bluuebunny/crossref_metadata_2025 huggingface dataset:
Results from experiments measuring the effects of large amounts of fertilizer and of farmyard manure on main-crop potatoes grown in sandy soil at Woburn, Bedfordshire
Authors: Widdowson F. V. , Penny A. , Flint R. C.
Published: March 2009

The largest yields of potatoes in the Woburn Reference Experiment were obtained by giving both farmyard manure (FYM) and fertilizers, rather than fertilizers alone; an explanation was sought in experiments made on the coarse sandy loam there from 1968–71. Each year, single and double amounts of NPK fertilizer (supplying 250 or 500 kg N/ha plus P and K) were incorporated, either deeply or shallowly, into the seed bed. From 1969, FYM also was tested at rates giving the same amounts of N, similar amounts of K, but more P than the fertilizers; it was tested both alone and with fertilizers.

FYM was less effective than fertilizer when given alone. The combination of FYM and fertilizer gave a larger yield than the single amount of fertilizer and a larger yield than the double amount of fertilizer incorporated shallowly, but a smaller yield than the double amount of fertilizer incorporated deeply, which gave the largest yield each year.

The NPK contents of the potato tubers were used to construct nutrient balance sheets; large residues of N, P and K remained in the soil after harvest. Winter wheat was grown to value these in 1971 and 1972. Fertilizer residues increased only straw yields, but FYM residues increased yields of both grain and straw. Both kinds of residues were less effective than freshly applied N, so most of the N leached during winter.

The yield of saleable tubers was increased, not decreased, by the double amount of fertilizer.
Improved technique in grading of coarse and fine sands during mechanical analysis of soils
Authors: Beater B. E.
Published: March 2009

In the accompanying article attention is drawn to a source of error which arises in grading coarse and fine sand subsequent to dispersion. The method of mechanical analysis in which the error arises, and to which the writer refers, is the revised official method adopted several years ago by the Agricultural Education Association(1). The usual procedure is to wash the dispersed soil on to a No. 70 I.M.M. sieve with a jet of hot water, and to rub it gently with a rubber pestle or the finger until no more will pass through. Robinson(2) states that this rubbing is generally unnecessary. The writer has found, however, that even prolonged washing and rubbing with a rubber pestle are ineffective in removing all the fine sand. In the wet mixture the sands are held together closely by surface tension. In order to overcome this, it would seem reasonable first to dry the sieve and its contents at 105° C. and give a further light sieving. This has been done with a large variety of soils, and it has been found that an extremely high proportion of fine sand is withheld when working with certain soils. The amount of fine sand sieved out of the dried mixture increases or decreases in proportion to the amount of total sands present. This is illustrated in the accompanying graph (Fig. 1), where it is to be noticed that, in soils increasing in total sands from 50 per cent (or thereabouts) upwards, the error begins to assume serious proportions.
Compressibility curves as a quantitative measure of soil tilth, II
Authors: Blair G. W. Scott , Cashen G. H.
Published: March 2009

1. The method described in an earlier paper for measuring the compressibility of soils in situ has been used to study the gradual consolidation of soil following digging with a fork, and a new method in which the rate of flow of water through rubber tubes buried in the soil gives a measure of compression, is described.

2. By means of this latter method some measure can be obtained of the changes that take place in the soil after it has been loaded and trampled.

3. The results of the experiments confirm and amplify the earlier conclusions. Without further data it is hard to distinguish quantitatively the effects of moisture and time, but it is of interest that whereas the compressibility of newly dug soils is hardly affected by differences in moisture for the range of stress used, that of soils which have rested for some time since cultivation is much increased by an increase in moisture content.

4. Experiments on a wider scale should be undertaken in order that a more complete analysis may be effected.
The digestion of huskless oats by poultry
Authors: Moon F. E. , Thomas Brynmor
Published: March 2009

The digestibility for poultry of a variety of huskless oats recently placed on the market has been investigated, and a comparison made with a widely grown variety of more usual fibre content.

It was shown that the fibre of the huskless oats was completely undigested, while that of the control variety had a digestibility coefficient of 8·8 per cent.

The digestibility of the crude protein in huskless oats was higher than in the variety Victory. It is suggested that this difference has resulted from the same cause as that which operates in ruminants, whereby fibre has a depressant effect on protein digestibility.

Both the organic matter and N-free extract were digested to a greater extent in the huskless oats than in the control variety. This is in keeping with the findings of other workers on the relation between fibre content and the digestibility of these constituents.
Note on the effect of temperature on a mixed culture of two organisms in symbiotic relation
Authors: Richards E. H.
Published: March 2009

1. A study was made of nitrogen-fixation byAzotobacter chroococcumalone in a medium containing dextrose (which it can utilize) and in mixture with a coliform organism on a medium containing no carbohydrate except starch, whichAzotobactercannot utilize unless it be hydrolysed by the coliform organism or some other agency.

2. The amount of nitrogen fixed in the mixed cultures was found to be maximal at two temperatures, and a discussion is given of the causes thought to be operative in producing the double maximum.
The base status of Scottish soils: II. Further studies of the effects of lime on typical soils from north-east Scotland
Authors: Whelan L. A.
Published: March 2009

An investigation into the effects of lime on five acid soils in north-east Scotland has been continued during the second and third years after the application of lime and also extended to two other centres.

On four of the original soils the full effect of the lime on the surface soil has been largely maintained up to the end of the third year. The fifth, a soil of low base-exchange capacity, shows a considerable loss of lime by the end of the second year.

The lime leached from the top nine inches of soil appears to be retained to only a slight extent in the second nine inches. This was particularly noticeable on a soil of low base-exchange capacity, where, during the two years after liming, the percentage saturation of the subsurface soil showed an increase from 64 to 67%, and the surface soil a decrease from 92 to 74%.

The existence of a low liming factor (1·5), previously found to hold for a geologically basic soil, has been verified and found to apply also to a soil derived from slate.

A fundamental property of the soils with a low liming factor is the high content of inorganic and organic fine material. Secondary characteristics that distinguish these soils from the others are the relatively high values for hygroscopicity and heat of wetting.
Meat qualities in the sheep with special reference to Scottish breeds and crosses. I
Authors: Pálsson H.
Published: March 2009

1. By establishing the relationship between linear carcass measurements and the quantitative composition of the carcass in terms of bone, muscle and fat, we have provided a scientific basis for the use of many measurements hitherto only presumed to provide an index to carcass quality.

2. External carcass measurements are correlated with weight of the skeleton. The most useful for this purpose are length of tibia + tarsus and length of the fore-cannon.

3. As indices of muscle, external measures are only of indirect value. Thus, both F – T and G/F × 100 are strongly correlated with weight of muscle as a percentage of skeletal weight.

4. Similarly, F provides an index of fat, being negatively correlated with fat as a percentage of bone.

5. For muscle and fat internal measures permit a more precise estimate to be made. A + B is the best index of the former while C + J + Y provide the most accurate estimate of the weight of fat.

6. Still better indices for muscle and fat are provided by suitable combinations of external and internal measurements. Thus L/10 + A + B is very highly correlated with the weight of muscle, and L/10 × (C + J + Y) is the best index of fat in the hoggets. For bone, a most efficient single index is shown to be the weight of the fore-cannon bone.

7. The weight of the skeleton can be estimated with a high degree of accuracy from the weight of the bones in either one leg or loin. Both these joints combined, however, provide a still better estimate.

8. The muscle in one leg or loin + leg provides an excellent index of the weight of muscle in the whole carcass.

9. The fat in one leg, loin, or both these joints combined provides a good index of the weight of the total fat in the carcass. Both joints combined give the most precise measure.

10. The value of certain measurements which are not necessarily associated with the quantity of the major tissues of the carcass, but which nevertheless have important qualitative significance, is emphasized.
Reproductive performance of Merin, sub-tropical Egyptian sheep and their crosses
Authors: Aboul-Naga A. M.
Published: March 2009

Ewe reproductive traits of imported Merino local Ossimi and Barki, their first crosses, backcrosses to Merino and the interbred groups of the backcrosses, were considered in this study. Records of 2168 ewes born from 1960 through 1970 were used in the study; they totalled 6959 records.

Reproductive performance was different in the three purebred groups, with more multiple births but more lamb losses and abortions in Merinos. However, the three groups weaned similar numbers of lambs/ewe run with the rams (0·98). Merino × Ossimi ewes had the best performance, they lambed and weaned 27% more lambs than local Ossimi. They were followed by MB ewes weaning 0·96 lambs/ewe run with the rams. Reproductive performance of the backcross ewes was lower than that of the first cross, but still better than the purebred groups. Inter-breeding of back-crosses reduced their hybrid vigour markedly.

Non-maternal heterosis contributed greatly to the reproductive performance of cross-bred ewes, while the effect of maternal heterosis on reproductive traits was fairly small.

Multiple births showed least heterotic effect.
The limiting effect of plant size at inflorescence initiation on subsequent growth and yield of oilseed rape (Brassica napus)
Authors: Mendham N. J. , Scott R. K.
Published: March 2009

A substantial loss in yield usually occurs when oilseed rape is sown later than mid-September. Field experiments in 1972–3 tested whether this is because all plants, irrespective of size, initiate inflorescences during the winter, thus restricting the eventual size of the leaf canopy and the yield potential of late-sown plants, which are still very small when the change to the reproductive phase occurs.

Sowing a standard winter variety, Victor, from mid-August to mid-October resulted in initiation occurring from late October to February. When sown after mid-September yields were proportional to plant size at initiation. The winter was mild, and in colder conditions earlier sowing may be required to enable plants to reach a critical size before initiation takes place. When sown in August plants were very large but yield was not improved. A study of the development of the pod canopy showed that the extra yield potential was not realized because heavy losses of pods and seeds occurred, particularly in the more shaded positions.

When a range of winter varieties, chosen to contrast the timing of phasic development, was sown on two dates yield was proportional to the interval between sowing and initiation, particularly when late sown, presumably because late initiators were able to lay the foundation of a more substantial root and shoot system. This has implications for plant breeding programmes because the low erucic acid varieties currently being grown initiate inflorescences early. When spring types were sown in mid-October they formed floral initials very early, and gave particularly small and weak plants, with a low yield. Winter types sown in March did initiate flowers and produce large plants, but yields were no better than spring types as flowering and ripening were irregular and late, the cold requirement for initiation being only marginally fulfilled.
The effect of ammonium sulphite on plant growth
Authors: Lewis A. H. , Marmoy F. B.
Published: March 2009

Summary and Conclusions

A review of the literature gave conflicting evidence as to the effect of sulphites on plant growth, so that a pot culture experiment was conducted to study the effects of the addition to ammonium sulphate of varying amounts of ammonium sulphite on the germination, growth and yield of mustard and rye on a heavy loam soil.

Under the conditions of the experiment described, ammonium sulphite had no adverse effect on the germination, growth and yield of dry matter of mustard or rye.
A study of the exchangeable bases of some East Anglian soils derived from the Jurassic and Cretaceous sediments, with special reference to their marine origin
Authors: Salgado M. L. M.
Published: March 2009

1. The results are recorded of an investigation of the exchangeable bases of some East Anglian soils derived from the Oxford, Ampthill, Kimeridge and Gault formations of the Jurassic and Cretaceous ages.

2. As they were formed under the sea the original sediments contained sodium-clays but on the return of terrestrial and fresh-water conditions the character of the deposits was completely changed and they now contain only traces of exchangeable sodium.

3. In the unweathered clay, represented by the 2 ft. below the top 18 in., exchangeable calcium forms only 75 per cent. of the total, and magnesium 20 per cent. As a result of leaching and weathering the magnesium on the surface is replaced by calcium which in the top 18 in. forms 85 per cent., while the magnesium is only 10 per cent. Thus the surface and deeper soils are distinguished by characteristic calcium: magnesium ratios.
Nutritive value of lucerne. I. Preliminary studies of yield, composition and nutritive value (Season 1932)
Authors: Woodman H. E.
Published: March 2009

The main object of the present investigation (season 1932) has been to secure as much information as possible concerning yield, composition and nutritive value from crops of lucerne already established in several different localities. This work may be considered as preliminary to the more systematic investigations which have been designed to begin in the season 1933.

The 1932 investigation comprised work on the following crops: (1) 4-year-old lucerne (variety Provence) grown on the Howe Hill University Farm at Cambridge. (2) 1-year-old lucerne (variety Provence) grown at Willingham, Cambridgeshire. (3) 1-year-old lucerne (variety Hungarian) grown on the Gravel Hill University Farm, Cambridge. (4) 4-year-old lucerne (variety Provence) grown at Tunstall, Suffolk. The season was characterised by its cold, wet, late spring and the prevalence of droughty conditions in June.
Wool characters in “half-bred” sheep (Border Leicester Rams x Cheviot Ewes) (With Plate V and five text-figures.)
Authors: Nichols J. E.
Published: March 2009

Data from the laboratory examination of fleece samples from representative animals of the parental Border Leicester and Cheviot stock, the F1 “half-breds” and the F2 ewes, are submitted.

The characters of mean fibre length, fineness and mean fibre volume are discussed, the variability found in the various types being particularly noted. The distributions of fibre lengths are also considered, it being found that all the parental forms also appear in the succeeding generations.

Evidence of blending inheritance is not manifest in the results, which support the interpretation of multiple factors as responsible for the expression of the wool characters of length and fineness.

Attention is called to the importance of considering fibre volumes as criteria of follicle activity.
Studies on the Carbon and Nitrogen Cycles in the Soil VI. The Extraction of the Organic Nitrogen of the Soil with Alkali
Authors: Hobson R. P. , Page H. J.
Published: March 2009

The alkali-extraction of the nitrogen from soils of certain plots of the classical permanent experiments on Barnfield and Broadbalk at Rothamsted, follows a closely similar course to the alkali-extraction of carbon from the same soils.
Rapid, plant-conserving estimation of heat tolerance in plants
Authors: Onwueme I. C.
Published: March 2009

Two methods were developed for the rapid estimation of heat tolerance in plants using excised tissue pieces. The first method was a modification of the conductivity-bridge method and could yield results in less than 3 h. The second method combined plasmolysis with vital staining for the estimation of tissue injury following a regulated heat stress. This method was first developed and perfected using onion bulb epidermis tissue. It was later adapted for estimation of heat tolerance in intact tomato plants. Results from this method could be obtained within 1 h. The advantages and limitations of the two methods are compared and discussed.
Effect of season and previous seasonal fertilizer N application rates on the response of an S.24 perennial ryegrass/white clover sward to fertilizer N
Authors: Marsh R. , Gordon F. J. , Murdoch J. C. , Stevenson W. E. G.
Published: March 2009

The effect of season of harvest and previous seasonal applications of fertilizer N on the response of perennial ryegrass/white clover swards to pre-cut applications of fertilizer N was studied in three consecutive years on different sites. Herbage D.M. yield responded in a curvilinear manner to increased pre-cut N application rates. There was a tendency in all experiments for the marginal response of herbage D.M. to increased pre-cut N application rates to decrease as previous seasonal fertilizer N application rates increased. Although the effect of season of harvest on the response of herbage D.M. to pre-cut N application rates varied with site/years, it was concluded that the marginal response of herbage D.M. to pre-cut N application rate varies little throughout the greater part of the growing season. The exceptions to this are the very early and late harvests and swards that receive low supplies of N from the sward/soil complex. The results are discussed in relation to other published data and to their possible use in the control of the seasonal pattern and total seasonal supply of herbage D.M. for rotational grazing management systems.
The effect of interval between harvests and nitrogen application on the digestibility and digestible yield and nitrogen content and yield of four ryegrass varieties in the first harvest year
Authors: Wilman D. , Droushiotis D. , Koocheki A. , Lwoga A. B. , Shim J. S.
Published: March 2009

The effect of six intervals between harvests and three levels of N application on digestibility, digestible yield and nitrogen content and yield was studied in four ryegrass(Lolium) varieties during a 30-week period in the first harvest year in a field experiment.

Digestibility was higher with a 3-week than with a longer interval between harvests. Yield of digestible organic matter was increased by extending the interval from 3 to 6 weeks, but was slightly reduced by extending from 6 to 10 weeks.

Increase in the level of applied N increased the degree of curvature downwards in the response to extending the interval in both yield of digestible organic matter and yield of N, supporting the view that N use should be accompanied by shortened intervals between harvests.

Digestibility varied by up to 15 units D-value from one time of the year to another with a constant interval between harvests. The highest values were in the spring. Autumn values were low in spite of a relatively high proportion of green leaf.

During the period immediately following the main period of stem development, doubling the interval from 4 to 8 or from 5 to 10 weeks reduced digestibility by 10 units and reduced digestible yield by 22%.

In the absence of applied N, the N yield of S. 321 was 31% greater than the average of S. 22, S. 23 and S. 24. However, the apparent recovery of applied N in S. 321 was much lower than in the other varieties.
Lodging studies in Lolium perenne grown for seed: 2. floret site utilization
Authors: Burbidge A. , Hebblethwaite P. D. , Ivins J. D.
Published: March 2009

In these experiments lodging not only decreased the number of seeds harvested, but also had an effect in determining which spikelets on the ear set most seed. These data have also shown that many more seeds are set than are harvested, even when the crop is not lodged. It is suggested that there is a lack of assimilate supply to fill the developing seeds, some of which abort, allowing the remainder to attain a viable seed weight. Mechanical support of the crop may increase the assimilate supply to the seed thus allowing seed further up the ear and spikelet to develop fully.
Lamb and milk production of a flock of dairy ewes under an accelerated breeding regime
Authors: Eyal E. , Lawi A. , Folman Y. , Morag M.
Published: March 2009

The management of an experimental flock of dairy sheep was changed from a onceyearly to a frequent-lambing regime. Results are reported on the performance of the flock under the new regime in the course of 3 years. There were 53 and 160, 46 and 242, and 70 and 237 Awassi and Assaf (East-Friesian x Awassi) ewes, respectively, in the flock at the beginning of the 3 consecutive years. A breeding calendar was adopted to produce four mating seasons each year, namely June–July; September–October; December–January; March–April.

Average annual production was 1·16 ± 0·24 lambs and 209±9 kg milk for Awassi ewes, and 2·07 ± 0·20 lambs and 287 ± 19 kg milk for Assaf ewes. Hoggets of the same breeds produced 0·61 ± 0·14 and 1·23 ± 0·10 lambs and 99 ± 37 and 220 ± 21 kg of milk, respectively.

Following the February-March lambing, conception rates of hormone-treated ewes weaned 2 or 70 days post-partum were 57·1 and 48·8% respectively (P < 0·10). There were no differences in the length of the post-partum interval to conception between low and high milk-yielding ewes. Fertility was highest in the September–October and December–January mating periods, intermediate in June–July and lowest in March–April.

Twenty-seven per cent of the original 126 mature Assaf ewes and 15% of the original 46 mature Awassis remained in the flock at the end of 3 years for further breeding. Thirty-one per cent of the mature Assaf population (mixed ages) and 21% of the hoggets were culled in the course of 3 years due to failure to conceive within 6 months post-partum. With Awassi ewes the rate of failure was much higher.

Ewes which had lambed twice and completed, on average, 1·5 lactations in a year, produced 30% more milk per year than those which lambed only once during the same period. The more frequent lambing resulted in shorter lactations (156 days) and lower average daily milk yields (1·27 kg) compared with the 182 days and 1·41 kg in the less frequently lambing groups. Pregnancy during early stages of lactation had a small but significant (P < 0·05) effect on the concurrent lactation. Shortening the breeding interval had a much more marked effect on the subsequent lactation. Ewes that conceived, on average, 120 days post-partum, in the subsequent lactations produced 17% more milk than those conceiving 60 days post-partum (P <0·02).

Ewes gaining weight at a rate of 5–7 kg during the first 2 months of pregnancy produced, on average, 0·27 kg less milk per day than those which either lost or maintained their weight in that period (P < 0·01).
A seedling test for cold hardiness in Lolium perenne L.
Authors: Fuller M. P. , Eagles C. F.
Published: March 2009

A seedling test for measuring cold hardiness in Lolium perenne cultivars is described. Seedling performances of the cultivars in this test were closely related to those of mature plants in an artificial freezing test and to reported survival under field conditions in U.K. winters.

With two-leaf seedlings it was possible to analyse hardiness into leaf damage, regrowth and plant kill enabling an index of hardiness to be compounded. Using this index in conjunction with lethal dose 50% estimates, meaningful separation of cultivars was possible.

The possible application of this technique for screening breeding material and for detailed physiological work is discussed.
Formic acid as a desiccant for grass leaves
Authors: Thaine R. , Harris C. E.
Published: March 2009

Detached, fully turgid leaves of S. 24 perennial ryegrass were sprayed with 1, 3 and 5 mg of a solution of 85% formic acid per leaf and dried in controlled conditions (temperature 28 ± 1 °C, relative humidity 22 and 64%, air speed 40 cm/s). The lowest rate of application increased the rate of leaf drying approximately four times when the relative humidity was 64%. Increasing the rate of formic acid or reducing the relative humidity to 22% did not enhance the drying further. The mode of action of formic acid is discussed. It is suggested that formic acid might be utilized to obtain quicker drying of grass for hay, and further investigations are called for.
Wool growth as affected by nutrition and by climatic factors
Authors: Coop I. E.
Published: March 2009

The weight, length and quality (fineness) of wool produced at different times of the year and under different nutritional conditions has been determined over a period of three years by clipping at monthly intervals the wool grown on delineated skin areas of sheep. The treatments consisted of

(a) wet ewes, grazing on pasture all the year, subjected to high and low levels of feeding during the ‘dry’, pregnancy and lactation periods;

(b) dry ewes and lambs fed differentially on grazing during the winter and spring;

(c) wet ewes fed in stalls on a diet of constant composition at rates sufficient to maintain constant effective body weight (i.e. making allowance for pregnancy increase and fleece weight increase). A small number of these ewes was also subjected to increased environmental temperature during the winter.

The experiments have shown the existence of a marked seasonal rhythm in wool growth having a maximum in January (midsummer) and a minimum in July (midwinter). Changes in weight of wool grown are caused by sympathetic changes in both length and diameter. At the same level of feeding the rate of wool growth in midwinter is about onethird of that in midsummer.

The nutritional demands of pregnancy reduce the rate of wool growth in winter and those of lactation delay the rise in production in spring. Nutrition also plays an important part in determining the time of the maximum and minimum. In dry sheep the maximum tends to occur before midsummer when pasture growth is at its best, but lactation in wet sheep prevents the expression of a maximum early in the summer, so that in these ewes it generally occurs after weaning, and therefore after midsummer. The level of nutrition also determines within limits the magnitude of the maximum and minimum.

The fundamental cause of the seasonal rhythm of wool growth remains obscure. Nutrition, pregnancy and lactation can modify the rhythm, but it exists strongly even when variations due to these are eliminated. The seasonal rhythm of solar radiation has recently been shown to influence rate of wool growth, particularly during winter, and though this is undoubtedly one factor it is not the only one. Temperature has been suggested elsewhere as a possible cause, but the experiments described do not support the theory that environmental temperature has any direct effect on wool growth. It is suggested, however, that the seasonal rhythm of temperature may be a second factor.
Copper and molybdenum in swayback pastures
Authors: Alloway B. J.
Published: March 2009

Swayback disease of lambs occurs widely in Britain, its incidence varying from year to year, but is usually most severe in lambs born in March and April after a mild winter. It is known to be related to a copper deficiency in both the ewe and the lamb, but not all copper-deficient owes give birth to swayback lambs. The disease can be effectively prevented by administering copper compounds to ewes in susceptible flocks at mid-pregnancy (Allcroft, Clegg & Uvarov, 1959).
Effect of plant population on growth and yield of soya bean(Glycine max)
Authors: Enyi B. A. C.
Published: March 2009

In soya beans (var. 3H55F4/149/1) grown in Tanzania, the total dry matter per plant, pod weight/stem weight, shelling percentage, number of nodes per plant, number of pods per plant, percentage number of nodes with pods, number of filled pods per plant, number of branches per plant, and grain weight from side branches decreased with increase in plant density from 74 to 111, 222, and 444 thousand plants per hectare. Grain yield per hectare decreased by 38, 51, and 72% respectively with the increases in plant population, but yield of total dry matter per hectare showed a significant increase with density. Crop growth rate increased with increasing leaf area, which in turn increased with increasing plant density. Relative growth rate, however, decreased with rising population. Over the range of the densities studied grain yield was positively related to number of side branches but negatively related to dry-matter production, leaf area duration and percentage of light intercepted. The proportion of dry matter accumulated in the pods and side branches decreased with increase in population, whereas the proportion accumulated in the main stem increased. Light seems to be the major factor controlling grain yield in this variety of soya bean, low light intensity under the plant leading to a reduction in the number of side branches, number of pods per plant and number of nodes with pods.
On the relationship between fertility and light-reflecting power in bull spermatozoa
Authors: Lindahl P. E. , Kihlström J.-E. , Ström B.
Published: March 2009

The fertility of a number of ejaculates from normal dairy bulls in regular service is found to be positively correlated to the light-reflecting capacity,NE, of the spermatozoa in the ejaculates.
Response of cow pea (Vigna unguiculata L.) to CO2 enrichment environment on growth, dry-matter production and yield components at different stages of vegetative and reproductive growth
Authors: Bhattacharya Sheila , Bhattacharya N. C. , Biswas P. K. , Strain B. R.
Published: March 2009

This study examines the effects of increased atmospheric carbon dioxide concentrations on vegetative and reproductive growth and partitioning of biomass during pod and seed development of cow pea in controlled environment chambers at 350, 675, and 1000μl CO2/l.

The length of main stem and branches, the number of leaves and branches, and leaf area were all greater at high CO2 than at low CO2 concentration. The appearance of flowers was 10–12 days earlier in high CO2 than in ambient CO2 atmosphere. The senescence of leaves started about 7 days earlier in plants grown at 675 and 1000 μl CO2/l than in those grown at 350 μl CO2/l. The rate of leaf senescence was more rapid in 1000 μl/l than in 675 μl CO2/l. The dry weight of roots, stems and leaves increased with CO2 enrichment, being greater in 675 μl/l than in 1000 μl CO2/l. Plants grown in 675 and 1000 μ1/1 produced more pods and seeds than in 350 μl CO2/l. Total seed weight and number of pods, as well as number of seeds per pod, were significantly greater in CO2 enriched atmosphere than ambient CO2 level. Although CO2 enrichment caused a significant increase in the total number and weight of seeds as well as pods, it did not affect the ratio of seed dry weight to the total dry weight of above-ground plant parts (harvest index). It is concluded from the present investigation that CO2 enrichment significantly enhanced vegetative as well as reproductive growth resulting in the increase in yield and early plant maturation in this leguminous crop.
Water and nitrogen management in wheat-lentil intercropping system under late-sown conditions
Authors: Ahlawat I. P. S. , Singh A. , Sharma R. P.
Published: March 2009

Experiments comprising various ratios of wheat and lentil in a mixed cropping system under two irrigation regimes and three levels of N application are described and the results discussed. In all experiments the highest yield of grain was obtained by growing wheat alone and the highest yield of lentil grain by growing lentil alone. No mixture could equal the yield obtained by wheat alone.
Seasonal effects on the growth and time to maturity of lettuce
Authors: Gray D. , Morris G. E. L.
Published: March 2009

The increase in dry weight of field lettuce from sowings made between March and August in 1973 and 1974 started exponentially but this did not persist throughout growth. Departures from exponential growth were most marked in the 10 days of growth prior to maturity and a logistic rather than an exponential curve gave a better overall fit to the data. The rates of increase in plant dry weight were similar from all sowings made between mid-May and early to mid-July, when air temperatures and total radiation during the growth period of these crops exceeded 11–12 °C and 250 mWh/cm2, respectively. Sowings made earlier than mid-May took longer to mature and in 1973 gave crops with lighter heads. Quadratic regressions of harvest date on sowing date gave good fits to data obtained in different years at different sites but separate equations were required for each site.
Visual estimation of plant water status in cereals
Authors: Jones H. G.
Published: March 2009

The potential offered for plant breeding programmes by visual scoring techniques for plant water status was investigated in rice and spring wheat. It was found that differing plant morphology could seriously bias visual estimates of leaf water potential, particularly in spring wheat. In spite of this problem, it was found that at least for rice, this type of approach may have potential in future breeding programmes where an estimate of leaf water status is required, such as those for drought tolerance, so long as a high intensity of selection is not necessary.
Foetal stunting in sheep: 1. The influence of maternal nutrition and high ambient temperature on the growth and proportions of Merino foetuses
Authors: Cartwright G. A. , Thwaites C. J.
Published: March 2009

Two experiments designed to compare lambs born to Merino ewes subjected to either nutritional deprivation or high ambient temperatures (diurnal: 8 h at 42·2 °C, 16 h at 32·2 °C) during the last two thirds of gestation are described.

In Expt 1, lambs from ewes group-fed to maintain maternal body weight at high ambient temperature were lighter (P < 0·01) and had shorter metacarpal bones (P < 0·01) than those from ewes fed to either lose, maintain or gain weight at prevailing temperatures (– 2·0 °C to + 16·4 °C). The regression of metacarpal length on the cube-root of birth weight (‘linear equivalence’) was linear. Simple maternal under-nutrition was thus not indicated as a cause of foetal stunting in heat-stressed ewes, though the proportions of affected lambs closely resembled those of the nutritional dwarfs.

In Expt 2, in which all ewes were individually fed, heat-stressed ewes fed ad libitum consumed 40% less feed and produced lambs which were markedly lighter than those from controls at prevailing temperatures. Other control ewes pair-fed at the level of intake of heat-stressed ewes gave birth to lambs of similar weight to those fed ad libitum. Thus, although feed intake was substantially reduced at high temperatures, the amounts actually eaten by heat-stressed ewes were sufficient to enable control ewes to produce lambs of normal weight. The relationships between birth weight and the weight of the adrenals, cerebellum, cerebrum, heart, kidneys, liver, spleen and thyroid were linear, irrespective of treatment, and as in Expt 1 metacarpal length was linearly related to the linear equivalence of birth weight. However, not all changes in body components were directly proportional to changes in the body as a whole, and heat-affected lambs were thus neither true miniatures nor achondroplastic dwarfs. Until these relationships are clarified it is suggested that ‘stunting’ is the most appropriate description of the influence of high ambient temperature on the sheep foetus.

The findings are consistent with the suggestion that the adverse effects of high temperature arise from an extreme form of foetal undernutrition.
Exponential relation between sweat rate and skin temperature in hot climates
Authors: Gatenby Ruth M.
Published: March 2009

The sweat rates, skin and rectal temperatures and other components of the heat budgets of cattle were measured in Kenya and in England. Mean sweat rate (Ec) was more closely related to mean skin temperature (T8) than to rectal temperature. The results were described by an exponential relationship between T8, (°C) and Ec (mg/m2.sec) of the form Ee = E0 exp (T8, — T0)/B, where T0 and B are parameters (both with units of °C) which describe the sweating response of the animal, and E0 is 1 mg/m2.sec. T0 was 30·8 °C for a single Bos taurus in England and 33·8 °C for five animals in Kenya suggesting that chronic acclimatization to a hot environment resulted in the cattle being able to tolerate a higher mean skin temperature. The effect of species (Bos indicus cf. B. taurus) was small compared with the effect of acclimatization, although the mean value of B was significantly higher for B. indicus (1·58 cf. 0·94 °C) indicating that the physiological mechanism controlling sweat rate in B. indicus was less sensitive to skin temperature.
The utilization of maize silage for intensive beef production: 3. Nitrogen and acidity as factors affecting the nutritive value of ensiled maize
Authors: Thomas C. , Wilkinson J. M.
Published: March 2009

Twelve rumen-fistulated British Friesian castrated male calves, initially three months of age and 77 kg live weight (LW) were fed, both ad libitum and at a restricted level of 21 g organic matter (OM)/kg LW, on either maize silage (26% dry matter, 8.6% crude protein in D.M.) alone or with 2% of urea in the silage D.M., added at the time of feeding. At each level of urea (0 or 2%) silage pH was either increased to pH 5·45 by the addition of sodium bicarbonate, or left unchanged (pH 3·95) in a change-over design within each urea level. Addition of urea increased voluntary silage D.M. intake by 8% (P < 0·05) and partial neutralization increased consumption by 12% (P < 0·01). However, the response to urea only occurred when the silage was partially neutralized.

At restricted intake, addition of urea increased rumen ammonia nitrogen from 3·17 to 13·41 mg/100 ml (P < 0·001) and blood urea nitrogen from 2·20 to 10·06 mg/100 ml (P < 0·001). There was no significant effect of addition of urea or of bicarbonate on rumen pH, VFA concentration or energy digestibility. However, the addition of urea significantly increased N retention (P < 0·01). Partial neutralization of silage was associated with an increase in venous blood pH from 7·366 to 7·396 (P < 0·001), and urine pH from 7·43 to 8·42 (P < 0·001).

It is suggested that both low nitrogen content and acidity limit the nutritive value of ensiled maize, and that the effects of addition of urea and of partial neutralization may be metabolic rather than ruminal.
The effects of slurry on the acceptability of swards to grazing cattle
Authors: Broom D. M. , Pain B. F. , Leaver J. D.
Published: March 2009

Grass plots, designed to provide 4 days grazing for three heifers, were divided into four equal sub-plots which were dressed with cow slurry in March at rates between 0 and 100 t/ha. The heifers were put into the plots 7 and 13 weeks after slurry application and were able to choose in which of the sub-plots they spent their time and grazed.

The main effect of slurry on the pasture at 7 weeks was to increase the height of the sward but to decrease herbage dry-matter production. Herbage dry-matter utilization over the 4 days ranged from 94% on the no-slurry sub-plot to only 41% when slurry had been applied at 100 t/ha. The heifers spent most time in and grazed more often in sub-plots with little or no slurry for the first 2 days, but as the grass was eaten down the frequency of grazing on areas with more slurry increased. This was reflected in the amount of grass removed by the heifers from each treatment on each day.

At the beginning of the second grazing, grass height and herbage dry-matter production were both directly related to level of slurry application. The heifers did not distinguish between treatments up to 50 t/ha, but herbage utilization on the 100 t/ha sub-plot was reduced.
The interaction of nutrition and body condition at mating on ovulation rate and early embryo mortality in Scottish Blackface ewes
Authors: Gunn R. G. , Doney J. M.
Published: March 2009

One hundred and fifty-six Scottish Blackface ewes were differentially group-fed over a 2-month period to achieve three distinct levels of body condition (good, moderate and very poor). Over 5 weeks prior to mating, one group of good-condition ewes was maintained in that condition, one group of good- and one of moderate-condition ewes were brought down in condition by restricted feeding and one group of moderate and the very poor condition ewes were raised in condition by a high level of feeding. Ewes were therefore in good, moderately good or poor condition at mating. After mating, ewes were killed either on return to service or at 25 ± 5 days for counts of corpora lutea and viable embryos.

Poor body condition, irrespective of feeding level, was associated with a delay or suppression of oestrus and with a high return-to-service rate. Ovulation rate was positively related to body condition at mating but not to the level of pre-mating food intake at the condition levels studied.

Embryo mortality decreased as body condition at mating increased and the interaction between condition and the level of pre-mating food intake had a differential effect on mortality of single- and multiple-shed ova. The lowest rate of embryo mortality was found in ewes in moderately good condition which had been well-fed before mating.
Calcium and phosphorus balances of lactating ewes at pasture
Authors: Sykes A. R. , Geenty K. G.
Published: March 2009

Differences in maternal body weight (12–15 kg) were induced in two groups (n = 43–50) of ewes during pregnancy by controlled allowance of pasture. Following parturition equal numbers (9–12) were allocated to one of three herbage allowances in a 2 x 3 factorial design during 42 days of lactation. This design was employed on two occasions; in one (Expt 1) the sheep were machine-milked twice daily, in the second (Expt 2) they each suckled two lambs. Balances of Ca and P in the body were determined by comparative slaughter during early pregnancy, at parturition and after 42 days of lactation. Herbage Ca intake and milk Ca output were determined on a weekly basis.

Mean daily milk production during the 42 days of lactation ranged from 1·48 to 2·68 kg/day amongst treatment groups. The general trend, irrespective of level of milk production, was for negative Ca balances, ranging from 0·71 to 1·42 g Ca/day. It is argued that variation in apparent absorbability (0·17–0·46) and in rate of absorption (30–113 mg/kg W per day) of Ca among groups suggest that these factors are not in themselves responsible for the poor Ca balances observed.

It is suggested that demand for Ca from the diet during early lactation is reduced as a consequence of bone Ca resorption due to matrix osteoporosis resulting from a protein deficiency state. Negative Ca balances in sheep undernourished during pregnancy were similarly attributed to poor protein balances.

Although negative P balances were observed these were not attributed to low P intake.
The effect of drilling date on the growth and yield of oil-seed rape (Brassica napus L.)
Authors: Lutman P. J. W. , Dixon Fiona L.
Published: March 2009

The effects of drilling date (18 August–22 September) on the growth and yield of oil-seed rape (Brassica napus) was studied in a series of five experiments over three seasons. Autumn and winter growth of the crop, as measured by dry weight of tops and leaf area, was severely reduced by delayed drilling, especially if it was later than 10 September. However, during the spring and early summer the differences in crop weight due to drilling date declined and in four of the five experiments there were no detectable differences in seed yield between early- and late-sown crops. The yield decline in the fifth trial was small. Measurements of components of yield showed that later-sown crops had fewer pods per plant and slightly smaller seeds but apparently more seeds per pod. The practical significance and reasons for the recovery of late drilled crops from early poorer growth are discussed.
Seasonal variations in the composition of Pinus halepensis and Pinus sylvestris twigs and needles essential oil
Authors: Zafra María , García-Peregrín E.
Published: March 2009

Influence of season on the terpene composition of Pinus halepensis and Pinus sylvestris was investigated. The essential oil of twigs and needles from a preselected plot of pines was investigated from October to June. In P. halepensis, the average composition during this time was 27·2% α-pinene, 65·0% sabinene, 7·2% 3-carene and 0·5% β-pinene in the essential oil of twigs; 32·1% α-pinene, 35·9% sabinene, 18·5% terpinolene, 4·3% 3-carene, 3·1% β-pinene and 6·1% thujene, limonene, β;-phellandrene and γ-terpinene in the essential oil of needles. In P. sylvestris, the average composition was 49·2% α-pinene, 30·1% sabinene, 14·9% β-pinene and 7·9% limonene in the essential oil of twigs; 69·5% α-pinene, 14·9% camphene, 9·1% β-pinene, 3·6% sabinene and 2·8% limonene in the essential oil of needles. The maximum amount of sabinene coincides with the minimum of α-pinene, both in twigs and needles essential oil from P. halepensis and P. sylvestris. The month-to-month changes in the oil composition are statistically significant for the most part. It is of interest to point out the decrease of sabinene content of needles essential oil in comparison with the twigs essential oil, with the simultaneous increaseof terpinolene in P. halepensis and camphene in P. sylvestris.
The pollination of oilseed rape (Brassica napus) and the behaviour of bees on the crop
Authors: Free J. B. , Nuttall P. M.
Published: March 2009

In spite of the entomophilic structure of the rape flower, which is very attractive to nectar- and pollen-gathering bees, the crop gives good yields without insect pollination.