bluuebunny/crossref_metadata_2025_split huggingface dataset:
The volume-changes associated with variations of water content in soil
Authors: Haines William B. 
Published: March 2009

(1) A new and simple method of measuring the shrinkage of moist soil on drying is described, which at the same time gives values for the pore space and specific gravity of the soil.(2) Diagrams for a number of diverse soils are given, illustrating the character of soil shrinkage.(3) The shrinkage is shown to take place in two stages in both of which there is a linear relationship to the moisture content.(4) Tentative explanations of these two stages are advanced, based on the well-known colloidal-coating hypothesis, and confirmatory experiments described.(5) By means of the method the effect of alternate wetting and drying of soil in producing a good tilth is illustrated.
Errors in feeding experiments with cross-bred pigs
Authors: Berry Reginald Arthur , O'Brien Daniel Grant 
Published: March 2009

The probable error on one pig calculated on the average daily live weight increase was found to be for cross-bred pigs about 7 per cent.; for pure-bred pigs from the same litter and each of similar live weight about 3 per cent.; for cross-bred pigs each of similar live weight but from different parents about 4 per cent.The error is greatest in experiments of short duration and it decreases as the period of the experiment is lengthened. The decrease is slight if the experiment is prolonged beyond seven weeks.The errors on 18 separate pens containing four pigs to each pen (the total initial live weight of each pen being similar) varied from 2·3 per cent, to 12·08 per cent., the average being 6·21 per cent.The percentage probable error is relatively low when the pigs are fattening rapidly and high when the pigs are fattening slowly. The average daily increase of the quicker fattening female pigs when un-speyed appears to be depressed as a result of periodic sexual disturbances.The stage of fattening does not appear to influence the probable error. Animals in the later stages of fattening show a greater range in their rate of fattening than animals in the early stages, see Fig. 2, p. 284.Weekly weighing of individual pigs is recommended as it gives an indication of the health of each pig. It also enables each experimenter to discriminate between differences in the rate of fattening due to individuality and differences due to ill health, etc.The rate of fattening of pigs is very variable, periods of rapid fattening are followed by periods of depression.
A valid restriction of randomization for certain field experiments
Authors: Taylor J. 
Published: March 2009

Two examples are given of field trials for which randomized blocks would seem the most suitable design, but in which special considerations of the future of the trial or the nature of the treatments make complete randomization impossible or impracticable. A type of design which takes account of these difficulties is described, together with the appropriate methods of analysis.The author wishes to thank Mr S. C. Pearce for much valuable advice throughout this investigation.
Nitrification in Egyptian Soils
Authors: Prescott James Arthur 
Published: March 2009

An attempt has been made to determine the intensity of the biological processes in the soil during the most important periods of the Egyptian farm rotation. The fluctuations of the nitrate content in the surface soil have been taken as the most important index of this activity.In all cases the moisture content of the soil limited these processes more than any other factor.There was observed throughout the season in a cotton field a relatively large amount of nitrate, more than sufficient for the immediate needs of the cotton plant. The lack of response on the part of the Egyptian cotton crop to nitrogenous fertilisers may be accounted for in part, if not entirely, by the fact that nitrification in the soil is well ahead of the needs of the crop.Nitrification under wheat and maize shows in general the same characteristics in Egypt as in other parts of the world; there is no accumulation of nitrate in the soil.The winter fallow, depending for its water on the rainfall, may be a period of steady nitrification when the amount of the rainfall is sufficiently high.
The effect of late nitrogenous top-dressing on the digestibility of hay
Authors: Ferguson W. S. 
Published: March 2009

SUMMARYComparative digestibility trials have been carried out on hays top-dressed with nitrogenous fertilizers 8–13 days before cutting and on similar hays which were not top-dressed.The top-dressing resulted in an increase of 2·0% crude protein and 1·2% true protein.The digestibility of the protein was significantly higher in the top-dressed hays and no other constituents were affected.The protein equivalents in hay dry matter were increased from 4·4 to 6·0% by the top-dressing.
Some investigations on the electrical method of soil moisture determination
Authors: Deighton Thomas 
Published: March 2009

In this paper an examination is made of the processes operative and the limits of accuracy of the electrical method of determining soil moisture.The resistance over a small plot is found to vary under similar conditions and it is concluded that these differences are most probably due to actual differences in moisture or other factors.The effect of the distance apart of the electrodes is investigated and a probability of a minimum resistance between two electrodes being observed under certain conditions is indicated.
A new method for the mechanical analysis of soils and other dispersions
Authors: Robinson Gilbert Wooding 
Published: March 2009

(1) The expression of mechanical composition by means of continuous curves is discussed. It is suggested that a convenient representation will be obtained by showing summation percentage as a function of the logarithm of settling velocity.(2) The effect of a gel coating on the settling velocity of a particle is examined and it is shown that a reduction in velocity takes place which is a simple function of the thickness of the gel coating.(3) A method is outlined by which the mechanical composition of a soil or clay is derived from determinations of the concentration of a settling suspension for different values of depth/time.(4) A shortened method for mechanical analysis is described which gives results in good agreement with results obtained by the present standard method.(5) The effect of various modifications in conditions of working is discussed.(6) The nature of the concentration gradients in a settling column of a suspension is examined. It is shown that below the first few centimetres the change in concentration with depth is very gradual.
The effects of copper deficiency and of chronic overdosage with copper on Border-Leicester and Merino sheep
Authors: Marston Hedley R. , Lee Hector John 
Published: March 2009

SUMMARYThe effects of copper deficiency and of copper excess on mature Merino and Border-Leicester ewes were studied experimentally over a period of 3½ years with five evenly matched groups of each breed which were all depastured together as one flock on terrain where sheep develop cobalt and copper deficiency. All were treated with the equivalent of 1 mg. Co/day. Copper was administered thrice weekly in doses which provided for individuals of the respective groups the equivalent of nil, 1, 5, 50 and 100 mg. Cu/day.All of the individuals that received only cobalt became anaemic; they lost weight and developed marked symptoms of copper deficiency.The supplement of 1 mg. Cu/day was sufficient to delay the onset of these symptoms, but it failed to increase significantly the concentration of copper in the blood and it was insufficient to ensure normal myelin formation in the central nervous system of lambs born of the ewes which had received this treatment for 2 years prior to mating.
Digestion trials with swine: III. The digestibility of a coarse grade of middlings
Authors: Woodman Herbert Ernest 
Published: March 2009

In the foregoing communication on maize digestibility (i), reference has already been made to the early difficulties which arose as a consequence of attempting to make measurements on rations consisting wholly of maize and milk. During, the period in which a mixture of milk and flaked maize was being fed, the pigs developed constipation troubles, due, as subsequent results proved, to the almost complete digestion and assimilation of the ration by the animals. At the time, however, it was deemed expedient to alter somewhat the scheme of the experiment and to feed the maize along with a definite weight of coarse middlings. In this manner it was anticipated that the fibre of the coarse wheat offal would promote peristaltic activity in the intestinal tract and thus assist the passage of undigested food residues.The introduction of the middlings into the experimental ration made necessary the determination of the digestibility of this feeding stuff. The results of this trial are given for convenience in this separate communication.
On the presence of supernumerary mammary glands in cows and on their functional activity
Authors: Mackenzie K. J. J. , Marshall F. H. A. 
Published: March 2009

(1) Rather over 50 per cent, of the cows in this country probably possess accessory or supernumerary teats, the number of which varies from one to three.(2) In many cases at any rate, these teats are associated with additional glands.(3) These additional glands are frequently functional and secrete milk.(4) Ordinarily this milk is absorbed into the circulation, the lactose being secreted in the urine.(5) The presence of active accessory or supernumerary glands is an undesirable characteristic since it involves the formation of milk which is not utilised.
Experiments and observations on forms and strains oftrifolium repensL
Authors: Ware W. M. 
Published: March 2009

Attention is drawn to the fact that there is variation, both morphological and physiological, within the aggregate of plants known as “white clover.” After a detailed study of some of the characters of the plant, it has been determined which of these are constant and which are alterable by external conditions.The cyanogenetic behaviour has not been found correlated with any recognizable external feature of the plant, and has been found constant from year to year, and under different soil conditions. For this purpose, separate plants grown in pots and “clone” plants on various soils were used.As a result of the study of distribution of cyanogenetic and acyanogenetic forms of white clover, it has been found that “positive” or “negative” plants give rise, under “open” conditions of pollination, to offspring approximately 75 per cent, of which are possessed of like cyanogenetic character.
A method for estimating the number of active protozoa in the soil
Authors: Cutler D. W. 
Published: March 2009

1. A method is described by which it is possible to estimate the numbers of active protozoa in a soil.2. The total number of protozoa is first found by a dilution method. A fresh portion of the soil is then treated with 2 per cent. HCl (sp. gr. 1·15) overnight. By this means all active forms are killed. A second count by the dilution method gives the number of cystic protozoa in the soil. From these results the number of active forms can be ascertained.
The value of covariance in analysing field experimental data
Authors: Garner F. H. , Grantham J. , Sanders H. G. 
Published: March 2009

It is suggested that the covariance method of statistical analysis is of considerable value in correcting for uncontrolled inequalities arising early in an experiment, and in analysing the effects of developmental factors on yield. As an example its application to the results of an experiment with beans is described.It is with great pleasure that the writers acknowledge their indebtedness to Dr J. Wishart for his helpful criticism throughout the work.
Studies in soil cultivation. II. A test of soil uniformity by means of dynamometer and plough
Authors: Haines William B. , Keen Bernard A. 
Published: March 2009

Measurements are recorded of soil resistance to ploughing, taken with a view to testing the uniformity of a soil over a single field. The results have been examined for significance and indicate large variations over short distances. The differences have been represented by means of isodyne contours (i.e. lines of equal drawbar pull), drawn on a map.The importance is emphasised of assuming and allowing for such variations before drawing conclusions from the drawbar pull recorded by different implements.Preliminary work is described showing that the variations are correlated with clay content and also with the growth of a crop in its early stages.
The Carbon-Nitrogen Ratio of Soil Organic Matter
Authors: McLean W. 
Published: March 2009

1. The average carbon-nitrogen ratio for fifty British soils from widely distributed areas approximates to the figure 10: 1 given by other investigators. The range of variation is from 6·5 to 13·5: 1. Sixteen foreign samples gave C/N ratios varying from 2·0 to 23·0: 1.2. Soils from limited areas, whether high or low in organic carbon, give approximately constant ratios, but these ratios vary from place to place according to soil, climate, etc. It is suggested that the C/N ratios may be specific.3. The C/N ratios of arable soils do not differ appreciably from those of grassland soils. The percentages of carbon and nitrogen are somewhat higher in the grassland samples than in the arable samples.
Studies on calcium cyanamide. IV. The use of calcium cyanamide and other forms of nitrogen on grassland
Authors: Richardson H. L. 
Published: March 2009

Summary1. Ammonia added as sulphate of ammonia disappeared rapidly from a pasture grassland soil, while very little nitrate accumulated. In winter or early spring three-fourths of the added nitrogen had gone in less than 4 weeks. After the first fortnight there was little difference in the soil inorganic nitrogen from calcium cyanamide and from sulphate of ammonia. A moderate dressing of dicyanodiamide slightly reduced but did not inhibit nitrification; it did not appreciably retard the disappearance of inorganic nitrogen from the soil in winter.2. Winter applications of sulphate of ammonia produced less increase in yield or nitrogen content of repeatedly mown herbage than did spring ones. A late autumn application was almost as effective as a spring one. Calcium cyanamide in late autumn or early winter was on the whole less effective than sulphate of ammonia, but in spring the two were substantially equal. There was little evidence that calcium cyanamide was “slow acting” in comparison with sulphate of ammonia. Dicyanodiamide was practically inert so far as the effect of winter dressings on yield or nitrogen uptake was concerned.
The Development of the Soil Profile in North Wales as Illustrated by the Character of the Clay Fraction
Authors: Robinson G. W. 
Published: March 2009

1. The changes in composition of the clay fraction in different horizons of some typical North Welsh profiles have been studied.2. The changes in the molecular ratio of silica to sesquioxides (SiO2/Al2O3+ Fe2O3) throughout a soil profile afford an indication of the nature of the eluviation which has affected the mineral portion of the soil.3. The data for North Welsh soils indicate a general tendency to enrichment of the lower layers in sesquioxides, particularly ferric oxide, at the expense of the surface layers.4. The silica-sesquioxide ratio of the clay fraction is an important aid to series definition.5. The soils of North Wales, particularly in the uplands, have probably been subjected to considerable erosion in the past. The profiles are therefore considered to be more or less truncated.
Studies of the nutrition of young animals. I. Energy exchanges in the growing pig.
Authors: Wood T. B 
Published: March 2009

The facts and considerations set out above provide the information necessary to enable an intelligent pig-keeper to compute on a logical and scientific basis a series of rations which from the energy point of view will produce any desired rate of live weight increase within the capacity of his animals. It is however necessary to make the reservation that the data apply strictly only to pigs of the Large White breed kept under good conditions and liberally fed.It should also be noted that the method can only be applied to animals of known age and weight.The method is applied as follows:1. From the age of the animals read off from the basal metabolism chart, Fig. 1, the intensity of the basal metabolism per square metre per hour.2. From the live weight—surface chart, Fig. 2—read off the surface area in square metres corresponding to the animal's live weight.3. Multiply the basal metabolism per square metre per hour by the area of the animal's surface in square metres. The product multiplied by 24 gives the basal metabolism of the animal per day.4. To get the practical maintenance requirement add to the basal metabolism per day 1000 calories to allow for an average amount of muscular effort.5. Decide the growth rate in pounds of live weight increase per day at which it is desired to aim. The growth rate curve, Fig. 4, will help in assessing this figure.6. Read off from Fig. 3 the calorie value per lb. of live weight increase corresponding to the live weight of the animals under consideration, and multiply the figure there found by the desired live weight increase in lb. per day. This will give the productive ration in calories per day.7. The total ration is then found by adding together the maintenance requirement estimated in 4 above and the productive ration estimated in 6 above. This gives the total ration in calories of net energy.8. Transform calories of net energy into lb. of meal on the assumption that 1 lb. of meal supplies to the pig 1000 calories, or preferably that 1 lb. of starch equivalent supplies 1500 calories.
Observations on the effect of method of management at mating on bovine fertility
Authors: Laing J. A. 
Published: March 2009

1. The fertility records of two groups of bulls, one group used for controlled service, and one group used for free service, were compared over a period of one year.2. The fertility of the free-service group was consistently better except during the months of December, January, February and March.3. The difference in fertility between the two groups was correlated with the varying length of the oestral periods of the cows at different seasons of the year.4. It is suggested that the higher fertility in the free-service group was due to a closer relationship of service to the end of heat and thus to ovulation.
The chemical composition and nutritive value of ryegrass-seed meal, clover-seed meal, lucerne-seed meal and sainfoin-seed meal
Authors: Woodman H. E. , Evans R. E. 
Published: March 2009

The wartime expansion in the home production of grass, clover and other seeds raised the question of the value of such seeds as food for livestock, since during the later years of the war, surpluses that had been discarded on account of low germination or other causes were being sold to compound manufacturers for inclusion in cattle foods. During 1944, the writers made determinations of the digestibility and starch equivalents of the following seeds: ryegrass (a mixture of Italian and Perennial), red clover, lucerne and un-milled sainfoin. All the samples were reduced to a fine meal before being submitted to test in the digestion trials.Apart from its lower content of digestible ether extract, ryegrass-seed meal resembles oats in respect of chemical composition, digestibility and starch equivalent. It is a carbohydrate concentrate, containing, on the dry matter basis, 69·4% of starch equivalent, including 7·3% of digestible protein.
Chick Rearing II. The bacterial syndrome arising from a diet which is conducive to six-day disease
Authors: Mann T. Barton 
Published: March 2009

In his observations on six-day disease, Taylor (1944) reported that the chicks which died on his preliminary experiments gave negative results on bacteriological examination.Many workers hold that for routine examination of poultry, a quick, convenient and inexpensive method of detecting certain specific bacterial infection is to inoculate slopes of nutrient agar with liver or other tissue, and incubate at 37° C. It is claimed that some organisms often grow in pure culture from diseased chicks, and that this method is especially suitable in the detection of S. pullorum or S. gallinarum infections. The resultant growth can be washed off in saline solution and tested by specific agglutinating sera or by testing on certain carbohydrates.
A Comparison of Methods for Determining the Hydrogen-Ion Concentration of Soils.
Authors: Best R. J. 
Published: March 2009

1. The antimony oxide electrode has been applied in a simple form to measure thepH value of soils.2. ThepH values of representative Australian soils have been determined by means of the hydrogen, quinhydrone and antimony oxide electrodes and the results compared.3. The limitations of the quinhydrone electrode have been investigated and their nature elucidated, special attention being paid to alkaline and manganiferous soils.
The inter-relationships of individual proteins and carbohydrates during fermentation in the rumen of the sheep. II. The fermentation of starch in the presence of proteins and other substances containing nitrogen
Authors: Lewis D. 
Published: March 2009

1. The inter-relationships of starch and proteins during fermentation in the rumen are measured by estimating volatile fatty acids, ammonia, lactic acid and amino acids after administering the starch and protein supplements alone or together.2. The presence of casein stimulates the formation of volatile fatty acids from starch. Simpler nitrogen-containing compounds are less effective than casein; other proteins are as effective as casein provided they are fermented as rapidly in the rumen.3. Proteins can be divided roughly into three groups on the basis of the rapidity with which they give rise to ammonia in the rumen: casein, gelatin, ground nut protein > soy protein, wheat gluten > bovine albumin, zein.4. The proportion of acetic acid falls and of propionic acid and higher acids rises as proteins that are rapidly fermented are placed in the rumen.
An index of soil texture
Authors: Hardy F. 
Published: March 2009

1. A procedure is described for evaluating an “index of texture” (I.T.), based on determinations of moisture contents at the point of stickiness (P), and of sand contents (S) of soil samples.2. The procedure is simple, and allows of a rapid laboratory examination of a great number of spot samples, so that detailed texture maps can readily be constructed.3. Employed in conjunction with soil-reaction maps, the texture maps form a useful basis for detailed investigations of soil genesis and soil fertility.
The capillary pull of an ideal soil
Authors: Hackett Felix E. , Strettan John S. 
Published: March 2009

1. The capillary pull of an ideal soil has been determined by measuring the maximum hydrostatic pressure (H) sustainable by a liquid surface formed, amongst an assemblage of uniform spheres of mean diameter 0·0374 cm. (2a). It has been found that using liquids of low surface tension like benzene to avoid contamination, the constant K in the equation Hgp = KT/2a has the weighted value 9·5.2. Values of K for single apertures between three and four spheres in contact have been determined, using steel spheres of a diameter ⅛ in. and benzene. It is found that K does not vary rapidly for four spheres and has a value between 9 and 10 for apertures in which the ratio of breadth to length varies between 1·0 and 0·4.3. The equivalent capillary tube is the circular or elliptic cylinder touching the spheres forming the aperture. This assumption gives values of K in fair agreement with observation.4. The value of K is practically independent of variations of pore-space ranging from 36 per cent, to 40 per cent, such as usually occur in ordinary packing.