bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations on the mineral metabolism of pullets. III
Authors: Common R. H.
Published: March 2009

1. An experiment on pullets combining daily calcium and phosphorus balance determinations with carcass analyses is described.

2. It is shown that fat content of pullets is affected by the calcium content of the ration. The fat content was higher on a low calcium ration than on a high calcium ration.

3. The CaO content of pullets was raised considerably by feeding a high calcium ration before laying. This CaO must have been stored in the bones, which contained between 97·2 and 98·7% of all the CaO in the body.

4. The experiment suggests that pullets may use up to about one-quarter of their body calcium at the outset of laying for purposes of shell formation.

5. The composition of the inorganic material of the skeleton of pullets may be modified by alterations in their mineral metabolism due to egg production on diets with and without a calcium carbonate supplement. The nature of these modifications and their relationship to calcium metabolism during laying is discussed.
On alimentary acetonuria and ketonuria in dairy cattle induced by feeding grass silage of the butyric acid type
Authors: Brouwer E. , Dijkstra N. D.
Published: March 2009

Attention has been directed to the occurrence of acetonuria in apparently healthy and in diseased cattle.

It has been shown possible to cause analimentary acetonuriain milch cows experimentally by feeding large quantities of grass silage of the butyric acid type. The reaction of the urine remained alkaline and the ammonia content was within a normal range, showing that there was no real acidosis. The animals seemed by no means to be ill.

As to the cause of the acetonuria,a priori, there seemed to be little doubt that in these cases the ketones resulted, in the animal body, from the incomplete oxidation of the butyric acid of the grass silage. Yet, further experiments with a lactic acid silage containing no butyric acid at all indicated that the question may be more complex.
A study of the chemical and bacteriological changes occurring in grass silage
Authors: Allen L. A. , Harrison J. , Watson S. J. , Ferguson W. S.
Published: March 2009

Although silage Has Been Made in this country for more than 50 years, the exact nature of the chemical and bacterial changes which occur during the period of ripening is still very imperfectly understood. There are several reasons for this.

(1) The chemical changes are compounded of those due to plant respiration and those brought about by bacterial growth, and since these take place to a large extent simultaneously, it is difficult to apportion the amount of the total change to each factor separately.

(2) There is good reason to believe that the extent and rapidity of the changes which occur in the body of the silo are influenced by such variable factors as the external temperature, the moisture content, botanical species and age of the crop, and the season of the year when cut.

(3) They are also dependent upon the method of packing at the time of ensiling, since this ensures more or less anaerobic conditions, and will therefore affect both the nature of the plant respiratory changes and the kind of bacterial flora which develops.
A note on the effect of different cereals in the fattening ration on the composition of the body fat of the fowl
Authors: Cruickshank E. M.
Published: March 2009

Over a 12-day fattening period the use of maize in the poultry-fattening ration has no detrimental effect on the consistency of the body fat.

When fattening is rapid and live-weight gains are satisfactory, the type of fat deposited in the bird is harder than that laid down on a normal ration containing mixed cereals and a protein supplement.
Soil improvement in the Sudan Gezira
Authors: Greene H. , Snow O. W.
Published: March 2009

After reviewing the possibility of soil deterioration in the Gezira and its dependence on change in the exchangeable bases in the soil we have given an account of field trials with soil improvers. Increased penetration of water, improved supply of nitrogen and higher yields were obtained, but the effects were not lasting. A part of the initial response is ascribed to the flocculating action of salts formed near the soil surface by interaction between soil and soil improver. With continued watering these salts are washed from the surface soil, but the applications of soil improver were insufficiently heavy and the leaching insufficiently thorough to effect any deep-seated change in the soil. Drainage experiments in which effluents were measured and analysed showed small changes in the right direction, but their main outcome has been strikingly to confirm the view that lateral movement of water through Gezira soil is so slight as to promise small hope of achieving any large-scale improvements by means of subsoil drainage. Analyses of saltbush have been made and showed that although these plants remove much sodium from the soil they can hardly be regarded as a practicable agent in soil improvement, since the amount of sodium in the soil is comparatively large. On the other hand, it appears that by including saltbush in rotation and by removing the crop from the land it is possible to guarantee that no progressive deterioration will occur in consequence of accumulation of sodium introduced in the irrigation water. Further analyses of irrigation water were made in this connexion and substantially confirmed Beam's earlier data.

We do not yet know whether, under normal irrigation, the general tendency is for an accumulation of sodium or whether, on the contrary, salts are slowly being washed from the soil column (Greene & Peto, 1934). Until the nature and extent of chemical changes in the soil are accurately assessed it is impossible to say what annual expenditure on soil improvers, drainage, growing and disposal of saltbush is needed for maintenance of soil fertility. Further laboratory work should be directed to the detailed study of base exchange in Gezira soil and to observation of the physical characters on which permeability depends while, in the field, further experiments should be made in the use of soil improvers and drainage; information should also be sought as to the most convenient and least expensive way of including saltbush in the rotations best suited to different parts of the Gezira and as to the economic disposal of saltbush ash.
Experiments on the spacing of sugar beet: I. Results based on plot yields
Authors: Garner F. H. , Sanders H. G.
Published: March 2009

Since sugar beet was first introduced into this country many experiments have been conducted to determine the effects of spacing on yield: the general advice based on these experiments is that beet should be spaced as closely as working conditions permit. Davies (1931) carried out a series of experiments in the West Midlands, and came to the conclusion that yield was not related to the number of roots per acre, but was affected by their distribution. His work demonstrated that wide row distances could not be compensated by narrow spacing in the row. He found that yield increased as row distance decreased down to 16 in., but that singling distances of 4—10 in. produced no differences in yield of roots: the yield of green leaves, on the other hand, was increased as singling distance decreased, but was unaffected by row distance (Davies & Dudley, 1929). Although Davies' results would be generally accepted as a true expression of the general rule, many isolated spacing experiments fail to conform to them; it is possible that discrepancies in results, that undoubtedly occur, may be due to variations in the “plant” actually obtained in the experiments. Engledow et al. (1928), as a result of counts and weights taken on ordinary farm crops of sugar beet, concluded that uniformity of “plant” was a most important spacing factor affecting yield. In America Brewbaker & Deming (1935) have found yield to be related to percentage stand (correlation coefficients varying from +0·35 to +0·70), the regression between the two variables being approximately linear over the range studied. They also found that uniformity of “plant” was more important than spacing distances, either between or in the rows. Their work showed that single gaps had little effect on yield, because neighbouring beet compensated for them to the extent of 96·2%; serious loss of yield only occurred, therefore, with adjacent gaps. Pedersen (1933) studied the relationship between percentage of gaps and yield in a large number of Danish experiments with sugar beet and mangolds. In the case of sugar beet he found that the compensatory growth of neighbouring roots amounted to 76% for a single gap, and that the percentage compensation decreased as the size of gap (i.e. number of missing beet) increased. In an earlier paper (Pedersen, 1931) he had shown that under ordinary field conditions the distribution of gaps was approximately random.
Pig-feeding experiments with cod-liver oil
Authors: Foot A. S. , Henry K. M. , Kon S. K. , Mackintosh J.
Published: March 2009

Six litters of pigs farrowed, reared and fattened on a ration of barley meal, weatings, soya-bean meal, meat meal and minerals failed to thrive and in the later stages of fattening many of the pigs showed typical symptoms of vitamin A deficiency.

Six comparable litters raised under similar conditions and on the same meal mixture with ° 1 or 2% of a commercial cod-liver oil of guaranteed purity and standardized vitamin content made good progress and nearly all the pigs weaned in these litters were fattened for pork or bacon.

Estimations of liver reserves of vitamin A of the pigs receiving no cod-liver oil indicated that the liver store was exhausted soon after weaning. All pigs receiving cod-liver oil gradually increased their liver store of vitamin A. The stores rose approximately in proportion to the level fed and period of feeding. There was no evidence that the higher levels of cod-liver oil had any practical advantage over °%.

The symptoms shown by the pigs receiving no cod-liver oil included loss of appetite, cessation of growth, impairment of vision in daylight, abnormal gait, convulsive fits and nervous collapse. Pneumonia and/or inflammation of the intestines was found in all of seven pigs that died during the fattening period.
The effect of low-temperature grain pre-treatment on the development, yield and grain of some varieties of wheat and barley
Authors: Bell G. D. H.
Published: March 2009

1. The effect of low-temperature grain pre-treatment on two winter varieties of wheat and two winter varieties of barley is seen in a very definite reduction in the number of tillers produced, which, however, had no subsequent effect on the number of ears surviving at harvest. Very little effect resulted from the treatment of spring varieties of wheat and barley in the number of tillers produced, although the spring wheat variety did show a slight reduction.

2. Gross yields per plot were unaffected by the treatment in all the varieties, but the yields per plant were affected in the wheat experiment, and the yield per ear in the barley experiment. There was a general increase in the yield per plant of all wheat varieties, while in the yield per ear one barley variety was unaffected, another showed an increase, while the third suffered a reduction.

3. The grain from treated plants was affected in 1000-grain weight and nitrogen content in the wheat experiment, while only the 1000-grain weight suffered any change in the barley experiment. Only one wheat variety showed an increase in 1000-grain weight, while each of the three varieties responded differently with regard to the nitrogen content of the grain. Similarly, each of the three barley varieties was affected differently with regard to 1000-grain weight, one being unaffected, another showing a decrease, while the third showed an increase.

4. Analysis of the behaviour of the varieties with regard to tillering and ear production showed clearly that the maximum of tillers produced bears little relation to the number of ears at harvest. In the barley varieties high yield and low nitrogen were associated with the largest number of ears, which in turn was associated with the lowest tillering. In the wheat varieties high yield was associated with high 1000-grain weight. In both experiments the spring varieties outyielded the winter varieties whether the latter had been treated or not.
The quantitative extraction of carotene from grass
Authors: Moon F. E.
Published: March 2009

The majority of methods for determining carotene involve a preliminary determination of total carotenoids, followed by a phase separation of the two pigments. This phase separation considerably limits the usefulness of such methods, and in order to dispense with it a direct extraction of carotene is necessary. For this purpose petroleum ether may be used in the presence of alcohol.

The use of hot alcoholic potash for the disintegration of leaf material and separation of chlorophyll leads to a very undesirable precipitate which hinders subsequent extraction. Two alternative methods are available, which overcome this difficulty, viz. (1) extraction with hot alcohol, followed by treatment of the extract with potash, and (2) saponification with hot aqueous potash, followed by filtration and extraction of the grass residue with alcohol. The second of these methods has been adopted, being of greater general utility and capable of producing complete cellular breakdown, which is essential for efficient extraction. Details of this extraction process have been described.

A comparison of the results obtained, with those from two other methods, has been made by a colorimetric determination of the extracted pigment. The variance and standard error have been shown to be smaller than those for the other two methods, and it has been concluded that the results obtained are reproducible with considerable accuracy.
The composition and digestibility, when fed to pigs and sheep, of potato cossettes and potato meal
Authors: Woodman H. E. , Evans R. E.
Published: March 2009

Artificially dried potatoes are being marketed in this country at the present time in two grades, known as potato cossettes and potato meal. “Chat” potatoes are first washed in water tanks provided with revolving paddles and are then elevated into a machine that pulps them into pieces about the size of fingers. The resulting cossettes enter the drier directly from the pulper, forming a layer about 4 in deep. The wet material passes on an endless conveyer, consisting of a drying belt of perforated sheet metal, through three zones of temperature. The hot-air current has a temperature of 250–260° F. in the first stage and 180–200° F. in the third. The dried cossettes, which are suitable for feeding to sheep and cattle, may be ground to potato meal for use in the rations of pigs.
A Study of the metabolism of fowls: I. A calorimeter for the direct determination of the metabolism of fowls
Authors: Deighton Thomas
Published: March 2009

Some years ago my colleague, Mr E. T. Halnan, suggested the construction of the present instrument for the purpose of determining figures for domestic fowls corresponding to those of Kellner for ruminants.

Owing to the activity of the fowl, it is essential that an instrument for this purpose should be capable of recording accurately a heat output which may be varying with some rapidity.

From this point of view the advantages of the indirect method were considered but were eventually rejected for the following reasons: (a) the advantage accruing from our greater experience of the direct method in this laboratory, (b) the work of Adams & Poulton (1933, 1934, 1935) calling in question the fundamental bases of the indirect method, and (c) the very variable R.Q.'S obtained in earlier work by numerous investigators working with birds.

That the decision was wise soon became apparent when work on birds was begun. It is certain that no ordinary apparatus of that kind could possibly take account of the variations caused by the constant changes in activity.

The principle of a “compensatory” or “balanced” calorimeter more or less as developed by Noyons (1927), Benedict (1927) and Heyster (1933), was selected as the most likely to give promptness in registration, and this choice has been amply justified in the result. Such instruments can be very lightly constructed, although where living animals are concerned, since their movements cannot be controlled, as can those of a human being, a greater margin of strength has to be provided, which naturally increases the heat capacity and lag and reduces sensitivity to small changes in heat evolution.
Competition between maize and Rottboellia exaltata
Authors: Thomas P. E. L. , Allison J. C. S.
Published: March 2009

One pot and five field experiments were made to study different aspects of the competition between R. exaltata and maize.

The growth of young maize plants was not inhibited by being grown together in pots with young R. exaltata plants. In the field the soil tended to be somewhat wetter when the two species were grown together than when maize was grown alone, and was wettest with R. exaltata grown alone. Maize grain and total yield decreased and shoot yield of R. exaltata increased with R. exaltata plant density on both irrigated and unirrigated blocks of land, but yields were not much affected on either block by increase in plant density of maize or in nitrogen supply; maize yield was increased by irrigation but that of R. exaltata was not. Maize plant arrangement did not greatly affect maize grain and total yield or R. exaltata shoot yield, nor did arrangement of R. exaltata plants have much influence on their depression of maize yield, but R. exaltata caused a greater decrease in the grain yield of a short than of a tall maize cultivar.

R. exaltata plants germinating at the same time as the crop plants did not have much effect on maize grain yield if they were removed by 8 weeks after the seedlings emerged, but decreased it considerably if allowed to remain for 12 weeks or more; weeds sown 2 or more weeks after the maize emerged hardly grew and had little effect on maize yield. When maize and R. exaltata were grown together leaf area of the maize was little affected up to the time of flowering, but was decreased after flowering, while leaf area of the weed was greatly depressed. Up to 7–8 weeks after seedling emergence more of the ground area was covered by foliage when maize was grown with R. exaltata than when it was grown alone, but later the ground was completely covered by foliage in both cases. Dry weight of grain and shoot of maize increased and that of shoot of R. exaltata decreased when the weed plants were shortened with growth regulators.
Rapid methods of examining soils. II. The use of p–nitrophenol for assessing lime status
Authors: Schofield R. K.
Published: March 2009

By the use of a solution of p–nitrophenol in lime water a rapid and simple measurement can be made of the lime taken up by a soil sample in reaching neutrality. The same method applied to acid-washed samples gives the exchangeable base content at pH 7.
The relations of Bacillus mycoides with ammonification, nitrification, and soil fertility. (With seven text-figures.)
Authors: Tyagny-Ryadno M.
Published: March 2009

1. B. mycoides is an organism which energetically decomposes organic nitrogenous matter forming large amounts of ammonia. When soil was inoculated with a culture of this organism, active ammonification took place and the rate of nitrification was raised.

2. The first effects of the inoculation of soil by B. mycoides were a parallel development of ammonification and nitrification; later the rate of ammonification fell off, but nitrifying organisms continued to transform ammonia into nitrate.

3. The degree of nitrification in chernosiom soils is a function of the activity of B. mycoides. By creating conditions appropriate to these bacteria, both ammonifying and nitrifying processes are likewise intensified.

4. Fertilisation with dung is beneficial not solely on account of the nutrients supplied ad hoc, but also because it leads to an increase in the numbers of B. mycoides. Farmyard manure is a source of B. mycoides, and acts similarly to an inoculation with those bacteria.
The determination of total sulphur and sulphate sulphur in feeding stuffs
Authors: Woodman H. E.
Published: March 2009

Recent work on the growth of wool in relation to the cystine supply in the sheep's diet, together with the discovery in proteins of a new sulphur-containing amino acid, methionine, has directed attention to the importance of being able to determine, by methods easily and quickly carried out, the amounts of total and inorganic sulphur in plant products and feeding stuffs. Details are given in the present note of the methods employed by the writers for the estimation of total sulphur, sulphate sulphur and, by difference, organic sulphur.
A statistical Analysis of the interrelations of litter size and duration of pregnancy on the birth weight of rabbits
Authors: Wishart John , Hammond John
Published: March 2009

In order to disentangle the various causes affecting foetal growth, and so the birth weight of the animal, it is necessary to employ statistical methods in addition to physiological ones. This paper presents methods suited to a study of growth where two such factors have to be separated and their effects on growth measured quantitively.
Growth and yield of sugar beet on contrasting soils in relation to nitrogen supply: II. Growth, uptake and leaching of nitrogen
Authors: Last P. J. , Draycott A. P.
Published: March 2009

Nine field experiments with sugar beet in 1968–70 tested eight amounts of nitrogen fertilizer (0–290 kg N/ha) on a shallow calcareous loam (Icknield Series), on a deep sandy loam (Newport Series) and on a heavy clay loam (Evesham Series). The amount of mineral nitrogen in the top and sub-soils was determined before applying fertilizer and at monthly intervals from May to October in plots given 0, 125 and 250 kg N/ha. The crop on these plots was also sampled at monthly intervals throughout the growing season and the yield and nitrogen uptake determined. The soil analyses indicated that in springs with average rainfall, the leaching losses of nitrogen fertilizer are negligibly small, although there was some evidence that losses may be greatest on sandy loams. In very wet springs such as 1969, with almost double the normal rainfall, losses through leaching are considerable – on average, 40 kg N/ha. Dry-matter yields and response to nitrogen fertilizer differed between the three soils consistently from year to year. On the calcareous loam, neither amount of fertilizer changed the dry-matter yield of roots in any year. The crop on the clay loam needed a small dressing and on the sandy loam a larger dressing of fertilizer for maximum root dry-matter yield. Uptake of nitrogen by the crops usually paralleled the decreases in soil mineral nitrogen although on the clay loam nearly a third of the nitrogen applied could not be accounted for in the soil or plants, suggesting that some denitrification may have taken place. When the amount of nitrogen taken up by unfertilized crops is allowed for, the percentage recovery of applied fertilizer nitrogen at final harvest ranged from 42% on the calcareous loams to 62% on the sandy loams.
The effect of growth rate on muscle distribution in sheep
Authors: Murray D. M. , Slezacek Olga
Published: March 2009

There is little information available on the effect of growth rate on muscle distribution in sheep. Although Lohse, Moss & Butterfield (1971) and Lohse (1973) have reported data on muscle distribution of Merino sheep, the growth rates of animals in both these studies were neither controlled nor reported. In another experiment using Merino sheep, Lohse, Pryor & Butterfield (1973) studied the effect of a period of live-weight loss on the relationship of selected muscles to total side muscle during subsequent re-alimentation. They found that the interrupted growth path decreased the proportion of total side muscle formed by the weight of ten muscles which had previously been classified as muscles with a high growth impetus (Lohse, 1971). Data are presented herein for the muscle distribution of sheep grown along three growth paths.
Investigations into the Intensive System of Grassland Management. By the Agricultural Research Staff of Imperial Chemical Industries, Limited. X. A Further Study of the Mineral Content of Intensively Treated Pasture
Authors: Ferguson W. S.
Published: March 2009

1. The mineral content of pasture as grazed under the Intensive System of Grassland Management has been examined. The pasture samples were collected from two centres in 1927 and from one centre in 1929. Magnesium, manganese, iron, sulphur and chlorine were determined in addition to the more common elements.

2. The mineral content of intensive pasture is equal to that of the best type of pasture produced by other systems of management, and superior to that of average good cultivated pasture in Great Britain.

3. The seasonal variations of the soluble ash, potash, soda and phosphoric acid depend principally on the climatic conditions.

4. The effect of drought at one centre has been to lower the percentages of soluble ash, potash and phosphoric acid.

5. Correlations exist between nitrogen and phosphoric acid, and soluble ash and potash. There is no evidence of further correlations between the constituents.
Studies on Calcium Cyanamide. II. Microbiological Aspects of Nitrification in Soils Under Varied Environmental Conditions (With Four Text-figures.)
Authors: Mukerji B. K.
Published: March 2009

1. Calcium Cyanamide (the commercial form of Calcium Cyanamide) markedly increased the bacterial numbers of soils in uncropped pots and both the bacterial numbers and carbon dioxide production in flasks under laboratory conditions.

2. Improvements in the aeration of soil cultures in the laboratory not only increased the numbers of bacteria and accelerated the production and disappearance of ammonia but reduced the initial nitrification lag and increased the final accumulation of nitrate from Calcium Cyanamide. Urea formed from Calcium Cyanamide disappeared much more quickly in soils aerated by daily shaking than in undisturbed soils.
Relationship between sperm concentration, initial fructose concentration and different measures of fructolysis in buffalo semen
Authors: Dhanotiya R. S. , Srivastava R. K.
Published: March 2009

FI (mg of fructose utilized by 109 sperms in 60 min at 37 °C), fructolytic coefficient, Ku (fractional decline in the spermatozoal fructolytic activity per minute on an instantaneous basis) and maximum fructose utilization, MFU (mg of fructose utilized by 109 sperms in 1 min at zero incubation time on an instantaneous basis), have been estimated for buffalo spermatozoa. Out of these three attributes, the fructolytic coefficient was found to be independent of the initial fructose concentration (IFC), sperm concentration and incubation period and was a better criterion for the assessment of the quality of buffalo semen than the fructolytic index.

Simple and partial correlation coefficients between sperm concentration, IFC and FI, fructolytic coefficient and maximum fructose utilization are presented.
Seasonal fleece changes in two selection lines of Scottish Blackface sheep during their lifetime on the hill
Authors: Ryder M. L.
Published: March 2009

Ten Scottish Blackface ewes from each of three lines, a line selected for hairiness, a line selected for a fine fleece, and an unselected control, were fleece and skin sampled in April, June, September and December, during their 6J year life-span on the hill.

Fleece weight differed between individuals and between lines, and declined by 4% per year from 1·5 kg at 1 year, to 1·3 kg at 6 years. Fleece grade was inadequate as a method of denning fleece differences between the lines.

The height of the spring ‘rise’ in growth in April differed between years, and between lines, declining 2 mm a year from 26 mm at 1 year. Staple length was greatest in the Hairy group and least in the Fine group (P < 0·05). Growth in length was faster between September and December (autumn) than between April and June (spring). Staple length decreased by 14 mm a year.

The lines differed significantly (P < 0·05) in mean fibre diameter but not in modal fibre diameter. There was a highly significant decrease in diameter from summer to winter, ranging from 20% in the Fine line to 31% in the Hairy line, the greater decrease in the Hairy line being attributed to loss of medulla.

The selection had between 1954 and 1972 changed the S/P follicle ratio of 3·0 in the control to 2·8 in the Hairy line and 3·2 in the Fine line. Most seasonal follicle inactivity occurred in April, December came second, and June invariably had more follicle inactivity than September. The control line had the greatest values of primary follicle inactivity and the Fine least. Among the secondary follicles the Hairy line had most inactivity, and the control line least. Maximum primary fibre medullation occurred in either June or September, and medullation was at a minimum in December or April.
The performance of cowpea (Vigna unguiculata (L.) Walp) as influenced by weed competition
Authors: Remison S. U.
Published: March 2009

Experiments were made in a glasshouse and in the field to estimate the effect of weed competition on cowpea performance.

In the glasshouse experiment, plant height, number of nodes, green leaves, peduncles, weight of poda and seeds of cowpea were decreased by competition from Euphorbia heterophylla and the decrease was greater with increasing density of the weed associate. Generally cowpea did not respond to application of fertilizers. In the field experiment, competition from the natural weed flora affected the number of days to 50% flowering and yield components of the four cowpea varieties studied. The yield of the climbing variety, Dinner, was least affected by competition whilst the semi-erect variety, Ife brown, was the most affected.
The phosphorus requirement of lettuce: II. A dynamic model of phosphorus uptake and growth
Authors: Scaife M. A. , Smith R.
Published: March 2009

A dynamic model is presented in which the problem of predicting P response is broken down into various components, such as:

(a) Weight and P content of emerging seedling.

(b) Normal growth curve of the fully nourished plant.

(c) A ‘deficiency-tolerance’ factor relating depression of relative growth rate to plant P concentration.

(d) An ‘affinity’ term relating sink concentration to P status of plant.

(e) A perirhizal resistance term for diffusive transport to roots.

(f) Capacity and intensity of P supply from the soil. Mass flow supply via the transpiration stream is also included.

By changing parameter values one may attempt to simulate the effect of any of these factors on the shape of the P response curve and any other part of the system throughout crop life. At present the model over-estimates growth at low levels of P supply, but predicted plant P concentrations agree reasonably well with observed data.
The free- and protein-amino acids of the rumen phycomycete fungi Neocallimastix frontalis and Piromonas communis
Authors: Kemp P. , Jordan D. J. , Orpin C. G.
Published: March 2009

The proteins and the amino acid profile of the rumen fungi Neocallimastix frontalis and Piromonas communis have been examined and the in vitro digestibility of the vegetative growth determined.

The mean true protein content of N. frontalis was 24% of the dry weight and 30% for P. communis, which has a lower chitin content. 50% of the protein extracted from cells and examined by HPLC was in the 200000 MW range and 40% in the 50000 MW range. Polyacrylamide gel electrophoresis after treatment with sodium dodecylsulphate and 2-mercaptoethanol indicated that the native proteins were composed of smaller units in the MW range 25000–50000.

The amino acid profiles of the two fungi were similar and compared favourably with those of casein and fraction 1 protein of lucerne.
Enhanced soil temperature during very early growth and its association with maize development and yield in the Highlands of Kenya
Authors: Cooper P. J. M. , Law R.
Published: March 2009

Previous work has shown a strong relationship between the mean soil temperature during the first 5 weeks of growth of a maize crop, and the final grain yield, warmer soils leading to greater yields. Trials were laid down in 1975 and 1976 to establish how early in the development of a maize crop higher soil temperatures would lead to increased yields. Soil temperatures were raised by polythene mulching applied at planting with six times of mulch removal: at crop emergence, 1, 2, 3, 4 and 5 weeks after emergence. Raised soil temperature led to a greater rate of development and leaf area production during early growth. Greater leaf area was due to greater leaf emergence rate rather than increase in leaf size, since increase in soil temperature was associated with a decrease in individual leaf size. This trend was reversed from leaf number 15 onwards resulting in no differences in leaf area, leaf weight or total dry matter at tasselling. In spite of this, yield differences were observed. Increase in soil temperature during germination alone had a beneficial effect on final grain yield, and this effect increased with duration. Increasing soil temperature for longer than 3–4 weeks from emergence caused no further yield increase. Yields increased from 133 and 172 g/ plant to 220 and 238 g/plant in 1975 and 1976 respectively. Yield increases were associated with more grains per plant rather than greater grain size. The period during which increased soil temperature led to increased yields coincided with the period when the apical meristem was below ground level. The mechanism involved is not yet clear.
General and specific combining ability of potato parents for resistance to the white potato cyst nematode (Globodera pallida)
Authors: Phillips M. S. , Wilson Linda A. , Forrest J. M. S.
Published: March 2009

The practical value of obtaining estimates of general combining ability (GCA) from data accumulated in a breeding programme has been discussed by Gilbert (1967). In this study use has been made of data collected during the course of screening potato breeding material, derived from Solanum vernei Bitt. et Wittm., for resistance to the white potato cyst nematode, Qlobodera pallida (Stone) Mulvey & Stone, to assess the relative contributions of GCA and specific combining ability (SCA) by the procedure described by England (1974) which is based on Gilbert's (1967) method.
Changes in major element composition of developing barley grain
Authors: Duffus Carol M. , Rosie Roberta
Published: March 2009

Changes in the amounts of nitrogen, phosphorus, magnesium, calcium and sodium present in intact grain, endosperm, testa pericarp and embryo throughout the developmental period were recorded. While the overall pattern in intact grain was one of steady accumulation, considerable variation from this pattern was found within the different parts. The results are discussed in relation to the biochemical events accompanying maturation.
Thin sows: 2. Observations on the energy and nitrogen exchanges of thin and normal sows in environmental temperatures of 20 and 5 °C
Authors: DeB. Hovell F. D. , Gordon J. G. , MacPherson R. M.
Published: March 2009

The experimental animals were sows which had been made thin by underfeeding for several parities (thin sows), and siblings which had received adequate energy (standard sows).

The energy metabolism of three thin anoestrous and three non-pregnant standard sows were measured at 20 and 5 °C. There were no differences between the two groups of sows. The fall in temperature increased the average maintenance requirement by 60% from 476 to 753 kJ/kg0·75/day (1192–1922 kJ/kg0·56/day).

The tissue insulation of the thin sows was 28% lower than that of the standard sows, although this difference was not statistically significant. The thin sows compensated by having a better external insulation. The average total body conductance was 306 kJ/m2/°C/day.

The standard sows were in positive nitrogen balance (+ 4·2 g/day, 95% confidence limits 1·5 to 7·0 gN) and the thin sows in negative nitrogen balance (– 4·4 g/day, 95% confidence limits – 2·1 to – 6·8 g N) at energy equilibrium. It is suggested that this difference might be explained if the total nitrogen requirement of the two groups of sows was similar, but that their requirement for energy was related to their body surface area.

There were no differences between the two groups of sows in their digestive efficiency, but the digestibilities of both energy and nitrogen were reduced at 5 °C.

It is concluded that the primary cause of the ‘thin sow syndrome’ is underfeeding, particularly in cold environments. Other features of the syndrome are probably a consequence of undernutrition and depletion of the body energy reserves.
A histological technique, using cellulolytic enzyme digestion, for assessing nutritive quality differences in grasses
Authors: Selim O. I. , Wilson D. , Jones D. I. H.
Published: March 2009

Transverse sections of Festuca arundinacea Schreb. leaves were incubated in cellulase at 40 °C with and without pepsin pretreatment. The sequence of tissue breakdown (mesophyll-phloem-adaxial epidermis) was the same in both treatments, but the rate of breakdown was much slower without pepsin pretreatment (up to 30 h compared with up to 90 min). Pepsin appeared to make the primary cell wall more susceptible to cellulase attack. Young leaves were digested faster than old. Possible applications to the evaluation of grass nutritive quality are discussed.
Nitrogen response curves of spring barley
Authors: Sparrow P. E.
Published: March 2009

The results of 83 experiments with nine levels of nitrogen and six experiments with seven levels were used to investigate models of the response of spring barley to nitrogen. Of the eight models tested, the inverse quadratic, Greenwood's modification of the inverse linear and two intersecting straight lines represented the yield/fertilizer relationship well, although no one model fitted best at every site.

The three models differed little in their average predicted optimal yields, but a slightly smaller average optimal dressing was predicted from two straight lines.
The amount of flower shedding in some kharif pulses
Authors: Kaul J. N. , Singh K. B. , Sekhon H. S.
Published: March 2009

It has been observed that there is an appreciable from the beginning of flowering till its completion percentage of flower shedding in pulse crops but and the total number of flowers shed was calculated, reliable data are lacking. Preliminary studies were, At maturity, the number of full-size pods per plant therefore, vindertaken to collect information on the was counted and the percentage of flowers shed extent of flower shedding in some kharif (rainy was calculated, season) pulses.
The effect of field drying on the concentrations of some major elements in herbage
Authors: Wilman D. , Mzamane Nthoana
Published: March 2009

Herbage from a grass-white clover sward was dried in the field to the hay stage (≤ 0·33 g moisture/g dry matter) at three times of year in 2 years comparing, in each case, all combinations of two stages of maturity, two levels of applied nitrogen and two thicknesses of swath. Samples taken at intervals during drying were analysed for nitrogen, phosphorus, potassium, calcium, magnesium and sodium.

When there was little or no rain during drying, there was no change in the concentration of any of the six elements in the herbage dry matter between cutting and the hay stage, whatever the stage of maturity, level of N applied or swath thickness.

The concentrations of potassium and sodium in the crop were greatly reduced by rain in the later stages of drying, but were less affected by rain in the early and middle stages; the concentrations of calcium and magnesium appeared to be reduced by rain as readily in the middle as in the later stages; the concentrations of nitrogen and phosphorus were relatively little affected by rain, but seemed likely to be more at risk in the later stages. The extent of the reductions in the concentration of elements was not markedly affected by the stage of maturity or level of N applied. There were reductions in the thin but not in the thick swaths when rain fell during the early and middle stages of drying, probably partly or wholly because the herbage in the thin swaths was drier, with a higher proportion of dead cells, at that time than the herbage in the thick swaths. At least 70 kg K/ha was leached out of the crop in the thick swaths by rain in the late stages of drying.
Evaluation of lentil harvest systems for different sowing methods and cultivars in Syria
Authors: Erskine W. , Diekmann J. , Jegatheeswaran P. , Salkini A. , Saxena M. C. , Ghanaim A. , Ashkar F. El
Published: March 2009

Hand harvesting is a major constraint to lentil production in North Africa and West Asia. This study, in north Syria, compared hand harvesting, cutting by mower (double-knife) and cutting with angled blades on two lentil cultivars differing in standing ability and using two sowing methods (broadcast and drilled) both with and without the use of a heavy bar for field levelling in the 1984/85 season. Seven treatments were selected for testing in five locations in the 1985/86 season; and in the 1986/87 and 1987/88 seasons, agronomic comparisons of mowing v. hand harvesting were conducted on five farmers' fields.

Both machine methods of harvesting resulted in significant harvest losses compared with hand harvesting. The angled blades performed well on a ridged broadcast crop, but tended to mix soil with the harvested crop. The loss of straw associated with harvesting by mower was reduced by levelling the seedbed after sowing. The superiority in seed yield of cultivar 78S26002 over the local cultivar increased from 9% when hand harvested to 39% with mowing because of its lower likelihood of lodging. In the 1986/87 and 1987/88 seasons, the seed yield from a hand harvest was 1650 kg/ha compared with 1508 kg/ha following harvest by mower, representing a loss of 8·6% from mechanization. The corresponding straw loss was 16·6% of the mean from a hand harvest of 2140 kg straw/ha. However, the harvest losses from mechanical harvesting by mower were compensated for by the reduced labour costs compared with hand harvesting.
Nitrogen nutrition of wheat following different crops
Authors: Echeverría H. E. , Navarro C. A. , Andrade F. H.
Published: March 2009

A trial using a split-plot with blocks design was carried out at the INTA Balcarce Experimental Station, Argentina on a typic argiudol soil to evaluate N nutrition in wheat after different preceding crops and using two rates of N fertilization (0 and 90 kg N/ha).

Wheat (Triticum aestivum), soyabean (Glycine max), sunflower (Helianthus annuus) and maize (Zea mays) were grown in different combinations for two successive years (1984/85 and 1985/86).

No water stress was detected during either growing season. Nitrogen availability was altered by the previous crops grown, but the effect lasted only for one season. Wheat following maize yielded least with no N and responded most to N fertilization. The highest yields of wheat without N and the lowest response by wheat to N fertilization were found after crops of soyabean and sunflower.

Wheat after a fertilized wheat crop did not respond to N fertilization because of a serious attack of take-all (Gaeumannomyces graminis tritici).

The nitrate concentration in wheat stem bases was found to be a good estimator of the availability of soil N.
Influence of variety, row type and time of sowing on the morphology, chemical composition and in vitro digestibility of barley straw
Authors: Capper B. S. , Sage G. , Hanson P. R. , Adamson A. H.
Published: March 2009

Leaf proportions (LP) were determined in spring barley straws harvested at Cambridge in 1984 and 1985. Linear regression equations showed that a greater number of days to flowering increased LP whilst greater plant height decreased LP in spring barley straws. Plant height accounted for more than 70% of the variance in LP. By contrast, grain yield and stem diameter accounted for only a small percentage of the variance in LP. Straws from two-rowed winter barleys had slightly higher LP than six-rowed winter barleys but LP in winter and spring barleys were similar.

Leaf blade and leaf sheath fractions of the straws had lower acid detergent fibre and lignin contents and were more digestible than the stem fractions. Linear regression equations of straw digestibility in spring barleys on LP, grain yields, days to flowering and plant heights showed that LP accounted for a higher percentage of the variance in digestibility in 1984 than the other characteristics. In 1985, when harvesting conditions were unusually wet, grain yield accounted for the highest percentage of the variance in straw digestibility.

There were no differences in chemical composition and straw digestibility between two-rowed and six-rowed barleys, but winter barleys had higher straw digestibility than spring barleys. Date of sowing did not influence straw quality in two-rowed winter barleys.

The ranking of two-rowed spring barleys for LP, chemical composition and digestibility suggested that varieties with consistently better straw quality could be identified.
Effect of ruminal infusion of acetic acid and sodium acetate on the concentrations of ciliate protozoa
Authors: Borhami B. E. A. , El-Shazly K. , Akkada A. R. Abou
Published: March 2009

Two fistulated rams were infused through the rumen cannulae with acetic acid or sodium acetate for 4 consecutive days. This infusion has caused a significant drop in the daily feed intake and in the concentrations of rumen ciliate protozoa. The holotrich protozoa were the most susceptible, whereas entodinia were the least sensitive, to the reducing effect of acetic acid or sodium acetate. Decreasing the daily feed intake by 30% has caused little or no change in the concentrations of rumen ciliate protozoa. The in vitro incubation of sodium acetate and rumen contents has resulted in a remarkable depression in the protozoal numbers. Most of this decrease occurred after 5 h of incubation. The addition of acetic acid or sodium acetate to washed suspensions of mixed populations of rumen ciliate protozoa has decreased the in vitro volatile fatty acid production. It is suggested that both the low pH and acetate, ion were responsible for the reduction in the protozoal numbers in the rumen of rams infused with acetic acid or sodium acetate. The effect of acetate on the ciliate protozoa could be an explanation of the diurnal changes in the concentrations of various protozoal groups usually observed in the rumen of the host animal.
Absorption of atmospheric sulphur by mustard (Sinapis alba) grown in a glasshouse
Authors: Bromfield A. R.
Published: March 2009

Soils and plants can absorb more S than is brought down in rain (Johansson, 1960). Much of the S absorbed from the air by light sandy soils (Mann, 1955) during the autumn, winter and spring is lost by leaching and only that absorbed by soil during crop growth can be used. The crop can also absorb atmospheric S directly through the leaves; the amounts may be larger than soils supply when crops have a leaf-area index larger than 1 (Olsen, 1957; Spedding, 1969).