bluuebunny/crossref_metadata_2025 huggingface dataset:
The evaluation of a standardized commercial cutting technique for determining breed differences in carcass composition
Authors: Kempster A. J. , Cook G. L. , Smith R. J.
Published: March 2009

Data for 383 steer carcasses from the first 3 years of the Meat and Livestock Commission's Beef Breed Evaluation programme were used to evaluate a standardized commercial cutting technique for estimating breed differences in carcass composition. The sample included carcasses from cattle out of Friesian, Hereford × Friesian and Blue-Grey dams by sires of the main traditional British beef breeds and by Charolais, Limousin and Simmental sires. The left side of each carcass was divided into 14 standardized commercial joints which were deboned and trimmed of fat to a fixed level (commercial cutting); the other side was jointed in the same way and each joint fully separated into lean, subcutaneous fat, intermuscular fat and bone (full separation). Breed means for characteristics obtained by commercial cutting were adjusted to equal carcass subcutaneous fat percentage (SF) estimated by visual appraisal, while those for full separation characteristics were adjusted to equal SF obtained by tissue separation. Breed differences in deboned fat-trimmed joints (saleable meat) as a percentage of carcass weight were in good agreement with those for carcass lean percentage (between-breed correlation, rb = 0·92), as were those for saleable meat to bone ratio and lean to bone ratio (rb = 0·91). There was a poorer relationship between fat trim and separable fat (rb = 0·62) but there was little breed variation in these characteristics at equal SF. Breed differences in the percentage of total saleable meat distributed in higher-priced joints were very similar to those for lean distribution in higher-priced joints (rb = 0·87).
Comparison of the effects of phosphate fertilizer on the yield, phosphate content and quality of 22 different vegetable and agricultural crops
Authors: Greenwood D. J. , Cleaver T. J. , Turner Mary K. , Hunt J. , Niendorf K. B. , Loquens S. M. H.
Published: March 2009

Fifty-six experiments, each with 15 levels of P fertilizer in the presence of excess N and K fertilizer, were carried out on adjacent sites of the same field where the soil was maintained at the same low P status. Yields, in every experiment where there was a response, were related to level of P fertilizer by a diminishing-retums type curve, and fitted an inverse polynomial equation with a single parameter to define responsiveness. Responsiveness of many crops were similar but there were, nevertheless, considerable inter-crop differences.

Applications of P fertilizer increased the % P in the dry matter of lettuce and spinach as well as yields. They increased the % P in the Cruciferae and Chenopodiaceae without appreciably affecting yield. Conversely, theyhad little effect on the % P of leeks, onions, broad beans and French beans but increased yields.

When the optimum levels of P fertilizer were applied, % P (in the entire plant) of the different crops was negatively correlated with total dry weight per unit area and total uptake of P was related by a single curved relationship to total dry weight. In addition, the difference between the % P in the foliage and in the storage roots of the various root crops was asymptotically related to mean plant weight.

Percentage recovery of added P (100 kg/ha) by the different crops was largely determined by the total weight of dry matter. It varied from 1% when crop dry weight was 2 t/ha to 12% when it was 15 t/ha.

Applications of phosphate suppressed leaf scorch of spinach. On occasion they alleviated stem rot in summer cabbage and influenced the bolting of onions and the number of defective Brussels sprouts. Otherwise, the effects on quality were small.
Studies on the habits of Zebu cattle IV. Errors associated with recording technique
Authors: Rollinson D. H. L. , Habker K. W. , Taylor J. I. , Leech F. B.
Published: March 2009

To obtain records of individual animals' habits when a small herd is observed for long periods of time, several observers are essential. The errors between observers were so much less than those between animals and between periods of observation that for most purposes records made by a succession of different observers will be adequate.

The errors of observations at 1 and 4 min. intervals, using the grazing records of ten animals, were 3·20 and 7·36% of the mean respectively. The latter figure being of sufficient accuracy for practical application, it is concluded that the 4 min. interval is suitable for records of a major habit.

The errors for the minor habits were large relative to the mean time occupied on them, but still reasonable in relation to the purposes for which work of this sort would usually be required.
Investigations into the chemical composition and nutritive value of certain forage plants at medium altitudes in the tropics II. The digestibility and nutritive value of three grasses at different stages of growth
Authors: Todd J. R.
Published: March 2009

1. The results of nine digestibility trials on three East African grasses, using sheep as experimental animals, are reported.

2. In five of the trials Bothriochloa insculpta, at various stages of growth during the season, was used. Chloris gayana (Rhodes grass) was used in two trials, as was Pennisetum clandestinum (Kikuyu grass).

3. The results are discussed and are compared with other results from East Africa.

4. P. clandestinum has a high digestible protein content and is highly digestible in the early stages of growth, and maintains its high protein content when 9 to 12 in. in height.

5. Bothriochloa insculpta and Chloris gayana are moderately highly digestible in the-young stages but are relatively low in digestible protein. As growth ceases during the dry season the digestible protein content falls more rapidly than the starch equivalent with consequent widening of the nutritive ratio.

6. It is suggested that the differences between Pennisetum clandestinum and the other grasses may be due to its predominantly vegetative habit.
Studies on the habits of Zebu cattle V. Night paddocking and its effect on the animal
Authors: Harker K. W. , Taylor J. I. , Rollinson D. H. L.
Published: March 2009

The results of 8 days' observations with ten animals, under both free-grazing and night-paddock systems, are given. These results are discussed in relation to changes in the food consumption of the animals. The indications are that when the animals are on rough grazing, the pattern of behaviour is not influenced by the night-paddocking system, but that the food consumption of the animals is affected by the relative abundance of herbage in the day and night enclosures. In this trial one comparison shows a significant reduction in average ruminating times by 1 hr. without any effect on the grazing time, when the herbage was scarce in the night paddock; and in the other comparison, when there was more herbage in the night paddock than in the day paddock, the food consumption, as indicated by the ruminating times, was unaffected, but at the same time the animals needed to graze 1 hr. more under the free-grazing conditions than under the night-paddocking system.
The effect of date of planting on the yield of potatoes
Authors: Dyke G. V.
Published: March 2009

Evidence obtained in the Agricultural Improvement Council Survey of Maincrop Potatoes 1948–50 and in experiments shows that yields in England and Wales are decreased by delay in planting after about 11 April at the rate of about 0·4 tons per acre per week. The effect is rather greater in years with fine springs, and on high-yielding fields.

In Rothamsted experiments the responses to dung and fertilizers were all greatly reduced when planting was delayed; between early April and late May the effects of dung, nitrogen and phosphate were halved, while that of potash was reduced by about 80%. The evidence on the responses of different varieties to early planting in English experiments is contradictory, except for an indication that higher yielding varieties respond better. Data from Craibstone suggest that, if bulk yield is the only criterion, ‘early’ varieties which make rapid growth early in the season have a later optimum planting date than maincrop varieties.

The effect of chitting seed at Craibstone is to increase yields by 1·7 tons per acre for March plantings, and by 2·5 tons per acre for plantings in mid-April and later. There is negligible loss of yield from sprouted seed at Craibstone for plantings delayed up to mid-April, but for unsprouted seed there is evidence of a gain from plantings a month earlier. Sprouted seed planted even as late as 1 May yielded as well as unsprouted planted two months earlier.
Observations on the relationship between riboflavin, hatchability and clubbed down
Authors: Coles R. , Cumber F.
Published: March 2009

A brief account is given of the accepted view that riboflavin supplements in the diet of breeding stock lead to improved hatchability and that clubbed down is specific for a deficiency of this vitamin. Attention, however, is drawn to the apparent failure of various workers to achieve a hatching rate with a riboflavin supplemented diet substantially in excess of 80% of fertile eggs which appears to be the national average figure. An experiment is described in which range managed breeding stock received diets supplemented with riboflavin at varying levels, the lowest of which, in the light of available evidence, would be sufficient for good hatchability having regard to the riboflavin obtained by the stock from grass and their own droppings. The hatching rate of fertile eggs was maintained at about 80% with all rations and little change took place consequent on changing over from high to low or vice versa. Only a very small improvement was observed with a very high level of riboflavin. It is therefore concluded that either a figure around 80% hatchability represents the maximum influence of riboflavin on hatching rates or that there are generally other factor(s) present (or absent) in the embryo that prevent a higher rate being achieved. The evidence submitted suggests that this factor may be B12 or more probably, one of the unidentified factors in the A.P.F. complex, and that for hatching rates materially above 80% the A.P.F. complex must be increased above the levels presently supplied to range managed breeding stock, or the high hatching rates induced by high levels of riboflavin may greatly increase the birds' requirements for this factor(s) to a level well above that normally necessary.

Attention is also drawn to the incidence of clubbed down among dead-in-shell with varying levels of dietary riboflavin. It is concluded that the presence of this embryonic abnormality is rapidly and almost completely influenced by changes in the level of dietary riboflavin and that these changes take place much more rapidly than changes in hatchability, once a moderately high hatching rate has already been reached. It is also contended that high riboflavin levels will almost eliminate the incidence of clubbed down, although an already moderately high hatching rate will remain unaffected. For this reason it is argued that the presence of clubbed down in some dead-in-shell is no conclusive evidence that an improvement in hatchability will follow supplementation of the diet with riboflavin unless the hatching rate is below average.
The feeding of fodder beet to pigs
Authors: Rees D. H. , Westmacott M. H.
Published: March 2009

1. An examination has been made of the results of a number of experiments on the feeding of fodder beet to fattening pigs.

2. When beet is introduced, the daily energy intake and hence the growth rate are slightly reduced.

3. The value of beet as a replacement for meal, neglecting the reduction in growth rate, may be assessed satisfactorily from a knowledge of the dry matter content of the beet and of the starch equivalent of the meal, using the average values given by Woodman (1954).

4. Where beet is used to replace meal, the available digestible protein is reduced. It is possible that the addition of protein-rich supplements to the ration will improve the performance of the pigs.

5. The effects of beet on carcass quality are not clear. The Danish reports examined indicate slightly lower quality, but the English reports similar or slightly higher quality.
Fertilizer placement for horticultural crops
Authors: Cooke G. W. , Jackson M. V. , Widdowson F. V. , Wilcox J. C. , Goodway N. D.
Published: March 2009

In field experiments on vegetable crops dressings of appropriate fertilizers were placed 2 in. to the side of the seed and 2–3 in. below the soil surface, and compared with the same amounts of fertilizer broadcast and worked into the surface soil. The work was carried out on ordinary arable land carrying rotations which included vegetables.

Placing fertilizer gave higher yields of cabbage, lettuce, beetroot, onions, broad beans, runner beans and maize, than broadcasting. Fertilizer, however applied, had no regular effect on the yield of french beans.

Both placed and broadcast fertilizer were tested at two rates of dressing. On average of all experiments on each crop, placing fertilizer at the low rate gave higher yields than broadcasting at the high rate. Broadcast fertilizer had little effect on yields of runner beans and broad beans, while placed dressings gave marked increases.

In two-thirds of all individual experiments placing gave higher yields than broadcasting, and in one-third of the experiments placement was significantly better than broadcasting. There were no instances of significantly higher yields from broadcasting as compared with placing.

Placing fertilizer made most of the crops grow more rapidly in the early stages than broadcasting, this improvement being often reflected in earlier maturity. For cabbage, lettuce and runner beans the relative gains from placing, as compared with broadcasting fertilizer, were much higher at the first than at the second harvest.

By drilling fertilizer beside the seed of vegetable crops grown on ordinary soils, it is possible to economize in the dressings needed. In addition, some crops having placed fertilizer may be ready for market earlier. These advantages may be very profitable where high-value crops are grown and will justify the purchase of special placement drills.

A small series of field experiments on established Brussels sprouts and autumn-planted cabbages compared mid-season top-dressings of nitrogen fertilizer broadcast by hand over the whole soil surface, with dressings placed at one point beneath the surface and near to the plants. The dressings used had practically no effect on yields of Brussels sprouts. Top-dressings broadcast in spring increased yields appreciably in two experiments on cabbage, and at both centres placing gave lower yields than broadcasting.
A study of the effects of potassium fertilizer with special reference to wheat on boulder-clay soils
Authors: Ralph R. L. , Ridgman W. J.
Published: March 2009

A long-term rotation experiment testing the effects of applying K fertilizer in combination with N fertilizer and cropping treatments, and two experiments comparing the effects of residual and freshly-applied K together with N treatments over 3 years, all on boulder-clay soils, together with two detailed studies of the effect of K on the growth of wheat on a chalk soil very deficient in K, are described and the results discussed.

Restricting the K supply had little effect on the growth of wheat until stem elongation began, but from then the growth of almost all organs was affected. It is concluded that there is no one mechanism by which lack of K in the soil restricts yield. It can decrease the area of the upper leaves, the dry matter produced in the upper internodes and ears, reduce the number of grains per unit area and the size of grain, but which of these is most important in a particular crop will depend on other cultural and environmental conditions.

It is argued that boulder-clay soils should not be considered as a single class when giving advice on K manuring; more experiments are required to make practical recommendations more precise.
Effect of mating management and PMSG dose on lambing outcome in ewes bred in late anoestrus
Authors: Boland M. P. , Crosby T. F. , Gordon I.
Published: March 2009

Oestrus and ovulation was controlled by progestagen-impregnated sponges in 279 adult dry ewes in late anoestrus: at pessary withdrawal, ewes received doses of 0, 250, 500 or 750 i.u. pregnant mare serum gonadotrophin (PMSG). Rams were introduced to half the number of ewes which did not receive PMSG at the time of sponge withdrawal and to the remainder 48 h later. A significantly lower (P < 0·05) oestrous response was observed in ewes which did not receive PMSG but were introduced to rams at 48 h, when compared with ewes introduced to rams at time of sponge withdrawal. With iams introduced at 48 h a greater precision of synchronization was achieved by the use of PMSG (P < 0·05). Differences in conception rates were not evident between the various treatment groups, but a significantly higher (P < 0·05) litter size followed the use of the 750 i.u. PMSG dose.
Growth, development and yield of pigeon pea (Cajanus cajan (L.) Millsp.) in the lowland tropics:1. Effect of plant population density
Authors: Tayo T. O.
Published: March 2009

The growth, development and yield of pigeon pea (cv. Cita-1) grown at three population densities of 27 000, 55000 and 83000 plants/ha were evaluated in two field trials during the growing season of 1980.

The results obtained showed that there was a progressive reduction in the developmentv per plant of vegetative characters, dry-matter accumulation and yield characters as population density increased. The calculated growth rates (net assimilation rate, crop growth rate, relative growth rate and leaf area ratio) were more or less the same at all population densities. The yields of seeds were 0·39 and 0·51 t/ha for the lowest population density, 0·43 and 0·65 t/ha for the medium population density and 0·58 and 0·75 t/ha for the highest population density for the two trials respectively.

It would seem, therefore, that under the prevailing lowland humid tropical conditions, a population density of at least 80000 plants/ha would be needed to ensure maximum productivity in the sole cropping of pigeon pea.
Effect of mulches and transpiration suppressants on yield, water use efficiency and uptake of nitrogen and phosphorus by sorghum under dryland conditions of north-western India
Authors: Raghavulu P. , Singh S. P.
Published: March 2009

Field experiments consisting of three mulch treatments (no mulch, straw mulch and dust mulch) and six transpiration suppressants (no suppressant, kaolin, phenyl mercuric acetate, atrazine, mobileaf or alachlor and 2-chloro ethyl trimethyl ammonium chloride) were conducted under dryland conditions during the summer rainy seasons (July–November) of 1976, 1977 and 1978. Compared with no mulch, straw mulch increased yield in all 3 years, water use efficiency in 1977 and 1978, and uptake of N and of P in 1977 and 1978. Dust mulch had only a marginal advantage. Amongst transpiration suppressants, only kaolin and atrazine had a marked effect. Both these chemicals increased grain yield, water use efficiency and uptake of N and P, compared with no suppressant.
Fourier series and response curves
Authors: Dyke G. V. , Smith Gina L. , Yeoman D. P.
Published: March 2009

Simple series of trigonometric terms (Fourier series) give good representations of response curves including sigmoid curves and intersecting straight lines.
A model to predict the effects of complex row spacings on the yields of root crops
Authors: Benjamin L. R.
Published: March 2009

A mathematical plant competition model developed by Currah (1975), and subsequently modified by the author, is briefly described. The model has two useful properties: (a) it can cope with complex irregular row spacing systems such as occur in commercial practice and (b) it can be ‘calibrated’ to the yield values at any site by using data from previous crops.

Parameter values of the modified model are calculated for both carrot and red beet crops. At least 70% of the variation in these data could be accounted for by fitting the model, a performance which was similar to, but never as good as, fitting analysis of ariance models. There were no systematic deviations between the fitted and observed values.

Previously estimated parameter values were used to predict mean root weights of carrot and red beet storage roots. Overall agreement between predicted and observed data was good, although some systematic deviations occurred.

The practical value of the modified version of the model and its strengths and weaknesses are discussed.
Yield response of sorghum cultivars to inorganic nitrogen fertilizer
Authors: Pal U. R. , Murari K. , Malik H. S.
Published: March 2009

Field experiments were conducted during the rainy seasons (June–October) of 1978 and 1979 in order to determine the effect of fertilizer N rates (0, 40, 80 and 120 kg N/ha) on yield and yield attributes of some new sorghum cultivars in northern India. Sorghum hybrid varieties yielded more than pure line varieties, hybrid CSH 5 outyielding all other cultivars including other hybrid varieties because of its greatest number of grains per panicle. Nitrogen application at 80 or 120 kg N/ha brought about significant improvement in number of grains per panicle and yield per ha.

Cultivar Χ N rate interactions were significant, in affecting the yield per ha and number of grains per panicle in 1978, whereas such differential response of sorghum cultivars to N rates did not occur in 1979. Sorghum hybrid varieties, even at lower N rates, produced identical yields to the pure line varieties supplied with higher N rates.
Effects of feeding frequency and level of feed intake on chemical composition of rumen bacteria
Authors: John A.
Published: March 2009

Cell mass (dry matter per cell) and cell composition (concentrations of DNA, RNA, phospholipids, total N, a-dextran, diaminopimelic acid and 18 common amino acids) of rumen bacteria were measured at various times after feeding sheep chaffed lucerne hay (Medicago sativaL.) once daily. Cell composition was measured with sheep fed once hourly. Total DNA and RNA pool sizes in the rumen were also measured.

While cell composition was not affected by level of feed intake (700 gv. 1050 g dry matter/day), total DNA, RNA and D.M. pool sizes in the rumen increased with increasing feed intake. With sheep on the once daily feeding regimen relative rumen pool sizes in rumen digesta at various times after feeding were: RNA, 4 > 14 > 0 h; DNA, 4 and 14 > 0 h; D.M. 4 > 14 > 0 h. With the hourly feeding regimen pool sizes were similar to the averaged daily values for sheep fed once daily.

When sheep were fed once daily bacterial cell mass, DNA and phospholipid concentrations peaked at 12–14 h after feeding and subsequently decreased to the 0 h value. RNA concentration was maximal at about 4 h after feeding and declined to near the 0 h value at about 14 h. RNA concentrations in bacteria were highly correlated with gas production rates by whole rumen digesta. The ratio RNA:DNA was highest shortly after feeding, decreased to below the 0 h value at about 14 h and then increased to the 0 h value. The relative concentrations of a-dextran in bacteria were: 4 > 14 > 0 h. Cell composition witli sheep fed hourly tended to reflect the averaged daily values for sheep fed once daily.

These results are discussed with regard to changes in estimated fermentation rate and pool size of bacteria in the rumen. It is suggested that changes in average composition (DNA, RNA, total N and RNA: DNA ratio) of mixed rumen bacteria reflect changes in the average growth rate of the population.
The relative importance of some sources of root-weight variation in a carrot crop
Authors: Benjamin L. R.
Published: March 2009

The relative importance of some sources of plant-to-plant root-weight variation in a field-grown carrot crop was investigated in two experiments sown in contrasting soil conditions but using the same seed lot and experimental design. In each experiment the following possible causes of root-weight variation were recorded on an individual plant basis: umbel order and size of seed, sowing depth, time taken for seedling emergence, length of cotyledons at emergence, distance to nearest neighbours within a row and row position within the seed bed. The relative importance of these differing sources of root-weight variation was assessed by determining how much of the variation in In (root dry weight) they accounted for at two harvests in each experiment.

In the first experiment, carrot seeds were sown in warm, moist conditions in May. These conditions gave a near-ideal emergence, 82% of seedlings emerging over only 5 days. Thirteen days after sowing, the most important source of root-weight variation, out of the variables measured, was position of the row within the bed. However, approximately two-thirds of the root-weight variation could not be attributed to any of the measured variables.

In the second experiment carrot seeds were sown in hot, drying conditions in July. The subsequent spread of seedling emergence extended over approximately 40 days. The total sum of squares of In (root dry weight) in this experiment was six times greater than the sum of squares in the first experiment. At 105 days, 61% of the rootweight variation in Expt 2 was accounted for by differences in time of seedling emergence. Differences in cotyledon length, measured when fully expanded, accounted for 24% and sowing depth differences accounted for 19% of the root-weight variation. Differences in umbel order, seed size and distance to the nearest neighbouring plants within a row never accounted for more than 8% of the sum of squares of In (root dry weight) in either experiment. Thus these variables were not important sources of rootweight variation. In contrast variables which affected the time of seedling emergence, such as sowing depth and physical conditions around the seed, were major sources of root-weight variation.
Direct drilling and shallow cultivation compared with ploughing for spring barley on a clay loam in northern England
Authors: Clutterbuck B. J. , Hodgson D. R.
Published: March 2009

An experiment was made on a clay loam soil to compare direct drilling, shallow cultivation and ploughing for spring barley over a period of 3 years (1975–7). At a uniform rate of fertilizer application (75 kg N, 40 kg P2O6, 40 K2O/ha) combined drilled with the seed, the mean grain yields over 3 years were 5·89, 6·07 and 6·13 t/ha, respectively, direct drilling producing significantly less grain than shallow cultivation or ploughing in 1975 only.

For 1975 and 1976 the mean uptake of nitrogen by shoots of barley at anthesis was 25 kg N/ha less after direct drilling than after ploughing but in 1977 there was no difference. The smaller uptake of nitrogen by direct-drilled barley in 1976 was more likely caused by less available nitrogen in the soil than by smaller root systems. Soil strength (cone resistance) and soil bulk density of the direct-drilled treatments were greater than those of the ploughed and shallow cultivated. Although concentration gradients of extractable phosphorus and potassium formed in direct-drilled and shallow-cultivated soils, the quantities of these nutrients in the top soil differed little between the treatments. After 3 years there were more deep burrowing earthworms (particularly Lumbricus terrestris) in tilled than in untilled soil.
Resistance in vegetable marrow and other Cucurbita spp. to two British strains of cucumber mosaic virus
Authors: Walkey D. G. A. , Pink D. A. C.
Published: March 2009

Most commercial cultivars of Cucurbita pepo L. reacted by producing severe leaf symptoms when infected with either of two British strains of cucumber mosaic virus. Resistance was identified in some pumpkin-types of C. pepo, with the highest level in cv. Cinderella. Studies with selfed populations produced from selected resistant plants demonstrated that resistance in cv. Cinderella is heritable.
Utilization of poor quality roughages: response of sheep fed native hay supplemented with urea by different methods
Authors: Umunna N. N.
Published: March 2009

Sheep were used to study the utilization of low quality native hay supplemented with urea by different methods. Urea supplement was fed either once daily or twice daily or the same quantity of urea used to spray the hay before feeding. These treatments were compared with basal and groundnut cake based supplemented controls. An attempt was made to balance both the mineral and energy intakes. The provision of extra nitrogen in the form of either urea or groundnut cake resulted in improved weight gain, feed intake and feed conversion. Feeding of urea-sprayed hay marginally improved live-weight gain, feed intake and feed conversion over the other methods of urea supplementation. Dry-matter digestibility and nitrogen retention were increased and urinary nitrogen excretion reduced by feeding the urea-sprayed hay.
A reappraisal of stem reserve contribution to grain yield in spring barley (Hordeum vulgare L.)
Authors: Daniels R. W. , Alcock M. B. , Scarisbrick D. H.
Published: March 2009

Pre-anthesis stem reserve contribution to grain yield was assessed in two spring barley cultivars of contrasting height. It was greatest in the taller, but final grain yields were similar. Partitioning of total reserve capacity to various plant parts showed that the leaf and sheath below the peduncle were most important, followed by stem internodes which had increasing reserve capacity up to internode 4.

It is suggested that stem reserves are valuable for yields commonly achieved in U.K. commercial practice.

High grain yields were associated with large positive increases in stem dry weight after anthesis. This would indicate that the source capacity to boost yield is more than proportional to that required to fill the grain alone.
The effects of white clover mosaic virus infection on the yield of red clover (Trifolium pratenseL.) in mixtures and in pure stands
Authors: Scott S. W.
Published: March 2009

The effects of white clover mosaic virus infection on the yield of two red clover varieties grown alone and in mixtures with either perennial or hybrid ryegrasses were examined. The spread of this virus within the pure clover plots was rapid. Clover drymatter yields were reduced and these losses were greater in the grass–clover mixtures than in the pure clover plots. Reductions in yield of about 70% were recorded at the first cut in mixtures of Sabtoron and Sabrina. The response of the clover to different levels of virus infection was best described by a negative linear relationship.

Yields of Sabrina hybrid ryegrass increased as the levels of virus infection in the clover increased. This compensated for the losses in yield of the legume, leaving total sward yields unaffected by the virus.
A study of mole drainage with simplified cultivation for autumn-sown crops on a clay soil
Authors: Ellis F. B. , Christian D. G. , Bragg P. L. , Henderson F. K. G. , Prew R. D. , Cannell R. Q.
Published: March 2009

Grain yield of winter barley in the year preceding the experiment (1978) was relatively uniform over the site. In 1978–9 after the drainage treatments had been introduced, growth and yield of winter wheat were not affected by drainage, probably due to a compact layer at 20 cm that prevented the mole drains from controlling the water table (Harris et al. 1984).

In 1979–80 after disrupting this layer, root growth in undrained plots during the winter and spring was severely restricted by the presence of a water table 20 cm from the soil surface, although some root axes were able to grow down to 75–100 cm below the soil surface. The differences in root distribution patterns between drained and undrained plots disappeared after the water table declined in April. Uptake of nitrogen, phosphorus and potassium were less on undrained plots. Dry-matter production, leaf area index and peak number of tillers was also depressed, so that the yield of winter wheat was 0·74 t/ha greater on the drained treatment; the grain from the drained plots contained fewer impurities and weed seeds.
Calcium metabolism in dairy sheep
Authors: Economides S.
Published: March 2009

Calcium metabolism in dairy sheep was studied using radioisotope and balance techniques. The rate of calcium absorption increased, but the efficiency of calcium absorption decreased, with increasing calcium intake in dry sheep. Endogenous faecal and urinary calcium losses, and the rate of calcium absorption, decreased, but the efficiency of calcium absorption increased in pregnant sheep given a calcium-deficient diet. The rate and the efficiency of calcium absorption and the calcium balance of lactating ewes were not influenced by the prepartum level of calcium intake, when calcium intake in early lactation was high. Endogenous faecal calcium loss was related to dry-matter intake, and total faecal calcium loss was related to calcium intake.
Breeding of improved open-pollinated populations of spring-sown onions
Authors: Dowker B. D. , Horobin J. F. , Crowther T. C. , Fennell J. F. M.
Published: March 2009

Various population improvement methods were applied to the spring-sown bulb onion crop. Synthetic populations were developed by recurrent selection, basing this selection on the performance of inbred lines per se for improved yield, bulb quality and storage performance. From the synthetic populations, partially inbred populations were also developed by half-sib selection methods. Results showed that gains, primarily in storage performance and marketable yield, were obtained in many of the synthetics. The mean gain in yield per cycle was of a similar magnitude to gains reported for maize using similar selection procedures although individual onion synthetic populations varied considerably in their achieved gains. Further gains in quality and storage performance, with no reduction in yield, were obtained by the development of partially inbred populations from the synthetics. These results are discussed in relation to the breeding of improved onion cultivars in the U.K.
Effect of intake and feeding frequency on feeding behaviour and quantitative aspects of digestion in sheep fed chaffed lucerne hay
Authors: Ulyatt M. J. , Waghorn G. C. , John A. , Reid C. S. W. , Monro J.
Published: March 2009

Chaffed lucerne hay of 64% apparent organic matter (OM) digestibility was fed to wether sheep under four feeding regimens: two levels of dry matter (D.M.) intake (700 (L) and 1050 (H) g/day) and within each level two feeding frequencies (once a day (daily) and once an hour (hourly)). Three separate groups of sheep were used concurrently: a slaughter group was used to obtain feeding behaviour data and to measure pool sizes and obtain samples from the reticulo-rumen; a digestion group, in which each sheep was prepared with a rumen and a duodenal cannula, was used to measure duodenal digesta flow, rumen microbial growth and reticulo-rumen motility; a balance group was used to measure digestibility and nutrient balances.

High D.M. intake increased reticulo-rumen pool sizes and flow rates but it did not affect apparent digestibilities or the proportions of OM, fibre, cellulose, hemicellulose, lipid and nitrogen digested in the stomach and intestines. Increased feeding frequency had a major effect on reticulo-rumen pool sizes but did not affect apparent digestibilities or partition of digestion of non-nitrogenous constituents. Daily feeding resulted in increased total-N flow to the duodenum; however, N retention was significantly greater with frequent feeding. It is suggested that this was due to a more efficient tissue utilization of N.

The kinetics of digesta flow within the reticulo-rumen, expressed as fractional flow rates, were studied with data from sheep fed hourly. The fractional inflow, outflow and disappearance rates for OM, fibre, cellulose and hemicellulose did not change with an increase in intake because of an equivalent increase in reticulo-rumen volume. Increasing D.M. intake by 50% resulted in a 24% increase in water intake, a 19% increase in reticulo-rumen water volume, and a 49% increase in water outflow rate. The data suggest that the increased outflow of water was achieved by increasing the net flow of water across the mucosa into the reticulo-rumen, rather than by increasing salivation.

There was no difference between treatments in the frequency of reticulo-rumen contractions. It was calculated that for each A sequence contraction, OM flow was 0·26 and 0·37 g and water flow was 4·38 and 0·36 g on L and H intakes respectively. A 50% increase in intake resulted in a 42% increase in OM passage per A sequence contraction. This increased passage with intake was not accompanied by an increase in reticulorumen contraction frequency.
Evaluation of some chemical extractants for predicting response of wheat grown in pots to copper in Sub-Himalayan soils
Authors: Sakal R. , Singh A. P. , Singh B. P. , Sinha R. B.
Published: March 2009

Seven out of ten chemical extractants were found to be promising for the evaluation of critical limit and response of wheat grown in pots to Cu application in Sub-Himalayan hill and forest soils of recent alluvium origin. The critical limit of available Cu using DTPA-CaCl2(pH 7·3), DTPA-NH4HCO3 (pH 7·6), EDTA-(NH4)2CO3 of pH 8·6, EDTANH4OAc (pH 7·0), n-NH4OAC (pH 7·0), n-NH4OAC (pH 4·8) and n-Mg(NO3)2 of pH 5·9, was 0·66, 1·73, 1·95, 1·38, 0·13, 0·20 and 0·47 mg Cu/kg, respectively. The amount of Cu extracted by these extractants was positively and significantly correlated with ‘Bray's percent yield’. Apart from ‘Bray's per cent yield’, the Cu extracted by most of these extractants was positively and significantly correlated with Cu concentration in the third leaf of wheat, Cu uptake by wheat shoots and organic carbon content of the soils, and negatively correlated with soil pH but the value of this relationship did not approach the 5% level of significance. n-Mg(NO3)2 of pH6·7, N-NH4NO3 and 0·1 n-HCl were found to be ineffective extractants. Among chelating agents, DTPA-CaCl2 was found to be most and EDTA-NH4OAc least promising extractant. N-NH4OAC (pH 4·8) proved to be better than N-NH4OAC (pH 7·0). The critical Cu concentration in the third leaf of wheat was 8·8 mg Cu/kg, below which responses in dry weight to Cu application may be expected.
The evaluation of artificially dried grass as a source of energy for sheep:III. The prediction of nutritive value from chemical and biological measurements
Authors: Armstrong D. G. , Blaxter K. L. , Waite R.
Published: March 2009

1. The metabolizable energies and net energies for fattening and for maintenance of the organic matter of sixteen dried grasses have been related to their apparent digestibilities and to their chemical compositions.
The use of two mating systems in breeding for resistance toMaruca testulalisGey. in cow peaVigna unguiculata(L.) Walp.
Authors: Woolley J. N. , Evans Alice M.
Published: March 2009

Resistance to insects in cow peas was studied in a diallel cross and in a test cross. Number of pods and seed yield under unsprayed conditions, expressed as a percentage of their values under sprayed conditions, were confirmed as reliable characters for the assessment of resistance and as suitable for diallel analysis. Non-allelic interaction was not detected for these ratios despite its presence in yields. Resistance to flower damage byMarucaand resistance to all damage by post-flowering pests were both highly heritable and were controlled polygenically by alleles showing partial dominance.

The test cross was not as informative as the diallel cross in the analysis of the genetic control of resistance in a group of moderately resistant lines, but was useful in selecting the best of these for future crosses. The results from both schemes suggested that resistance should be accumulated by intercrossing resistant lines before attempting to transfer it to agronomically-preferred susceptible lines.
Movement of potassium in an Ustochrept soil profile in a long-term fertilizer experiment
Authors: Ganeshamurthy A. N. , Biswas C. R.
Published: March 2009

Downward movement of potassium (K) was studied in the soil profiles of a longterm fertilizer experiment. The distribution of different forms of K and the percentage K saturation of the CEC of soil, at various depths of the differentially treated plots, indicated that applied K moved down to 75 cm depth in the high-K plots after nine cycles of a maize-wheat-cow peas crop rotation. However, movement of K was not noticed in plots not given K fertilizers. Plant uptake of K far exceeded the amounts of applied K. Application of K fertilizer reduced the release of K from the non-exchangeable reserves. Forms of K and the percentage K saturation of the CEC of soils were significantly correlated.
Water relations of winter wheat. 5. The root system and osmotic adjustment in relation to crop evaporation
Authors: McGowan M. , Blanch P. , Gregory P. J. , Haycock D.
Published: March 2009

Shoot and root growth and associated leaf and soil water potential relations were compared in three consecutive crops of winter wheat grown in the same field. Despite a profuse root system the crop grown in the second drought year (1976) failed to dry the soil as throughly as the crops in 1975 and 1977. Measurements of plant water potential showed that the restricted utilization of soil water reserves by this crop was associated with failure to make any significant osmotic adjustment, leading to premature loss of leaf turgor and stomatal closure. The implications of these results for models to estimate actual crop evaporation from values of potential evaporation are discussed.
Dormancy responses to post-harvest application of growth regulators in Dioscorea species. 2. Dormancy responses in ware tubers of D. alata and D. esculenta
Authors: Wickham Lynda D. , Passam H. C. , Wilson L. A.
Published: March 2009

The effects of post-harvest application of gibberellic acid on dormancy of tubers of Dioscorea alata and D. esculenta were examined. In both species, gibberellic acid extended the dormancy of immature and mature tubers but when GA3 application was made after storage for varying lengths of time, there was a decreasing effect with increased storage time. Dormancy was also reinduced in germinating tubers, that had gone through a normal dormant period, as a result of gibberellic acid treatment. A possible mechanism of dormancy in tropical yams is discussed. It is concluded that use of gibberellic acid as a means of extending the storage life of yam tubers by post-harvest application is a distinct possibility.
The assessment of the quality of sugar-beet seed
Authors: Durrant M. J. , Brown S. J. , Bould A.
Published: March 2009

The accurate prediction of the performance of individual lots of sugar-beet seed in the field is critical when constituting blends of seed for commercial use. Previous studies indicated a need for ‘vigour tests’ to supplement the standard germination test. In many of the studies emphasis was placed on evaluation of tests in the laboratory, whereas in this study equal emphasis was placed on the determination of the values to be predicted. The performance of 20 seed lots with a range of germination between 75 and 95% was assessed in field and laboratory studies in 1981. Further investigations of ten seed lots were made in 1982 and in 1983.

The results in 1981 showed little evidence of agronomically important differences in the relative performance of seed lots with respect to establishment in the field at different sites. Similarly, most seed lots showed consistent differences over a range of tests under controlled conditions. However, use of the experiment mean as a measure of stress revealed marked differences in the range of performance between the best and poorest lota in both the field and laboratory. There were clear indications that performance in the field could be modified by non-random factors that tended to reduce the magnitude of differences among seed lots. In 1982 grazing of seedlings by birds was identified as a factor that could cause greater reduction in the establishment of seed lots with high viability relative to those with low viability. Thus, under some circumstances, a single count of seedlings in non-protected field experiments can give misleading estimates of the differences among seed lots (and probably among other treatments which affect the rate of emergence). Correlation coefficients (γ) were about 0·88 for relationships between establishment from pelleted seed in plots protected from birds and germination or emergence under controlled conditions. These results reduced the need for additional vigour tests. However, the studies emphasized that small differences in germination percentage are important as they can be associated with much larger differences in establishment, particularly under adverse seed-bed conditions. The average standard error for the mean viability of individual seed lots was ±1·89 in germination tests with four replicates of 100 seeds at each of six centres. Although inincreased accuracy may not be possible without much greater replication, we found that the distinction between normal and abnormal seedlings was an important source of experimental error. A less subjective measurement, based on hypocotyl height, warrants further study.
The effect of ridging on the performance of pigeon pea (Cajanus cajan (L.) Millsp.) in the lowland tropics
Authors: Tayo T. O.
Published: March 2009

In earlier papers, it has been demonstrated that many features of the production system in the lowland tropics affect the growth and development of pigeon pea differentially depending on the prevailing conditions (Tayo 1982 a, b, c, 1983 a, b). It has also been noted that when plant size is reduced as a consequence of reduced soil moisture, slight variations in production input tend to have a more significant effect on crop performance (Tayo, 1983b).
The role of a soil × dietary sulphur interaction in the impairment of copper absorption by ingested soil in sheep
Authors: Suttle N. F. , Abrahams P. , Thornton I.
Published: March 2009

Four repletion experiments were carried out to clarify the roles of molybdenum, sulphur and iron in the inhibition of copper absorption by ingested soils. In each experiment, groups of four to six hypocupraemic Scottish Blackface ewes were repleted for 21 days with diets containing CuSO4 and/or soil Cu and the responses in plasma Cu used to assess the availability of the Cu supplied.

In Expts 1 and 2, three soils varying in Mo but high in Fe content and derived from Lower Lias Clay, Namurian Shale and Weald loam were added at 100 g/kg D.M. to diets of low (1·0) and high (4·1 g/kg D.M.) S contents: they provided 3·1, 2·8 and 0·1 mg Mo/kg D.M. respectively. When compared with groups given no soil, each soil increased plasma Cu repletion in the low S experiment and decreased it in the high S experiment. Inhibition was thus not completely dependent on soil Mo but dependent upon dietary S.

Soils varying in Fe content were compared in the manner of the above experiments in Expts 3 and 4. Two Fe-rich soils, developed from the Upper Chalk and a Barton Clay and providing 2·8 and 1·5 g Fe/kg D.M., impaired Cu repletion on the high S diet but not on the low S diet. A soil, developed on a sand from the Bagshot Beds and providing only 0·15 g Fe/kg D.M., did not impair repletion but FeSO4, providing 0·8 g Fe/kg D.M. did so, irrespective of dietary S content. Ingestion of Fe-rich soils in a high S diet caused three-fold increases in rumen sulphide concentrations 5 and 24 h after feeding. It is suggested that soil ingestion impairs Cu absorption in sheep by trapping S as heavy metal sulphides such as FeS and releasing sulphide in the acid abomasum.