bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Decomposition of Urea in Soils
Authors: Gibson T. 
Published: March 2009

The decomposition of urea has been investigated in 59 soil samples of extremely varied character. Urea was decomposed readily in all and very rapidly in most of the samples.In mountain and heath soils the decomposition was generally active, especially in soil tests. Strongly acid peat samples (pH. 3·1 to 3·3) decomposed from 0·44 to 0·86 per cent, of their own dry weights of urea in 24 hours at 22° to 23° C.In solution and soil tests samples from permanent pastures produced a more rapid decomposition than those from cultivated land. In soil tests with pasture samples quantities of urea as large as 1 per cent, of the dry weight of soil were converted to ammonia in 24 hours at 22° to 23° C. Fertile arable soils produced a relatively slow decomposition in soil tests.
Experiments on the use of home grown foods for milk production: II. The effect of feeding concentrated and bulky foods prior to calving on subsequent milk production
Authors: Blaxter K. L. 
Published: March 2009

1. A field experiment in which six farms cooperated, supplying fifty-one experimental cows and heifers, has been conducted. The object was to find whether feeding before calving 156 lb. of concentrates or its equivalent in feeding value as bulky food increased milk production.2. The results showed that animals fed concentrates gained more weight before calving, were in better condition at calving, and produced a maximum of 7 lb. more milk per cow per day than the controls. Although those fed bulky food increased in live weight more than the controls, they did not calve in such good condition and produced only 3 lb. of milk per cow per day more than the controls.3. Nearly half the animals fed bulky food refused appreciable amounts of this supplement, and it is probable that this refusal of food is one of the factors responsible for the differences in milk production between the two groups receiving additional food.4. The correlation (r) between the weight of the cow and the weight of the calf was +0·507, and there was no statistically significant difference between the weight of the calves produced by cows receiving different treatments.5. Although the fat percentage of the milk of the cows receiving supplementary food was higher than that of the cows receiving no supplement, the difference was not statistically significant.6. Correlation analysis showed that the farmers' judgement of the condition of their cows at calving time was very closely related to the cows' subsequent performance.
Studies on calcium cyanamide V. The Utilisation of Calcium Cyanamide in Pot Culture Experiments
Authors: Richardson H. L. , Crowther E. M. 
Published: March 2009

1. In pot culture experiments with barley and mustard conducted in several soils over a number of years, the yield differences between calcium cyanamide and ammonium sulphate were generally small. Calcium cyanamide gave slightly poorer results than ammonium sulphate in soils with high responses to added nitrogen but definitely better ones in soils which contained much available nitrogen and in which calcium cyanamide greatly retarded nitrification.2. The pot culture experiments confirmed the conclusion from earlier laboratory work that in normal soils calcium cyanamide was converted through urea into ammonia within a few days. Nitrate accumulation was less complete and slower from calcium cyanamide than from ammonium sulphate. In one soil the nitrogen from calcium cyanamide remained as ammonia for several weeks, the nitrate content being below that even of unmanured soil.
Studies on the fats of the bacon pig with reference to carcass quality. The relation between growth rate and chemical composition of pig depot fat
Authors: Shokland F. B. , De La Mare P. B. D. 
Published: March 2009

Consideration of the composition of pig depot fats from the point of view of Callow's growth-rate theory (Callow, 1935a,b), shows that the theory appears to explain the iodine values of fats both of groups of animals and of depots of an individual pig. When, however, the fatty acid compositions of the fats are considered, the theory is untenable in respect of the depots of an individual pig. Differences in unsaturation between outer back fat, inner back fat, and perinephric fat are essentially determined by differences in the ratio of oleic acid to stearic acid, differences in linoleic acid content being inconsiderable.It can equally be shown that the growth-rate theory does not explain the results obtained by Hilditch & Pedelty (1941) for depot fats of sheep. Differences between different depots both of the pig and of the sheep seem to be characteristic of the species and cannot readily be altered by altering either the quantity or the quality of the diet.
The composition and digestibility of Northern Irish ryegrass seed and ryegrass seed cleanings
Authors: Common R. H. 
Published: March 2009

1. Data are presented for the chemical and botanical compositions of ryegrass seed and various by-products of the ryegrass seed cleaning industry.2. Digestibility data are presented for a more limited range of samples of ryegrass seed, ryegrass seed cleanings and, for comparative purposes, of certain by-products of the milling of oats.3. Ground high quality perennial ryegrass seed has a chemical composition and digestibility comparable with that of oats.4. Ground rough (i.e. uncleaned) perennial ryegrass seed has a chemical composition and digestibility such that its starch equivalent is 90–95 % of that of oats.5. Ground bulked ryegrass seed cleanings has a starch equivalent of about four-fifths that of oats and is comparable in feeding value with better grades of oat feed, i.e. those containing not more than about 20 % of fibre.
Calcium and Hydrogen ion Concentration and the Interfacial Tension of Pyrethrum Extracts (With Four Text-figures.)
Authors: Hobson R. P. 
Published: March 2009

1. The addition of a pyrethrum extract to a petroleum solvent, semirefined white spirit, considerably lowers its interfacial tension against water. The tension also depends upon the reaction of the aqueous phase, decreasing as the alkalinity increases.2. The addition of agral W.B. to a solution of pyrethrum extract further lowers the interfacial tension more especially against acid solutions, thereby decreasing the sensitivity of the tension value to thepH of the aqueous phase.3. The presence of calcium salts in the aqueous phase raises the interfacial tension of solutions of pyrethrum extract.4. Alkaline salts counteract the effect of calcium salts, and the resulting tension values can be correlated with the ratio of calcium to hydroxyl ion concentration.
Seed disinfection VI. Stripe smut of rye
Authors: Taylor R. Eric , Dillon Weston W. A. R. 
Published: March 2009

1. The occurrence of stripe smut of rye, Urocystis occulta (Wallr.) Rab. in Great Britain is recorded.2. Control of seed-borne infection by disinfecting seed prior to sowing with an approved organomercury seed disinfectant has been shown.3. Experiments have confirmed that the disease may be soil-borne.4. With the increase of the acreage of rye grown in Great Britain it is suggested that seed should be treated with an approved organo-mercury seed disinfectant as a preventive measure.
The Influence of Systematic Plot Arrangement upon the Estimate of Error in field Experiments.
Authors: Tedin Olof 
Published: March 2009

Summary and ConclusionsThe effect of systematic plot distribution upon the estimate of error of a field-plot experiment of 5 × 5 plots has been studied on ninety-one blocks taken from eight different uniformity trials, representing a wide variation in plot size and plot shape, crop, climate, and soil.The arrangements studied are: two different knight's moves, two different diagonal arrangements, and eight irregular arrangements, seven of which have been chosen at random.The investigation has shown that the use of systematic plans introduces a bias in the estimate of the error of the experiment. The use of the knight's move arrangement causes an over-estimation of the error, whereas the use of the diagonal causes an under-estimation.
Dye adsorption by hydrous alumina in soils
Authors: Croucher H. H. 
Published: March 2009

1. A historical review of the dye adsorption method for the estimation of soil colloids is presented, and the method is criticised chiefly from the point of view of the isoelectric theory.2. A procedure for the detection of hydrous alumina in soils is described, involving the demonstration of the isoelectrio point of hydrous alumina by means of preferential dye adsorption in suspensions of variouspH values.3. Satisfactory results were obtained with a mixture of acidic Biebrich Scarlet and basic Iodine Green. The former is adsorbed by hydrous alumina only on the acid side of its isoelectric point, and the latter only on the alkaline side.4. The characteristics of an ideal dye for use in studies such as those described are tabulated.5. The applicability of the mixture of dye-stuffs finally selected is demonstrated for a series of soils of varying basic ratio, and including examples of lateritic soils and clays.
The effect of the growth-promoting, appetite-stimulating or “physin” factor on the live-weight increase of swine
Authors: Dunlop George 
Published: March 2009

Attention has been drawn to the remarkable growth rates obtained in certain litters of pigs under farm conditions.It has been pointed out that no explanation has been put forward to account for their occurrence.The literature relating to the new dietary factor, physin (Mapson), essential for optimum growth and reproduction in experimental rats, trout and dogs, has been reviewed.Experiments are reported in which rations, adequate as far as our present knowledge of essential dietary constituents goes, were fed to young growing swine. In each of three experiments, animals which received in addition 4 oz. of raw minced liver per day showed a 40 per cent. increase in growth rate compared with the controls.When food intake was controlled according to the new method of individual feeding, the liver animals showed the same gains in weight as the animals receiving the basal diet alone.
Changes occurring in the organic matter during the decomposition of compost heaps
Authors: Ashworth M. R. F. 
Published: March 2009

1. The decomposition of the organic matter of four medium to large-scale composts has been studied by analysis of samples taken at intervals.2. The bulk materials of the composts were grass-cuttings, oat-straw,Sphagnumpeat and anEriophorumandSphagnumpeat. All were made up to the same nutrient-content and relative water content.3. The analytical method used was a modification of the scheme of proximate analysis used by Waksman and by Shewan. It was supplemented by ammonia and nitrate determinations, using Olsen's method.4.Observations.A.All composts.(i) An increase in ammonia, water-soluble nitrogen and water-soluble organic matter took place during the first month.(ii) Only low nitrate concentrations were developed.(iii) Very closely parallel changes in H2SO4-soluble nitrogen and residual nitrogen were recorded.(iv) Other nitrogen changes can be described as slight and on the whole as mutually compensating fluctuations.
Digestibility trials with poultry. IX. The digestibility and metabolizable energy of sunflower seeds
Authors: Halnan E. T. 
Published: March 2009

1. Field tests indicate that sunflower seeds are suitable as a wartime substitute for cereal grains for fowls, and that eggs produced on rations containing these seeds are excellent in both flavour and quality.2. Digestibility trials indicate that sunflower seeds are a good source of protein and energy.3. On an energy basis, metabolizable energy determinations indicate that sunflower seeds yield more energy than cereal grains on a weight-for-weight basis, with the exception of yellow maize.4. Under commercial conditions of management, sunflower seeds appear to be quite palatable to poultry, but not under conditions of individual cage feeding.
The Obligate Anaerobic Microflora of Farmyard Manure
Authors: Glathe Hans , Cunningham Andrew 
Published: March 2009

1. In a preliminary investigation of the obligate anaerobic microflora of samples of ordinary farmyard manure and of Edelmist strains ofBac. sporogenes, Bac. bifermentans, Bac. tertius, Bac. tetanomorphusandBac. saccharobutyricuswere isolated and characterised.2. Anaerobic decomposition of cellulose was observed in media inoculated from both of the samples of Edelmist examined.3. For the cultivation and enumeration of the anaerobic bacilli in samples of farmyard manure the superiority of liquid over solid media was demonstrated. Of the liquid enrichment media tested egg meat and liver-liver broth proved to be the best.
Maize fertilizer experiments in Western Tanzania
Authors: Scaife M. A. 
Published: March 2009

SUMMARYResults of 132 maize fertilizer experiments (NP and NPK) carried out over 3 years in Western Tanzania have been grouped to give sixteen ‘response areas’. Responses to N and P were very large in the south-western half of the research zone, where rainfall is fairly well distributed. On granitic soils around Lake Victoria, responses were mainly to N alone. In the drier areas, notably Shinyanga district, responses to both N and P were on average very small. No significant positive responses to K were found, except for one trial in Karagwe district.It was found that all observed responses to N and P could be accounted for in terms of a generalized two-factor Mitscherlich-Baule yield equation, with constant curvature terms, cn and cv.Using this equation it is possible to define ‘maximum economic requirements’ of the nutrients N and P for various maize and fertilizer prices and potential yields. The difference between this maximum requirement and the amounts of these nutrients supplied by the soil (given by the Mitscherlich-Baule parameters bn and bp',)represents the optimum rate of fertilizer application, where profit per acre is at a maximum.Empirical equations are presented for estimating b from soil analysis results for areas not adequately covered by these experiments, but such estimates may not always be accurate.
Studies in the geology and mineralogy of soils: I. A detailed study of a region characterised by diverse rocks and partly covered by glacial drift
Authors: Hart R. 
Published: March 2009

1. An account is given of the geology and mineralogy of the soils of a small area characterised by diverse rock groups, which are mainly covered by glacial drift. The topography is also varied. The soils are mainly derived from boulder clay, glacial sands and gravels, and alluvium, the remaining soils being formed on screes and hill-wash. The underlying rocks are lavas of Old Red Sandstone age and sandstones and shales of Carboniferous age.2. A similarity in mineral content of the soils on glacial material and alluvium is shown. All these soils have a high content of fresh ferro-silicates. The soils on the screes and hill-wash are characterised by their content of rock fragments and iron oxides, but minerals from glacial material are also present, though to a minor extent.3. The soils on the drift material contain potash, phosphate and lime-bearing minerals.4. The varied nature of the parent materials has given rise to varied textures in the soils. The soils on the boulder clay are the heaviest, while, the soils on the fluvio-glacial material are very variable.5. The mineral content of the matrix of the boulder clay is similar to that of the local rocks, only the rarer minerals being derived from external sources.
The action of certain chemical substances on the zoospores ofPseudoperonospora Humuli(Miy. et Takah.) Wils
Authors: Goodwin W. , Salmon E. S. , Ware W. M. 
Published: March 2009

1. BothPseudoperonospora HumuliandPhytophihora infestansare extremely susceptible in the zoospore stage to the action of weak solutions of soap or saponin. The zoospores are caused to disintegrate suddenly, apparently by changes in surface tension, within 60 seconds, in solutions containing over 0·1 per cent, soft soap. Those ofP. Humuliare more vulnerable than those ofP. infestans.2. The fungicidal action of soap and saponin mixed with certain adherent substances was tested on hop plants.3. The power of adhesion and the fungicidal efficiency of the mixtures were tested by allowing single drops to dry on the surface of watch glasses and by then adding drops of water containing zoospores.4. Other substances,e.g.aluminium-lime mixture, glycerine, iodine, bromine, were also found to kill zoospores rapidly.
Studies in crop variation: VI. Experiments on the response of the potato to potash and nitrogen
Authors: Eden T. , Fisher R. A. 
Published: March 2009

The development is recorded of the series of experiments with potatoes at Rothamsted during 1925–27, designed to examine the quantitative response of yield to varying quantities of nitrogenous and potassic manures, and to test the relative value with this crop of different sources of potash.While rather precise comparisons were obtained on the qualitative question by means of Latin squares in 1925–26, the reality of the depression ascribable to chloride could not be demonstrated in these years, but became clearly apparent when in the following year, the qualitative experiment was merged with the quantitative one.In the earlier quantitative experiments, although satisfactory responses were obtained, the precision of the results left much to be desired, since only four replicates could be used. When by merging the experiments this was increased to nine replicates, much smaller responses were clearly measurable.The large and complex type of experiment finally adopted thus supplied more precise information on both heads than could previously be obtained, and in addition to a more thorough exploration of the different combinations possible.
Factors affecting the yield and quality of milk: I. The age of the cow
Authors: Kay R. R. , M'Candlish Andrew C. 
Published: March 2009

1. The variations in production due to age have been investigated with the records of 738 Ayrshire cows for 4380 lactations.2. Milk and butterfat production increase up to about 7 years of age and then show a decrease.3. The fat percentage for 3-year-olds is higher than that for older cows.4. After 3 years of age there is little change in the fat percentage with age that is of any practical significance until advanced ages are reached, when there may be a fall of importance.5. The increase in production associated with age is probably attributable, in part, to the growth of the secretory tissue of the udder and to body growth in general.6. Part of the increase may also be due to an improvement in functional activity through use.7. The tendency for milk to show a slightly lower fat percentage as the cow advances in age is probably due to the fact that as the milk yield changes the fat yield changes in the same direction but at a slower rate.8. There is little known regarding the influence of very advanced age on production, but it is probable that many cows maintain for a long time the production associated with maturity, and then decline slowly.9. Heifers with a low fat percentage need not as a rule be expected to test higher on reaching maturity.10. It is probable that the increase in production with maturity is associated more closely with high initial production than with persistency of production.11. Correction factors for age are presented.
Pyrethrin I and II: Their estimation in pyrethrum (Chrysanthemum cinerariaefolium). II
Authors: Tattersfield F. , Hobson R. P. 
Published: March 2009

1. The acid method previously described has been used to evaluate samples of pyrethrum derived from both Swiss and Japanese seed, with equally successful results.2. A rapid method for the evaluation of pyrethrum by a determination of pyrethrin I is described.
The effect of heat on milk: (A) On the coagulability by rennet. (B) On the nitrogen, phosphorus and calcium content
Authors: Mattick Elfreida C. V. , Hallett Howard S. 
Published: March 2009

Milk which has been heated to temperatures varying from 105–209° F. for half an hour differs from raw milk in its reaction to rennet in all cases.There is no change in the diffusibility of the nitrogenous substances in milk after heating to temperatures varying from 105–209° F. for half an hour.Heating to 175° F. and above for half an hour appears to reduce the diffusibility of the phosphorus content of milk.Heating to 125° F. and above for half an hour causes marked diminution in the diffusibility of the calcium content of milk.
The Decomposition of Green Manures in Soil
Authors: Daji J. A. 
Published: March 2009

SummaryFour plant materials of widely different origin and age were used as green manures mixed with soil for decomposition studies under laboratory conditions.Provided the conditions of temperature, moisture, aeration, and micro-flora, are optimal, the decomposition depends upon the chemical constituents of the plant materials. It is shown that the soluble carbohydrates, hemicelluloses and cellulose are the compounds mainly responsible for the loss of total organic matter during decomposition.
Growth cabinet studies into cold-tolerance of Festuca arundinacea populations: I. Effects of low temperature and defoliation
Authors: Thomas W. D. , Lazenby Alec 
Published: March 2009

SUMMARYThe survival of potted plants of the North African Festuca arundinacea populations syn. 1 and syn. 2 was compared to that of the British cultivar S. 170 following 18 h periods in a growth cabinet at 24 °F, 21 °F and 18 °F. No plants in any of the three populations were killed by the 24 °F or 21 °F treatments but, following the 18 °F treatment, survival of both synthetics was greatly reduced, especially amongst plants that had been cut back to 1 in. (2·5 cm) 6 days prior to the cold treatment. Reduction in tillering and deaths in syn. 1 were both greater than in syn. 2. Both cut and uncut plants of S. 170 survived the 18 °F treatment, their tillering being relatively little affected.In a subsequent study, survival of syn. 1 and syn. 2 at temperatures decreasing to 16 °F was less amongst plants cut back to soil level than amongst those cut back to 3 in (7·5 cm) or left uncut. No differences were detectable between survival in the two synthetics, nor was there any significant effect, on such survival, of time interval prior to the cold shock.The results showed close agreement with previous patterns of winter survival of these populations in the field.
Transition from anoestrus in the mare and the effects of artificial lighting
Authors: Burkhardt John 
Published: March 2009

1. The recommencement of the sexual rhythm from deep anoestrus, is described in barren pony mares. Follicular development and oestrus follow after an interval of preliminary changes in the ovaries and accessory reproductive organs.2. The onset of oestrus can be accelerated by general irradiation with strong artificial light. Local irradiation with a mercury vapour lamp has no effect on the ovaries.3. Pregnant matings will result from such artificially induced heat periods provided that ovulation is induced.4. Doses of less than 10 c.c. of sperm injected will cause fertilization when ovulation is so induced.5. There is a close connexion between the shedding of the coat and renewed ovarian activity.6. The stimulus to the ovaries probably passes through the eyes as in the ferret.