摘要:

The leaf‐area indices (LAI) of simulated swards of three populations ofFestuca arundinaceaSchreb. were estimated by use of an inclined point quadrat and an air‐flow planimeter.Both for comparisons of leaf areas before defoliation, and for comparisons of leaf areas removed by defoliation, very highly significant relationships were found between estimates by the two methods. In five out of six cases the airflow‐planimeter estimates of leaf area became greater than those from the inclined point quadrat as sward leaf area increased.It is suggested that the major factor responsible for departure from complete agreement between the methods is a difference in leaf areas actually measured by the two methods; in addition, there was some indication of operator error with the inclined point quadrat. The results indicated that these factors were not greatly influenced by leaf canopy arrang

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00585.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

In each of a series of sub‐divided containers, two plants of cocksfoot (Dactylis glomerata) were planted in one of four arrangements to study the effects of: (a) no competition; (b) aerial competition, considered to be competition for light; (c) edaphic competition, considered to be competition for nitrogen; (d) full (aerial plus edaphic) competition, for light and N.The weight of seed produced per plant was reduced by aerial compeition, but not by edaphic competition, except where aerial competition also existed. With the exception of the seed, the weights of the components of the plants at harvest were reduced substantially by edaphic competition.The concentration of N in the various parts of the plant varied considerably, but only in the culms was it significantly affected by treatment so that the uptake of N was approximately proportional to the weight of the plant. Edaphic competiton gave most tillers per plant and full competition least. Aerial competition decreased the number of ears per plan

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00586.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Previous work has shown that on deep peat the root systems of sown grasses are shallow. In order to study the effect of cultivation on root development, an experiment was laid down in an area of deep peat where sown grass swards were established on plots which had been subjected to different cultivation treatments. Root development is shown to be affected by depth of cultivation and this is discussed in relation to surface sowing of peatland areas.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00587.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

In order to study the interaction between burning and grazing on heather areas, an experiment was set up in which six paddocks were subjected to different systems of controlled grazing. One quarter of each paddock was burned at two‐yearly intervals. The effects of burning and grazing on the regeneration of the vegetation are described. The chemical composition of heather is known to change with age and season; in this experiment grazing was shown to have an effect also. The amount and earliness of the growth of the current season's shoots of heather were affected by both age of plants and grazing intensity. This result was thought to be related to temperature gradients near the ground. Sheep did not graze the sub‐plots of different age within each paddock evenly; more recently burned sub‐plots were preferred, the preference being most marked with the grazing regimes of lower intensity. At the highest grazing intensity the older and younger sub‐plots were grazed to a similar extent. It is concluded that, in addition to controlled burning, effective management of heather moors must include some measure of grazing

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00588.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

It is suggested that the growth of a grass sward may be affected by heterogeneity of plant height. An initial test of this possibility was made by cutting a stand ofDactylis glomeratain such a way as to produce adjacent areas of tall and short herbage. This pattern was obtained by using three different cutting treatments, two of which gave yields which were greater than predicted from controls. The results are discussed in relation to alternative methods of harvesting grass.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00589.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

A series of trials was carried out in which barn‐dried hay and silage were fed to young fattening cattle with or without supplementary barley. Liveweight‐gains on silage and barn‐dried hay alone were too low to provide an adequate finish during winter feeding. Liveweight‐gains on hay alone were always higher than those obtained on silage alone, the difference being more marked in lighter animals. There was a marked response to supplements of 3 and 4 lb (1.4 and 1.8 kg) of barley, the response being significantly greater in silage‐fed cattle than in those fed on barn‐dried hay. There was some evidence of growth compensation with the introduction of a barley supplement to cattle on silage diets, but there was no such response in those fed on hay. Compensatory growth was not accompanied by improved digestibility or

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00590.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Several perennial grass species commonly found or used in Canada and in the northern areas of the USA were studied. Most of the native species accumulated starch as the principal vegetative storage polysaccharide, indicating their possible tropical origin. All of the temperate‐origin introduced species accumulated fructosans. Species in the Hordeae, Aveneae, and Festuceae tribes, whether native or introduced accumulated fructosans. Species in the Hordeae tribe accumulated only short‐chain fructosans; species in the Aveneae tribe accumulated a series of fructosans predominantly of long‐chain lengths, while both types of fructosan accumulators occurred in the Festuceae

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00591.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

A number of experiments are reported in which comparisons were made, using calves, or ewes and lambs, between Tetila Tetrone and S22 or Danish Italian rye‐grasses or between Reveille and S24 perennial ryegrasses.In general, the differences over the whole growing season were not large, but grazing experiments with calves during 1963‐5 all showed that a substantial advantage in live‐weight gain, can be obtained in the later part of the grazing season (July to September) by using T. Tetrone rather than S22 or Danish Italian ryegr

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00592.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Timothy (Phleum pratense) and cocksfoot (Dactylis glomerata), although indigenous and commonly distributed, found no place in alternate husbandry in Britain until the end of the eighteenth century. Their value was then discovered as an indirect consequence of the search by the London Society of Arts for plants able to grow during the ‘dead season’ of the year. Letters on the subject were addressed by the society to Europe, Asia, North America and to people at home, but with no positive results. There was, however, in the New England provinces of America a developing enthusiasm at that time for timothy and, although not a winter grower, its merits became a matter for correspondence and discussion within the Society. A consequence was the arrival from America early in 1763 of various lots of seeds, but without any information as to sender(s) or the species. Both timothy and cocksfoot must have been received, for each were sown later that year at Walham Green, London, and the optimism and controversy regarding them led ultimately to a recognition of their worth and place in ley farming. The earliest sowing of American timothy in England occurred in 1743, but was without influence on agricultural thinking.Reference is made to the introduction of European species into North America, and also to the Georgical Committee set up in 1664 by the Royal Soci

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00593.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

A study of birdsfoot trefoil (Lotus corniculatusL.) variety trial management was conducted with three variables, variety, stubble height and harvest date. The range in maturity for the three varieties used was 12‐14 days. All plots were harvested thrice per season. The harvest dates for the two management regimes imposed differed by about two weeks for the first cut, by about one week for the second and were identical for the third cut. Stubble heights were two and six inches (5.08 and 15.24 cm).Late‐cut material outyielded that cut early, but suffered more winter damage. Material cut at a stubble height of two inches (5.08 cm) outyielded that cut at six inches (15.24 cm), but it also suffered more winter‐killing. The ranking of varieties varied with management.Alternative management schemes, designed to provide maximum yields and survival consistent with good‐quality forage, are proposed and di

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1968.tb00594.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY