摘要:

In a survey in the West of Scotland, utilized‐starch‐equivalent (U. S.E.) outputs from the grassland of 67 farms, mainly dairy farms, and 9 hill‐grazing units associated with them, were assessed by the farm‐recording method. The limitations and possibilities of the method are discussed. The results obtained were above average, but the farms were a selected group. The wide range of U. S.E. outputs from farms of similar type indicates the scope for improvement on farms with low levels of output. The need for more surveys to clarify existing production levels on commercial farms is emp

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00400.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Swards based on a mixture of SI 70 tall fescue and S215 meadow fescue were very early in spring, gave high yields for conservation in mid‐season and, rested from mid‐August, gave good grazing in November‐December. Under this treatment, the tall fescue assumed dominance, and the swards were persistent and remained productive. The digestibility of the tall fescue swards was always higher than that of swards based on cocksfoot with which they were compared. During spring and autumn the former sward was better grazed by stock, but the position was reversed in mid‐summer. Cattle grazing tall‐fescue‐dominant swards made better liveweight gains than those grazing cocksfoot swards during Novemb

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00401.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The viable‐seed content of soils under grass swards was investigated in relation to the potential weed flora which may occur in chemically‐renewed swards. The viable‐seed populations in the top 6 in. of the soils ranged from 46 million per acre for a 1‐year ryegrass ley to 1·7 million in an old permanent pasture. On the limited evidence available, there appears to be no close correlation between the broad‐leaved weed species present in the original pasture, the viable seeds in the soil, or the volunteer species in the new sward. Large populations of viable seeds of indigenous grass species occurred in most swards, while there was an almost complete lack of seeds of cultivated grasses. The effect of surface cultivation following the application of paraquat to a grass sward is to stimulate the dormant weed seeds in the upper layers of the soil to germinate. If these layers were left undisturbed a relatively weed‐free environment would eventually

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00402.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Thermocouples were used to measure temperatures at shallow depths (top 39 mm) in soils during late winter burning of hayed‐off native pasture. Different intensities of burning were investigated. The maximum temperature recorded for any treatment was 75–5°C, at 1 mm below the soil surface, and marked temperature rises were recorded only in the upper 10 mm of the soil. The results suggest that the temperature rise induced by burning would have little direct effect on soil organic matter, the microbial populations, or buried seeds. The possible significance of these results in practice is discu

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00403.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Three experiments examine the effects of giving small supplements of flaked maize to steers on the digestibility and retention of nutrients from rations of grass silage, lucerne hay and fresh lucerne. The digestibility of the dry matter, crude fibre and crude protein of the silage ration was depressed by the successive additions of 1, 2 or 3 Ib flaked maize per day. There was a tendency for the steers to retain more nitrogen as the level of starch supplementation increased, in spite of a lowered crude‐protein digestibility. The digestibilities of the constituents of lucerne hay and fresh lucerne were slightly increased by the addition of 2 and 4 Ib flaked maize per day. The reasons are discussed for the different effect of the supplemental starch on the digestibility of the crude fibre from grass silage and from fresh or cured lucerne. Attention is drawn to the increase in the retention of N following the supplementation of silage with starc

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00404.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The effects of N and K fertilizers on the yield and chemical composition of herbage and the serum Mg and Ca levels of grazing ruminants were investigated, using 64 lactaling ewes in a 4x4 Latin square arrangement of plots. During the 2‐year experiment there was no evidence that application of N alone has a depressing effect on the Mg content of either herbage or blood serum. The sheep grazing plots treated with combined N and K fertilizer had significantly (P<0·01) lower serum Mg levels during the early spring grazing period of 1961. It is suggested that individual variability within a group of animals may considerably influence the results of investigations of this ki

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00405.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Wethers fitted with permanent rumen cannulae were used in a study of the effect of various doses of ammonium salts and E. D.T. A. (ethylene‐diamine‐tetra‐acetic acid, disodium salt) on the pH of rumen digesta and the levels of serum calcium and magnesium. Doses of up to 200 g ammonium acetate had little effect on the pH of rumen contents or on serum Mg levels, but appeared to produce a fall in serum Ca. Ammonium carbonate, however, when given alone or with E. D.T. A., caused a marked increase in the pH of rumen fluid and a temporary fall in the serum Ca level. When given singly, neither ammonium carbonate nor E. D.T. A. significantly affected the levels of serum Mg which were, however, reduced when these compounds were given together, possibly because the increased pH of rumen contents produced by the ammonium carbonate was conducive to chelation of Mg by the E. D.T. A. High levels of ammonia may occur in rumen liquor after the ingestion of young nitrogen‐rich herbage, and it is suggested that chelation of dietary Mg by such compounds as amino acids and peptides, which abound in young herbage, may be a factor concerned in the low ‘availability’ of this

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00406.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Data on the growth rates of ‘worm‐free’ Iambs were collected at different seasons over 4 years. In 1959 and 1960 the Iambs were set‐stocked on a perennial ryegrass/white‐clover sward, and in 1961 and 1962 lambs were rotationally grazed on a pure S23 perennial rye‐grass sward. Although significant differences were obtained between seasons, there was no correlation between lamb growth rate and any one factor of herbage quality or

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00407.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Results from current trials indicate that soil type, time of application and weather influence responses to applications of gulle. Over 3 sites gulle N had an efficiency of about 60% of that of fertilizer N. Best results were obtained from heavy clay soils or those containing much organic matter. Winter applications of dilute gulle to light soils under wet conditions may result in large losses of N through leaching. Generally, winter gulle applications may lead to severe losses of plants in short‐term ryegrasses with associated heavy uptakes of K in spring. It is concluded that much of the gulle produced should be broadcast in winter on to swards destined for mowing in early summer. Optimum utilization of gulle calls for supplementation with fertilizer N, when the full potential of the K derived from the sludge can be exploite

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00408.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The effect of rate of nitrogen fertilizer and clipping frequency on total production of dry matter (DM),in vitrodigestible organic matter (DOM), and crude protein (CP) was investigated in the first harvest year of intermediate wheatgrass. The highest yields of DM and DOM, but not of CP, were obtained at the longest clipping intervals and at the higher rates of fertilizer application. Fertilizer failed to give satisfactory increases in yield even at very high rates of application when a 2‐week clipping interval was used. The interaction between clipping frequency and fertilizer rate had a highly significant effect on yields of both DM and DOM. A sharp decline in percentage DOM that occurred with increasing length between clippings was offset to some degree by application of N fertilizer. A similar assessment of treatments was obtained from DOM and DM yield data when the grass was fertilized with N, but not when N was deficient. The CP data gave a different assessment of treatments from that obtained from either DOM or DM dat

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00409.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY