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dc.contributor.authorRichards, J. A.en
dc.date.accessioned2018-01-31T11:35:54Z
dc.date.available2018-01-31T11:35:54Z
dc.date.issued1960en
dc.identifier.urihttp://hdl.handle.net/1842/27263
dc.description.abstracten
dc.description.abstractAt the beginning of the present century active interest was being shown in the agronomic characteristics of various herbage plants. The need for establishing uniformity in the seed trade also had its impact on the testing of seed samples , at first for cleanliness as regards weed seeds , and later for yield , habit of growth and , especially , date of flowering. The main improvement sought ( Stapledon , 1957 ) was greater persistence and leafiness , a pasture rather than a hay typo of grass. Work led to the differentiating of three distinct types ( Stapledon , 1933); namely (1) the early , erect , lax , low tillering hay tape , (2) the multi-tillered , more spreading medium -early , relatively dense , intermediate hay pasture type , and (3) the high tillering , late flowering , dense and prostrate growing pasture type. This work came to fruition in the synthesis of herbages of the desired pasture and hay types. Through breeding and selection fcr leafiness and later for seed production , the Aberystwyth bred types have become known in the trade as " S " varieties , all of which have certain features in common. The other types , which have developed over the years primarily on the basis of seed production characters , have become known as " Commercial " varieties.en
dc.description.abstractDifferences in yield of commercial and pedigree herbage as single plants ( Stapledon , 1920 -3 , Green , 1948.51 ) and as swards (Prendergast and Brady , 1955a , Hunt and Thomson , 1955 , Hughes , 1956 ) have been shown under cutting managements , but such differences are commonly not reflected in animal experiments when using such swards. The reasons 2. are many , but at times are due to the fact that sampling methods have failed to mea sure adequately the total herbage on offer to the animal which may well graze below the height of cut ( Raymond. , 1943 , Wliliams , 1949 ) : the animal then consumes more herbage than has been estimated by sampling. Evidence exists ( Roberts , 1931 , 1932 , Roberts and Williams , 1940 ) which indicates differences in yield between commercial and pedigree swards under animal grazing conditions , though not on a closed farm system , where , in practical farming terms , there is no direct application. There exists no literature of a similar comparison elsewhere.en
dc.description.abstractSurveying the present sampling techniques gross insufficiencies and lack of precision have been observed . Using existing techniques a critical attitude was maintained throughout with the hope of finding a way of either improving existing methods or formulating new ones with a view to creating greater statistical and practical precision.en
dc.description.abstractThe comparative simplicity of managing a simple grass or a one grass - one clover sward makes necessary the study of the total herbage production and of animal output from such swards under practical grazing conditions. It also allows a comparison between the yield of commercial and pedigree varieties , sown singly or in such mixtures as advocated by Percival (1923 -4) , Gilchrist (1911) and others. The main problem in complex mixtures is the inability of many species to stand up to competition with other species either through lack of , or delay in , seed germination , or as Davies (1928) showed , because of inter -species competition due to time of starting active growth. Italian ryegrass for instance often dominates the sward early in the season , and consequently suppresses the other constituents.en
dc.description.abstractThe present investigation thus seeks to measure the productivity of 3. commercial and pedigree swards under two different types of management , ( grazing and no- grazing ) to see whether similar differences obtain; under both systems , and whether such yields bear any relationship to the animal returns from them. A new technique , discussed later , is employed in sampling herbage at 3- weekly intervals without the grazing animal , using a Wolseley sheep shear modified for herbage sampling. The technique is varied for sampling under the second management regime . This shear cuts down to ground level and is powered by direct drive from an Allen mower. The total amount of herbage available may be estimated by this technique.en
dc.description.abstractThe investigation concerned was carried out on two existing experiment: at the Grassland Research Institute , Hurley, H138 ( List of Experiments , 1957 ) , H15 ( List of Experiments , 1958 ) , on swards established respectively in 1956 and from 1950 onwards , sown for direct comparison of both commercial and pedigree swards maintained on a closed farm system. Previous comparisons were made only of animal live- weight and wool returns, sheep alone were used on H138 : sheep and cattle were used on H15 either grazing together or singly. The techniques described have been used in measuring herbage differences , and they are checked by intake observations.en
dc.description.abstractA cursory attempt was made to study the root mass under grazed sward conditions to see if there were varietal differences and to what extent clover influenced this. The root mass has been considered in terms of total organic matter accumulated in the top three inches of soil as measured by total carbon.en
dc.description.abstractAn evaluation of varieties that takes all these aspects into account under practical conditions is necessary on scientific and economic grounds , and refined techniques should be used for such evaluations .en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2017 Block 16en
dc.relation.isreferencedbyAlready catalogueden
dc.titleThe productivity of "commercial and pedigree" varieties of grassesen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelen
dc.type.qualificationnamePhD Doctor of Philosophyen


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