摘要:

AbstractThree white clover cultivars, S184 (small‐leaved), Menna (medium‐leaved) and Olwen (large‐leaved), were broadcast or sown in 15, 30 or 60 cm drills at a seed rate of 3 kg ha‐1. The three cultivars were either sown without a cover‐crop or sown under a cover‐crop of spring barley (cv. Crescent) or peas (cv. Countess). The effects of these methods of establishment on the stolon growth and components of seed yield were subsequently measured.Stolon growth and development was influenced by row spacing, cultivar and season. The overall plant response at all but the widest row spacing (60 cm) was to increase stolon growth such that inflorescence production, the number and proportion of ripe inflorescences and the other seed yield components were unaffected by row spacing. Cultivars differed in their response to row spacing. Cultivar Olwen produced most inflorescences and more ripe inflorescences when broadcast, cv. S184 when sown at 60 cm row spacing and cv. Menna at 15 or 30 cm row spacing. Cultivars also differed in their response to cover‐crop, with cvs Menna and S184 producing more inflorescences and more ripe inflorescences when sown under barley and peas than when pure sown. The inflorescence production of cv. Olwen was not influenced by cover‐crop.The relationship between vegetative and reproductive growth is discussed in relation to establishment, cultivar and climate and the possible implications for the establishment of white clover seed

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01830.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn field experiments conducted over 2 years, triticale was compared with barley, bread wheat and oats for its dual‐purpose (forage and grain) capability.The effect of spring forage removal on grain yield ranged from small yield increases (in the triticale and barley genotypes that otherwise lodged) to a 53% decrease, and was dependent on species, genotype, stage of development when cut, and time for recovery before grain harvest. A key factor influencing grain yield after early cutting was the number of spikes that developed.Thecompletetypes of triticale were better than the onesubstitutedtype tested for dual purpose but, as there is variability among them, selection for good mixed aptitude is possible.The production of the best triticale averaged over 2 years 3 t of forage DM ha‐1(with 684 kg of crude protein ha‐1) and then 4–3 t of grain ha‐1. In this instance, neither the grain yield nor the number of spikes per plant were reduced after clipping, in spite of the fact that the shoot apices were removed.Plant height and lodging were reduced by a forage cut. In triticale, the number of days to heading was increased even more when the cut was late, but no effect was observed

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01831.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractStable hybrids were produced between tetraploid perennial and Italian ryegrasses derived from commercial varieties and germplasm introduced from European collections. Spaced plant characteristics were used to select Fl plants for the production of F2 families which were assessed in small plots for growth and quality traits. Ten of the 19 selected hybrid families were based on perennial ryegrass collected from the Zurich Uplands. The influence of this parental material in improving vegetative growth during early spring, late summer and autumn was demonstrated. Its use in improving feeding value by increasing the water‐soluble carbohydrate content of hybrids was also shown. Consequently, selected hybrid varieties based on this new genetic resource showed considerable improvements in seasonal growth and quality over the older hybrid variety Augusta and Italian ryegrass variety Rv

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01832.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe definitions of the grass growing and grazing seasons as climatic parameters are investigated using a grass growth model. Taking a mean air temperature of 6°C to define the start and end of the growing season at nine UK stations, the model indicates the following: (1) dry matter growth rates at the start are 6 to 9 times greater than those at the end; (2) growth rates at the start of the growing season are higher in those areas where it begins late (i.e. late March/ early April) than in areas where it begins earlier (i.e. late February/ early March). When defining the grazing season in terms of a delay after the start of the growing season, the model indicates that (3) growth rates at the start of the grazing season are higher in upland areas and in areas where the growing season begins late than in lowland areas and in areas where the growing season begins early.A definition of growing season in terms of growth rates shows that 5 and 8°C are more suitable temperatures to define the start and end than 6°C.Grazing season was more adequately described using growth rates than in terms of a delay after the start of the growing seas

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01833.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractExperiments were conducted on a grassland site at Wrest Park, Silsoe, Bedfordshire between 1987 and 1989, to compare herbage yields from slurry applied by deep and shallow injection, low trajectory and conventional vacuum tanker methods. Slurry application rates for all spreaders were calibrated at 86 ± 5 t ha‐1, an equivalent ofc.200 kg NH4+‐N ha‐1applied in autumn or in spring.As expected, herbage yields following spring applications were higher than from autumn applications, with average mineral fertilizer equivalents of 122 and 89 kg N ha‐1respectively. Yields from the conventional and low trajectory spreaders showed no consistent differences. However, in both years, first cut yields from plots were significantly lower (P<0·05) where slurry had been injected than where surface applications had been used by an average of 0·7 t DM ha‐1. Subsequent cuts in 1988 demonstrated higher residual effects from injection so that annual total yields were similar from all slurry applications irrespective of spreader type.Analysis of N content revealed high N levels in herbage from deep injection plots. Mean concentrations of N in the herbage, expressed as a percentage of the dry matter, were 1·43 for surface treatments and 1·79 for deep injection in 1988, and 1·84 for surface treatments, 2·13 for shallow injection and 2·68 for deep

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01834.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effects of two commercial cellulase/hemicellulase enzymes derived fromTrichoderma reeseion silage fermentation were investigated in three laboratory‐scale experiments. In Experiment 1, perennial ryegrass (Lolium perenne) was treated with enzyme A at the rates of 0, 0·125, 0·250, 0·500 and 0·750 cm3kg‐1. In Experiment 2, Italian ryegrass (Lolium multiflorum) was treated with the same enzyme at the rates of 0, 0·250 and 0·500 cm3kg‐1and with 85% formic acid (3·5 cm3kg‐1). In Experiment 3, perennial ryegrass was ensiled untreated, with enzyme A (0·250 and 0·500 cm3kg‐1) and with 0·200 and 0·400 cm3kg‐1enzyme B which also contained glucose oxidase. All silages were well preserved. In general enzyme treatment reduced pH and the contents of ammonia nitrogen, neutral detergent fibre and acid detergent fibre, whereas the contents of water‐soluble carbohydrates, acetic acid, lactic acid an

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01835.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effects of two commercial cellulase/hemicellulase enzymes derived fromTrichoderma reeseion silage fermentation and aerobic stability were investigated in three laboratory‐scale experiments. In Experiment 1, perennial ryegrass (Lolium perenne) was treated with enzyme A at the rates of 0. 0·125, 0·250, 0·500 and 0·750 cm3kg‐1. In Experiment 2, Italian ryegrass (Lolium multiflorum) was treated with the same enzyme at the rates of 0, 0·250 and 0·500 cm3kg‐1and with 85% formic acid (3·5 cm3kg‐1). In Experiment 3, perennial ryegrass was ensiled untreated, with enzyme A (0·250 and 0·500 cm3kg‐1) and with 0·200 and 0·400 cm3kg‐1enzyme B which also contained glucose oxidase. All silages were well preserved. Aerobic deterioration was related to numbers of lactate assimilating yeasts. In Experiment 1, all silages were stable over a 4‐day period. In Experiment 2, enzyme A treatment delayed the temperature rise compared with the untreated control (P<0·05), whereas the formic acid‐treated silage was stable. In Experiment 3, the temperature rise in the silage treated with the higher level of enzyme B occurred one day later than in

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01836.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractPerennial ryegrass, harvested as second‐cut material on 10 and 11 July 1990, was treated with either formic acid at 31 t‐1or an acid‐salt type additive at 61 t‐1and ensiled in roofed 150 t bunker silos. Subsequently both silages underwent a predominantly lactic fermentation. Nevertheless the acid‐salt‐treated silage had a significantly higher quantity of formic acid (19vs12 g kg DM‐1) and significantly lower levels of lactic (98vs118 g kg DM‐1) and acetic acid (11vs17 g kg DM‐1) compared with formic acid‐treated silage. In‐silo losses and effluent production were similar.Each silage was individually fed to 10 October‐calving Friesian dairy cows (average weight 565 kg) from weeks 2 to 15 of lactation, together with 3 kg d‐1of a compound feed containing 190 g kg DM‐1crude protein and with an estimated metabolizable energy content of 12·6 MJ kg DM‐1. The acid‐salt additive had no significant effect on silage DM intake, daily milk yield, milk protein or cow liveweight change, but significantly increased milk butterfat content compared with formic acid‐treated silage.It is concluded that the acid‐salt type additive produced little difference in terms of either silage fermentation or animal performanc

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01837.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effect of applying a commercial inoculum (at 1.5 × 105cfu g‐1) containing Streptococcus faecium (Lacticil M74®. Medipharm, Sweden), and cell wall degrading enzymes (Celluclast® and Viscozyme®, Novo, Denmark) to pea, ryegrass and wheat silages was studied under laboratory conditions. Celluclast was applied at 0.03 Novo Cellulose Units (NCU) and Viscozyme at 0.024 Fungal β‐glucanase (FBG) per g fresh crop. The peas and wheat used were at three stages of maturity, and the ryegrass used was either direct‐cut or wilted. This yielded a wide range of dry matter (DM) and fibre content.Inoculum use improved the ensiling process of most of the forages tested, as indicated by a faster and greater decrease in pH, and by a faster and larger build‐up of lactic acid. Inoculum, however, lowered the aerobic stability of wheat silages. The addition of the enzymes alone did not affect the ensiling process. In silages of peas and wheat at the flowering stage, the combination of inoculum and enzymes resulted in a improvement to the ensiling process, as compared with inoculum only.The combined treatment of inoculum and enzymes resulted in a lower percentage of neutral detergent fibre (NDF) and acid detergent fibre (ADF) in the silages of the flowering peas and of the direct‐cut ryegrass. The NDF and ADF contents in the inoculum plus enzyme‐treated pea silages made at the flowering stage were 322 and 296 g kg‐1, compared with 365 and 327 g kg‐1in the control silages. The NDF and ADF contents in the silages made from the direct‐cut ryegrass were 312 and 205 (treated with inoculum plus enzymes) vs 383 and 257 g kg‐1(control). However, the DM rumen digestibility of the silages was not improved by any of the treatments.It is concluded that a suitable inoculum could be beneficial to the ensiling process. The benefit expected from the application of cell wall degrading enzymes to s

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01838.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA field experiment was conducted to clarify the factors responsible for poor seed set in four white clover (Trifolium repensL.) cultivars. Although the mean number of ovules per floret was 5·18–5·29, the average number of seeds per floret was found to be only 1·23‐1·82. A stainclearing technique was used to examine the cytoplasmic state of the embryo sac in intact, unfertilized, mature ovules and it was found that 28–33% of ovules per carpel were sterile. The abortion rate of fertilized ovules and immature seeds (7 days after pollination) ranged between 32 and 34%. Beyond this period, it was observed that only a very small proportion of the total seeds were lost. The observation of high pollen fertility and a high pollen load strongly suggests that poor pollination does not account for the reduced number of seeds per floret. A ‘nutrient competition’ hypothesis was proposed for high ovule sterility and post‐fertilization abortion of d

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1993.tb01839.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY