共查询到20条相似文献，搜索用时 203 毫秒
1.
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
2.
Productivity of red clover grown alone and with companion grasses over a four-year period 总被引：1，自引：0，他引：1
J. M. McBRATNEY 《Grass and Forage Science》1981,36(4):267-279
Six red clover cultivars, three diploid—Essex, Sabtoron and Violetta—and three tetraploid— Teroba, Red Head and Hungaropoly—were sown alone and with each of three companion grasses—timothy (S48), tall fescue (S170) and perennial ryegrass (S24). The productivity and persistency of the red clover cultivars were compared over 4 years. Dry matter (DM) yield, DM digestibility and the crude protein (CP) concentration were assessed and botanical analyses conducted on herbage samples from each treatment at each of three harvests per annum. Annual fertilizer application consisted of 165 kg P and 312 kg K ha-1. Comparing clover cultivars alone Essex was significantly less productive and less persistent than the other five cultivars. Yield and persistency of the five other cultivars did not differ markedly within years with the exception that the diploids were significantly less productive than the tetraploids in the fourth year. Over all 4 years mean annual total DM and clover DM yields of the five cultivars were between 12·2 and 13·2 t ha-1 and between 9·2 (79·2% of total DM yield) and 10·2 (83·2%) t ha-1 respectively, and differences were not significant. Up to the end of the third year there was little or no advantage gained by the inclusion of a companion grass, annual total DM yields being between 11·2 and 14·2 t ha-1 for clover alone and between 10·2 and 14·2 t ha-1 for clover-grass mixtures. In the fourth year there was an overall tendency for the yield of the clover alone to be lower, between 7·2 and 12·2 t ha-1, than that of the clover-grass mixture, between 8·2 and 13·2 t ha-1, and this was more pronounced with the diploid than with the tetraploid clover cultivars. Sown with companion grasses, Essex and Hungaropoly were lower in yield and in contribution than the other cultivars over the 4 years. The influence of the companion grass on total dry matter yield showed that the contribution of timothy was low relative to that made by tall fescue and perennial ryegrass. Perennial ryegrass made the most varied contribution from year to year. Tall fescue was the most consistent contributor with all clover cultivars and at the end of 4 years both yield and clover-grass balance had not changed materially. No pronounced differences in DM digestibility were evident between treatments. Crude protein concentration of the pure clover was similar to that of the clover-timothy treatments and both would appear to be superior to either the clover-perennial ryegrass or clover-tall fescue mixtures. It is considered that red clover dominant swards are suitable for use under a cutting regime and can provide high yields of DM at a low cost for up to 4 years. Such swards are self-sufficient in N and in addition soil N accumulation can be exploited in the production of succeeding crops. 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.
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
5.
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
6.
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
7.
The dry matter (DM) yield and herbage quality of swards of sainfoin ( Onobrychis viciifolia ), meadow fescue ( Festuca pratensis ,) and tetraploid perennial ryegrass ( Lolium perenne ) grown in monocultures and in four sainfoin:grass mixtures (0·33 sainfoin:0·66 meadow fescue, 0·66 sainfoin:0·33 meadow fescue, 0·33 sainfoin:0·66 perennial ryegrass and 0·66 sainfoin:0·33 perennial ryegrass), established by direct sowing or undersowing in spring barley, were investigated over 3 years in a field experiment in the UK. Direct sowing produced a mean yield across all species and mixtures of 1·8 t DM ha−1 in the establishment year, whereas undersowing produced no measurable yield except for that of the spring barley. Undersowing reduced the yields of sainfoin and sainfoin-grass mixtures in the first full-harvest year but not in the second. The annual yield of a monoculture of sainfoin was 7·53 t DM ha−1 and that of sainfoin-grass mixtures was 8·33 t DM ha−1 averaged over 3 years. Both sainfoin and the sainfoin-grass mixtures had higher annual DM yields than the grass monocultures. The mixture of 0·66 sainfoin:0·33 meadow fescue gave the highest mean annual yield (9·07 t DM ha−1 ) over the 3 years. There was a higher proportion of sainfoin maintained in mixtures with perennial ryegrass than with meadow fescue. The proportion of sainfoin in sainfoin–meadow fescue mixtures declined from 0·62 in the first year to 0·32 in the third year, whereas the proportion in sainfoin–perennial ryegrass increased from 0·48 in the first year to 0·67 in the second year and remained stable in the third year. 相似文献
8.
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
9.
Red clover cv. Hungaropoly was slot-seeded into a perennial ryegrass-dominant sward in April 1979. Glyphosate and paraquat were applied separately as bandsprays each at two doses and at two band widths. Control plots were either slot-seeded without a herbicide bandspray or received ±150 kg N ha−1 a−1 . Red clover establishment was assessed and amounts of dry matter (DM) and total N accumulated were measured at two harvests in 1979 and three harvests in 1980. Bandspraying increased seedling vigour and development and resulted in the eventual replacement of 1 t grass DM ha−1 by an equivalent amount of red clover. Of the treatment variables investigated, bandspray width had the greatest influence on red clover establishment and productivity. The slot-seeded area, meaned for all treatments, produced a total of 6.40 and 13.16 t DM ha−1 in 1979 and 1980. This was estimated to be equivalent to the all-grass sward receiving 112 kg N ha−1 a−1 during the second year of the experiment or 238 kg N ha−1 over the 2 years when measured in terms of N yield. Slot-seeding overcomes several of the problems associated with conventional establishment of red clover. 相似文献
10.
Small plots of red clover cv. Sabtoron, S123 (diploids) and Hungaropoly (tetraploid) were harvested for seed production at two-week intervals from 19 August to 17 October inclusive in 1981, inflorescence appearance rate, bee density and components of yield having been monitored throughout the summer. Inflorescence appearance rate reached a maximum at the end of July/early August for Hungaropoly and Sabtoron and during mid-August for S123. Bee density followed a similar pattern. Florets and seeds per inflorescence and 1000-seed weight decreased as flowering progressed except during the first three weeks in July. Potential seed yield was calculated from the components of yield for the harvests taken on 3 and 18 September. Losses in seed yield (difference between actual and potential) up to and during harvesting, threshing and cleaning were lower in the tetraploid cultivar (27–39%) than the diploid cultivars (35–l55%). Each cultivar had an optimum harvest time before which yield was affected by immature seeds and beyond which it was adversely affected by shedding of inflorescences and seeds and sprouting of seeds on the inflorescences. The optimum time to harvest Sabtoron was early September, Hungaropoly early to mid-September and the late flowering cultivar S123 mid-September when less than 4% of the inflorescences were still unripe. Seed yield and inflorescences per unit area were lower in the tetraploid cv, Hungaropoly (maximum 542 kg ha−1 ) than diploid cv. Sabtoron and S123 (864 and 897 kg ha−1 respectively) although the tetraptoid had heavier seeds. It is concluded that the optimum time to harvest red clover for seed production is about three or four weeks after the end of the period of rapid inflorescence production and that this coincides with the time when only a small proportion of unripe inflorescences remain. 相似文献
11.
M. S. CAMLIN 《Grass and Forage Science》1981,36(3):169-178
In an experiment of four years duration, the competitive relationships between three cultivars of white clover ( Trifolium repens L.) and ten cultivars of perennial ryegrass ( Lolium perenne L.) were studied under a N fertilizer regime of 200–240 kg ha-1 a-1 . The clover cultivars were selected to embrace the various leaf sizes from medium large to small and the ryegrasses included early, mid-season and late cultivars with a known range of persistence.
During the experiment there was a progressive decline in the contribution of clover, though the different characteristics of each of the clover and ryegrass cultivars produced substantial deviations from the average trend. The clover cultivar Kersey was significantly more aggressive towards the companion grass cultivars than either S100 or S184. It produced consistently greater clover contribution to total yield than the other two cultivars and significantly depressed the yields of some of the companion grass cultivars. There was evidence that compatibility of the ryegrass cultivars with clover was inversely related to persistence; the non-persistent ryegrass cultivars S321 and Presto consistently produced lower grass yields than the more persistent cultivars and consequently permitted greater clover contribution. In the second and third years yield substitution effects between clover and grass components substantially reduced differences in the total grass-clover yield.
The interactions revealed in the experiment showed that both ryegrass and clover cultivars have the potential to influence each other when in association although, with minor exceptions, total annual yields were similar for all grass and clover mixtures at the moderately high level of N applied. 相似文献
During the experiment there was a progressive decline in the contribution of clover, though the different characteristics of each of the clover and ryegrass cultivars produced substantial deviations from the average trend. The clover cultivar Kersey was significantly more aggressive towards the companion grass cultivars than either S100 or S184. It produced consistently greater clover contribution to total yield than the other two cultivars and significantly depressed the yields of some of the companion grass cultivars. There was evidence that compatibility of the ryegrass cultivars with clover was inversely related to persistence; the non-persistent ryegrass cultivars S321 and Presto consistently produced lower grass yields than the more persistent cultivars and consequently permitted greater clover contribution. In the second and third years yield substitution effects between clover and grass components substantially reduced differences in the total grass-clover yield.
The interactions revealed in the experiment showed that both ryegrass and clover cultivars have the potential to influence each other when in association although, with minor exceptions, total annual yields were similar for all grass and clover mixtures at the moderately high level of N applied. 相似文献
12.
Potential pasture production in the uplands of Wales 总被引：1，自引：0，他引：1
Only a very limited number of species, including red fescue (Festuca rubra) , perennial ryegrass ( Lolium perenne) , timothy (Phleum protense) and white clover (Trifolium repens) are considered as suitable for wet hill land. Detailed comparison of red fescue, perennial ryegrass and timothy on contrasting acid brown earth and stagnogley soils from 1966 to 1969 at Pant-y-dŵr Hill Centre (305 m OD) highlighted the advantages of red fescue in annual DM production and its more even distribution over a longer growing season but also indicated drawbacks of slow initial establishment and lower feed quality. In vitro DOMD of red fescue averaged 645 g kg−1 over the year compared with 690 g kg−1 for perennial ryegrass and timothy. Assessment of a narrow range of species under surface seeding conditions on a stagnogley soil from 1971 to 1975 confirmed the value of red fescue in DM production and persistence. The results are discussed in relation to the characteristics required in herbage species for hill land improvement. 相似文献
13.
B. E. Frankow-Lindberg M. Halling M. Höglind† J. Forkman 《Grass and Forage Science》2009,64(3):236-245
Diversity of clovers in grass-clover swards may contribute to greater herbage yields and stability of yield. This possible effect was evaluated in an experiment carried out over three harvest years at two contrasting sites, differing in precipitation and soil composition, using mixed swards containing either one, two or three clover species sown together with timothy ( Phleum pratense L.) and meadow fescue ( Festuca pratensis L.). The clover species were red clover ( Trifolium pratense L.), white clover ( Trifolium repens L.) and alsike clover ( Trifolium hybridum L.) sown in various proportions in a total of ten treatments. All swards were fertilized with nitrogen with amounts that increased from year to year, and three harvests were taken in three consecutive years. There was a significant interaction between site and species mixture on total dry matter (DM) yields (range 27–32 tonnes ha−1 ) and DM yields of clovers (range 5–15 tonnes ha−1 ); red clover as a single species or in a mixture was superior at the dry site while multi-clover species mixtures were superior at the wet site. Alsike clover was the least productive species of clover. Stability of yield of clovers was generally higher by including white and red clover in the seed mixture but total DM yield was not. 相似文献
14.
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
15.
Yields of grass were measured on three dairy farms in 1981. Farm 1, on free-draining loamy soil over chalk, produced 10.3 t DM ha−1 using 336 kg N ha−1 . Farm 2, on poorly-drained loam over Oxford clay, produced 12.8 t DM ha−1 using 354 kg N ha−1 . Farm 3, on loam over clay with some free-draining sandy loam, produced 9.5 t DM ha−1 with 169 kg N ha−1 . Allowing for differences in soil nitrogen and summer rainfall these yields were quite close to expectations from experimental results, despite considerable poaching damage to some swards.
Animal production records were kept and all livestock were weighed every 6 months, so as to calculate the utilized metabolizable energy (UME) output from grassland on each farm. These were 73, 62 and 59 GJ ha−1 on farms 1, 2 and 3 respectively.
The UME output, expressed as a proportion of the yield of grass (converted to ME), was taken as the 'efficiency of utilization' of grass. This was 70% on farm 1,44% on farm 2 and 58% on farm 3. Results are presented separately for the summer and winter 6 months. Utilization by grazing appeared to be markedly reduced under very wet soil conditions. Major losses occurred in the conservation of grass.
The results begin to establish a valuable base of data from commercial farms. 相似文献
Animal production records were kept and all livestock were weighed every 6 months, so as to calculate the utilized metabolizable energy (UME) output from grassland on each farm. These were 73, 62 and 59 GJ ha
The UME output, expressed as a proportion of the yield of grass (converted to ME), was taken as the 'efficiency of utilization' of grass. This was 70% on farm 1,44% on farm 2 and 58% on farm 3. Results are presented separately for the summer and winter 6 months. Utilization by grazing appeared to be markedly reduced under very wet soil conditions. Major losses occurred in the conservation of grass.
The results begin to establish a valuable base of data from commercial farms. 相似文献
16.
A. S. LAIDLAW 《Grass and Forage Science》1988,43(3):347-350
The annual contribution of clover to a mixed sward for 5 years was compared for a range of cultivars, viz. S1OO, Sabeda, Blanca and Olwen, in order of increasing leaf size. The contribution referred to as'clover-derived nitrogen N', was measured as the difference between N harvested in mixed swards and that in similarly treated swards devoid of clover. The swards were harvested four or five times each year and received N fertilizer, annually, at 0, 30, 60 or 90 kg N ha−1 in March.
Blanca swards had the highest clover-derived N yield in the second year and lowest in the fourth year. By the fifth year Sabeda and S100 (medium leaved cultivars) were contributing more N than the other two cultivars. When related to the amount of clover harvested, S100 had the highest value in the second year and S100 and Sabeda in the third year. Relating the total lover-derived N harvested over the 5 years to the amount of clover harvested, S100 had an efficiency of contribution of 54-3 kg N t−1 dry matter (DM) compared to a mean of 49 0 kg N t−1 clover DM for the other three cultivars. Nitrogen fertilizer reduced the contribution of clover N in the first 3 years owing to a reduction in clover yield, but it did not affect clover's efficiency to contribute N.
It is concluded that although the smallest leaved type of the four (S100) made the most efficient N contribution to the sward more information is required to relate morphology of clover to its capability to contribute N directly or indirectly to the sward. 相似文献
Blanca swards had the highest clover-derived N yield in the second year and lowest in the fourth year. By the fifth year Sabeda and S100 (medium leaved cultivars) were contributing more N than the other two cultivars. When related to the amount of clover harvested, S100 had the highest value in the second year and S100 and Sabeda in the third year. Relating the total lover-derived N harvested over the 5 years to the amount of clover harvested, S100 had an efficiency of contribution of 54-3 kg N t
It is concluded that although the smallest leaved type of the four (S100) made the most efficient N contribution to the sward more information is required to relate morphology of clover to its capability to contribute N directly or indirectly to the sward. 相似文献
17.
J. FRAME 《Grass and Forage Science》1989,44(3):267-276
The productivity of fourteen grasses was measured under a silage cutting regime of four harvests per year for 3 years (1984-86) with an annual fertilizer N rate of 360 kg ha−1 , applied at 120, 100, 80 and 60 kg ha−1 for successive harvests. The grasses were: red fescue (Festuca rubra) cvs Reptans, Dawson and Ruby, perennial ryegrass (Lolium perenne) cvs Perma and Sprinter, Yorkshire Fog (Holcus lanatus) commercial types I and II, smooth meadow-grass (Poa pratensis) cvs Parade and Arena, creeping bentgrass {Agrostis stolonifera) cv. Penncross, crested dogstail {Cynosurus cristatus) cv. Southlands and rough meadow-grass (Poa trivialis) cvs Dasas, Omega Øtofte and Sabre.
Red fescue gave the highest dry-matter (DM) production over the 3 years but because of low organic matter digestibility (OMD), its production of digestible organic matter (DOM) was lower than that of perennial ryegrass. Rough meadow-grass was relatively low yielding in the first year and did not persist thereafter. Three-year mean DM production ranged from 9-22 kg ha"'(crested dogstail) to 14-37 kg ha-1 (red fescue cv. Reptans), while mean annual OMD values ranged from 0-660 (smooth meadow grass cv. Arena) to 0766 (ryegrass cv. Sprinter). The mineral composition (P, K, Ca and Mg) differed among species; creeping bentgrass, crested dogstail, perennial ryegrass and Yorkshire fog had moderate to high mineral concentrations while smooth meadow-grass had low concentrations. Mean two-year (1985-86) mineral composition (g kgDM−1 ) ranged from 3-1 to 40 (P), 234 to 31-0 (K), 3-8 to 6-0 (Ca) and 1-6 to 2-6 (Mg),
It was concluded that while red fescue and Yorkshire fog showed considerable potential for silage DM production, there is scope for breeding red fescue cultivars with improved digestibility and more winterhardy Yorkshire fog; characterization of their ensiling qualities would also be useful. 相似文献
Red fescue gave the highest dry-matter (DM) production over the 3 years but because of low organic matter digestibility (OMD), its production of digestible organic matter (DOM) was lower than that of perennial ryegrass. Rough meadow-grass was relatively low yielding in the first year and did not persist thereafter. Three-year mean DM production ranged from 9-22 kg ha"'(crested dogstail) to 14-37 kg ha-1 (red fescue cv. Reptans), while mean annual OMD values ranged from 0-660 (smooth meadow grass cv. Arena) to 0766 (ryegrass cv. Sprinter). The mineral composition (P, K, Ca and Mg) differed among species; creeping bentgrass, crested dogstail, perennial ryegrass and Yorkshire fog had moderate to high mineral concentrations while smooth meadow-grass had low concentrations. Mean two-year (1985-86) mineral composition (g kgDM
It was concluded that while red fescue and Yorkshire fog showed considerable potential for silage DM production, there is scope for breeding red fescue cultivars with improved digestibility and more winterhardy Yorkshire fog; characterization of their ensiling qualities would also be useful. 相似文献
18.
Tetraploid red clover (cv. Hungaropoly) was sown at seed rates of 6,12 or 18 kg ha?1 alone and in mixture with timothy (cv. Scots) at 2, 4 or 6 kg ha?1 or with tall fescue (cv. S170) at 6,12 or 18 kg ha?1. Two ‘silage’ crops and an ‘aftermath grazing’ crop were harvested in 2 successive years. In harvest years 1 and 2, total herbage production levels of 11.12 and 7.47 t dry matter (DM) ha?1 respectively were obtained from pure-sown red clover compared with 11.84 and 8.78 t DM ha?1 for red clover-timothy and 12.23 and 9.64 t DM ha?1 for red clover-tall fescue. Corresponding red clover production levels were 10.93 and 5.30 t DM ha?1 (red clover swards), 8.04 and 3.131 ha?1 (red clover-timothy), and 6.42 and 109 t ha?1 (red clover-tall fescue). Total herbage organic matter digestibility was improved by the timothy companion grass but not consistently by the tall fescue, whereas crude protein (CP) concentration was decreased by the addition of either grass. Increased seed rate intensified these effects, as well as the general effect of the companion grass in depressing red clover DM, digestible organic matter (DOM) and CP production. Total herbage DM, DOM and CP were not markedly affected by increasing red clover seed rate but red clover DM, DOM and CP were increased as red clover seed rate was raised, due to increases in the red clover component. The potential for silage cropping of red clover swards was confirmed but there was advantage in sowing a companion grass. Taking yield and quality parameters into consideration, timothy proved a better companion than tall fescue. A seed rate of 2 or 4 kg ha?1 timothy and 12 kg ha?1 red clover proved the most satisfactory. 相似文献
19.
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
20.
A field experiment with mixed swards of perennial ryegrass and while clover carded out in 1982–83 using small cut plots is described. With perennial ryegrass, lime slightly decreased annual dry matter (DM) production in 1982 (the sowing year) but increased it in 1983 (the first harvest year) by about 1 t ha-1 . Applications of N and P produced small increases in DM in 1982 and greater increases in 1983. In the latter season annual DM production varied from an average of 3·5 to about 10 t ha-1 with 0 or 480 kg N ha-1 applied in three equal-sized dressings throughout the growing season. Application of 40 kg P ha-1 in 1982 increased DM production by about 2·5 t ha-1 in 1983 but higher rates had little effect. Fifteen mg extractable P kg-1 soil seemed sufficient to support levels of production normally expected from ryegrass pastures in upland Scotland, Applications of K did not affect DM production. N increased tiller weight and sward height of ryegrass; lime and P tended to increase tiller weight but this effect was not statistically significant. Leaf appearance and tiller number were not affected by treatments.
The white clover content of the pasture was decreased 10-fold by application of N and increased by lime and P (1·45 and 1·46-fold. respectively). The DM response to P was most apparent in limed soil and was also affected by the siting of the plots in the experimental area. Effects of lime and P on growth of white clover were to increase the number of stolon growing points and root nodule numbers per unit area.
The results emphasize the importance of lime and P fertilizer for establishment and growth of pasture in this soil and the differences between white clover and ryegrass in their responses to these. 相似文献
The white clover content of the pasture was decreased 10-fold by application of N and increased by lime and P (1·45 and 1·46-fold. respectively). The DM response to P was most apparent in limed soil and was also affected by the siting of the plots in the experimental area. Effects of lime and P on growth of white clover were to increase the number of stolon growing points and root nodule numbers per unit area.
The results emphasize the importance of lime and P fertilizer for establishment and growth of pasture in this soil and the differences between white clover and ryegrass in their responses to these. 相似文献