bluuebunny/crossref_metadata_2025 huggingface dataset:
Minimum mineral requirements in cattle
Authors: Theiler A. , Green H. H. , Toit P. J. Du
Published: March 2009

1. Records are offered of year old cattle reared to adult weight on rations of varying content in respect to calcium, phosphorus, sodium, potassium and chlorine. Minimal requirements for growth are higher in the case of phosphorus than in the case of calcium, and a ratio of P2O5to CaO so high as three to one is not necessarily disadvantageous. Sodium requirements for growth are very low, 2 gm. Na2O being more than sufficient. Chlorine requirements are below 5 gm. per day. A relatively high ratio of potassium to sodium is not productive of specific disease. There is no good reason to suppose that excess of basic over acidic constituents is necessary in a dietary, and cattle can grow normally to full adult weight when the usual alkaline reaction of the urine is shifted to the acid side.

2. Explanation of certain observed abnormalities in calving is left open, except in the case of phosphorus deficiency, in which definitely abnormal calves may be born.

3. “Aphosphorosis,” or clinically recognisable phosphorus deficiency disease, is experimentally produced, and shown to be identical with the naturally occurring South African disease Styfsiekte.

4. The chemical composition of the milk of animals suffering from aphosphorosis meed not mecessarily be abnormal, but the “inorganic” fraction of the blood may drop to a quarter of the normal value even before the disease can be diagnosed clinically. Other phosphorus compounds of the blood remain normally high. Blood calcium remains practically normal.

5. Vitamine deficiency of the diets had no adverse effect. Exogenous requirements of cattle for vitamines A, B, and C are so low that they are covered by a few pounds of poor quality roughage, and therefore do not enter into consideration under any natural system of cattle rearing.
The specific conductivities of soil extracts
Authors: Wright C. H.
Published: March 2009

1. Considerable differences were found in the specific conductivities of different soils at any one time of the year, and considerable differences in any one soil at different times of the year, the specific conductivities being highest in March and lowest in June and July. Hence it is only possible to compare different soils when samples of these soils are taken at the same time of the year.

2. A relation has been found between the specific conductivities of the soil extracts and the mean weights of lint per plant per row in the case of 2 strains of Ishan cotton. Other data are presented showing that the specific conductivity of a 1 to 5 soil extract is an index of the fertility of the soil.

3. It has been found that the specific conductivity of a soil decreases under continuous cultivation. There is evidence that the rate of solution also decreases under the same condition.
The mechanical analysis of heavy ferruginous soils
Authors: Groves Ruby C.
Published: March 2009

Certain heavy ferruginous soils do not respond to the usual preliminary treatment with hydrogen peroxide for mechanical analysis by the pipette method.

A method of preliminary treatment is described, involving the use of ammoniacal hydrogen peroxide and repeated gentle rubbing with a rubber pestle which appears to give a satisfactory dispersion with such soils.

The results are not affected by mechanical shaking, which may therefore be omitted.
Nutritive value of pasture. III. The influence of the intensity of grazing on the composition and nutritive value of pasture herbage (Part I)
Authors: Woodman H. E.
Published: March 2009

The present investigation was undertaken with the object of ascertaining the effect of cutting at fortnightly instead of weekly intervals on the yield of pastures, and on the composition, digestibility and nutritive value of the herbage.

The main trial was carried out on the 1925 light-land pasture. The plot was divided into 14 sub-plots, and one sub-plot was mown per day. The whole plot, therefore, was cut over once per fortnight during the season. The results in respect of yield, composition and nutritive value were compared with corresponding results obtained on the same pasture plot under a system of weekly cuts during 1925.

A second trial was carried out on sub-plots 2 and 3 of the 1926 heavy-land pasture, one sub-plot being cut weekly and the other fort-nightly. The work in this case was restricted to securing comparative data in respect of yield and composition of herbage.

The results from both trials lead to the conclusion that the differences in chemical composition, both organic and inorganic, between pasture grass cut at weekly and fortnightly intervals are inconsiderable. The dry matter of the fortnightly-cut grass is extremely rich in crude protein and contains, in comparison with grass cut at the hay stage of maturity, a low percentage of crude fibre. Moreover, these characteristics are retained, by systematic cutting at fortnightly intervals, over the entire season.

The results of the digestion trials justify the conclusion that the dry matter of the pasture herbage grown under a system of fortnightly cutting is a protein concentrate equal in digestibility and nutritive value to that obtained by weekly cutting. There is no significant running off in respect of composition and feeding value during the second week of growth. At the end of a fortnight the herbage still consists of the same immature, non-lignified. tissue as it was at the end of a week's growth.
Digestibility trials with poultry: VII. On the influence of the size of a ration upon its digestibility
Authors: Halnan E. T.
Published: March 2009

1. Four White Leghorn cockerels were fed with widely varying quantities of a Sussex ground oats and milk mixture without material alteration in the coefficients of digestibility of the digestible nutrients.

2. The amounts fed varied from a sub-maintenance ration of 50 gm. to a “limit of appetite” ration of 150 gm. A slight depression in the coefficients of digestibility of the organic matter, the crude protein and the N-free extract, and a slight increase in the coefficient of digestibility of the ether extract was obtained, but the differences shown are attributed to normal fluctuations in digestibility due to individual variation and not to differences in the quantity of food given.

3. In feeding experiments carried out with fowls, in which variable amounts of food are fed, these experiments indicate that it may safely be assumed that the coefficients of digestibility of the food nutrients are not materially affected by the variations in the amounts of food fed.
Experiments on growing sugar beet under continuous illumination. III. The production of a seed crop in the field and the resolution of a heterogeneous population
Authors: Bell G. D. H. , Bauer A. B.
Published: March 2009

1. Experiments are described demonstrating a technique for raising sugar beet seedlings under glass during the winter to provide plants for seed production after transplanting into the field.

2. The use of 24 hr. illumination for this purpose is discussed, and the effect of this illumination in resolving a heterogeneous population is described.

3. The association between the growth habit of the seeding plant and root characters, glomerule yield, weight and size, and the time of anthesis is considered in relation to the recognition of types showing B. maritima and B. vulgaris characteristics.
The estimation of yield in cereal crops by sampling methods
Authors: Clapham A. R.
Published: March 2009

1. Cereal plots were sampled by three different methods; two systematic, and one involving a random location of sampling units.

2. The disadvantages of the systematic methods as compared with random sampling, emerged clearly.

3. These disadvantages were further emphasised in an analysis of earlier data on sampling methods. For this purpose the methods and. results of certain recent contributions to statistical theory were used.

4. By the use of a random sampling method, the variance due to sampling errors may be made a satisfactorily small fraction of the total variance of cereal plots one-fortieth of an acre in area.
Total carotenoids in carrots
Authors: Dark S. O. S. , Booth V. H.
Published: March 2009

1. 238 samples of carrots comprising over seventy varieties were analysed for total carotenoids (t.c.) during five autumns.

2. The average t.c. value for common types (excluding certain very high value varieties and the almost colourless varieties) is 13·8 mg./100 g. fresh carrot. Assuming 90% of the carotenoids to be ‘carotene’ the average for the latter is 12·4 mg./100 g. Negligible correlation is found between named variety and t.c. Red-cored and small-cored varieties are slightly richer than others. The pedigree of the seed is the most reliable indicator of probable t.c. content.

3. Six high t.c. varieties and a Red-Cored Chantenay are described in detail. Four of them are of the long slim type with small red cores. One of them (Dippe's Surrey Long) has a mean t.c. value of 37·1 mg./100 g. The high values have been further improved by selection in two subsequent generations.

The authors thank Drs L. J. Harris and T. Moore for their interest in this work, and Miss D. Bailey, Messrs A. G. Dockrill and K. R. Symonds for technical assistance.
Wartime changes in the winter diet of dairy cows in the Eastern Counties of England
Authors: Pettit G. H. N.
Published: March 2009

The general characteristics of a group of thirtynine herds of dairy cows in the Eastern Counties of England, and the method of obtaining information about their diet during the winters 1938–9 to 1942–3 inclusive, are briefly described.

The first three winters of the war show a continuous decline in starch equivalent and protein equivalent per cow, followed by a recovery during winter 1942–3.

Comparing winter 1942–3 with winter 1938–9: Consumption per cow of concentrates declined by one-third, reductions in proprietary compounds and mixtures and in maize and wheat products being outstanding.

The more important increases were in oats, straw and succulent foods, notably mangolds, sugar-beet tops and kale.

Hay retained its important place with little overall change; a modest increase in silage was restricted to a few herds.

The crude weight of the average daily ration increased from 44 to 61 lb., but its dry matter only from 21·0 to 22·6 lb.

The residue: total dry matter less digestible organic matter—increased from 7·2 to 8·4 lb. per cow daily. Reference is made to changes in palatability.
A survey of the analytical composition of field beans (Vicia faba L.)
Authors: Eden A.
Published: March 2009

Studies were made of the proximate and mineral compositions of modern strains of both spring· and winter-sown beans. The majority of the winter beans were of the Throws M.S. variety, of the spring beans Minors. On the dry-matter basis spring beans averaged 31·4% crude.protein, winter beans 26·5%—a highly significant difference. The true protein values showed a parallel trend. Winter beans averaged 9% crude fibre, spring beans 8%, again a highly significant difference. The strains confirmed the usually accepted levels of oil and of the principal mineral components, except that modern beans appear to be richer in phosphorus.
The influence of the addition of calcium carbonate to a ration low in lime on the appetite and digestibility of the food in swine
Authors: Evans R. E.
Published: March 2009

(1) Animals on a calcium-deficient diet suffer periodically from loss of appetite though the ration is in every other respect satisfactory.

(2) The results of twenty-two digestion trials show no enhanced effect on the digestibility of the organic constituents of the food on adding calcium carbonate to a lime-deficient ration.

In conclusion, I wish to express my thanks to Prof. T. B. Wood, F.R.S., for giving me the necessary facilities to carry out the work; to Mr H. R. Davidson, M.A., for placing the experimental animals at my disposal and also to Dr H. E. Woodman for his active interest and supervision at all stages of the work.
Seasonal and management effects on the composition and availability of herbage, steer diet and live-weight gains in a Themeda triandra grassland in Kenya. I. Methods and study of techniques
Authors: McKay A. D.
Published: March 2009

A 2·year grazing trial was carried out on an equatorial Themeda triandra range grassland in the Rift Valley of Kenya, at 1890 m altitude with a bimodal rainfall of 700 mm p.a., to characterize seasonal changes in the pasture and to determine the influence of climatic and management factors on forage availability and composition, grazing selection and live-weight gains on Boran steers (Bos indicus).

Fourteen categories of sampling and measurement techniques used in this work are described and some methodology problems in rangeland evaluation discussed.

For precise estimation of herbage yields in large paddocks unacceptably large plotsizes and numbers were required so an arbitrary sample of twelve 10 yd x 1 yd plots per paddock was adopted giving c.v.s of 16–50%. Subsequent sampling was limited to three contrasting treatments in the most uniform block. A ‘forceps point’ method was developed for botanical estimation of oesophageal fistula samples and provisional weight correction factors calculated. In a parallel feeding trial regressions were calculated for relating the chemical composition of oesophageal fistula samples to that of the herbage ingested.
Body composition studies with the milk-fed lamb. III. The effect of the protein and energy intake on the composition of the live-weight gain
Authors: Norton B. W. , Jagusch K. T. , Walker D. M.
Published: March 2009

Nineteen male cross-bred lambs, aged between 2 and 5 days, were allotted to each of three dietary treatments. The protein contents of the diets (on a dry-matter basis) were 12·0% (diet A), 28·5% (diet B) and 45·5% (diet C). The energy intakes of groups of lambs within each dietary treatment varied from below maintenance to ad lib.

The experimental period was of 3 weeks and the composition of the live-weight gain was estimated by the comparative slaughter method.

Body composition within each dietary treatment was highly correlated with empty body weight, but not with the previous energy intake. The fat content of the gain decreased, and the water and protein contents increased, as the dietary-protein concentration increased.

When compared at the same empty body weight, the protein content of the fat-free body of lambs given diet C was significantly higher than that of lambs given diet A. This effect of dietary-protein concentration could not be explained by differences in the amounts of protein stored as wool.
The ensiling characteristics of different herbage species and varieties
Authors: Jones D. I. H.
Published: March 2009

The ensiling characteristics of grasses and of red clover were examined by means of a small scale vacuum silage technique. Eight grasses, comprising three varieties each of perennial ryegrass and cocksfoot and two varieties of timothy, were evaluated after application of two levels of nitrogen fertilizer. Three varieties of red clover were evaluated at two stages of growth with and without sucrose supplementation during ensiling.

Perennial ryegrass varieties contained more water soluble carbohydrates than cocksfoot and timothy varieties. At the low level of fertilizer N, silages made from the first cut in mid-May were all well preserved 3 weeks after ensiling. At the high level of fertilizer only perennial ryegrass varieties and S345 cocksfoot were well preserved. After ensiling for 14 weeks perennial ryegrass silages remained well preserved but secondary fermentation in the cocksfoot and timothy varieties resulted in poor preservation. Silages made from the second cut at the end of May were all badly preserved except for silage made from tetraploid ryegrass at the low nitrogen level.

Significant correlations were established between the water soluble carbohydrate content of the grasses and the quality of the resulting silage, but herbage dry-matter content and buffering capacity were not significantly correlated with silage quality.

The red clover varieties were lower in water soluble carbohydrate and higher in buffering capacity than the grasses. Although the silages from red clover were well preserved they were of high pH. Supplementation with sucrose significantly reduced pH and ammonia content and increased lactic-acid content.
A study of the effect of supplementing a concentrate diet with roughages of different quality on the performance of Friesian steers. II. Growth rate, efficiency of food conversion and carcass yield
Authors: McCullough T. A.
Published: March 2009

Concentrate diets supplemented with 5, 20 and 40% high- and low-quality hay were given ad libitum to British Friesian steers from 9 weeks of age to slaughter.

The performance of the animals was studied over 91 kg weight ranges from 91 to 363 kg live weight and from 9 weeks of age to slaughter. In the whole experimental period the daily live-weight gain was significantly greater on diets containing high-quality hay. There was also an increase in the daily live-weight gain in each of the weight ranges studied on diets supplemented with high-quality hay but this increase was not significant at the stage of growth from 272 to 363 kg live weight. As the level of concentrate in the diet increased there was a significant increase in the daily live-weight gain at each stage of growth studied and over the complete experimental period.

The mean feed conversion ratio was greater for diets containing low-quality hay. Except during the stage of growth from 272 to 363 kg live weight the proportion of hay in the diet significantly affected the mean concentrate conversion ratio. With increasing levels of hay in the diet there was a significant increase in the total dry-matter conversion ratio.

The conversion ratio of metabolizable energy was also increased on diets containing low-quality hay. The proportion of concentrate in the diet significantly affected the conversion ratio of metabolizable energy at all stages of growth studied.

There were significant differences in the killing-out percentages, weight and contents of the reticulo-rumen and the omasum plus abomasum expressed as a percentage of empty body weight, with increasing levels of hay in the diet. These measurements were not significantly affected by the quality of hay in the diet.

Indirect measurements of carcass composition indicated that the level of hay in the diet tended to affect the amount of fat in the carcass but the amount of lean was similar at the different ratios of concentrate to hay. The ratios of the weight of separable lean to the weight of separable bone in the 9–10–11th rib cut were similar at different levels of hay supplementation. The organoleptic appraisal of sample joints indicated that carcass quality was satisfactory.
A contribution to the study of the infertility of the subsoil
Authors: Merwe C. R. Van Der
Published: March 2009

Although the infertility of the subsoil in humid, semi-arid and arid regions has received much attention from investigators in Europe and America, in South Africa, as far as the writer is aware, no such work has been done.
Studies of a Scottish drift soil
Authors: Hendrick James , Newlands George
Published: March 2009

1. An examination is made of some aspects of the replacement or exchange of bases by ammonium chloride solution, in a soil about which considerable information had been acquired regarding its physical, chemical, and mineralogical constitution, namely, the soil of Craibstone Experiment Farm, Aberdeen. Certain data in this connection are given.

2. The “course of replacement” of calcium by ammonia, by successive applications of equal amounts of a normal solution of ammonium chloride is examined, according to the method of Gedroiz. Comparison is made between the results got for the Craibstone soil and those for a tshernoziem soil examined by Gedroiz. By means of graphs the agreement between the two soils as to the “course of replacement” is shown, and a distinction made between easily extractable calcium, and that more slowly removed in solution. The “course of replacement” of potassium and magnesium in the Craibstone soil is also examined.

3. The presence of silicon, aluminium, iron and manganese is also noted in the extracts.

4. The soil is also examined for “Total Exchangeable Bases” by extraction with normal ammonium chloride, according to the method of Hissink, with minor modifications.

5. Exchangeable aluminium, iron, calcium, magnesium, manganese, potassium and sodium were found and in addition silicon was present in the extracts.

6. The question of the presence of silicon, aluminium, iron and manganese in measurable amounts in extracts from acid soils is discussed.

7. The relative proportions of exchangeable divalent and monovalent bases found were as follows. Calcium 85·02 per cent., magnesium 8·11 per cent., potassium 2·18 per cent., sodium 4·68 per cent. These results are in general agreement with those found for acid soils.
The relative proportions of exchangeable bases in some Scottish soils
Authors: Smith A. M.
Published: March 2009

1. The relative proportions of exchangeable bases in nine soils from the east of Scotland area and the changes effected by dilute chloride solutions have been examined.

2. The changes due to N/50 solutions are large, and magnesium is displaced to a greater extent by calcium than by potassium.

3. The changes due to N/500 solutions are very small, comparable to what might be expected in manurial practice, and not greater than field sampling error.

4. The content of exchangeable bases and their relative proportions, therefore, seem to be fairly permanent for any soil under normal conditions, but vary considerably from soil to soil, and should prove useful as an additional characteristic of soil type as distinguished in the field.
The length of the interval between calvings
Authors: Sanders H. G.
Published: March 2009

An attempt has been made to ascertain the best interval between calvings, so that the cow's average weekly yield over a long period may be at a maximum. It was only possible to consider the case of the “average cow,” but it is claimed that the general principle has been established, that cows should calve at intervals of not less than a year, and not more than thirteen months; this optimum will probably be subject to a slight variation in particular cases. This is approximately the state of affairs in practice—though Norfolk farmers appear to err on the side of serving too early in the lactation, rather than too late.
The mechanism of secretion of calcium and phosphorus in milk
Authors: Wright Norman Charles
Published: March 2009

1. The formation of colloidal CaHPO4by the interaction of CaCl2and Na2HPO4in the presence of neutral casemates has been demonstrated.

2. The colloidal CaHPO4is shown to be non-diffusible across a membrane of cellophane.

3. A theory is outlined which will account for the secretion of the high concentrations of calcium and phosphorus in milk from the low concentrations of these elements in the blood.
The Composition of Crude Fibre
Authors: Norman A. G.
Published: March 2009

The crude-fibre determination is misleading, because the fraction obtained does not bear any definite relationship to the structural constituents of the material. The cellulose is partially attacked, and lignin extensively removed. Considerable variation is found in the lignin content of crude-fibre fractions. Highly lignified materials do not necessarily yield a crude fibre high in lignin.

Since the presence of lignin exercises a direct effect on the digestibility of the material, any empirical method should include all the lignin, and alkaline treatment must be avoided. Acid hydrolysis may be a possible alternative method, if a correction for protein be made in the case of materials high in nitrogen, and a determination of the lignin content made.
The chemical composition of bracken (Pteridium aquilinum)
Authors: Ferguson W. S. , Armitage E. R.
Published: March 2009

Samples of bracken were taken at fortnightly intervals from June to November at two centres. These were separated into leaf and stem and analysed.

Larger samples were treated for the preparation of proteins and sugars by passing the bracken through a roller-mill, precipitating the protein with acid and concentrating the juice for sugars.

Chemical composition. The main points in the analyses of the whole plants were as follows, all figures quoted being on a dry-matter basis:

(1) The crude and true protein contents of young bracken in early June were high, 21 and 18%, but these fell rapidly to 10% in mid-July and finally to 3% in October.

(2) The lignin content was high throughout, rising from almost 20% in young bracken to 34% in the nearly dead material.

(3) The cellulose content followed the lignin content.

(4) In July and August the bracken contained about 10% of total sugars. A rapid fall occurred in October, and the final samples contained very little sugars.
Fertilizer requirements of sugar beet on fen peat soils
Authors: Tinker P.B.
Published: March 2009

Eighteen trials were carried out to test factorial combinations of N, P, K and Na fertilizers on sugar beet over 3 years on deep light peat soils in the area surrounding the Wash. The average yield responses to all fertilizers were very small, and only rarely profitable, except to sodium. Nitrogen increased yield on a few sites, but there was no obvious way of distinguishing these, and on average there was no justification for using this fertilizer, which depressed sugar percentage. The difference from earlier work, which showed good responses to P and K, is ascribed to repeated heavy dressing of fertilizer given to these soils during the last two decades.
Infertility and neonatal mortality in the sow III. Neonatal mortality and foetal development
Authors: Pomeroy R. W.
Published: March 2009

1. An analysis of pre-weaning mortality in inbred Large White pigs showed that the over-all mortality in ten generations of sows was 47·3%. During the first four generations mortality fluctuated between 30 and 45%; from the 5th to the 9th it fluctuated between 50 and 68% and in the 10th rose to 88%.

2. 70·2% of all deaths occurred in the first 3 days post-parturition and the average birth weight of pigs which died within 3 days was only 1003·5 g. compared with 1258·5 g. for those which survived. 83·0% of pigs weighing less than 900 g. at birth died within 3 days, whereas only 18·5% of pigs weighing more than 1400 g. died within the same period.

3. There were marked seasonal variations in mortality, this being highest during the winter months. Mortality was highest in litters of under 5 and over 15, but between 5 and 15 there was no increase in mortality with litter size. There was no difference in mortality between males and females.

4. Foetal growth was studied in 80 outbred sows of various breeds. Foetal weight was affected not only by age but also by litter size. The withinlitter variation in foetal weight increased with litter size but no increase in between-litter variation with litter size could be demonstrated statistically. Male foetuses were slightly heavier than females at all stages of pregnancy investigated.

5. The growth of the inbred Large White foetus was also studied at an early and late stage of inbreeding, and the reduced birth weight in the latter was shown to be reflected in slower growth of the foetus from mid-pregnancy onwards.

6. The anatomical composition of inbred Large White foetuses at a late stage of inbreeding has been compared with that of similar foetuses at an earlier stage and also with normal outbred Essex foetuses, at 51, 74, 97 and 108 days of pregnancy. The chemical composition of inbred Large White foetuses of a later stage of inbreeding was compared with that of outbred Essex foetuses at 51, 74, 97 and 108 days. The differences in anatomical composition between the smallest and largest foetuses within litters are comparable with those found postnatally in pigs fed on a high or low plane of nutrition, but this was not reflected in a very definite way in the chemical composition. X-ray photographs showed that ossification was more advanced in the largest foetus within a litter than in the smallest but the appearance of the ossification centres was not delayed in the latter.

7. Attempts to make reciprocal ovum transfers between inbred Large White and outbred Essex sows met with little success, probably due to the low fertility of the Large Whites, the prolonged exposure of the ovum during transference and the necessity of effecting the transfer of the ova at the 2-cell stage. The latter was conditioned by the rate of passage of the ova through the tube and the fact that they enter the uterus in the 4-cell stage.
The relation of production to mortality in the domestic fowl
Authors: Munro S. S.
Published: March 2009

1. In both Barred Plymouth Rocks and White Leghorns, the birds which died in Canadian Egg-Laying Contests during the year 1929–30 were, on the average, poorer layers than pen mates which survived.

2. The majority of deaths occurred in the lower producing pens.

3. The rise which has occurred in the death-rate since the inception of egg-laying contests in Canada is not connected with the rise in production which has occurred during the same period.

4. During the year 1929–30, although there is a tendency for the rate of production to parallel the rate of mortality throughout the year, a critical analysis of the data shows that the two rates are, in reality, independent.

5. It would appear that practices which contribute towards increased production, in the aggregate at least, contribute also toward health and lowered mortality.
The transport of water through heavy clay soils. I
Authors: Childs E. C.
Published: March 2009

Assuming a uniform heavy soil, without tilth, the water movement in which obeys diffusion laws, expressions have been deduced for four quantities, starting with a known moisture profile.

(a) The moisture profile at any subsequent time in the absence of rainfall or irrigation (neglecting evaporation, transpiration, and any other source of loss of moisture).

(b) The moisture profile at any subsequent time during such rainfall as causes flushing of the drains.

(c) The minimum rainfall necessary to cause flushing of the drains (maximum acceptable rainfall).

(d) The acceptable rainfall after a period of recovery following the previous drainage period.
The Determination of phosphorus in soils
Authors: McLean W.
Published: March 2009

1. Phosphorus in hydrochloric acid extracts of soil may be conveniently determined by digestion with sulphuric and nitric acids.

2. By boiling soil with hydrochloric acid (B.P. 110° C.) for 48 hours under reflux an end-point of extraction is reached.

3. Digestion of soil with sulphuric and nitric acids gives results in agreement with results by 48 hours” hydrochloric acid extraction.

4. It is suggested that the phosphorus thus extracted represents a definite category of soil phosphorus, which may be taken as the total phosphorus present in the soil.

5. Details of the suggested method are given.
Investigations in crop husbandry. IV. The preparation of the seed bed for wheat after potatoes
Authors: Garner F. H. , Sanders H. G.
Published: March 2009

Experiments were carried out in four successive years to compare the plough and the cultivator as implements for preparing a seed bed for wheat after potatoes: in the last two years direct drilling was introduced as a third treatment. Very diverse conditions were experienced, and an attempt has been made to formulate practical recommendations.
The buffer capacity and the specific gravity of bull semen
Authors: Anderson James
Published: March 2009

There was a significant positive correlation between the buffer capacity and motility of sperm and a highly significant negative correlation between the buffer capacity and thepH. There was no correlation between the buffer capacity and the volume of the ejaculate or the number of sperm per c.mm. Specimens which maintained a good motility on storage had a better buffer capacity than those which did not.

The specific gravity of 125 semen specimens was 1·0337. There was a highly significant positive correlation between the specific gravity and the number of sperm per c.mm. and the percentage motility and a highly significant negative correlation between the specific gravity and thepH. There was no relationship between the specific gravity of semen and the volume of the ejaculate, or thepH change. In general, the higher the specific gravity of the seminal fluid, the better was motility maintained on storage. The higher the specific gravity, the lower was thepH and the better the buffer capacity of seminal fluid.
Variation in the relationship between in vitro digestibility and voluntary dry-matter intake of different grass varieties
Authors: Walters R. J. K.
Published: March 2009

The relationship between digestibility (% DOMD in-vitro)and voluntary drymatter intake of a range of grasses conserved as artificially dried grass, has been studied in two experiments with reference to growth stage, percentage of leaf, stem and dead material, number of days to harvest and dry-matter yield.

In the first experiment digestibility accounted for 69% of the variation in intake during first growth and differences were established between varieties of the same and of different species in (a) intake at similar levels of digestibility and (6) the rate of change of intake per unit change of digestibility. In the second experiment differences in intake were established between varieties, within and between first growth and regrowth, when compared at a similar level of digestibility.

The variation in intake between varieties at a similar level of digestibility was not correlated with stage of growth or percentage leaf, stem and dead material in either first growth or regrowth. However, number of days to harvest and to a lesser extent, dry-matter yield, were associated with this variation, but only in first growth.

regrowths of grasses generally resulted in higher intakes than first growths, but the varietal variation in intake was not correlated between growths.
Growth in sheep. II. Efficiency of energy and nitrogen utilization from birth to 2 years
Authors: Graham N. McC. , Searle T. W.
Published: March 2009

Thirty sheep were pen-fed from age 2 days to nearly 2 years. Fifteen were fed ad libitum and the others were restricted to half that rate, age for age; daily food intakes were recorded. Sequential estimates of body composition were made on each sheep so that protein and energy gains could be obtained for specified age ranges.

In the sheep fed ad libitum, food intake increased several fold in the first few months of life but was relatively constant from 4 months despite large increases in body weight. Thus intake per kg¾ declined progressively as the sheep grew.

The data for the well fed and restricted groups were combined within each age range and linear regression was used to relate body growth (protein and energy) to food intake, variates being expressed as multiples of body weight (kg¾). Energy gain was zero when intake was 250–590 kJ metabolizable energy/day kg¾, depending on age. Wool growth per unit food intake was constant for each sheep throughout the experiment but was twice as great in some sheep as in others and was higher in the restricted group.

Efficiency of energy and protein utilization declined at weaning but otherwise did not vary much with stage of growth. Approximately 40% of energy storage was in protein during milk feeding; after weaning, the fraction declined from 25 to 10% (30 to 20% including wool protein) as the sheep grew.
In vivo measurement of rumen microbial growth using 35S
Authors: Kennedy P. M. , Lindsay J. R. , Milligan L. P.
Published: March 2009

A method for the measurement of the net rate of synthesis of rumen microbes, entailing separate infusions of 35S-sulphate into the blood and rumen, is described and compared with estimates derived using digesta flow markers. Measurements were made on seven occasions with sheep and on eight occasions with cattle given chopped hay or pelleted hay diets at intervals of 60 or 90 min. Additional measurements were made on two sheep and two cattle given lucerne hay at intervals of 6 or 12 h. Estimates of microbial synthesis using the proposed method for animals fed at intervals of 60 or 90 min were 0·95–1·23 (mean 1·05) that derived using flow markers. For animals fed at intervals of 6 or 12 h the ratio was more variable, 0·91–1·35 (mean 1·17). The agreement between methods tended to be poor in animals with a low rate of irreversible loss of serum sulphate. The proposed method can be accomplished with a low analytical load, and appears to have potential for application in animals fitted with rumen fistulae only, and fed at infrequent intervals.
Growth changes in the distribution of dissectable and intramuscular fat in pigs
Authors: Davies A. S. , Pryor W. J.
Published: March 2009

The subcutaneous, intermuscular and cavity fat depots of the half carcasses of 15 Large White × Landrace castrated male pigs, forming a growth series from 8 to 62 kg live weight, were dissected. Seventy individual muscles of these pigs were analysed for intramuscular fat content. The growth rates of each of the four fat depots, relative to total fat, were similar. Subcutaneous fat was the predominant fat depot over the growth range studied. Both intramuscular fat and non-fat dry matter grew faster than the entire muscles containing them. Growth gradients for the intramuscular fat of muscle groups, relative to either total intramuscular fat or to total fat, were similar to those for the entire muscles. The growth gradients for muscle groups were affected by neither the growth of the contained intramuscular fat nor the contained non-fat dry matter. Intramuscular fat density, but not non-fat dry-matter density, varied throughout the carcass. The fat content of muscles was highest in those that could be useful as subcutaneous insulators.
The Control of Chocolate Spot (Botrytis Fabae) Infection of Field Beans (Vicia Faba L.) by the Fungicides Benlate, Bavistin, Cercobin and BAS352F
Authors: Elliott Jennifer E. M. , Whittington W. J.
Published: March 2009

In a field trial performed within a winter-bean crop (cv. Throws MS) during 1975, Benlate, Bavistin, Cercobin and BAS352F were shown to effect some control over a mild, non-aggressive chocolate spot attack after one foliar application. Following a second foliar application, disease incidence on the leaves was significantly reduced by all except the Cercobin treatment, and reductions in the incidence of aggressive lesions on the leaves and the degree of infection on the pods were effected by all except the BAS352F treatment, indicating this chemical to be non-systemic. A reduced rate of leaf loss was observed for plants treated with Benlate, Bavistin or Cercobin, suggesting that part of the disease control effected by these chemicals might indirectly result from a delay of leaf senescence.
Comparative studies of meat V. Factors affecting the iodine number of the fat from the fatty and muscular tissues of cattle
Authors: Callow E. H. , Searle S. R.
Published: March 2009

1. Carcasses of twenty-one fat cattle (from six cows, ten steers and five heifers, aged from 12 months to 12 years and representing seven breeds) have been dissected into nine joints, and the fatty and muscular tissue from each joint dissected and analysed for fat. The iodine number of each sample of fat has been determined.

2. The fat in fatty tissues ranged from 28·3 to 96·7%, and in muscular tissues from 1·3 to 14·2%. Iodine numbers of fat from fatty tissues ranged from 34·0 to 69·0 and those of fat from muscular tissues from 45·9 to 73·2.

3. By an analysis of covariance it has been possible to reduce these data to two families of regression lines—those for fatty tissue and those for muscular tissue.

4. The equations for fatty tissue have the following generalized form:

I.N. = AFT + CFT + JFT + b1F/FT,

where AFT = 55·6 ± 1·7 and is a general constant,

CFT is a series of constants for the various carcasses and ranges from +12·6 to −6·7,

JFT is a series of constants for the various joints and ranges from +6·6 to −10·3,

b1 is a general constant with the value −0·052(± 0·025),

F/FT is the percentage of fat in any given sample of fatty tissue, and I.N. is its iodine number.

5. A similar set of equations has been deduced for muscular tissue. Here, however, the relation between iodine number and percentage of fat is a rectangular hyperbola. Consequently, the inverse (Z) of the percentage of fat (in order to get a straight-line relationship) has been used.
Nutrition of the bacon pig. XIX. The requirement of the bacon pig for certain essential amino acids
Authors: Evans R. E.
Published: March 2009

The addition of essential amino acids to all-vegetable diets, so as to raise the biological value of their proteins to the level of animal-protein concentrates, has often been advocated in the past by animal nutritionists. This aim was frustrated in practice since it was impossible, until recently, to secure the necessary supplies at prices that would make such additions economical. Feeding stuffs with added amino acids are now being sold commercially. This is possible following the manufacture of synthetic DL-methionine and crude L-lysine monochloride.

It seemed desirable, therefore, to carry out investigations into the potential value of these amino acids to the pig feeder. This paper deals with the effect on growth, food utilization and retention of nitrogen of adding small amounts of lysine and methionine to the diet. An attempt is made to correlate the amino acid composition of the pig's diet with its rate of growth, the energy supply being adequate.
The value of nitrophosphate fertilizers
Authors: Cooke G. W. , Mattingly G. E. G. , Widdowson F. V.
Published: March 2009

The phosphorus effects of several nitrophosphates were compared with those of superphosphate and dicalcium phosphate in field experiments in 1954 and 1955. In both years immediate effects were measured on radishes, and in 1954 residual effects were measured on a crop of ryegrass which was cut twice.

None of the nitrophosphates tested were more than one-third as efficient as superphosphate for radishes. The residual effects of nitrophosphate (relative to superphosphate) for grass were much larger than their corresponding immediate effects on radish; several materials were as good as superphosphate for increasing the yields of the second cut of grass. The immediate effects of nitrophosphates were much increased by preparing finely ground powders from commercial granulated products.

In both years dicalcium phosphate was equivalent to superphosphate and gave significantly higher yields of radish than any of the granulated nitro-phosphates. At the second cutting of grass in the 1954 experiment there were no significant differences between yields given by dicalcium phosphate and the nitrophosphates.

The solubilities of the phosphorus of nitrophosphates in solutions of citric acid, neutral ammonium citrate, and alkaline ammonium citrate, were of little value in estimating immediate effects of granulated products. It is suggested that physical properties of the granules affect the rate at which phosphate ions can diffuse and so complicate the interpretation of solubility tests.
Effect of nitrogen and sulphur application and seed inoculation with Rhizobium leguminosarum on the yield of beans (Vicia faba) in field trials
Authors: Olivares J. , Martin E. , Recalde-Martinez L.
Published: March 2009

The effect of nitrogen and sulphur application and seed inoculation on the yield of beans (Vicia faba) was studied at two locations in 1979–80 and 1980–1. Nitrogen was applied at flowering, whereas sulphur was applied as foliar applications in elemental form, several times during the growth cycle of plants or only once at four different growth stages. Results showed high and significant increases in yield, particularly when the three treatments were combined. Results additionally suggested that a single application of sulphur at 45 days after emergence was as effective as four separate applications.
The fertilizer requirements of sugar beet
Authors: Boyd D. A. , Garner H. V. , Haines W. B.
Published: March 2009

The paper describes the results of over 300 factorial experiments carried out in each factory area in the years 1934–49 for the Sugar Beet Research and Education Committee of the Ministry of Agriculture as a result of co-operation between Rothamsted workers and the agriculturists and fieldmen attached to the beet factories. All the experiments tested the effects of levels of nitrogen, phosphate and potash, and rather more than half tested the effect of salt also.

Except on fen soils, nitrogen gave substantial responses in all factory areas, especially in the presence of high levels of potash or salt. Large variations in response from season to season were closely associated with the rainfall of the preceding winter months, responses being greater after wet winters than dry ones.

In spite of some selection of sites in favour of greater responses, the average net returns from phosphate were relatively small.

The effect of potash was closely linked with the amount of nitrogen applied; in the presence of nitrogen, dressings well above the level of 1·2 cwt. K2O per acre tested in the experiments are likely to give a useful net return. Soils derived from the Chalky Boulder Clay seem to be exceptional in showing no response. Apart from this, there were only small variations in responses to nitrogen and potash between factory areas. The application of 5 cwt. salt gave substantial responses in almost all parts of the country, whether or not potash was also applied; on the other hand, responses to potash were usually small when salt was also applied.

Whilst there was a general relationship between soil analysis for phosphate and potash (citric acid method) and crop response, adjustments to the optimal dressings according to soil analysis were not of sufficient reliability to be of much practical value.
Accumulated temperature and maize development in England
Authors: Bunting E. S.
Published: March 2009

Information is given on dates of sowing and mid-silk for Inra 200 in 40 experiments (two each year at Oxford, 1962–75, and at Cambridge, 1970–5), together with cumulative temperatures between these dates. Two methods of defining effective temperature for maize development have been considered, namely the method advocated by U.K. Meteorological Office with 10 °C as the base temperature (the Ag. Met. method) and that defined in Ontario units. The regression relation between accumulated temperature and dry-matter content of the grain during ripening has also been calculated, from data obtained in the years 1966–74, and assessments made of cumulative totals in Ag. Met. day °C and in Ontario units from the date of silking until the grain D.M. content is 40%, when the crop is considered suitable for ensiling, and from silking until grain D.M. content is 60%, when the crop may be considered ripe.

Cumulative temperature totals were significantly more stable over experiments than time expressed in calendar days. Totals of Ontario units were less variable than totals of Ag. Met. day °C. Estimated requirements for Inra 200 were 405 day °C or 1380 Ontario units from sowing to mid-silk, 255 day °C or 800 Ontario units from silking to 40% D.M. in the grain (for silage crops), and 380 day °C or 1235 Ontario units from silking to 60% D.M. in the grain.