bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth and yield of irrigated groundnuts (Arachis hypogaea L.) grown at different spacings in the Sudan Gezira. I. Flowering, yield and yield component
Authors: Ishag Hassan M.
Published: March 2009

The effect of different spacings between and within rows on the pod yield of Ashford (semi-spreading, alternately branched type) and Barberton (upright, sequentially branched type) were studied.

The largest yield of Ashford was obtained at 60 cm x 15 cm spacing, while in Barberton the largest yield was obtained at 40 cm x 15 cm. It is suggested that the optimum spacing for these varieties varied because of differences in their growth habits.

Differences in yield were generally associated with differences in the number of pods and weight of pods per plant. An inverse relation between number of pods per plant and number of seeds per pod suggested internal competition between alternative sinks.

The number of flowers per plant decreased with closer spacing. The percentage of flowers which set pods ranged from 14 to 21%. Wider spacing increased the number of branches, total number of pods and the proportion of pods which matured, but did not affect the mean individual kernel weight.
Finishing steers on high-grain rations. Effects of type of silage, level of urea, vitamin A and cobalt supplementation on body-weight gain, feed efficiency and carcass composition
Authors: Morris J. G. , Gartner R. J. W.
Published: March 2009

1. A 23 factorial with a split-plot allocation of treatments was used to investigate the effects of silage type, (sweet v. grain sorghum); level of urea, (60ν. 120 g. per head per day); vitamin A,(0ν. 40,000 i.u. per head per day), and intraruminal cobalt oxide pellet on the performance of steers fed rations of 90% sorghum grain, 10% sorghum silage.
The growth of lambs grazing on perennial ryegrass, tall fescue and cocksfoot, with and without white clover, as related to the botanical and chemical composition of the pasture and pattern of fermentation in the rumen
Authors: Grimes R. C. , Watkin B. R. , Gallagher J. R.
Published: March 2009

1. An experiment was conducted in which lambs grazed on pastures of cocksfoot, ryegrass and tall fescue grown with and without white clover, as well as on pastures of pure white clover.
Digestibility of Theobroma cacao pods when fed to cattle
Authors: Bateman John V. , Fresnillo Olga
Published: March 2009

1. Six heifers were used in eight experiments to determine the digestibility of cacao-pod meal when fed in all-ground mixes of rice bran and rice bran with cottonseed meal.
The electronic measurement of the yield of growing pasture I. A statistical assessment
Authors: Alcock M. B. , Lovett J. V.
Published: March 2009

1. A modified capacitance meter used to make rapid non-destructive measurements of growingpasture is briefly described.
The control of lodging in cereals by (2-chloroethyl)-trimethyl ammonium chloride (CCC):Field trials in Britain in 1964 and 1965
Authors: Barrett D. W. A. , Meens B. E. , Mees G. C.
Published: March 2009

1. The effects of CCC, (2-chloroethyl)-trimethyl ammonium chloride, on the grain yields of wheat and barley in Britain were studied in field experiments in 1964 and 1965.
A comparison of the nutritive value of hybrid Napier, Napier and Jowar grasses with or without starch supplementation
Authors: Gupta Jagdish Chandra , Pramanik Suniti Kumar , Majumdar B. N.
Published: March 2009

1. The nutritive value and chemical composition of hybrid Napier, Napier and Jowar grasses and also a leguminous fodder, berseem, were studied using adult kumaoni steers.
Net assimilation rate in barley, oats and wheat
Authors: Cannell R. Q.
Published: March 2009

Net assimilation rate (E) was measured in three experiments involving related species and cultivated varieties with increasing grain yield potential in the genera Hordeum, Avena and Triticum. No consistent differences in E between the barley varieties were found, but in the oat and wheat experiments, Abundance and Atle respectively had lower values of E. However, these differences did not suggest that E had been influenced in selecting for grain yield. The relationship of E to dry-matter production was calculated and discussed.
The influence of density and nitrogen in seed production stands of S 37 cocksfoot (Dactylis glomerata L.)
Authors: Lambert D. A.
Published: March 2009

1. Seed production stands of S 37 cocksfoot were obtained with varying plant densities by utilizing two drill widths, removing sections of drill, or over-sowing drilled material. All density treatments were operative at two levels of N, 87 or 174 lb. N per acre per annum.

2. Tillers in selected quadrats were labelled at monthly intervals during autumn and/or winter for 3 years. Performances of tiller populations were assessed from these quadrats.

3. Seed yields were increased in many cases by reducing plant density from a continuous drill pattern. Increased plant density reduced yields. With plant communities on a 1 ft. square arrangement at the high level of nitrogen, an increase of 33%, or 243 lb. seed, per year over a 3-year period was obtained compared with continuous rows at any level of N. The yield of gapped stands increased over the 3-year period, whilst the yields of continuous rows dropped in the final year.

4. Nitrogen significantly increased the yield of cocksfoot, except in the third year, by increasing the weight of seed per ear.

5. Tiller numbers per quadrat increased in most treatments over the course of the experiment, both within years and from year to year; seasonal peaks of tillering were apparent. The effect of N on tiller numbers differed each year, presumably due to the state of the populations when the N was applied.

6. Higher tiller numbers per plant were obtained with lower plant numbers per unit area. Percentage fertility of tillers was generally higher with lower plant densities, and lower tiller numbers per plant, other factors being equal. The only significant effect of N on fertility was to decrease it in the third year.
Field experiments on the value of urea as a fertilizer for barley, sugar beet, potatoes, winter wheat and grassland in Great Britain
Authors: Devine J. R. , Holmes M. R. J.
Published: March 2009

1. Urea containing less than 1% biuret was compared with ammonium nitrate in field experiments on barley, sugar beet, winter wheat and grassland, and with ammonium sulphate on potatoes, in various parts of Great Britain in the years 1957–61.

2. When broadcast on the seed-bed for barley at rates supplying 25–45 lb./acre of nitrogen in twenty-five experiments, urea and ammonium nitrate gave similar mean increases in grain yield on acid soils, while on alkaline soils urea gave smaller increases than ammonium nitrate. The relative effect of the two sources was similar on light and heavy soils and in the east and west of the country.

3. When broadcast on the seed-bed for sugar beet at 50–60 lb./acre of nitrogen in nineteen experiments, mostly on alkaline soils in eastern England, no difference was detected between the mean increases in yield of sugar and tops from urea and from ammonium nitrate.

4. In twenty-two experiments on potatoes urea gave slightly smaller mean increases in yield of tubers than those from ammonium sulphate when applied at 40–60 lb./acre of nitrogen, with a larger difference at 80–120 lb./acre. No influence of soil pH, soil texture, region of the country or method of application (broadcast on the flat or over the open ridges) was detected.

5. When broadcast as spring top dressings in seventeen experiments on winter wheat, mostly in western England and Scotland, at rates supplying 34–45 lb./acre of nitrogen, urea and ammonium nitrate gave similar mean increases in yield of grain.
On the areas of the stomach of sheep that are sensitive to formic acid and histamine
Authors: Neumark H.
Published: March 2009

1. The infusion into the rumen via a cannula of 11. of aqueous solutions containing formic acid and/or histamine had no influence on the time sheep took to eat their food offered immediately after the infusion.

2. The infusion of formic acid solutions containing histamine into the rumen via stomach tube had variable effects when the length of stomach tube introduced was random. When they were introduced through 72 cm of stomach tube (measured from the incisor teeth), so that the end of the tube was at the cardia, one sheep consistently refused food or ate only a little but another sheep was only occasionally affected in this way.

3. Solutions marked with phenol red passed rapidly to the abomasum when introduced into the region of the cardia via a stomach tube. Only insignificant quantities of phenol red were detected within the same time in the abomasum when the solution was introduced into the rumen via a rumen cannula.
The effect of cutting frequency and root segregation on the yield from perennial ryegrass-white clover associations
Authors: Bland B. F.
Published: March 2009

1. Dry-matter and nitrogen yields were recorded from perennial ryegrass-white clover associations which were defoliated 2, 4 or 6 times a year during the period 1963 to 1965.

2. The average yearly output of dry matter was approximately 4000, 7000 and 6000 lb/acre for 1963, 1964 and 1965 respectively. Nitrogen harvested amounted to 132, 184 and 179 lb N/acre.

3. The mean annual dry-matter yields from 2, 4 and 6 defoliations were 5300, 6100 and 6000 lb/acre and the corresponding figures for nitrogen yields were 112, 166 and 217 lb N/acre.

4. Both segregation of the species below ground and increasing the defoliation frequency were responsible for higher contributions towards drymatter and nitrogen yield from the clover component.

5. A comparison of the nitrogen yields between the plots with species segregated rather than integrated below ground suggests that the effects of underground nitrogen transference from 30–31 lb N/acre could first be demonstrated in the spring of the third year.
The relationship between productivity and some components of canopy structure in ryegrass (Lolium spp.)
Authors: Rhodes Ian
Published: March 2009

Two experiments are described in which the potential production of genotypes selected from within S. 321 perennial ryegrass for differing leaf length was assessed (a) in micro-swards composed of populations of similar genotypes and (b) in micro-swards of individual genotypes. In Experiment 1 the long- and short-leaved populations were also compared with the base population of S. 321 and with several other natural populations and bred varieties.

Under infrequent cutting the population of long-leaved genotypes was more productive than the short-leaved and base populations. Under frequent cutting, however, the population of short-leaved genotypes was most productive. Similarly, whilst Ba 6280 ryegrass was highly productive and the natural Ynyslas population unproductive under infrequent cutting the situation was reversed under frequent cutting. The population of long-leaved genotypes and Ba 6280 had a higher leaf area index (L) than other populations and varieties at complete light interception.

Considerable differences in productivity existed between individual genotypes, and there was also an interaction between genotypes and cutting frequencies. The relationships between yield and both leaf length and chlorophyll content are presented and the physiological basis of inter-genotypic and inter-population differences in production are discussed.
Statistical research on the fate of dietary mineral elements in dry and lactating cows V. Potassium
Authors: Paquay R. , Lomba F. , Lousse A. , Bienfet V.
Published: March 2009

Statistical analyses were carried out on the data obtained under strictly controlled conditions in metabolism stalls with 41 different rations fed to 127 adult non-pregnant dry cows, and with 14 other different rations fed to 35 adult non-pregnant lactating cows that had calved 2–6 months earlier and whose daily milk production ranged from 11 to 20 kg.

The authors have calculated and studied the correlations between faecal and urinary potassium losses, potassium excretion in the milk, digestible potassium and potassium balance, and the 75 other nutritive factors which were analysed for each of the 55 above mentioned experimental diets.

The results show that three nutritional factors, potassium, dry-matter and nitrogen intakes, influence the fate of dietary potassium. The apparent digestibility of potassium is hyperbolically related to potassium content of the diet since the true digestibility of potassium is very high, unrelated to potassium intake and rather constant and since about 2·2 g of endogenous potassium are excreted in the faeces per kg of ingested dry matter.

The quantities of digestible potassium strongly influence both the potassium urinary outputs and potassium balance. An increase in digestible dry matter enhances too the urinary potassium excretion as well as faecal output and lower potassium balance twice as much.

But the most interesting feature in the potassium metabolism is that at any level, ingestion, digestion, excretion, there is a very close correlation between potassium and nitrogen.
Genotype-environment interactions in the wintering of lambs
Authors: King J. W. B. , Watson J. H. , Young G. B.
Published: March 2009

An experiment to investigate the differential response of lambs of various breeds and crosses to different planes of nutrition is described.

Two groups of twin lambs were used comprising Blackfaces and their crosses ( x Lincoln, Wiltshire and Border Leicester rams) and Welsh and their osses ( x Suffolk and Wiltshire rams).

From October to January, each cross was divided between high and low planes of nutrition. Approximately half of the twin pairs were split and the remaining pairs distributed between the environments. Significant differences were found between the crosses and twin pairs of the same cross for body weight, body measurements and wool production but not for various blood characters. For almost all characters studied, plane differences were found. There was, however, only one significant (P < 1%) cross-plane interaction—for non-protein nitrogen concentration in the blood.

At the end of January, each plane was subdivided to produce high-high, high-low, low-high and low-low groups. The lambs remained in these groups until May. As before, differences between crosses were found for body weights and measurements, and wool characters but not for most blood characters. The majority of characters were affected by plane of nutrition. Cross-plane interactions were not found except in antibody response toErisipelothrix rhusiopathiavaccine (P < 5%).

At the end of May the high-high group were slaughtered and the remaining three groups fattened on grass until each reached the same average weight as the high-high group. Carcass measurements showed that all the crosses shared a striking ability to recover from previous poor nutritional treatments. One significant (P < 5%) interaction of cross and plane was found in weight of cannon bone.

The most characteristic feature of the results has been the similarity of response of the different genotypes to the different nutritional environments. The few interactions found to be statistically significant by conventional methods are difficult to interpret because of the many tests of significance carried out in the analyses.
The energy requirements of lactating sows and the influence of level of food intake upon milk production and reproductive performance
Authors: Lodge G. A.
Published: March 2009

1. A theoretical feeding scale, designed to supply the full nutritional requirements of the lactating sow and prevent weight loss (allowing approximately 8 lb. meal per sow and 0·8 lb. per piglet), was tested against a much lower but commonly recommended level (2 lb. meal per sow and 1 lb. per piglet). The meal (barley meal, 40%; ground oats 25%; middlings, 20%; white fish meal, 7·5%;, groundnut meal, 2·5%; dried grass meal, 3·8%; ground limestone, 0·3%; common salt, 0·3%; vitamins A, D and B2supplement, 0·6%) contained approximately 16·25% crude protein and had a digestible energy value of approximately 1300 Cal./lb. During pregnancies all sows were fed equal amounts of a meal containing approximately 13·0% crude protein.

2. Four pairs of Wessex Saddleback litter sisters were divided between the two treatments and records taken over three lactations of food consumptions, sow body weights, milk yields, milk compositions, litter growth rates, creep-feed consumptions and reproductive performances. Litter sizes were standardized between pairs of sows within the first 10 days after farrowing.
The design of equipment for producing accurate control of artificial aerial environments at low cost
Authors: Evans G. C.
Published: March 2009

An account is given of the considerations which have been found in practice to govern the design of a small cabinet for growing plants under closely controlled conditions of atmospheric environment. Starting with questions of size, shape and material, the connexion between size of chamber and type of illumination is considered, followed by general policy on air supply. The main outlines of design having been laid down in this way, the various environmental factors to be controlled are reviewed. These include: (a) composition of the air, with particular reference to carbon dioxide; (b) light intensity. Various possible sources are reviewed, and the difficulties of imitating natural conditions of illumination are discussed, together with methods of measuring the illumination and checking for stability; (c) temperature. The degree of control needed for various purposes is considered, particularly in connexion with control of humidity, followed by systems of control, and the most advantageous arrangements for them. The cycle of operations of a control system is considered in some detail, and division of the system into a small relay-operated heater and a background heating or cooling system is advocated; (d) humidity. A similar division between background and relay-operated humidifiers is also advisable, and methods of achieving this are outlined. Dew-point control is shown to be most suitable for the background humidity, while a hot wick of low thermal capacity suffices for the relay-operated device. Finally, the principal uses of such cabinets are dealt with: (a) as adjuncts to field experimentation; (b) for work on plant pathology; (c) for producing standard plant material at any time of year; and rough estimates of running costs are given.
The relationship between fertility in the bovine and impedance change frequency
Authors: Manton V. J. A.
Published: March 2009

An investigation of the estimation of the fertility of bulls' semen was carried out using the Impedance Bridge. A significant relationship between fertility and Impedance Change Frequency was confirmed, and this relationship extended to a within-bull significance.
Estimation of water content by tritium dilution of animals subjected to rapid live-weight changes
Authors: McManus W. R. , Prichard R. K. , Baker Carolyn , Petruchenia M. V.
Published: March 2009

The use of tritiated water to estimate total body-water content of animals experiencing recovery from under-nutrition was studied.

The time for equilibration of tritiated water (TOH), given intraperitoneally, with total body water (TBW) was determined in rabbits and in rats. As judged by the specific activity of blood water, equilibration had occurred by 76–125 min in the rabbit and did not appear to be affected by the plane of nutrition. However, between slaughter groups the specific activity of water obtained from the liver 180 min after injection of TOH was significantly different from the specific activity of water simultaneously obtained from the blood plasma. It is concluded that the liver is not a suitable tissue to use for testing achievement of equilibration.

As judged by the specific activity of blood water compared to that of water from the whole body macerate, equilibration in mature rats either in stable body condition or undergoing rapid compensatory growth occurred in less than 60 min.

A trial comparing TOH-space (corrected by 3% body weight) and actual TBW (by desiccation) was conducted on thirty rabbits which experienced under-nutrition followed by compensatory growth.

Prior to under-nutrition the agreement between actual and estimated TBW was satisfactory and within 2·3%. During compensatory growth the agreement was poor— the TOH values over-estimating actual TBW by about 12%.

A trial with mature rats confirmed the findings with rabbits. For rats in stable body weight the mean estimated TOH-space for fourteen animals was within 1·2% of the actual TBW. For fourteen rats undergoing compensatory growth the mean estimated TOH-space (corrected by 3% body weight) overestimated actual TBW by 6·2%.
Effect of rate and method of application of ammonium sulphate on irrigated wheat sown on three different dates
Authors: Wahhab A.
Published: March 2009

An experiment on irrigated wheat was laid out in a split-plot design in which six levels of N, three dates of sowing and two times and methods of application were tried. The data were subjected to pooled analysis and it was noticed that years, dates of sowing, manures and the interaction of manures and dates of sowing were highly significant, while the time and method of application of the fertilizer and all other interactions were non-significant. Graphs have been presented depicting the law of diminishing returns. Optimum levels of N have also been given. Application of the fertilizer by placement to normal and late sown crops is much better than its application by broadcasting.
A note on the use of molassed wood pulp as a substitute for farm roughages in experimental rations for dairy cattle
Authors: Rook J. A. F. , Campling R. C.
Published: March 2009

In recent investigations at this Institute, attempts have been made to devise for dairy cows a ration extremely low in magnesium to be used in fundamental studies of magnesium metabolism. All common farm roughages are moderately rich in magnesium, and wood pulp, which is low in this element, has been tested as a roughage for use in these experimental rations. American workers (Titus, 1926; Mead & Goss, 1935; Byers, Stanbus, Nelson, Brown, Davis & Gardiner, 1955; Matrone, Ramsey & Wise, 1957; Smith, McLaren, Anderson, Welch & Campbell, 1957; Ellis & Pfander, 1958; Williams, Musgrave, Schul & MacVicar, 1958) have previously used wood pulp as a substitute for roughage in the development of purified rations for cattle and sheep, and it was fed extensively as a substitute farm feedingstuff in Norway during the war years (1940–44)(Edin, Helleday & Nordfelt, 1941; Hvidsten, 1946). This note records some observations on the feeding of wood pulp, often as the sole roughage, to both dry and milking cows.
The effect of thyroxine implantation on wool growth
Authors: Godfrey N. W. , Tribe D. E.
Published: March 2009

1. An experiment was carried out to determine the effect of L-thyroxine implantation upon the wool production and live-weight change of Corriedale and Suffolk × Border Leicester-Merino sheep.

2. Groups fed hay in restricted amounts gave approximately 12% more wool when treated with thyroxine. Since there was no change in fibre diameter, this was presumably due to an increase in staple length.

3. Groups fed hay ad lib. gave no significant increase in wool production when treated with thyroxine, nor did their rate of food consumption alter. Their level of wool production over the 5-month period was approximately the same as that of the thyroxine treated, restricted fed, sheep.

4. All thyroxine-treated groups lost approximately 10% of their live weight. This was in the nature of a steady decrease from the second to the seventh week after treatment. Live weights then remained at about the same level for a further 8–10 weeks when they commenced to return gradually to their original weights.
Some effects of implanted hexoestrol on the growth of steers
Authors: Callow E. H. , Finney D. J.
Published: March 2009

1. An experimental test of the effects of 15, 30 and 60 mg. of hexoestrol (ear implants) on growth (over a period of 95 to 98 days) has been carried out in Argentina, using 172 Hereford steers (all 4–5 years old).

2. On pasture where the growth rate was only about 0·4 kg. a day, the optimum dose was 30 mg., which gave an extra 0·14 kg. per day.

3. The carcasses from the 30 mg. group were significantly heavier by 8 kg., those from the 15 mg. group by 7 kg., but those from the 60 mg. group were only 3 kg. heavier than those from the control group.

4. It is suggested that both the poorer response and the lower optimum dose were due to the poorer pastures on which this experiment was carried out.

5. Evidence for the carcasses of the treated animals being significantly leaner than the controls was given by the 60 nag. group—the grading was poorer, the excess kidney fat was less, and the subcutaneous fat was thinner.

6. Carcass measurements showed differences in the treated groups, but these in general followed the differences in carcass weight.

7. Measurements of width of thigh and thorax provided evidence that the depth of carcass had been increased by hexoestrol.

8. The incidence of ‘tail raising’ had been increased from 10% in the control group, to 50% and more in the 15, 30 and 60 mg. groups. Carcasses from such animals had a slightly greater width at the thigh.

9. The existence of an optimum dose is not thought to be due to restlessness, as indicated by ‘tail raising’, but to a depressant action of hexoestrol on growth. In this connexion, data on the weights of the kidneys show that the 60 mg. dose decreases kidney weight (and implicitly the level of protein metabolism) to the value of the control.

10. Evidence was obtained of a rapid change in live weight when the steers were without food. During a single morning this was, on the average, about 13 kg. per animal, followed by a further 25 kg. during the subsequent 24 hr. (see Appendix II).
The effect of supplementing a low–protein hay on the cellulolytic bacteria in the rumen of sheep and on the digestibility of cellulose and hemicellulose
Authors: Van Gylswyk N. O.
Published: March 2009

A study was made of the effects of supplementing low-protein teff (Eragrostis tef) hay with (a) protein (egg albumin), (b) urea and (c) urea plus C4and C5branched-chain volatile fatty acids (VFA) on the cellulolytic flora in the rumen of sheep conditioned to these diets and on the digestibility of cellulose and hemicellulose. Addition of urea, as opposed to no supplementation, increased voluntary hay intake and the percentage digestibility of cellulose and hemicellulose, while counts of cellulolytic bacteria were not greatly affected. The proportion of ruminococci amongst the cellulolytic bacteria increased somewhat and that of the butyrivibrios decreased. When branched-chain VFA were added to the hay together with urea the numbers of cellulolytic bacteria per g rumen ingesta and the proportion of ruminococci increased over those for urea alone. This was accompanied by a further increase in voluntary hay intake. Percentage digestibilities of cellulose and hemicellulose were similar to those for the urea/hay diet. Supplementation with protein resulted in lower digestibility of α-cellulose and hemicellulose when compared with the urea-supplemented diets. The cellulolytic bacteria formed a lower percentage of the ‘total culturable’ counts than was the case for the other diets.
Phosphate responses in relation to soil tests and organic phosphorus
Authors: Friend M. T. , Birch H. F.
Published: March 2009

Phosphate responses of wheat in a number of soil types have been correlated with the amounts of phosphate extracted by ten different methods. Of these only total organic phosphorus, and inorganic phosphorus extracted with hot 0·1N caustic soda, were significantly related to phosphate response, the former at the 1% level and the latter at the 5% level. The amount of organic phosphorus in the soil was also found to be significantly related, in each instance at the 5% level, to phosphate responses of grass and the percentage phosphate in the grass. When the amount of organic phosphorus was considered together with the phosphate retention capacity of the soil, to give a measure of available mineralized phosphate, the relationships to response (and uptake of phosphorus by grasses) was more significant than with organic phosphorus alone.

The organic phosphorus fraction accounted for about 86% of the total soil phosphorus. Measurable amounts of water-soluble organic phosphorus were found with all the soils. The amounts were, however, not significantly related to phosphate response. Moreover, it was found that while the soil extract containing organic phosphorus decomposed, it did so without the production of mineral phosphate. From this, and further evidence in the literature, it is considered that the organic complex in the soil, rather than the water soluble phosphorus, is the main source for the plant.
Development of penis and sheath in the bull calf
Authors: Ashdown R. R.
Published: March 2009

1. The penises of five bull calves were examined during the first year of life, using epidural anaesthesia or sedation with chlorpromazine hydrochloride.

2. The process of separation between penis and sheath is described and data on age and weight of the calves are given.

3. There was considerable variation in times and rates of development, but in general terms the penis began to separate from the sheath at about 4 months of age, and the process was completed at about 10 months.

4. From the second to the sixth or seventh month of life the penises of these calves were short, and not manually protrusible.
The influence of temperature on flowering in species of Lolium and in Poa pratensis
Authors: Evans L. T.
Published: March 2009

The influence of various night- and day-temperature regimes on inflorescence initiation and earing in vernalized and unvernalized Lolium temulentum, L. multiflorum, short-rotation ryegrass, and two varieties of L. perenne, and also in the Athabasca strain of Poa pratensis, is described.

Vernalization response curves for the ryegrasses, when grown under controlled conditions, are presented, and are consonant with the operation of a first-order reaction as the rate-limiting step in the vernalization ofLolium perenne. Velocity coefficients for the rate of vernalization in various conditions are deduced, and are shown to be higher in seedlings than in seeds, and higher in short days at 10° C. than at 4° C. The Q 10 for the velocity of vernalization over this range is about 2·7.

Low-temperature vernalization in L. perenne can occur when low night temperatures are combined with moderately high day temperatures, and it can take place during abundant vegetative growth. In short days and in continuous light mean temperatures up to 10° C, at least, are fully effective, but in 16 hr. photoperiods even 7° C. was not a fully effective vernalizing temperature. The requirement of perennial ryegrass plants for cold treatment may be replaced by short-day induction if light intensities are low and if the plants are continually divided.
The value of calcium nitrate and urea for main-crop potatoes and kale
Authors: Widdowson F. V. , Penny A. , Cooke G. W.
Published: March 2009

1. Twenty-two experiments on main-crop potatoes in 1955–7 compared calcium nitrate and ammonium sulphate applied to the seedbeds before planting. Urea was also tested in fifteen of the experiments in 1956–7. The three fertilizers were compared at rates that supplied 0·5, 1·Oand 1·5 cwt. N/acre.

2. Seven experiments on kale in 1955–8 compared seedbed dressings of calcium nitrate and ammonium sulphate. Urea “was also tested in. five of the experiments in 1956–8. The rates used were 0·6, 1·2 and 1·8 cwt. N/acre in 1955 and 1·0 and 2·0 cwt. N/acre subsequently. Single dressings applied to the seedbed were also compared with divided dressings applied partly to the seedbed and partly in mid-season.

3. Generally the potatoes gave only small responses to N; there was no worthwhile gain from applying more than 1·0 cwt. N/acre in 1955 and 0·5 cwt. N in 1956 and 1957. Nitrogen gave much larger proportionate increases in yields of kale, at several of the centres crops continued to respond up to dressings of 2·0 cwt. N/acre.

4. Calcium nitrate generally gave lower yields of potatoes than ammonium sulphate and the superiority of ammonium sulphate was greater with the higher dressings. Losses in yield with the nitrate were usually associated with a severe check to early growth occurring in dry springs and with dressings concentrated close to the seed, but lower yields were also obtained at some centres where early growth was not damaged. Calcium nitrate and ammonium sulphate were roughly equivalent for kale when the nitrate did not damage germination; heavy seedbed dressings of the nitrate reduced kale plant numbers severely unless there was adequate rain after sowing.

5. Granulated urea tested in 1956 contained 4·5% of biuret, it delayed emergence and reduced plant establishment seriously in several of the potato experiments; damage increased with the level of manuring and was accentuated when dressings were broadcast over furrows before hand-planting. Yields given by this batch of urea were less than with other N fertilizers and when 1·5 cwt. N/acre was applied they were less than with no nitrogen at all. Purer crystalline urea (having less than 1% of biuret) used in the 1957 experiments caused no damage to emergence of potatoes and gave yields similar to those obtained with ammonium sulphate. There were similar effects in the kale experiments; granulated urea containing much biuret damaged germination severely in 1956; the purer products containing little biuret used in later years reduced plant numbers at one centre in 1957 and at the single 1958 centre. Where there was no damage to the establishment of kale, urea and ammonium sulphate gave similar yields.

6. Dressings applied partly to the seedbed and partly in mid-season gave slightly higher average yields of kale than an equivalent total amount of nitrogen all applied before sowing.
The effect of management factors on the intestinal bacteria and the growth rate of chicks
Authors: March B. E. , Goudie C. , Biely Jacob
Published: March 2009

1. The apparent cleanliness of the premises in which chicks are reared has little bearing on the growth rate of chicks within a given environment.

2. Bacterial counts of faeces from chicks reared under clean or extremely contaminated conditions showed no difference between the two sets of conditions.

3. Delaying feeding until 72 hr. after hatching retarded growth to at least 7 weeks of age. If the age of the chicks was calculated from the time at which the chicks were fed rather than the date of hatch, the weights of the chicks fed 72 hr. after hatching corresponded with those of the chicks fed immediately.

4. The contents of the duodenum and mesenteric intestine showed higher bacterial counts when feeding was delayed for 72 hr. than when feed was given shortly after hatching. This effect was no longer evident after the chicks were 1 week old.

5. Administration of penicillin in the water did not reduce the difference in growth rates between the chicks given feed immediately and those from which feed was withheld.

6. Antibiotics may decrease the thickness of the intestinal wall without stimulating growth.
The production of fattening cattle and extension of autumn grazing following three rates of application of nitrogenous fertilizer to a rye-grass/white clover sward
Authors: Tayler J. C. , Rudman J. E.
Published: March 2009

1. Three levels of a nitrogenous fertilizer, supplying 0,104 and 208 lb. N per acre were applied in 1955 and 1956 to a rye-grass/white clover sward in its fourth and fifth harvest years on a loam soil overlying chalk.

2. Levels of animal production were measured using fattening cattle maintained on the plots at a stocking rate of 1⅓ per acre: excess herbage was conserved and fed back to them later.

3. Low rainfall in 1955 seriously affected yields of herbage and response to fertilizer, and severely reduced the clover content in all treatments.

4. Rate of live-weight gain per head was not reduced by the application of fertilizer at either level. Vigour of the sward was maintained by fertilizer application in a dry spring period in 1956, whereas, in the control treatment, which was low in clover, gains per head were markedly reduced because of inadequate dry-matter production.

5. By applying two-thirds of the fertilizer in late summer, a considerable extension of grazing time was obtained, particularly when rainfall was adequate. At the highest level of fertilizer application in 1956 the grazing season was extended from 6 months to 7½, and the cattle continued on conserved feed to a total of 8½ months. Response to the medium and high levels of application on grazed herbage only was 12 and 15 bullock-days per acre, respectively, in 1955. In 1956 the response was 46, and 67/59 (the two high nitrogen treatments). In terms of total live-weight gain per acre the response in 1955 to medium and high levels was 23 and 32% above control, up to 427 lb. per acre: in 1956 it rose to 51 and 52/55% with the highest treatment reaching 657 lb. per acre. Greater financial returns than are indicated by live-weight gain should result from the rising price per pound of carcass as the supply of fresh beef dwindles in early winter.

6. Carcass data indicated that both greater rate of gain and the extra time spent on fertilized herbage and conserved feed increased carcass weight and maturity in the normal pattern of development, fat most rapidly, muscle next and bone least. No significant differences in conformation due to treatment was detected by analysis of grouped joints.
An experimental study of the early weaning of lambs
Authors: Wardrop I. D. , Tribe D. E. , Coombe J. B.
Published: March 2009

Two early weaning experiments are reported. When grazing young, high protein pastures, lambs weaned at 7, 10, 13 and 18 weeks of age grew equally well and there were no significant differences between their carcass weights, grades, and dressing percentages.

However, when grazing pastures in the preflowering and flowering stages of growth, lambs weaned at 8 weeks of age did not grow as well as unweaned controls. Their carcass weights, grades, and dressing percentages were also inferior. It is suggested that these differences were primarily due to an inadequate protein intake.

No difference in wool production was found either between the ewes of early weaned and control lambs, or between the lambs themselves.
The effect of urea on the utilization of ground, pelleted roughage by penned sheep: I. Food intake, live-weight change and wool growth
Authors: Coombe J. B. , Preston G. K.
Published: March 2009

Individually-penned adult Merino wethers were fed for 16 weeks on a basal diet of ground, pelleted oat straw orPhalaris straw. Urea was supplied either in a salt-urea block containing 30% urea, or as crystalline urea incorporated into the pellets. A commercial mineral supplement was given during the first 8 weeks, but this was replaced with a laboratory-prepared mineral mix during the second 8 weeks.

Urea supplementation significantly reduced live-weight loss. Over the 16 weeks control sheep lost a mean of 14·5 kg, and supplemented sheep 8·7 kg body weight. Most of this response to urea occurred during the second half of the experimental period.

Food intakes of all sheep increased over the first 2 weeks and then fell. In the unsupplemented groups, levels of intake then remained fairly low, whereas in the sheep fed urea food intakes rose over the final 6 weeks of the experiment. There was a significant linear regression of live-weight change on food intake only with the urea-fed sheep. Intakes of urea-N from the blocks were extremely variable between individual sheep and between periods within sheep; in most cases, however, they appeared to be adequate, as this type of supplementation gave results similar to those obtained by mixing urea throughout the roughage.

There was no significant effect of urea on total wool growth during the experimental period, although wool growth in the supplemented shepp showed a rise towards the end of the experiment. Wool growth in any 4-weekly period was closely related to food intake and live-weight change during that period.
Visual judgements of quality in meat II. A simplification of the assessment of the proportion of lean to fat in bacon
Authors: Gatherum D. P. , Harrington G. , Pomeroy R. W.
Published: March 2009

1. The visual judgement of bacon quality called the ‘proportion of lean to fat’ has been simplified by breaking down the overall assessment of the surface seen on the cut bacon side at the last rib into four simpler scores—of the ‘eye’-muscle size and shape, the amount and distribution of fat on the back rasher, the streak thickness and the proportion of lean to fat in the streak, each judged on a 10-point scale. An experiment is described in which eight experienced judges attempted to score these new characteristics in conjunction with the overall assessment.

2. The judging standard adopted in the overall assessment of the proportion of lean to fat varied less from batch to batch in this experiment (in which the seven batches were arrayed in fixed positions and assessed in one day) than in an earlier experiment (when the examples seen in each batch could be shuffled and the eleven batches were seen several days apart). The ranking of judges according to their discrimination and repeatability for the overall assessment was also changed in the second experiment.
Studies on the cutting management of grass-clover swards Part II. The effects of close cutting with either a gang mower or a reciprocating-knife mower on the yields from an established grass-clover sward
Authors: Reid D. , MacLusky D. S.
Published: March 2009

1. In an experiment conducted on an established perennial rye-grass/white clover sward close cutting was carried out over a 3-year period (1956–58), either with a lawn mower to simulate gang mowing or with a reciprocating-knife mower. The sward was cut either six or eight times in each season, and received 0 or 2 cwt. ‘Nitro-Chalk’/acre for each cut.

2. Swards cut with the gang mower yielded from 3·5 to 12·5% more herbage dry matter than swards cut with the reciprocating-knife mower and also gave a greater mean yield of crude protein.

3. The difference in dry-matter yield between swards cut with each of the mowers is attributed to the slightly closer cutting level of the gang mower having a greater inhibiting effect on flower development in the grasses and hence stimulating leaf production and increasing total yields.

4. In the second and third years of the experiment swards cut with the gang mower outyielded those cut with the reciprocating-knife mower by a proportionately greater amount when eight cuts rather than six cuts were taken in the season.

5. When no nitrogenous fertilizer was applied the proportion of broad-leaved weeds in the sward increased more rapidly over the 3-year period where the herbage was cut with the gang mower rather than the reciprocating-knife mower. This disadvantage of gang mowing did not apply where the fertility was maintained at a high level by applications of nitrogenous fertilizer.

6. It is concluded that the gang mower is a more suitable machine than the reciprocating-knife mower for close cutting on a field scale.
An experiment on the effects of straw ploughed in or composted on a three-course rotation of crops
Authors: Patterson H. D.
Published: March 2009

An experiment on the use of wheat straw (ploughed in or composted at the rate of 53⅓ cwt./acre every second year) and NPK fertilizers in the maintenance of fertility was carried out at Rothamsted between 1933 and 1958. The effects of these treatments on the yields of the crops of the rotation used in the experiment—barley, sugar beet, potatoes—are discussed in the present paper.

The treatments appear to have had no effect on crop yields through improvements to the soil caused by better structure or increased organic matter content. All the effects obtained can be attributed to changes in the supplies of available nutrients. The most important of these changes appear to have been: (1) nitrogen deficiencies due to the immobilization of soil nitrogen or nitrogen fertilizer by the straw: there is some evidence that this added to the store of slowly available nitrogen; (2) additions to potassium supplies from potassium in the straw. Factor (1) affected all three crops. Factor (2) affected potatoes, the only crop of the three to give good responses to potassium.

It was found that when the straw was ploughed in directly about 0·08 ewt. N fertilizer applied to the crops for each ton of straw was sufficient to overcome losses in yield due to nitrogen deficiencies. The straw improved the yields of potatoes in the first and second years after application. Provided that allowance was made for losses of available nitrogen the yields of potatoes from ploughed-in straw were about the same as the yields obtained by adding K fertilizer to the crop, equal in amount to the potassium in the straw. When part of the fertilizers was ploughed in with the straw instead of being given directly to the crop the yields of potatoes were reduced.

Compost made with NT fertilizers and straw and ploughed in with K fertilizer gave much poorer yields than were obtained by ploughing the straw in directly and applying the fertilizers to the crops. Losses of available nitrogen were severe, all the N fertilizer used in making the compost (0·15 cwt. N for each ton of straw) being either lost through drainage or immobilized by the straw. In addition, more than one half of the potassium in the straw was lost in composting.

There was no evidence that any of the nitrogen immobilized in the decomposition of the straw became available in the first or second years after application. Residues from repeated applications of straw every second year over 18 years increased the yields of potatoes and sugar beet in the last 6 years of the experiment. The increases may have been due to the release of previously immobilized nitrogen.