holcus lanatus L.) commercial types I and II, creeping bent ( Agrostis stolonifera L.) cv. Penncross and rough meadow-grass ( Poa trivialis L.) cvs Omega Øtofte, Dasas and Sabre were each sown with white clover ( Trifolium repens L.) cv. Donna and the productivity of the fourteen mixtures assessed under simulated grazing (six harvests per year) for 3 years. A single fertilizer-N rate (50 kg ha−1 ) in early spring was applied to all treatments each year.
Over the 3 years, mean annual dry matter (DM) production of the swards ranged from 5·25 t ha−1 (creeping bent) to 8·71 t ha−1 (red fescue cv. Reptans), with the species ranking order of: red fescue > perennial ryegrass > crested dogstail > smooth meadow-grass > Yorkshire fog > creeping bent. Rough meadow-grass only persisted over the first harvest year. Mean annual organic matter digestibility (OMD) values of the swards ranged from 0·712 (creeping bent) to 0·782 (ryegrass cv. Sprinter). Mixtures with the lowest proportion of grass (crested dogstail and smooth meadow-grass) generally gave the highest proportions of white clover. The creeping bent mixture had exceptionally low production of both components.
Red fescue, crested dogstail and smooth meadow-grass showed compatibility with clover and, therefore, have potential for use in grass/clover swards. Yorkshire fog had lower compatability with clover. Some breeding effort to improve selected characteristics of promising species, e.g. improvement of low OMD in red fescue, seems warranted. 相似文献
Over the 3 years, mean annual dry matter (DM) production of the swards ranged from 5·25 t ha
Red fescue, crested dogstail and smooth meadow-grass showed compatibility with clover and, therefore, have potential for use in grass/clover swards. Yorkshire fog had lower compatability with clover. Some breeding effort to improve selected characteristics of promising species, e.g. improvement of low OMD in red fescue, seems warranted. 相似文献
4.
The herbage dry matter (DM) harvested, N response and herbage quality of monocultures and mixtures of Holcus lanatus (local ecotype) and Lolium perenne (cv. S24) were compared in a field experiment. The species were seeded in the proportions 100:0, 75:25, 50:50, 25:75 and 0: 100; three rates of N were applied (150, 300 and 450 kg ha−1 ) and five or six cuts were taken in each of four harvest years.
H. lanatus established poorly in the seeding year and in the first full harvest year L. perenne contributed 1, 54, 76, 89 and 99% of the total herbage DM harvested from the five sward types (mean of N treatments). Only a small decline in the L. perenne content of the swards occurred during the experiment.
Total amounts of herbage harvested were significantly lower for H. lanatus monoculture than for the other sward types in three of the four harvest years However, L perenne monoculture yielded significantly more total DM than mixtures with H lanatus in only one of the four harvest years. The five sward types did not differ overall in response to N fertilization. Nitrogen, phosphate and potassium content of the herbage was greatest for H. lanatus monoculture and decreased with increasing proportions of L perenne present in the mixtures.
Thus the presence of a high proportion of H. lanatus in mixture with L. perenne cv. S24 had 相似文献
H. lanatus established poorly in the seeding year and in the first full harvest year L. perenne contributed 1, 54, 76, 89 and 99% of the total herbage DM harvested from the five sward types (mean of N treatments). Only a small decline in the L. perenne content of the swards occurred during the experiment.
Total amounts of herbage harvested were significantly lower for H. lanatus monoculture than for the other sward types in three of the four harvest years However, L perenne monoculture yielded significantly more total DM than mixtures with H lanatus in only one of the four harvest years. The five sward types did not differ overall in response to N fertilization. Nitrogen, phosphate and potassium content of the herbage was greatest for H. lanatus monoculture and decreased with increasing proportions of L perenne present in the mixtures.
Thus the presence of a high proportion of H. lanatus in mixture with L. perenne cv. S24 had 相似文献
5.
Swards of Phalaris aquatica-Trifolium subterraneum were subjected to four defoliation treatments—zero, low (11 sheep ha−1 ) and high (22 sheep ha−1 ) stocking rates, and weekly cutting. At high stocking rate the annual grass Hordeum leporinum dominated while clover was dominant at low and zero stocking rates. Weekly cutting suppressed species other than clover and so failed to simulate grazing.
There were similarities in net herbage production between zero and lightly grazed swards and between heavily grazed and repeatedly cut swards. Net herbage production decreased in the order undisturbed sward < lightly grazed sward < heavily grazed sward < repeatedly cut sward.
When sheep grazed swards where herbage mass was low their daily consumption of herbage, and therefore liveweight change, depended on their recent grazing experience. Sheep accustomed to swards where herbage mass was low ate more because they grazed for much longer each day than unaccustomed sheep, although they selected a diet of similar digestibility. 相似文献
There were similarities in net herbage production between zero and lightly grazed swards and between heavily grazed and repeatedly cut swards. Net herbage production decreased in the order undisturbed sward < lightly grazed sward < heavily grazed sward < repeatedly cut sward.
When sheep grazed swards where herbage mass was low their daily consumption of herbage, and therefore liveweight change, depended on their recent grazing experience. Sheep accustomed to swards where herbage mass was low ate more because they grazed for much longer each day than unaccustomed sheep, although they selected a diet of similar digestibility. 相似文献
6.
J. M. McBRATNEY 《Grass and Forage Science》1984,39(2):167-175
Three diploid—Sabtoron, Violetta and Essex—and three tetraploid—Hungaropoly, Teroba and Red Head—red clover cultivars were sown alone and with each of three companion grasses—timothy (S48), tall fescue (S170) and perennial ryegrass (S24). The productivity and persistence of the red clover cultivars were compared. Results obtained over the first four harvest years were presented in an earlier paper (McBratney, 1981) and this paper presents results from the fifth and sixth (final) harvest years.
The low yield obtained in the fifth and sixth year from Essex under each seeding treatment indicated a deterioration in its persistency or vigour or both. In the fifth year the remaining two diploids, Sabtoron and Violetta, were as highly productive and persistent as the three tetraploids but in the sixth year the decrease in productivity was greater in the diploids than in the tetraploids. In the fifth year Teroba, the highest yielder, produced 9 8 t total DM ha−1 over all seeding treatments of which 73% was clover DM; in the sixth year Teroba was again highest yielding, producing 9.3 t ha−l with 67% clover content. Tall fescue was the most consistent companion grass in the mixed swards, in the sixth year contributing 53% grass DM to the total 8 8 t DM harvested ha−1 .
The trial demonstrates the potential of a number of red clover cultivars grown either pure or with a suitable perennial grass to achieve and maintain a high output of herbage of good quality over a period of 6 years without any application of fertilizer N. The practical agricultural implications of using red clover are discussed. 相似文献
The low yield obtained in the fifth and sixth year from Essex under each seeding treatment indicated a deterioration in its persistency or vigour or both. In the fifth year the remaining two diploids, Sabtoron and Violetta, were as highly productive and persistent as the three tetraploids but in the sixth year the decrease in productivity was greater in the diploids than in the tetraploids. In the fifth year Teroba, the highest yielder, produced 9 8 t total DM ha
The trial demonstrates the potential of a number of red clover cultivars grown either pure or with a suitable perennial grass to achieve and maintain a high output of herbage of good quality over a period of 6 years without any application of fertilizer N. The practical agricultural implications of using red clover are discussed. 相似文献
7.
Two red clover ( Trifolium pratense ) cultivars, Red Head (tetraploid) and Kuhn (diploid), were sown at a seed rate of 13 kg ha−1 either alone or in mixture with Italian ryegrass ( Lolium multiflorum ) cv. RvP sown at seed rates of 10, 15, 20 or 30 kg ha−1 . RvP was also sown alone at a seed rate of 30 kg ha−1 and received nil or 300 kg ha−1 fertilizer a−1 fertilizer N. All plots were established using the barley cultivar Midas sown at a seed rate of 100 kg ha−1 as a nurse crop.
Neither clover cultivar nor ryegrass seed rate significantly influenced either dry matter harvested or botanical composition over the 3 harvest years. On average over all years the grass-clover mixtures produced 75% of the yield of the N-fertilized RvP, 125% of the clover monocultures and 225% of the unfertilized RvP. The red clover contribution to the total dry matter harvested of the mixtures averaged 45–60%. The dry matter concentrations of the mixtures were considerably higher than those of the pure clover stands. In the third year yields were markedly reduced in comparison with those in the first and second years.
It was concluded that Italian ryegrass can be a suitable companion grass for red clover. Its superior yielding capacity over other grasses such as perennial ryegrass or timothy under a conservation management can be coupled to advantage with red clover to give a sward which Is essentially stable, at least over a 2- to 3-year cropping period, although giving slightly reduced yields in the third year. Italian ryegrass-red clover mixtures, without the use of fertilizer N, can produce high DM yields of good quality herbage. 相似文献
Neither clover cultivar nor ryegrass seed rate significantly influenced either dry matter harvested or botanical composition over the 3 harvest years. On average over all years the grass-clover mixtures produced 75% of the yield of the N-fertilized RvP, 125% of the clover monocultures and 225% of the unfertilized RvP. The red clover contribution to the total dry matter harvested of the mixtures averaged 45–60%. The dry matter concentrations of the mixtures were considerably higher than those of the pure clover stands. In the third year yields were markedly reduced in comparison with those in the first and second years.
It was concluded that Italian ryegrass can be a suitable companion grass for red clover. Its superior yielding capacity over other grasses such as perennial ryegrass or timothy under a conservation management can be coupled to advantage with red clover to give a sward which Is essentially stable, at least over a 2- to 3-year cropping period, although giving slightly reduced yields in the third year. Italian ryegrass-red clover mixtures, without the use of fertilizer N, can produce high DM yields of good quality herbage. 相似文献
8.
An experiment was conducted to measure the effects of differrat ryegrass companion grasses and red-clover varieties on the productivity of red-clover swards. Three silage harvests per year were taken over a 2-year period. The addition of a companion grass increased total herbage yields; S24 perennial ryegrass gave the highest herbage yield over the two years, followed by Reveille perennial ryegrass. Because of lack of persistence, Tetila Italian ryegrass yielded poorly the second year. A companion grass had little effect on red-clover yields in the mixed swards but improved percentage digestibility of the OM of the total herbage and lowered the CP percentage. Its presence also reduced the ingress of unsown species. The variety of red clover used had little effect on total herbage yields or red-clover yields in the first harvest year. In the second year, Hungaropoly and Tilo persisted better and so gave higher total herbage yields and red-clover yields than Dorset Marl or Essex. The fall in total herbage yields from the first to the second year was entirely due to a fall in red-clover yield since yields of the ‘non-red clover’ fraction of the total herbage increased. A red-clover/grass sward may have advantages over a pure red-clover sward nutritionally, for silage-making and for its effect in diluting the oestrogenic activity of a pure clover sward. A major reappraisal of the role and potential of red-clover swards in the UK is warranted because of their many valuable attributes, particularly their ability to give high herbage yields of high nutritive value without the addition of fertilizer N. The improved persistency of some of the tetraploid varieties of red clover enhances the value of the plant. 相似文献
9.
JUNE M. McBRATNEY 《Grass and Forage Science》1987,42(2):147-152
Three diploid red clover cultivars—Sabtoron, Violetta and Essex—and three tetraploid, Hungaropoly, Teroba and Red Head, were sown separately in pure culture and with each of three companion grasses: timothy (Aberystwyth S48), tall fescue (Aberystwyth S170) and perennial ryegrass (Aberystwyth S24).
The effects of fertilizer N on yield and on clover/grass ratio over a 2-year period (seventh and eighth harvest years) subsequent to 6 harvest years during which no N fertilizer was applied were investigated. The data for productivity and persistence have already been published (McBratney, 1981; 1984).
Application of fertilizer N increased DM yields in the eighth year. In this year, the highest yield, 11·9t ha-1 , averaged over the six clover cultivars, was given in association with tall fescue. Tall fescue contributed 90% of this yield. Clover content continued to decrease in all swards but the decrease was greatest in the swards receiving fertilizer N. The yield of clover DM averaged over the six cultivars under N treatment declined from 5·6t ha-1 in the seventh year to only 0·4t ha-1 in the eighth year.
The results from this trial demonstrate the potential of red clover sown either pure or in mixture with a suitable perennial grass, to maintain high output of quality herbage over a 6-year period without the aid of fertilizer N. They further demonstrate that following decline in red clover content, both herbage yield and quality may be restored by the application of N fertilizer, particularly where the clover was seeded with a highly productive companion grass. 相似文献
The effects of fertilizer N on yield and on clover/grass ratio over a 2-year period (seventh and eighth harvest years) subsequent to 6 harvest years during which no N fertilizer was applied were investigated. The data for productivity and persistence have already been published (McBratney, 1981; 1984).
Application of fertilizer N increased DM yields in the eighth year. In this year, the highest yield, 11·9t ha
The results from this trial demonstrate the potential of red clover sown either pure or in mixture with a suitable perennial grass, to maintain high output of quality herbage over a 6-year period without the aid of fertilizer N. They further demonstrate that following decline in red clover content, both herbage yield and quality may be restored by the application of N fertilizer, particularly where the clover was seeded with a highly productive companion grass. 相似文献
10.
Diet selection from ryegass-and prairie grass-white clover swards, vertically stratified into three horizons (A > 6 cm, B 3–6 cm, C > 3 cm), was studied using oesophageally fistulated sheep during summer and autumn. Animals grazed for 3-day periods. Apparent herbage intake was calculated from total herbage disappearance. The composition of each horizon and of the diet selected was measured daily.
Herbage mass (DM ha-1 ) and sward height (cm) prior to grazing were not significantly different between swards in each season, and were 2·0 and 20 in summer and 1·6 and 10 in autumn. In summer, 36% and 5% of the green grass leaf (GGL) for prairie grass and ryegrass, respectively, was distributed in horizons A and B. In autumn 39% and 29% of GGL occurred above 3 cm for prairie grass and ryegrass, respectively. GGL distribution determined which sward horizons were grazed. Sheep grazed horizon C (0–3 cm) of summer ryegrass pasture, and the surface canopy (>3 cm) of all other swards.
In summer, apparent intake achieved by sheep grazing prairie grass swards was 87% higher than that achieved on ryegrass swards. In autumn a greater GGL distribution above 3 cm with prairie 相似文献
Herbage mass (DM ha
In summer, apparent intake achieved by sheep grazing prairie grass swards was 87% higher than that achieved on ryegrass swards. In autumn a greater GGL distribution above 3 cm with prairie 相似文献
11.
Replicated plots of Hungaropoly red clover were sown on a sterilized area in May 1975 alone (seed rate 11 kg ha-1 ) or with one of six cultivars of perennial ryegrass (seed rate 3·5 kg ha-1 ) viz. Cropper and S24 (early heading), Barlenna and Hora (medium heading) and Melle and Perma (late heading). In 1976 and 1977 primary growth was cut at one of four dates ranging from mid-May to mid-June and thereafter plots were harvested twice each year.
Varying the time of first cut did not have a significant effect on total dry matter (DM) yield in either year despite differences in means of cutting treatments on annual red clover yields of the order of 6–9%.
In some companion grass treatments total DM yield in 1976 was increased and total red clover yield and percentage red clover contribution were reduced relative to swards sown only with red clover. In 1977 a similar but non-significant trend was found. Swards containing early ryegrasses had higher total herbage DM yields but lower red clover yields and contents than all other swards at the first harvest in both years.
Delay in date of taking the first harvest in 1976 reduced DM digestibility in the first cut and increased it in the second in both years.
It is suggested that by cutting early and increasing the number of harvests from three to four per year, differences in the content of red clover between the first and second cut might be reduced, and it is concluded that more benefit is derived from red clover when medium or late heading ryegrasses are used as companion grasses. 相似文献
Varying the time of first cut did not have a significant effect on total dry matter (DM) yield in either year despite differences in means of cutting treatments on annual red clover yields of the order of 6–9%.
In some companion grass treatments total DM yield in 1976 was increased and total red clover yield and percentage red clover contribution were reduced relative to swards sown only with red clover. In 1977 a similar but non-significant trend was found. Swards containing early ryegrasses had higher total herbage DM yields but lower red clover yields and contents than all other swards at the first harvest in both years.
Delay in date of taking the first harvest in 1976 reduced DM digestibility in the first cut and increased it in the second in both years.
It is suggested that by cutting early and increasing the number of harvests from three to four per year, differences in the content of red clover between the first and second cut might be reduced, and it is concluded that more benefit is derived from red clover when medium or late heading ryegrasses are used as companion grasses. 相似文献
12.
The aim was to study the effects of white clover cultivar and combinations with perennial ryegrass cultivars on seedling establishment in autumn‐sown swards and on winter survival of seedlings. Large‐leaved white clover cv. Alice and small‐leaved white clover cv. Gwenda, and an erect and a prostrate perennial ryegrass cultivar were sown in autumn in pure stands and as four binary grass‐clover mixtures. Mixtures of white clover cv. Huia and Aberherald with perennial ryegrass were also sown. Companion grasses had no significant impact on the establishment of white clover. The number of seedlings of white clover cv. Alice in mixtures (335 m?2) was higher than cv. Gwenda (183 m?2) and pure swards had similar white clover population densities as mixed swards. White clover cv. Huia tended to have more seedlings than Aberherald (355 and 205 m?2 respectively). No stolons were produced prior to a severe winter, because of the late sowing date. Winter survival of clover seedlings was 0·56 in mixtures and 0·69 in pure stands, irrespective of white clover or companion grass cultivar. Stolon development of white clover in autumn is often considered essential for overwintering survival and spring growth. In this study, there was considerable survival of the non‐stoloniferous tap‐rooted seedlings of all four clover cultivars despite a severe winter. 相似文献
13.
Three small plot experiments were conducted to investigate the effects of species of grass and forbs, defoliation regime, inclusion of white clover and forb blend on the herbage dry matter (DM) yield, botanical composition and mineral content of swards managed with zero fertilizer inputs. The results of all three experiments were characterized by decline in herbage production and large variations in treatment effects over the harvest period.
When sown singly with a standard grass mix the species that competed well with grasses and produced annual forb herbage yields greater than 20 t DM ha−1 were black knapweed, oxeye daisy, ribwort plantain, burnet, birdsfoot trefoil, chicory, kidney vetch, red clover and white clover. When sown singly with a standard forb mix, grass species significantly affected the annual yield of total ( P <005). grass ( P <001) and forb ( P <0.001) herbage. The species that most surpressed the yield of forbs were common bent, Yorkshire fog and perennial ryegrass. Those that allowed for the highest yield of forbs were rough meadow grass, sweet vernal grass and crested dogstail. Averaged over the three harvest years, defoliation regime did not significantly affect herbage production, but the inclusion of white clover in mixtures increased the yield of grasses ( P <0.01) The use of rosette-type forb blends increased forb yield ( P <0.01), compared with erect-type blends.
The effects of treatments on herbage N and mineral contents and yields were inconsistent. However, there was some evidence to support the view that the presence of forb species in swards can result in greater contents of minerals in herbage, compared with grass-only swards. 相似文献
When sown singly with a standard grass mix the species that competed well with grasses and produced annual forb herbage yields greater than 20 t DM ha
The effects of treatments on herbage N and mineral contents and yields were inconsistent. However, there was some evidence to support the view that the presence of forb species in swards can result in greater contents of minerals in herbage, compared with grass-only swards. 相似文献
14.
Quantifying the effect of nitrogen fertilizer applications in spring on white clover content in perennial ryegrass-white clover swards 总被引：1，自引：0，他引：1
A. S. LAIDLAW 《Grass and Forage Science》1984,39(4):317-321
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. 相似文献
Dry matter (DM) harvested dropped from the fourth to fifth years over all swards by 1 −5 to 2 0 t ha
15.
Relative sheep production from Aurora (very early flowering), Mellra (late-flowering tetraploid) and Aberystwyth S23 (late flowering) perennial ryegrass ( Lolium perenne L.) varieties was compared during harvest years 4-6 (1988-90) as grass only (200 kg N ha−1 ) and grass/clover (75 kg N ha −1 in 1988, 0 kg N ha−1 in 1989 and 1990) at Bronydd Mawr Research Centre (310-363 m) in mid-Wales. The pastures were continuously stocked with Beulah Speckled Face ewes and their Suffolk cross lambs from spring to mid-July. From late July to early November only the weaned lambs grazed the swards.
Mean (1988-90) total annual lamb production per hectare from Aurora and Meltra was 70% and 16% more than that from S23. However, the difference between both varieties and S23 was much greater as grass/clover (Aberystwyth S184 small-leaved type) than as grass-only swards. Differences between the grasses in individual lamb growth rates were most pronounced during the post-weaning period, when that on Meltra was 38% and 23% more than on Aurora and S23 respectively.
Mean annual lamb output from grass/clover swards was only 70% of that from grass-only swards during the 2 years when the former swards received no fertilizer N. Averaged over the 3 years (1988-90) individual lamb liveweight gain post weaning was 38% higher on grass/clover than on grass-only swards.
The results are discussed in relation to those for the first 3 harvest years (1985-87). It is concluded that, although Aurora was less persistent than both late-flowering varieties, its superiority in providing an average of 29% more lamb output than S23 during the critical spring period (up to early June) would be of considerable practical significance in upland sheep systems, as would be the overall superiority of the tetraploid Meltra over S23. 相似文献
Mean (1988-90) total annual lamb production per hectare from Aurora and Meltra was 70% and 16% more than that from S23. However, the difference between both varieties and S23 was much greater as grass/clover (Aberystwyth S184 small-leaved type) than as grass-only swards. Differences between the grasses in individual lamb growth rates were most pronounced during the post-weaning period, when that on Meltra was 38% and 23% more than on Aurora and S23 respectively.
Mean annual lamb output from grass/clover swards was only 70% of that from grass-only swards during the 2 years when the former swards received no fertilizer N. Averaged over the 3 years (1988-90) individual lamb liveweight gain post weaning was 38% higher on grass/clover than on grass-only swards.
The results are discussed in relation to those for the first 3 harvest years (1985-87). It is concluded that, although Aurora was less persistent than both late-flowering varieties, its superiority in providing an average of 29% more lamb output than S23 during the critical spring period (up to early June) would be of considerable practical significance in upland sheep systems, as would be the overall superiority of the tetraploid Meltra over S23. 相似文献
16.
Botanical analyses were carried out on the herbage from plots of twelve early cultivars of perennial ryegrass (Lolium perenne) cut in their fourth year and the results related to visual persistence assessments carried out on the cultivars at the end of the second and third harvest years. Persistence assessments were found to be highly and positively correlated with the yields of sown cultivars (r=+0.96***,r=+0.99***) and to be highly and negatively correlated with the yields of unsown herbage species (r =+0.98***, r =?094***). The plots of the less persistent cultivars were invaded by unsown grass species and docks which contributed in varying degrees to total DM yield, reducing the correlation of total yield with persistence. Assessments of botanical composition of swards made at the end of the second year provided reliable predictions of the relative persistence of the cultivars. The results of the investigations indicated that assessment of persistence, as well as yield potential, is fundamentally important in cultivar evaluation. 相似文献
17.
A. S. LAIDLAW 《Grass and Forage Science》1981,36(3):227-229
White clover (cv. S184 or Blanca) or marsh trefoil (cv. Grasslands 4703 or Grasslands Maku) were sown alone and in combination with a companion grass (tall fescue, red fescue, perennial ryegrass or ryegrass cleanings) on a peat area of hill land originally dominated by Juncus articulatus and Molinia caerulea.
Lime and ground rock phosphate were applied in 1973, the area rotavated to a shallow depth and seeds sown in May 1974. No fertilizers were applied except at sowing time and two harvests were taken per annum for 4 years.
Differences in yield and legume content between companion grass treatments were small. After the first full harvest year Blanca swards usually had the lowest DM yields and those containing Maku the highest. The contribution of marsh trefoil to total herbage yield increased from 4·2% in 1975 to 22% in 1978, whereas white clover decreased from 4·2 to 1·2%. Legume yields in 1978 were less than half those in 1977. Overall, N yields were low, Maku swards fixing most N estimated to be highest in 1977 at 35 kg ha-1 .
It is concluded that marsh trefoil grows well on upland peat but more information on its response to grazing is necessary before conclusions can be drawn about its value in hill land improvement. 相似文献
Lime and ground rock phosphate were applied in 1973, the area rotavated to a shallow depth and seeds sown in May 1974. No fertilizers were applied except at sowing time and two harvests were taken per annum for 4 years.
Differences in yield and legume content between companion grass treatments were small. After the first full harvest year Blanca swards usually had the lowest DM yields and those containing Maku the highest. The contribution of marsh trefoil to total herbage yield increased from 4·2% in 1975 to 22% in 1978, whereas white clover decreased from 4·2 to 1·2%. Legume yields in 1978 were less than half those in 1977. Overall, N yields were low, Maku swards fixing most N estimated to be highest in 1977 at 35 kg ha
It is concluded that marsh trefoil grows well on upland peat but more information on its response to grazing is necessary before conclusions can be drawn about its value in hill land improvement. 相似文献
18.
The productivity of four forage legumes sown alone and with each of five companion grasses 总被引：1，自引：0，他引：1
Four legumes—white clover cv. Blanca, red clover cvs Violetta (diploid) and Hungaropoly (tetraploid) and lucerne cv. Europe—were established as pure-sown swards and with each of five companion grasses: timothy cv. Timo, meadow fescue cv. Bundy, sweet brome cv. Deborah and perennial ryegrass cvs Talbot (diploid) and Barlatra (tetraploid), both ryegrasses being of 'intermediate' heading date. Two 'silage' crops and an 'aftermath grazing' crop were harvested in each of three successive years.
In the first harvest year, total herbage DM production of red clover ranged from 15·03 to 17·01 t ha-1 . White clover and lucerne swards produced considerably less at 7·12 to 11·01 t ha-1 . In the second harvest year, lucerne swards were the highest producing at 15·54 to 17·14 t ha-1 , while DM production from red clover and white clover swards ranged from 6·75 to 11·87 t ha-1 . Lucerne swards maintained their production superiority in the third year at 16·48 to 17·87 t ha-1 , while production from white clover swards ranged from 6·41 to 10·23 t ha-1 . However, red clover swards declined to 3·30 to 5·81 t ha -1 ; this above-average decline was mainly caused by the onset of red clover necrotic mosaic virus which affected all red clover plots uniformly in the second harvest year, and by winter conditions before the third harvest year. Total herbage DOM and CP yields of the swards were influenced in a similar manner to DM production. 相似文献
In the first harvest year, total herbage DM production of red clover ranged from 15·03 to 17·01 t ha
19.
E. L. JONES 《Grass and Forage Science》1983,38(2):79-87
The effect of two heights of cutting (5 and 8 cm) on the dry matter harvested and persistency of a range of different grass species and varieties were monitored over a 3-year period (1976 to 1978). Dry matter harvested was measured in the second and third harvest year and persistence of sown grass was assessed at the end of the first and third harvest year. The grasses were managed under a frequent cutting system, i.e. simulated grazing. Results showed that at the low cutting height tetraploid hybrid ryegrasses and diploid Italian ryegrasses in the third harvest year gave lower annual dry matter harvests of sown grass and were less persistent than at the high cutting height, whilst, in contrast, perennial ryegrasses gave higher annual harvests of sown grass but persistency was unaffected. In general at the low cutting height varieties of cocksfoot, meadow fescue and tall fescue gave comparatively higher annual harvests of sown grass in the second harvest year but lower yields of sown grass in the third harvest year. A notable exception was Cambria cocksfoot which in the second harvest year gave higher yields of sown grass and was more persistent at the low cutting height.
However, at 5 cm cutting height, the proportions of weed grasses (mainly Poa spp.) in swards sown to tetraploid hybrid ryegrasses and diploid Italian ryegrasses were generally greater, particularly in mid-season. 相似文献
However, at 5 cm cutting height, the proportions of weed grasses (mainly Poa spp.) in swards sown to tetraploid hybrid ryegrasses and diploid Italian ryegrasses were generally greater, particularly in mid-season. 相似文献
20.
The productivity of permanent swards of mixed species composition was compared with that of sown Lolium perenne , cv. Melle at five fertilizer-N rates (0, 150, 300, 450 and 900 kg N ha−1 ) and with L. perenne/Trifolium repens , cv. Grasslands Huia at 0 kg N ha−1 . The investigation was conducted under two cutting frequencies at sixteen sites in England and Wales, representing a range of grassland environments.
Annual total herbage dry matter (DM) production from both permanent and reseeded swards increased with successive increments of fertilizer-N up to 450 kg N ha−1 . Herbage DM production from reseeded swards in the first year after sowing was signficantly higher than from the permanent swards, at all fertilizer-N treatments. In subsequent years the production advantage of the L. perenne reseeds was maintained only at the higher N rates, though sown L. perenne/T. repens was the most productive sward type at 0 N. Average differences in modified acid-detergent fibre suggested small advantages in herbage quality to the reseeded swards.
It is concluded that, while reseeded swards are more productive in the year after sowing, many permanent swards are capable of high levels of production and that reseeding to a L. perenne sward cannot always be justified, particularly for grassland receiving low or moderate inputs of fertilizer-N. 相似文献
Annual total herbage dry matter (DM) production from both permanent and reseeded swards increased with successive increments of fertilizer-N up to 450 kg N ha
It is concluded that, while reseeded swards are more productive in the year after sowing, many permanent swards are capable of high levels of production and that reseeding to a L. perenne sward cannot always be justified, particularly for grassland receiving low or moderate inputs of fertilizer-N. 相似文献