bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dispersion studies on Gezira soil
Authors: Jewitt T. N. 
Published: March 2009

1. The degree of dispersion on shaking of the heavy clay Gezira soil has been studied in relation to its initial moisture content when it is added to the water. A minimum dispersibility was found at about 7% initial moisture content. Such behaviour is different from that found with certain English soils by Puri & Keen.2. Spontaneous dispersion was studied using the same soil, and by this method it was found that the dispersion decreases with increasing moisture content over a range of zero to 9% moisture.3. This relation between dispersion and water content is discussed in relation to possible effects in the field of practice. Attention is drawn to possible seasonal and daily differences in the effect of rainfall.
The effect of the “gyrotiller” on crop yield
Authors: Garner F. H. , Sanders H. G. 
Published: March 2009

1. In two experiments on heavy land (one continued for four, and the other for three years) gyrotilling has been compared with normal cultivations, and no significant increase in yield has been obtained, although in five out of seven experimental crops the actual difference was very slightly in favour of gyrotilling.2. In two experiments on light land (one continued for three, and one for two years) gyrotilling has been compared with normal cultivations (ploughing and subsoiling, and also, in one case, ploughing alone), and in all five experimental crops there was a slight depression in yield, which was only significant in one case, connected with gyrotilling.
An apparatus and technique for measuring the respiratory exchange of fed sheep over periods of forty-eight hours
Authors: Lines E. W. L. 
Published: March 2009

The gaseous exchange of the sheep can be measured in the apparatus described with considerable accuracy and good agreement obtained with the energy absorbed from a maintenance diet. The apparatus automatically compensates for diurnal changes in temperature and humidity, and maintains a constant rate of ventilation.The precautions necessary to ensure that the metabolism as measured is a good sample of that of the animal when subsisting on the diet, consist of control of temperature and humidity within the chamber and training the animal so that it is free of psychic strain during the period of measurement. It was found that the sheep takes 14–20 days to adjust its energy turnover to a change in diet.Modification in structure and operation of the Haldane-Carpenter gas analysis apparatus are described in detail.The method of A. C. Andersen is used to compute the energy metabolism and respiratory quotient from the gaseous exchange and methane production.
Investigations on the root nodule bacteria of leguminous plants: XIX. Influence of various factors on the excretion of nitrogenous compounds from the nodules
Authors: Virtanen Artturi Ilmari , von Hausen Synnöve , Laine Tauno 
Published: March 2009

1. It has been shown experimentally that the excretion of nitrogen noted by us in cultures of inoculated legumes takes place from the nodule bacteria, probably from the intranodular ones, and not from the roots. No excretion of amino acids occurs in cultures of uninoculated legumes growing on nitrate nitrogen.2. Our earlier hypothesis that the legumes receive their nitrogen nutrition from the nodules in the form of organic nitrogen compounds, particularly amino acids, is in perfect accord with our new observations concerning the process of excretion. All facts indicate that the amino acids concerned are primary products of the nitrogen fixation, and not breakdown products of proteins. Bond's valuable work along quite different lines produced results which support this conclusion. He, however, did not study the chemical nature of the nitrogen compounds in question.3. The excretion of nitrogen occurs in media capable of absorbing the excreted nitrogen compounds (cellulose, kaolin, sand, soil). The demonstration of the excretion is not possible in water cultures except when very large quantities of water are used. On the basis of these facts a hypothesis is advanced to explain the nature of the excretion.4. The term total fixed nitrogen has been used as an expression for the extent of nitrogen fixation, while the term extent of excretion is employed to indicate that percentage of the total fixed nitrogen which is excreted from the nodules.5. The extent of excretion depends largely on the strain used for inoculation. With strains of apparently equal effectiveness in nitrogen fixation, the extent of excretion may vary considerably, so that actually such strains differ in their effectiveness.
Studies on the relation between cultivation implements, soil structure and the crop: III. Rolls: an account of methods employed in a study of their actions on the soil.
Authors: Culpin C. 
Published: March 2009

An account is given of methods which have been employed in laboratory and field studies of the actions of rolls on the soil. These studies have revealed little that is remarkable or unexpected concerning the actions of rolls on the soil, but they have clearly demonstrated that the exact actions of rolls differ widely according to the circumstances in which they are employed. When rolling is carried out in field experiments, it is necessary to perform tests to measure the exact effects produced on the soil. In this way it should gradually become more apparent when and how rolling is likely to be beneficial.Of the methods which have been described, the last two, viz. tests of the consolidation, moisture content and tilth by means of a sampling tube, and of the mechanical resistance to the penetration of a probe with the automatic “resistance” recorder, are well adapted to use in field experiments. These methods are being used in many field experiments involving cultivations, and it is hoped that it may at some time in the future be possible by such methods to relate cultivations and crop yields through a knowledge of the soil structure.
A study on the date of ear emergence in barley
Authors: Bell G. D. H. 
Published: March 2009

1. The discrepancy between the results obtained by various workers concerning the inheritance of earliness or the time of ear emergence in cereals, suggests that this character needs further elucidation physiologically before genetic analysis can be properly undertaken.2. A study of the ear emergence characteristics of varieties when grown under varying conditions indicates that the expression of this character is very much affected by the growing conditions, and the physiological basis must be understood before the various expressions of earliness and lateness are appreciated. It is therefore suggested that the genetic analysis should be conducted in conjunction with a physiological analysis and with a proper consideration and understanding of the effect of environment.3. A series of crosses involving parental forms differing in time of ear emergence, and in some cases belonging to different physiological groups, has shown how differences in genetic behaviour can to some extent be correlated with the physiology of ear emergence of the parents.4. In one cross involving similar types, no evidence of segregation or large genetic difference was obtained. In two crosses involving larger differences of similar types, evidence for a single major factor difference was obtained. In other crosses between different physiological types, and an unstable form, more complex genetic results including transgressive inheritance were obtained. Still other crosses superficially suggested a 3: 1 ratio in theF2, but the presence of a certain amount of transgression, and the behaviour of theF3, pointed to a more complicated relationship.5. Two crosses involving different physiological types were studied in theF1and theF2when sown at different times in the spring by dividing the progenies into separate portions. It was shown that the behaviour of theF1and theF2of the same cross was materially affected by the sowing time.
A study of relationships of breed, time of mating, level of nutrition, live weight, body condition, and face cover to embryo survival in ewes
Authors: Cumming I. A. , Blockey M. A. de B. , Winfield C. G. , Parr R. A. , Williams A. H. 
Published: March 2009

SUMMARYEmbryo survival was studied in flocks of 500 Saxon Merino and 500 Border Leicester × Merino ewes introduced to rams in either summer or autumn. The ewes were fed 200, 100 or 25% of a maintenance diet from day 2 to day 16 after mating. Embryo survival was greatest in ewes fed the maintenance diet. There was no suggestion that live weight, face cover or condition score were important factors affecting embryo survival. Embryo survival in the twin ovulating cross-breds was higher than in the twin ovulating Merinos, but there was no significant difference in embryo survival in ewes with single ovulations. Embryo survival in ewes with twin ovulations was significantly higher at the autumn mating than in summer.
Influence of Size and Shape of Plots on the Precision of Field Experiments with Potatoes
Authors: Justesen S. H. 
Published: March 2009

1. A uniformity trial with potatoes was used for investigating the effect of size and shape of plots on the precision of field experiments. Up to a certain limit the S.D. in per cent. of the mean decreases when the size of plots is increased; further increase of plot size increases the errors as a lesser part of the soil variation can be removed.2. Two-row plots show less variation than either 1 or 3-row plots. This may be explained by row competition.3. When the area to be used is fixed, smaller plots are more efficient than larger, owing to the greater number of replications in the former case. One exception occurs in the case where border rows are not harvested; here 4-row plots are more efficient than 3-row plots, owing to the fact that a larger part of the soil is included in the calculations when 4-row plots are used.4. Long and narrow plots are more efficient than shorter and wider of the same size. The only exception is again explained by row competition.5. In field experiments with potatoes fairly large plots should be used; at least 2 rows wide and preferably long and narrow strips.
Experimental Error and the Field-Plot Technique with Potatoes (With One Diagram and One Text-figure.)
Authors: Kalamkar R. J. 
Published: March 2009

The present investigation consists of the statistical analysis of a uniformity trial with potatoes conducted by Dr Kirk. In this study the standard error in per cent. of the mean decreased slightly with the increase in the widths up to plots 5 rows wide, but any further increase in the width of the plot resulted in the higher standard error. The fertility contour map of the field is given in Fig. 1 to show graphically the effect of soil heterogeneity on the yield. The increased size of the plot resulted in the decreased efficiency in the use of the land when the entire plot was harvested; in other words, given a piece of land of certain size, it is advantageous to have a greater replication of smaller plots than a smaller number of larger plots. Four-row plots proved to be the most efficient when the border rows are discarded. The superiority of long and narrow plots over shorter and wider ones is demonstrated.With the greatest pleasure I acknowledge my indebtedness to Dr Kirk, who supplied me with the data, to Dr Fisher for his valuable suggestions and to Dr J. Wishart for useful advice and criticism.
The Loss of Toxicity of Pyrethrum Dusts on Exposure to Air and Light
Authors: Tattersfield F. 
Published: March 2009

1. Pyrethrum powders and dusts, prepared by grinding or by the incorporation of extracts of pyrethrum flowers upon absorbent earths, such as talc and kieselguhr, lose their insecticidal activity on exposure to light and air. The loss is more rapid in the case of artificially prepared dusts than with ground flower-heads.2. Both light and air play an important part in the process of inactivation, as samples of kieselguhr-pyrethrum and talc-pyrethrum dusts stored in closed vessels in the dark or exposed to air in the dark are relatively stable; also samples exposed to light in an atmosphere of carbon dioxide, nitrogen orin vacuolose little of their toxicity under the same conditions of illumination; samples exposed in oxygen, however, rapidly lose their activity.3. Both wet and dry oxygen were effective in destroying the activity of the dusts, but apparently at different rates, and there is some suggestion that the type of reaction may be different in the two cases.
Fodder legumes affecting sequential crop production and fertilizer N use efficiency
Authors: De R. , Khan M. A. Salim , Katti M. S. , Raja V. 
Published: March 2009

SUMMARYExperiments made with winter fodder crops, lucerne (Medicago sativa), berseem (Trifolium alexandrinum) and oats (Avena sativa) and summer fodder crops, cow pea (Vigna unguiculata), guar (Cyamopsis tetragonoloba), sunhemp (Crotolaria juncea) and pearl millet (Pennisetum americanum) showed that a sequential crop of Sudan grass yielded more after the legumes than after the cereal fodders, oats or pearl millet. The legume advantage was noted in the crop not given fertilizers but also when Sudan grass was given N fertilizer. The yield increase in Sudan grass grown after legumes was equivalent to 32–60 kg fertilizer N/ha applied to Sudan grass following pearl millet.After harvesting the legumes more available N and NO3-N was present in the soil and the apparent recovery of fertilizer N by a subsequent crop was increased by the legume.
Repelling foraging honeybees with alarm pheromones
Authors: Free J. B. , Pickett J. A. , Ferguson A. W. , Simpkins Jacqueline R. , Smith M. C. 
Published: March 2009

SUMMARYThe honeybee alarm pheromones 2·heptanone and isopentyl acetate were repellent to honeybee foragers when applied to plots of oil-seed rape and field beans and to sunflower heads. Their possible use to repel bees from crops before insecticide application is discussed.
Green manuring for barley at Woburn
Authors: Dyke G. V. 
Published: March 2009

SummaryThree short-term experiments on green-manuring are described. In the first, trefoil (T) and ryegrass given fertilizer N (RN) increased the yield of a following barley crop grown without fertilizer N by 500–900 kg/ha, but did not affect yield of barley given N. In the second, T and RN increased yield by 1400 kg/ha whether or not fertilizer N was given to the barley. Ryegrass without fertilizer N (R) had smaller effects in both experiments. The third experiment (with different treatments) suggested that the effect of trefoil was caused by the greenstuff turned in, not by any physical or microbiological change in the soil.
Heritability estimates and correlations of agronomic characters in cowpea (Vigna sinensis L.)
Authors: Kheradnam M. , Niknejad M. 
Published: March 2009

SummaryHeritability in the broad sense and correlations were determined for six agronomic traits in cowpea (Vigna sinensis L.) using four parental and six F2 lines. Heritability values were found to be 75, 64, 47, 44, 35 and 15% for 100-seed weight, number of seeds per pod, number of clusters per plant, number of pods per plant, yield per plant and number of branches per plant, respectively. All of the traits studied, except number of branches per plant, showed positive significant correlations with yield. It is concluded that, for yield improvement in cowpea, number of pods per plant and number of seeds per pod have selective value equal to seed yield per plant, whereas 100-seed weight and number of clusters per plant have less selective value and number of branches per plant has no selective value.
Growth of body components in young weaned pigs
Authors: Whittemore C. T. , Aumaitre A. , Williams I. H. 
Published: March 2009

SummaryFour experiments with 133 piglets of between 21 and 55 days of age were used to examine, by slaughter and chemical analysis, the composition of the body of young pigs. Following removal from the sow, the lipid content of the empty body decreased from about 15 to 7·6%, and in the subsequent 4 weeks had recovered only slightly to between 7·7 and 10·9%; with the exception of pigs with a particularly high intake of energy whose 42-day lipid content had increased to 13·2%. Where Y3 was the lipid gain, X1 the digestible energy intake (MJ) and X2 the ratio of digestible energy to digestible crude protein (g), over all experiments Y3 = 7·83X1 + 4945X2−1260. There was little change in the protein content of pigs consequent upon the effects of either removal from the sow, pig age, diet type or nutrient intake. Over all experiments and slaughter weights; P = 0·164W−100, where P was the protein content of the body (g) and W the empty body weight (g). The efficiencies of conversion of digestible energy to energy gain in body protein and lipid were 0·36 and 0·33 respectively, associated with a constant (daily maintenance) term of 0·462 MJ ME/kg LW0·75. The low value for lipid is as would be expected for animals catabolizing lipid within the experimental period.
The fatty-acid composition of the subcutaneous brisket fat from steers obtained from Angus cows mated to 13 different beef breeds
Authors: Pyle C. A. , Bass J. J. , Duganzich D. M. , Payne E. 
Published: March 2009

SummaryMarked significant differences were found between the crossbreed means in the percentages of palmitoleic, stearic, octadecenoic and the ratio of palmitoleic to stearic acids and in the percentages of subcutaneous, intramuscular and internal fats.The percentage of carcass fats and age were strongly correlated with the acids palmitoleic, stearic (negative), octadecenoic and the ratio of palmitoleic to stearic. Covariance adjustment for percentage carcass fat and age made little difference to the significant differences of the variates which indicates that significant breed differences exist between these variates.
Effects of the addition of starch on the utilization by sheep of the protein and crude fibre contained in lucerne hay and soya-bean meal
Authors: Tagari H. , Gedalya D. Ben , Shevach Y. , Bondi A. 
Published: March 2009

SUMMARYA sheep-feeding experiment was carried out to compare the influence of starch supplementation on the utilization of protein contained in a roughage (lucerne hay) and in a concentrated feed (soya-bean meal). Twelve young rams were divided into four groups, all of which received 150% of the theoretical protein requirement for maintenance. Two groups received soya-bean meal, and the two other groups were given alfalfa hay as protein source. One soya-bean group and one lucerne hay group served as control groups and received the theoretical requirement of energy, whereas the energy content of both experimental groups was raised by addition of grain to 150% of the theoretical energy requirement.A N-balance experiment carried out with both control groups did not indicate the superiority of lucerne hay over soya-bean meal as had been found in previous experiments in which the sheep were fed diets just supplying the theoretical protein requirement. The advantage of roughage protein disappeared as a result of changes of dietary regime, such as the ingestion of protein surpluses and the reduction in the amount of cottonseed hulls.The N retention from the lucerne-hay ration was enhanced much more than the soya-bean meal ration by the addition of maize. Biochemical analyses of the rumen oontent showed that a much higher metabolic activity of the micro-organisms was induced by feeding a lucerne-hay diet supplying 150% of the theoretical protein requirement than that induced by ingestion of a corresponding amount of soya-bean meal. It was concluded that the increased biochemical potential of the lucerne-hay diet could be used advantageously only in presence of ample amounts of soluble carbohydrates. The digestibility of the carbohydrates contained in all four diets was examined by in vivo and in vitro methods. The digestibility of crude fibre in the lucerne-hay ration was somewhat raised by the addition of maize whereas the digestibility of crude fibre in the soya-bean meal ration was considerably depressed by the addition of maize.The digestibility of the carbohydrates contained in all four diets was examined by in vivo and in vitro methods. The digestibility of crude fibre in the lucerne-hay ration was somewhat raised by the addition of maize whereas the digestibility of crude fibre in the soya-bean meal ration was considerably depressed by the addition of maize.
Effects of shifting and continuous cultivation of cassava (Manihot esculenta) intercropped with maize (Zea mays) on a forest alfisol in south-western Nigeria
Authors: Aweto A. O. , Obe O. , Ayanniyi O. O. 
Published: March 2009

SUMMARYSoils in farmlands near Ibadan, Nigeria, where shifting or continuous cultivation of cassava intercropped with maize is practised, were sampled in February 1990 and their characteristics compared with those of similar, uncultivated, forest soil. Organic matter, total nitrogen, exchangeable calcium, magnesium, potassium and sodium, cation exchange capacity and pH were lower in the cultivated soils. Continuous cultivation exerted a greater effect on soil organic matter, total nitrogen and available phosphorus status then did shifting cultivation. It is suggested that inorganic and organic fertilizers and mulch should be applied to cultivated soil to conserve the soil nutrients. Fallows of 3–6 years following 1–3 years of cropping appeared incapable alone of adequately restoring soil fertility. They should, therefore, be supplemented with fertilizer applications.
Effects of poultry manure and mineral fertilizers on the quality of crops
Authors: Pimpini F. , Giardini L. , Borin M. , Gianquinto G. 
Published: March 2009

SUMMARYPoultry manure and mineral fertilizers at two rates of application (medium and high) and in different combinations, together with a non-fertilized control, were tested at the Experimental Station of the Agricultural University of Padova, Italy (45° 21′ N, 11° 58′ E) in 1985–89.Compared to the control, all the fertilization treatments increased the incidence of larger-sized bulbs of onion and tubers of potato, improved the fruit colour of processing tomato and the raw protein content of spinach, but reduced the acidity and acids: soluble solids ratio of tomato and the dry matter content of spinach leaves.In addition, the application of 140 kg/ha of N, 140 kg/ha of P2O5 and 100 kg/ha of K2O as mineral fertilizer or as poultry manure gave the best scores of processing suitability of potato, both for sticks and chips. All the fertilization formulae, except for 140 kg/ha of N, 140 kg/ha of P2O5 and 100 kg/ha of K2O as poultry manure alone, showed significant decreases in the extractable sucrose ratio in sugarbeet, compared with the control. In processing tomato, the best scores of suitability for paste transformation were obtained with mixed fertilization (1/3 poultry manure and 2/3 mineral fertilizers) applying 210 kg/ha of N, 210 kg/ha of P2O5 and 150 kg/ha of K2O and the plots receiving only mineral fertilizers produced fruits with less favourable values of pH and electrical conductivity compared to the poultry manured ones.