摘要:

ABSTRACTSeed crops of perennial ryegrass S321 and tetraploid hybrid ryegrass Sabrina were sprayed with 3 pt diquat in 30 gal. water/ac (4.21 diquat in 337 1 water/ha) a few days before the normal date for harvest. Very low germination values were obtained wben the harvested seed was later tested and the production of abnormal seedlings from the treated crops was attributed to the presence of diquat in the seed. On the basis of these results the use of diquat is not recommended as a pre‐harvest desiccant for ryegrass seed crop

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00744.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTAn experiment using 40 lactating dairy cows was conducted for 3 successive years to examine the effects of fertilizer N applied at 400 and 700 kg/ha (358 and 627 lb/ac) at stocking rates of 4.94 and 7.41 cows/ba (2 and 3 cows/ac). The animals were grazed in groups of 10 per treatment, using a fixed rotational grazing system, for 22 weeks in each year.Milk ontput/cow and/ha was significantly affected by stocking rate, the mean milk outputs being 2499 and 2218 kg/cow (5498 and 4880 lb/ cow) and 12313 and 16396 kg/ha (11032 and 14691 lb/ac) at the lower and higher stocking rates, respectively.Milk yield/cow at the lower stocking rate was not affected by N level. At tbe higher stocking rate, increasing the amount of N resulted in a 7.4% increase in milk output/cow and/ha. This response to N declined from 1.7% in the first year of the trial to 2.4% in the third year. The response in milk yield to N appeared to he greatest during the first part of the grazing season.Milk composition, liveweight change, and herbage availahilities and intakes were also recorded.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00745.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTIn a 16‐week grazing experiment with six spring‐calved Ayrshire cows, drinking water was available to the animals in three different ways, and the effect on milk prodnction was studied. The water was available from a water howl in the cowshed for 2.8 h/day in Treatment A, from a trough in the field for 21.2h/day in Treatment B, and from hoth sources for a total of 24 h/day in Treatment C. The cows on all treatments were grazed in individual plots of intensively‐managed perennial ryegrass, stocked at the rate of 1 cow/0.22 ha (0.54 ac). The mean daily intakes of drinking water were 10.1, 15.3 and 15.5 kg (2.23, 3.37 and 3.42 gal)/cow, and the mean daily milk yields were 17.0, 17.2 and 16.8 kg (37.5, 37.9 and 37.0 lb)/cow in Treatments A, B and C, respectively; milk yields were not significantly different The herbage had an average DM content of 17.3%, and contained 19.6% crude protein and 66.5% digestible organic matter in the DM. The weight of water drunk was significantly and positively related to the DM percentage of the herbage, the air temperature and the daily hours of sunshine, and negatively related to daily rainfall. It is concluded that when dairy cows are grazing leafy herbage of high digestibility as their sole feed, the time during which drinking water is available may safely be restr

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00746.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTA technique using a lead running on a suspended wire, is described which allows small plots, e.g. 0.01 ha (1/40 ac) or less, to he grazed individually at 30% of the cost of conventional fencing. It also offers a means of minimizing the concentration of nutrients in dung on camp areas.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00747.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTTo assess the effect of companion grasses on timothy productivity, swards of timothy sown alone or with one of eight companion grasses were harvested as for silage four times per year for two years. The companion grasses were: diploid perennial ryegrasses S24 and S23; tetraploid perennial ryegrasses Reveille and Taptoe; meadow fescues S215 and S53 and cocksfoots Trifolium and S143. Averaged over the N application rates (226, 339 and 452 kg N/ha per year) the total herhage yields of timothy/companion‐grass mixtures were all significantly superior to that from timothy alone in the first year. Only perennial ryegrass S24 and the cocksfoot mixtures significantly outyielded timothy alone in the second year. Winterkill hecame evident in April of the second year and pure timothy and timothy/meadow‐fescue swards were least affected. Over all swards, timothy DM increased hy a mean of 19% from the first to the second year, compared with a fall of 20% in total herhage DM. The contrihution of timothy herhage to the mixtures was very low with companions other than meadow fescue. Late‐heading varieties were more compatihie than early‐heading varieties, and tetraploid ryegrasses were more compatihie than diploid ryegrasses. It is concluded that if the inherently valuahle characteristics of timothy are to he exploited, it should not he sovm with aggressive companion

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00748.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTAuthorities responsible for the safety of aircraft have for a number of years been very concerned with the dangers and the damage caused by aircraft striking birds while in flight, particular since the introduction of the jet engine. Methods of reducing this risk have been sought, which have brought about the method of grass management described in this paper.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00749.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTThe response of established perennial ryegrass swards to irrigation was compared over 2 years. The swards received 250 (N1) or 500 kg N/ha (N2) and were cut 4 times each year. Water was applied in 5 irrigation treatments according to the potential soil water deficit: the soil was partially, or fully returned to field capacity after cutting; returned to field capacity after cutting and then whenever a 25 mm deficit arose; irrigated with 25 mm water whenever a 25 mm deficit arose independently of cutting; or irrigated at minimum intervals of 14 days, provided that the deficit was then at least 50 mm.There was little effect of irrigation on yield from the first cut in late May. Frequent irrigation gave the greatest increase in total annual yield (3.1 t/ha), hut partial irrigation after cutting was most efficient in use of water and equipment, provided that drought conditions were avoided.High concentrations of N in the herbage were associated with low DM yields, hut more N (percentage N DM yield) was recovered from the irrigated than from the unirrigated swards. More N was recovered than was applied in the N1treatment; less was recovered than was applied in N2. In the N1treatment the nitrate concentration was<500 ppm hut it was 1000–4000 ppm in N2. There was no consistent effect of irrigation on nitrate or K concentratio

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00750.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTArising from the need to improve the palatability of tussocky, rankFestuca rubraswards to provide a greaer area of grazing for overwintering wigeon which avoided these swards, the effect of sheep grazing on these and close‐mownF. rubraswards was studied by a point‐quadrat method. This showed that close mowing improved the palatability ofFestuca rubraswards for sheep to a degree comparable with swards made up ofPuccinellia maritimaandAgrostis stolonifera, for which sheep and wigeon had previonsly been shown to have a significant preference. The results of the study are discussed in relation to methods of managing an area of saltings pastnre made up of these two types of swards to increase the area of grazing available for wigeon; whilst still being compatible with the objectives of the grazier's sheep husban

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00751.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTFaecal samples from a continuous digestibility trial withEragrostis curvulawere analyzed for cell‐wall contents, acid‐detergent fibre, lignin, asb and N. DM digestibility was regressed on all these fractions and organic‐matter digestibility was also regressed on faecal organic‐matter N. The best predictions of digestibility were obtained by the use of faecal lignin as a percentage of acid‐detergent fibre, and by cell‐wall contents. N was a comparatively poor predictor and it is shown that its relationship with organic‐matter digestibility varies with the level of N in the diet. It is concluded that both lignin and cell‐wall contents could serve as useful internal indicators since their use is unlikely to be biassed by metabolic and microbia

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00752.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

ABSTRACTDetailed soil and vegetation analysis at Pant‐y‐dwr Hill Centre illustrated the main physical, chemical and biological factors involved in low output from rough grazing on 5 soil series, ranging from acid brown earth to undifferentiated peat, which are representative of most of upland mid‐Wales. While all the soils, derived from Silurian shale, had low pH and base saturation status and high lime, phosphate and potash requirements, the principal restraint on the productivity of resown grassland, particularly on the wet peaty gleys, was low available N s

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1973.tb00753.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY