bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of several ways of measuring soil phosphorus availability
Authors: Hagin J. , Hillinger J. , Olmert A. 
Published: March 2009

Laboratory indices of P availability were compared for six soils. Phosphorus soluble in sodium bicarbonate, ammonium fluoride and citric acid solutions, and in water was determined. Maximum P adsorption capacity was calculated from data by a batch method obtained from equations using the Langmuir isotherm. Adsorbed P values were derived from the same equations. Measurements of P adsorption obtained by leaching soil samples with a phosphate solution yielded asymptotic curves which also allowed the maximum adsorption capacity to be calculated. Results obtained by the two methods were very similar. Leaching of soil samples by water was the basis for calculating maximum P desorption values; these agreed well with the adsorbed P values obtained from the Langmuir isotherm.Phosphorus uptake by plants, determined in a greenhouse experiment, was correlated with the various data and parameters obtained in the laboratory; there were no significant correlations with the P values from extraction methods, but there were good correlations with some of the parameters from the equilibration and leaching experiments.
The effects of magnesium compounds and of fertilizers on the mineral composition of herbage and on the incidence of hypomagnesaemia in dairy cows
Authors: McConaghy S. , McAllister J. S. V. , Todd J. R. , Rankin J. E. F. , Kerr J. 
Published: March 2009

1. An experiment, lasting 3 years, was carried out to investigate the control of hypomagnesaemia on a medium-heavy loam soil in Northern Ireland, using as criteria herbage analysis and analysis of blood sera of grazing dairy cows.2. Applications of calcined magnesite and magnesian limestone as soil treatments raised the magnesium contents of herbage slightly but not to levels judged to be safe. Low blood sorum magnesium levels were recorded for cows grazing this herbage although no cases of tetany occurred.3. Magnesium sulphate, appliedas a spray, temporarily raised the ‘apparent’ magnesium content of the herbage but was easily washed off by rain.4. Finely powdered calcined magnesite applied as a dust to the herbage immediately before grazing appeared to be a promising method of control under Northern Ireland conditions.
Digestibility trials on forages in Trinidad and their use in the prediction of nutritive value
Authors: Butterworth M. H. 
Published: March 2009

Twenty-nine digestibility trials were carried out on various tropical forages and the results obtained were used to investigate possible prediction of nutritive value from chemical composition.1. The digestibility coefficient of crude protein could be predicted from the level of dietary crude protein. This prediction could be slightly improved by the incorporation of crude fibre in the expression. Results were somewhat higher than those reported from temperate areas.2. In order to investigate the above phenomena, a value for metabolic faecal protein was calculated. This was found to be similar to values reported from temperate areas. There was no correlation between faecal crude protein and either level of dietary crude fibre or undigested crude fibre.3. No significant relationships could be obtained to predict total digestible nutrients from either crude fibre or crude protein.4. There was a low (non-significant) negative correlation between the content of dietary crude fibre and the digestibility coefficient of organic matter; comparison of this value with those in the literature suggested that the effect of crude fibre in tropical areas was different to that reported from temperate areas.5. Results obtained were compared with standards of intake and nutrient requirements as recommended by the N.R.C. It was concluded that the factor most frequently limiting was digestible crude protein whilst total digestible nutrients were adequate in the greater part of the samples considered.
Water use by irrigated Arabica coffee in Kenya
Authors: Wallis J. A. N. 
Published: March 2009

The methods proposed by Pereira for unirrigated coffee have been followed in a study of water use by this crop for the 12 years 1950–62. Soil sampling has shown that the procedure provides a reliable measure of evapotranspiration from unirrigated coffee.A modification is proposed which has enabled the rate of water use by irrigated coffee to be followed satisfactorily for the 5 years 1957–62. Occasional soil sampling showed that the modified procedure provided an estimate of the soil moisture status sufficiently reliable and accurate for the regulation of irrigation timing and amount.Irrigation to maintain a favourable soil moisture status has had a marked and beneficial effect on the production of Grade ‘A’ coffee in dry years.The mean daily rate of evapotranspiration from irrigated coffee is estimated to range from 0·15 in. in hot weather to half this rate during the cool and cloudy season.The maximum computed annual totals of supplementary irrigation which were required over a 12-year period ranged from 5·5 in. to 31·5 in. with a mean value of 16·0 in. per year.
The control of bacterial blight in rain-grown cotton I. Breeding for resistance in African Upland varieties
Authors: Arnold M. H. 
Published: March 2009

Projects carried out in the Lake Province of Tanganyika for breeding Upland cotton resistant to bacterial blight are described.A programme in which Albar 51 was used as resistant parent was more successful than one in which an attempt was made to transfer the major gene B6m to breeding stocks.Backcrossing was found to be of limited value as a breeding technique with rain-grown cotton, line breeding in segregating stocks being preferred.It is demonstrated that resistant types can be synthesized by the systematic exploitation of residual genetic variability in locally adapted populations.Correlations between stem, boll andleaf resistance are discussed and some deviations attributable to environmental effects described. It is inferred that there is a basic resistance mechanism in all tissues which is under the same genetic control but that results may be confused by genotype-environment interactions and by other factors operating in particular tissues.The approach to resistance breeding is discussed in relation to the evolution of resistance in African Upland cotton. It is concluded that improvement by straight selection should be given equal emphasis with improvement by hybridization in resistance breeding programmes.
The effect of plant density upon the growth and yield of barley
Authors: Kirby E. J. M. 
Published: March 2009

1. Cereal plant density affects yield and growth parameters of fundamental importance. An experiment is described in which growth and development, and yield and yield components of barley grown over a wide range of density were examined.2. Four varieties of barley—Proctor, Plumage-Archer, Domen, and Moore—were grown at densities approximately equivalent to 35, 70, 140 and 280 lb/acre. Density was found not to affect seedling establishment or plant survival, but there was a variety effect on seedling establishment.3. Varietal differences were seen in maximum tiller number, and the percentage of tillers surviving to form ears. These differences were most marked between the six-row variety and two-row varieties. The effect of increasing density was to increase the maximum tiller number, but this was followed by different rates of tiller death until early June, after which there was no further compensation for tiller number. Ear emergence and ear number were affected both by variety and density.
The incorporation of the resistance ofAegilops ventricosatoCercosporella herpotrichoidesintoTriticum aestivum
Authors: Kimber G. 
Published: March 2009

The introduction of resistance to eyespot (Cercosporella herpotrichoides) fromAegilops ventricosatoTriticum aestivumis described.In the hybrids, amphiploids and in the amphiploid derivatives investigated, the eyespot resistance was apparently simply inherited. Furthermore, this character was controlled by a chromosome, or chromosomes of the D genome ofAe. ventricosaand thus could be introduced intoT. aestivumby recombination.
Tropical grass/legume pastures in Northern Rhodesia
Authors: Smith C. A. 
Published: March 2009

Three grass/legume pastures were evaluated under Northern Rhodesian conditions.A plot trial measured the herbage yields of Stylosanthes gracilis, velvet beans (Stizolobium deeringianum) and giant Rhodes grass (Chloris gayana) grown as pure stands, and in a mixed association with Rhodes grass. The herbage was harvested for 3 years, and the plots were then planted with a maize crop to test any residual effects.After the establishment year, the D.M. yields, and especially the C.P. yields of the legume and grass/legume treatments, were markedly superior to grass alone. The increased yield of the grass/legume mixtures was due to the net gain contributed by legume herbage. There was no evidence of an underground transference of N from the legume to the associated grass.Although there was no measurable treatment effect on soil N and C, the maize following the legume and grass/legume treatments had a higher leaf N level, and approximately double the yield, compared with the maize following the grass-alone treatments.There were no significant differences in cattle weight gains when Rhodes grass alone, Rhodes grass/Stylosanthes, Rhodes grass/velvet beans, and Rhodes grass/pigeon peas (Cajanus cajan) were utilized as hay and foggage in the dry season.Digestibility trials showed mature Rhodes grass hay to be a submaintenance feed, deficient in dietary protein. The addition of Stylosanthes raised the herbage digestible C.P. fourfold. The Rhodes grass/Stylosanthes hay was a maintenance feed.The N yield of the grass/legume mixtures, although low by temperate standards, was 2½ times the N yield of grass alone. The potential value of a tropical grass/legume pasture will depend on the efficiency of the legume to fix N.
Effects of drilling date on the growth and yield of sunflower (Helianthus annum) in the UK
Authors: Dixon F. L. , Lutman P. J. W. 
Published: March 2009

SUMMARYThe growth and yield of five cultivars of sunflower (Frankasol, Cerflor, Sunbred 246, Sokota 2057 and Sigco EX 10), sown from the end of March to the beginning of May, were studied in three experiments at Long Ashton Research Station, UK, during 1986, 1987 and 1988. The time from sowing to emergence and to maturity (as assessed by seed moisture content) was shortened by later drilling, although earlier sown crops were still ready for harvest slightly before the later sown ones. Cultivars differed in speed of development; Frankasol and Cerflor were the slowest to develop and Sigco EX 10 the fastest. Plant heights, head diameters and yields were all affected more by cultivar than by sowing date. The slower maturing cultivars produced the highest yields. Infection levels with Botrytis cinerea seemed to be related to the date of flowering, as early sown and fast developing cultivars became infected earlier. There were few benefits from early sowing and the optimum time appeared to be mid- to late April. Overall, Sunbred 246 was the most successful cultivar in these experiments, combining reasonable yields with moderately early maturity.
Effect of centre of production, maturity and storage treatment of seed tubers on the growth of early potatoes: I. Sprout development in storage
Authors: Goodwin P. B. , Brown A. , Lennard J. H. , Milthorpe F. L. 
Published: March 2009

SUMMARYThe effect of three centres of production, two times of lifting and two post-harvest treatments of apparently virus-free seed tubers on sprout development at planting was studied over two seasons. Sprout length and degree of development were determined mainly by the light and temperature conditions during storage. Under similar storage conditions tubers from the most southern region, lifted early and allowed to sprout from lifting produced longer sprouts than those from the more northerly regions, lifted late and sprouted from midwinter. At planting all tubers had sprouts longer than 2·5 cm. Desprouted tubers from the more southern regions had the highest number of sprouts at planting and tubers 'greened' immediately on lifting had the least.An index of sprout development at planting was defined. The conditions and duration of storage had most influence on the degree of development as measured by this index; sprouts were most developed on tubers sprouted over a long period and on those sprouted in a heated glasshouse. The effects of varying centres of production and times of lifting on sprout development at planting were small compared with those readily produced by varying the storage conditions.
Statistical research on the fate of dietary mineral elements in dry and lactating cows IV. Chloride
Authors: Paquay R. , Lomba F. , Lousse A. , Bienfet V. 
Published: March 2009

SUMMARYStatistical analyses were carried out on the data obtained under very strict conditions in metabolism stalls with 41 different rations fed to 127 adult non-pregnant dry cows, and with 14 other different rations fed to 35 adult non-pregnant lactating cows that had calved 2–6 months earlier and whose daily milk production ranged from 11 to 20 kg.The authors have calculated and studied the correlations between faecal and urinary losses of chloride, chloride excretion with the milk, digestible chloride and chloride balance and many other nutritive factors which were analysed for each of the 55 above mentioned experimental diets.The results show that the digestion and utilization of chloride is not influenced by the amount of ingested chloride at the time of the trial. The digestion is generally very high, negatively correlated with dry matter, energy, and pentosans intakes, and positively with nitrogen and potassium intakes. But the most important factor in the fate of dietary chloride seems to be the necessity for the cow to eliminate most of the time high amounts of potassium in the urines.
Fertility in Scottish Blackface ewes as influenced by nutrition and body condition at mating
Authors: Gunn R. G. , Doney J. M. , Russel A. J. F. 
Published: March 2009

SUMMARYTwo-hundred-and-seventy-three Scottish Blackface ewes in three ages (5, 4 and 2 years) were differentially group fed over 6 weeks in such a manner that at 6 weeks before mating there were approximately equal numbers in each of six subjectively assessed body condition groups ranging from score 1 (lean) to score 3½ (moderately fat). Over the 6 weeks prior to mating these groups were either well fed, fed at about maintenance, or underfed so that at mating the maj ority of ewes were in either condition 1½ or 3.A predetermined random sample of mature ewes from each of the six original condition groups was killed 2–3 days post-mating for ovulation counts. Surviving ewes were fed above maintenance post-mating and the number of lambs recorded at birth. Condition at mating had a significant, positive effect on both ovulation and lambing rates but had no effect on infertility measured as the difference between them.The level of food intake prior to and at mating had no effect on either ovulation or lambing rates of moderately fat ewes (condition 3) but the results can be interpreted as indicating that the level of food intake had a positive effect on both ovulation and lambing rates of lean ewes (condition 1½).
The effect of rate of gain during the growing and finishing periods on the feed efficiency and carcass composition of the pig: I. Rate of gain during the growing period from 18 to 57 kg live weight
Authors: Walker N. , Holme D. W. , Forbes T. J. 
Published: March 2009

SUMMARYTwo experiments were carried out in which pigs were grown at controlled high, moderate or low growth rates from 18 kg to slaughter at 57 kg live weight. Linear measurements and density determinations were carried out on the carcasses. In the second experiment the right-hand side of each carcass was divided into four joints and each joint was physically dissected into three components, bone, subcutaneous fat plus skin and ‘lean’ meat. The boneless tissue of each joint was analysed for moisture, ether extractable fat and nitrogen.It was found that an increase in the rate of live-weight gain tended to improve the efficiency with which feed was converted into live weight.The percentage of fat in the side was significantly increased by more rapid growth rates.The conformation of the side was altered by treatment, the proportion by weight of the middle region increased with increasing rate of live-weight gain and was accompanied by corresponding reductions in the proportions of the gammon and shoulder regions. These changes were largely due to an effect on the distribution of fat throughout the side, but there were also minor changes in the distributions of bone and fat-free lean.The high rate of gain was associated with a greater proportion of belly in the side. This was due to an increase in the proportion of lean meat in this region, presumably a functional effect caused by an increased intestinal volume.There was no treatment effect on the chemical composition of the fat-free boneless meat which was found to differ significantly between joints.
Observations on the onset of the breeding season and on the oestrous cycle of the Welsh Mountain ewe
Authors: Hutchinson J. S. M. , O'Connor P. J. , Robertson H. A. 
Published: March 2009

1.Within a flock of 55 Welsh Mountain ewes maintained under lowland conditions the first ewe
came into oestrus on the 14th October. The mean cycle length of 44 normal cycles was 16 days 3 hr.2. The onset of oestrus as assessed by the time of mounting of the ram does not appear to be
evenly distributed throughout the day (24 hr.).
The estimation of the intake of grazing sheep I. Establishment of faecal nitrogen regressions
Authors: Vercoe J. E. , Pearce G. R. , Tribe D. E. 
Published: March 2009

1. Regression equations for the ratio of organic matter (O.M.) feed intake to O.M. faecal output on faecal N%, and the N% in the O.M. intake on faecal N% were established over a 52-week period by feeding caged Corriedale wethers on pasture cut from a Wimmera rye-grass (Lolium rigidum Gaud.), subterranean clover (Trifolium subterraneum) sward in a Mediterranean-type environment.2. The regression equations and their application to grazing sheep together with the relation between O.M. intake and faecal N, are discussed.
The determination of chromic oxide in faeces samples by atomic absorption spectrophotometry
Authors: Williams C. H. , David D. J. , Iismaa O. 
Published: March 2009

A rapid and accurate atomic absorption method for the determination of chromium in faeces samples from pasture experiments using chromic oxide ‘markers’ is described. Of the elements present after ashing and digesting the samples in a phosphoric acid—manganese sulphate—potassium bromate solution silicate, aluminium, calcium and magnesium were found to interfere in the determination. The effects of these interferences were overcome by the addition of calcium to the test solution and by the addition of silicate to the standards, which were prepared in ‘blank’ solutions.The sensitivities of a number of alternate chromium resonance lines relative to that of Cr 3578·7 Å. are given. These lines may be used to increase the concentration range of the analysis.The results of a comparison of the atomic absorption method with a chemical method are given.
Interpopulational and intervarietal hybridization inLolium perennebreeding: heterosis under non-competitive conditions
Authors: Foster C. A. 
Published: March 2009

SUMMARYThe current status of herbage grass breeding is considered in relation to the utilization of first-generation hybrid vigour. A breeding scheme is outlined by which it is suggested that interpopulationalF1hybrid varieties could be developed to provide a simple and effective means of exploiting heterotic potential in herbage grass species. A survey of interpopulationalF1heterosis expressed, under two levels of fertility in non-competitive spaced-plants conditions, by the hybrids of a group of six adapted perennial ryegrass varieties, is reported here.Although theF1hybrid populations studied were not on average superior to the parental varieties there were large variations between specific hybrids. Two hybrids were particularly promising, exhibiting 25% and 31% heterosis over the higheryielding of their parents for total green-matter yield over two harvest years and two fertility levels. The bulk of this heterosis arose under high-fertility conditions, when the mean yield response of the interpopulationalF1hybrid was twice that of the parental varieties.The effects of inherent relationships between the parental varieties on the observed levels of heterosis are considered, as are the possibilities for the practice of recurrent selection procedures for the enhancement of heterotic expression in some of these hybrids. It is concluded that there is sufficient evidence for the existence of interpopulational heterosis in this species to merit an extension and application of this approach to include a wider range of varieties and. populations, both adapted and introduced.
Growth, Water use and nutrient uptake from the subsoil by grass swards
Authors: Garwood E. A. , Williams T. B. 
Published: March 2009

1. Plant nutrients, N, P and K, were applied to the soil surface or injected at a depth of 18 in. or 30 in. in perennial ryegrass swards, when the upper horizons of the soil profile were dry.2. When the surface soil was dry and a soil water deficit of 2 in. existed there was no response to surface applied N but injection of N into moist soil at a depth of 18 in. produced a marked increase of growth. At this depth of injection there was a significant positive interaction between N and PK.3. There was a substantial recovery in the herbage (59–80%) of the nitrogen applied to the subsoil, provided water was available in the soil horizon in which the nitrogen was applied.4. Failure of a grass sward to regrow after cutting when the water available to the plant has been removed from the uppermost soil horizons is largely due to a deficiency of plant nutrients in the subsoil. The major deficiency is that of nitrogen.
The hydrolysis by rumen and caecal microbial enzymes of hemicellulose in plant and digesta particles
Authors: Bailey R. W. , Macrae J. C. 
Published: March 2009

Summary:In sheep fed red clover hay nearly 40% of the feed hemicellulose left the rumen undigested and scarcely any of this hemicellulose was digested in the postruminal digestive tract. The caecal microflora from sheep fed the same diet did, however, yield enzyme extracts which readily hydrolysed isolated hemicellulose or xylan preparations. These caecal and rumen microbial extracts, were capable of hydrolysing the hemicellulose in undigested particulate plant material but were not capable of hydrolysing, to any extent, the hemicellulose in undelignified digesta particles from various parts of the postruminal digestive tract. The hemicellulose in delignified postruminal digesta and the hemicellulose polysaccharides isolated from the digesta were hydrolysed by both rumen and caecal hemicellulases. The results are discussed in the light of observations on the postruminal digestion of hemicellulosic material in roughage- and cerealfed animals.