bluuebunny/crossref_metadata_2025_split huggingface dataset:
The flocculation of soils
Authors: Comber Norman M. 
Published: March 2009

“Silt”, like most insoluble substances, when suspended in water is most easily flocculated by calcium salts when the suspension is neutral. The addition of alkali stabilizes the suspension and renders flocculation more difficult. Soil “clay,” however, behaves in an opposite manner and is precipitated from alkaline suspensions more readily than from neutral suspensions. In this behaviour clay resembles silicic acid and some other members of the so-called “emulsoid” colloids, and it is suggested that the clay particles are protected by such colloids and thus behave as an “emulsoid” and not as a “suspensoid.”If this is true then the action of lime, which being alkaline nevertheless flocculates clay, is seen to be in accordance with the facts of colloid chemistry.The view is advanced and some experimental support of it is described, that clay, as an “emulsoid,” protects the larger particles which by themselves are “suspensoid.” The soil aggregates are conceived as having large nuclei surrounded by particles which become smaller from the centre of the aggregate outwards, the clay ultimately imposing its “emulsoid” nature on the whole aggregate, and on the whole soil in normal cases. Fine silt soils are not flocculated by calcium hydroxide on account of the inefficiency of the relatively small amount of “emulsoid” clay to protect the large “suspensoid” surface exposed by the fine silt.
On the changes through which the nodule organism (Ps. radicicola) passes under cultural conditions
Authors: Bewley W. F. , Hutchinson H. B. 
Published: March 2009

It is shown in the preceding pages that under certain cultural conditions the nodule organism from the roots of red clover, broad bean, lucerne and lupin exhibits a tendency towards granular disintegration of the cell with the formation of small non-motile coccoid bodies, about 0-4μ diameter.In the cultures ordinarily in use these coccoid bodies are not formed extensively, but cultivation on soil extract media rapidly leads to their production, until finally they constitute the predominant type in the culture.
On the chemical nature and digestibility of roughage carbohydrates
Authors: Bondi A. H. , Meyer H. 
Published: March 2009

1. Egyptian clover, sweet lupin,Lathyrus ochrus, Eragrostis tefandVicia narbonnensishave been analysed as to their hexosan, pentosan and lignin content. The major part of the pentosan is soluble in 2 % HCl and therefore belongs to the hemicellulose fraction, whereas most of the hexosan is insoluble in 2 % HCl and forms part of the cellulose fraction.2. The digestibility of hexosan, pentosan and lignin has been determined by experiments with sheep. The digestibility of soluble pentosan and of insoluble hexosan (2 % HCl) was found to be very constant. It ranged from 64·0 to 66·2 % for pentosan and from 74·1 to 76·5 % for hexosan. ·Lignin was in all cases digested comparatively well, the digestibility coefficients being markedly variable, depending on the plant material. They ranged between 35·1 and 64·0.3. Faeces lignin yields lower methoxyl values than plant lignin. Therefore lignin appears to have been changed during passage through the animal body.4. The partition of hexosan, pentosan and lignin on crude fibre and N-free extract prepared from different plant materials is markedly variable.5. The major portion and best digestible fraction of plant lignin is soluble in alkali and is, therefore, contained in the N-free extract.
Carcass investigations with rabbits. Some observations on the weights of rabbits at time of killing
Authors: Dudley F. J. , Wilson W. King 
Published: March 2009

1. The data summarized in this paper relate to the live weight at killing, the carcass weight, the skin weight and the loss in dressing of 813 males and 289 females of various breeds and varieties of rabbit.2. The age at killing varied with the moulting process. The extent to which variation in age contributes to the variation in weight and accounts partly for some of the differences observed is not dealt with.3. Significant differences were noted between the live weights of the various breed groups, in both sexes.
The value of a uniformity trial in field experimentation with rubber
Authors: Murray E. K. S. 
Published: March 2009

1. Sanders’ method of utilising previous crop records to correct experimental results by means of a linear regression is briefly described.2. The method is applied to yield figures from rubber trees in Sumatra, and the precision of a dummy experiment is thereby increased nearly fourfold when the “preliminary” and “experimental” years are consecutive. When the “experimental” year is three years later than the “preliminary” year, the error variance of the adjusted yields is reduced to about a half.3. It is concluded that not only has the method of correction been of value in the particular instance investigated, but that a uniformity trial utilised in this way should be of practical value in any major field experiments with rubber.
“Single Value” Soil Properties: A Study of the Significance of Certain Soil Constants. V. On the Changes Produced in a Soil by Oven Drying (With One Text-figure.)
Authors: Coutts J. R. H. 
Published: March 2009

1. It is shown that results for the loss in weight of a soil on oven heating can be obtained to a very satisfactory degree of accuracy when a Hearson electrically controlled oven is used.2. Results obtained by heating soils to temperatures ranging from 5° to 250° give smooth curves connecting loss in weight with rise in temperature; from which it is concluded that there is no sudden alteration in the structure of a soil when it is heated to 100°, and that the airdry moisture of a soil, as determined with sufficient accuracy by the usual methods, is a convenient empirical factor, but not a representation of any fundamental soil property.3. An examination is made of the factors contributing to the observed total loss in weight when the soil is heated, and an explanation offered of the contributions made by the different types of soil water and by the soil colloids. It is found that the conclusions drawn from this discussion confirm views developed earlier with regard to the behaviour of the water in the soil, and the absence of any sharp dividing line between the different classes into which the soil water is usually divided.
The control of ovulation in the mare with reference to insemination with stored sperm
Authors: Davison W. F. 
Published: March 2009

1. In pony mares during oestrus in which a follicle was considered to be sufficiently ripe (thin walled) the intravenous injection of 500 i.u. pregnancy urine extract induced ovulation in nineteen out of twenty-three mares between 24 and 48 hr., in three cases within 24 hr., and in one case between the fourth and fifth days.2. Dialysed egg yolk as a medium for storage of horse sperm for 24 hr. was shown to give satisfactory results when ovulation is controlled by the above method, so that it occurs within 24 hr. after insemination. Nine single inseminations during one oestrus resulted in five pregnancies.3. The number of spermatozoa required for successful inseminations is discussed.4. Means of detecting a sufficiently ripe follicle before injection with pregnancy urine extract are described.5. It is shown that the duration of oestrus is shortened as the result of pregnancy urine injections.6. Data is given concerning the time which elapses between ovulation and the cessation of oestrus.
The riboflavin requirement of the White Wyandotte chick. II. Pure crystalline riboflavin as the vitamin supplement
Authors: Bolton W. 
Published: March 2009

1. An experiment on the riboflavin requirement of the White Wyandotte chick is described.2. The minimal requirement for optimal food consumption was found to be 3·0 μg. riboflavin/g. food; for optimal growth 3·0 to 3·5 μg./g. food and for the prevention of curled-toe paralysis 3·6 μg./g. food.3. At levels of riboflavin intake ranging from 1·7 to 6·2 μg./g. food the uric acid content of the blood plasma remained unchanged at approximately 6 mg./100 ml.
The significance of the extremities of the ox (Bos taurus) in thermoregulation
Authors: Whittow G. C. 
Published: March 2009

1. Measurements of the temperatures of the extremities, rectal temperatures, respiratory rates and heart rates have been made in calves during exposure at environmental temperatures within the range – 5·0° –45·0° C.2. Large variations in the skin temperatures of the extremities were recorded between environmental temperatures of –5·0° and 25·0° C. At environmental temperatures above 25·0° C. the extremity temperatures and the skin temperatures of the trunk were similar.3. Feeding and localized infra-red irradiation of part of the trunk of the animals resulted in marked increases in the skin temperatures of the unheated extremities.4. Evidence was obtained that the variations in the skin temperatures of the extremities were brought about by changes of blood flow to these parts.5. Respiratory rates varied also with the environmental temperature at which the animals were exposed. When the animals were exposed to localized infra-red irradiation of the trunk the increase in respiratory rate was significantly greater when the extremities were initially warm than when they were cool.6. In addition to spontaneous fluctuations in the skin temperatures of the ears at environmental temperatures of 10·0°–25·0° C, periodic increases in the skin temperatures of the ears were observed in all the calves at an environmental temperature of – 5·0° C. The increase in the skin temperatures of the ears persisted throughout the 7 hr. exposure to an environmental temperature of – 5·0° C.7. It was concluded that, in a temperate climate, variations in the skin temperatures of the extremities of the ox have a thermoregulatory function.
The nutritive value of dried spent hops
Authors: Davies W. L. , Sullivan R. S. 
Published: March 2009

Dried spent hops possess a high absorptive capacity, and attention is drawn to its use as a “filler” to absorb such by-products as molasses and treacle.The material possesses a high crude protein value and its ether extract is very high for a fibrous food, while the amount of crude fibre is the same as in good meadow hay. There is a high percentage of mineral matter present.The digestibility of the material has been determined by feeding with hay chaff and linseed cake meal to three sheep. The spent hops were not readily eaten and could only be included in a ration in an amount equal to one-seventh of the dry weight of the total ration.Its digestibility is low, a fifth of the crude protein and the nitrogenfree extractives, one-half of the ether extract, one-twentieth of the crude fibre and one-fifth of the total organic matter only being digestible. The production starch equivalent was 24.5.
The influence of soil heterogeneity on the growth and yield of successive crops
Authors: Eden T. , Maskell E. J. 
Published: March 2009

1. The interaction of physical conditions of the soil and the establishment of plant together with its subsequent growth and yield have been studied for wheat and swedes on a variable piece of land, maintained as a uniformity trial.2. Ploughing draught was taken as a criterion of the physical condition of the soil and various simple measurements on the crop were made from time to time during growth.3. The establishment of wheat showed substantial negative correlations with ploughing draught but the correlations between ploughing draught and the performance of the plant diminished as growth progressed. This was shown to be the result of the overwhelming importance of the spacing factor operating beneficially on plots where the plant was abnormally poor. The effect of this factor is traced step by step.4. Swedes differing from wheat in almost every detail of cultivation and growth, cycle showed no correlation between soil conditions and germination or between the various growth stages and physical soil conditions. The highest significant correlation was between the number of roots per plot after singling and ploughing draught and an explanation of this is given.5. There was a significant but only moderate correlation between the yields of the two crops.
A soil moisture meter. Depending on the “capillary pull” of the soil. With illustrations of its use in fallow land, grass orchard, and irrigated orchards
Authors: Rogers W. S. 
Published: March 2009

1. A soil moisture meter which gives direct and continuous measurement of the soil moisture content is described. The instrument consists of a special porous pot filled with water, connected by a tube to a mercury manometer. The pot is buried in the soil, whose capillary pull causes the mercury to rise. The height to which the mercury rises depends on the amount of moisture in the soil, and also on the size of soil particles and the degree of compactness of the soil. (The last two factors remain constant for an instrument in one position.)2. To read actual moisture percentage each instrument has to be calibrated for the soil in which it is placed. Once this is done, all sampling and weighing is eliminated.
The effect of nitrogen, phosphate and potash fertilizers on three grass species
Authors: Wolton K. Margaret , Brockman J. S. , Brough D. W. T. , Shaw P. G. 
Published: March 2009

SUMMARYThe effects of annual applications of up to 300 lb/acre of N, 100 lb/acre of P2O5 and 200 lb/acre of K2O on cut swards of S. 24 ryegrass, S. 37 cocksfoot and S. 215 meadow fescue were measured in an experiment lasting 3 years.There were some differences between species in their dry-matter and nutrient yield response to nitrogen and potash applications, but not to phosphate. These differences were inconsistent and over the 3-year period were negligible.A large response to nitrogen was only fully maintained when phosphate and potash were also applied. There was no response above 50 lb/acre of P2O5 in any year. In the second year, 100 lb/acre of K2O was sufficient, but more than this was necessary in the other years. Symptoms of phosphate and potash deficiency were seen where high rates of nitrogen were applied without phosphate and potash respectively.
Nutritive value of pasture: IV. The influence of the intensity of grazing on the yield, composition and nutritive value of pasture herbage (Part II)
Authors: Woodman H. E. , Norman D. B. , Bee J. W. 
Published: March 2009

The object of this series of investigations is to secure detailed information concerning the composition, digestibility and nutritive value of pasture grass in its different stages of growth. The results which were obtained in these respects by cutting the herbage of the experimental pasture plot at weekly and at fortnightly intervals have been described in previous communications. During the season of the present experiment, the trials have been carried a stage further by the adoption of a system of cutting at 3-weekly intervals. The main findings of the 1928 investigation are recorded below:(1) Chemical composition of 3-weekly pasture cuts: The adoption of a more lenient system of cutting at 3-weekly intervals led to a slight lowering of the percentage of crude protein in the grass and a slight raising of the percentages of crude fibre and N-free extractives. On the other hand, no corresponding effect was noted in respect of the ether extract, SiO2-free ash, lime and phosphate, the percentages of these constituents being very similar in the weekly and 3-weekly pasture samples obtained in 1928. The falling off of the percentage of crude protein in the 1928 3-weekly-mown herbage, as compared with the weekly and fortnightly-mown herbage of 1925 and 1927 respectively, was not wholly the consequence of the more lenient system of cutting, but was also due in part to the protein-depressing influence of the droughty periods which were experienced in the 1928 season.
Pyrethrin I and II: Their insecticidal value and estimation in Pyrethrum (Chrysanthemum cinebariaefolium). I
Authors: Tattersfield F. , Hobson R. P. , Gimingham C. T. 
Published: March 2009

1. (a) Pyrethrin I and II have been isolated by the method of Staudinger and Ruzicka from the insecticidal plant Pyrethrum (Chrysanthemum cinerariaefolium). Both are shown to be highly toxic to the insectAphis rumicis.(b) Pyrethrin I was found to be the most toxic substance so far tested by us and, as it was about ten times as toxic to these insects as pyrethrin II, it is concluded that it is mainly responsible for the contact insecticidal value of pyrethrum.2. Two micro-analytical methods of determining the pyrethrin content are described, (a) By means of the acids after hydrolysis, (b) By means of the semicarbazone. They are given on pp. 278, 282.3. The analytical results obtained for a series of pyrethrum samples agreed with their observed insecticidal properties toAphis rumicis.4. Comparisons of the pyrethrin contents, as estimated, with the results of direct toxicity experiments both on the pyrethrum samples and the pure pyrethrins, confirm the validity of the analytical methods.5. There was a significant and positive correlation, in the samples tested, between the amounts of pyrethrin I and II.6. Insufficient data are available to show a significant correlation between the size of flower-heads and the content of poison, or to draw conclusions as to the effect of external conditions such as soil, weather or age of bed.
The leaching out of autumnal dressings of nitrogenous fertilisers
Authors: Nicholson H. H. , Pantin Barbara 
Published: March 2009

The investigation bears out the conclusion of the Rothamsted experiments that leaching out may occur any time throughout the winter up to March, or rarely April.The loss of nitrates is directly limited by the amount of drainage and so is indirectly determined by the rainfall, and by temperature—as it affects the rate of evaporation.All three nitrogenous fertilisers are shown to lose well over 50 per cent, of a normal dressing by leaching out during the winter, but the loss is greatest in the case of sulphate of ammonia, least in the case of rape dust, calcium cyanamide being intermediate.The writers wish to express their indebtedness to Miss N. Sugg who carried out the experimental work in the first winter.
The influence of the number of nodule bacteria applied to the seed upon nodule formation in legumes
Authors: Thornton H. G. 
Published: March 2009

In a field trial with lucerne grown from seed treated with varying doses of culture it was found that the numbers of nodules were increased as the dose was raised from 2,500 to 20,000 organisms per seed (56 to 7 Ib. of seed per culture). Storing the seed for periods up to 28 days between inoculation and sowing, caused some loss in the nodule numbers. This loss was greatest between 1 and 7 days' storage.The difference in dose of culture and in period of storage did not significantly affect the crop subsequently obtained from the inoculated plots, whose yield was, however, much above the uninoculated.In a pot experiment made with runner beans, it was found that increase in the dose of culture above 1,280,000,000 organisms per pot containing six seeds was still capable of increasing nodule numbers but not to an extent proportional to the increase in dose.The experiment does not exclude the possibility that the restriction in effect of very heavy doses may be due to the soil population becoming saturated with the bacteria. On the other hand, observations on lucerne plants grown aseptically on agar and inoculated with a pure culture, showed that even when excessive numbers of the bacteria immediately surrounded the root hairs, only 4 per cent, of these were infected.
The effect of fresh straw on the growth of certain legumes
Authors: Thornton H. G. 
Published: March 2009

1. In pot experiments with Glycine hispida and Vicia faba L., fresh chaff incorporated with the soil caused a significant increase in the number of nodules produced on inoculated plants, this increase being augmented by the further addition of phosphates.2. Fresh chaff, added at the time of sowing and inoculation, had more effect than chaff which was allowed to decompose in the soil for a month.3. Fresh chaff increases the multiplication of the nodule organism in sterilised soil.4. In soy beans without nodules, the chaff depressed the growth of the tops, but this depression did not occur either with soy or broad beans where nodules were present.5. In a field experiment made at Rothamsted, chaff, freshly ploughed in, increased the growth of broad beans and also of wheat sown the next season on the same ground.
A comparison of some methods of supplying calcium to intensively kept chicks
Authors: Black D. J. G. 
Published: March 2009

1. An experiment was performed to compare some methods of supplying calcium to intensively kept chickens.2. The calcium content of a mash was adjusted to contain low (0·13%), normal (1·16%) and high (2·14%) amounts, and each of these mashes was fed to groups of chicks having access to: (a) no grit, (b) flint grit alone, (c) limestone grit alone, (d) both flint and limestone grit.3. The addition of flint grit significantly improved the efficiency of food utilization on all diets, whether limestone grit was provided or not.4. On all three mashes the total amount of calcium grit consumed was greater in the presence of flint grit than when it was fed alone.5. As the level of calcium in the diet increased, the amount of limestone grit consumed decreased, whether it was fed alone or in the presence of flint grit.6. The best results, judged on a live-weight basis, were obtained when the normal calcium mash was fed with flint grit alone, followed by the low calcium mash with both flint and limestone grit, followed by the normal calcium mash with no grit.7. On the basis of the efficiency of food utilization, the low calcium diet with flint and limestone grit was best followed by the normal calcium diet with flint grit alone.8. Access to limestone grit reduced the efficiency of food utilization in all but the low calcium diet.