bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water conduction by severed grass roots
Authors: Emerson W. W. 
Published: March 2009

It is suggested that part of the increased permeability of soil recently ploughed out from grass could be due to water conduction through the severed roots. Microtome sectioning of a root of Lolium perenne showed a continuous metaxylem element of about 30μ diameter, with only minor restrictions, forming a natural capillary tube. Further, being at the centre of the stele, the metaxylem should persist for some time after the grass has been killed. Hydraulic diameters calculated from laboratory experiments on the rates of water conduction by severed L. perenne roots were in reasonable agreement with the diameter of the metaxylem measured by direct sectioning.Similar experiments on Phleum pratense were more difficult to interpret due to the complexity of the metaxylem, the number of elements not being constant along the root. The rate of water conduction by roots of Dactylis glomeratus was found to be small compared with the other grasses, for although having the largest number of elements they are the smallest in size of any grass examined.The permeability of a severed Lolium perenne root system, calculated on the basis of the surface density of roots found on 4-year-old plots, indicated that the root system should significantly increase the unsaturated permeability of soil at low suctions. To obtain maximum benefit the ‘capillary tubes’ should be severed immediately under the turf and not at ploughing depth. Accordingly, two plots were laid out on old grassland to compare normal autumn ploughing with shallow rototilling on the subsequent germination and growth of spring wheat. In spite of repeated rototilling, however, it proved impossible to kill the grass in the wet winter conditions and the wheat was smothered. A comparison of the suctions developed at 5 cm. in the two plots showed that the unsaturated permeability of the rototilled plot was higher.Although the laboratory results are encouraging there is as yet no conclusive evidence that the natural water supply and drainage system formed by the severed roots is important under field conditions.
Seasonal fleece changes in some Cheviot sheep
Authors: Ryder M. L. 
Published: March 2009

SUMMARYTwo groups of five and six ewes were studied through two separate winters by monthly wool and skin samples in an attempt to follow the changes leading up to fleece casting, which occurred extensively in only two animals.Although no fleece break was observed, the animals that cast most showed the biggest decrease in fibre diameter. They also had a decrease in staple length where the wool was not cast.Follicle inactivity increased during the observations reaching a peak at the end of the winter, and the animals that cast most had most follicle inactivity. It is concluded that casting was associated not with fleece break but with increased follicle inactivity coupled with premature release of the fibres from the follicles.
The contribution of seed survival to yield in new Australian cultivars of oil-seed rape (Brassica napus)
Authors: Mendham N. J. , Russell J. , Buzza G. C. 
Published: March 2009

SUMMARYA series of experiments in Tasmania examined the growth, development, yield and components of yield of new Australian oil-seed rape cultivars from Victoria and Western Australia. The highest yields obtained were around 5·5 t seed/ha, from an autumn sowing with supplementary irrigation. Spring sowings with irrigation or autumn sowings without produced up to 4 t/ha. The Victorian lines with Japanese parentage clearly outyielded the Western Australian cultivars or Midas, a widely grown Canadian cultivar. When autumn sown, the Victorian lines grew more rapidly at low temperature, which under conditions of later stress contributed to a high yield relative to the other cultivars. However, the most consistent feature from both autumn and spring sowing was high rates of seed survival, up to near the potential number of around 30 per pod, giving very large numbers of seeds per m2. While individual seeds in the Victorian lines, particularly Marnoo, were smaller than in Midas, oil content remained high except under extreme stress in the later stages of seed development.
Further experiments on the drifting of honey-bees
Authors: Free J. B. , Spencer-Booth Yvette 
Published: March 2009

1. Worker bees learnt the colour of their hive in the close vicinity to their hive entrance and took little or no notice of colours above the lower brood chamber. They orientated to a colour below the entrance more than to a colour above. They did not learn combinations of colours.2. They distinguished between certain symbols placed immediately above the hive entrance.3. They learnt the height of their hive and the height of its entrance above ground.4. More worker bees and drones from queenright colonies drifted to queenless than to queenright colonies. Drones expelled from queenright colonies did not drift to queenless colonies.
White clover investigations I. Effect of seed rates and cutting treatments on flower formation and yield of seed
Authors: Zaleski A. 
Published: March 2009

Investigations on the effect of seed rates and cutting treatments on the inflorescence formations and yield of seed were carried out on S. 100, S. 184 and Kent wild white clover during 1957–60 at Cambridge. The study of primordial development under field conditions, establishment of the major characters contributing to the final yield and the factors affecting their contribution were the main object of these investigations.These factors and their relationship and contribution to the final yield results are discussed in some detail.
Urea as a fertilizer Laboratory and pot-culture studies
Authors: Low A. J. , Piper F. J. 
Published: March 2009

A laboratory and pot-culture investigation to seek reasons for the variable response of grass and other crops to top-dressings of urea, and to the occasional phytotoxicity to seedlings of urea either mixed in the soil or drilled in contact with the seeds is described.The part played by biuret, the chief impurity in commercial urea, has been examined. It can be phytotoxic to germinating seedlings when in contact, but in the quantities likely to be applied in agriculture in top-dressings, e.g. 150 lb. of urea with up to 2·5% of biuret, its effect is negligible. Up to at least 5% of biuret can be present in urea without affecting its ammonification or nitrification in soil.It has been shown that loss of nitrogen to the atmosphere can account for the poorer responses of grassland to top-dressings of urea as compared with ‘Nitro-Chalk’ or ammonium sulphate.The phytotoxic behaviour of pure urea to germinating seeds seems to be due to rapid production of ammonia. This gas is also evolved from topdressings of urea. Both the phytotoxicity and the loss to the atmosphere can be reduced by mixing urea with acid salts to neutralize the ammonia.
The rumen fermentation of lactose in the adult sheep
Authors: Walker D. M. , Lee Barbara A. 
Published: March 2009

1. A cross-bred sheep was fed successively with supplements of dried skim-milk or lactose. The effect of the supplements on the lactase activity of the rumen liquid was followed.2. Lactase activity was expressed as mg. lactose hydrolysed per ml. rumen liquid, or per mg. protein nitrogen. The enzymic activity fluctuated considerably after a change in the diet, and did not become constant even when the ration remained the same for 7 weeks.
The influence of different daylengths on ear emergence and seed setting in oats
Authors: Griffiths D. J. 
Published: March 2009

1. The study of the photoperiodic responses of varieties and forms of the genus Avena has revealed considerable diversity within the group.2. The investigation of a number of forms differing in geographical distribution confirms the close relationship between photoperiodism and region of origin. There appears to exist a definite relationship between the geographic origin of a given form and the limits of its tolerance to short day. The forms from the more southerly latitudes suffered less from short day than those of northern origin.3. Panicle exsertion was entirely suppressed under photoperiods of 12 hr. and less in A. sativa varieties Victory, S. 84 and Black Supreme, which have been selected for high yielding ability in more northerly latitudes.4. Plants which failed to produce exserted panicles in varietal tests were dissected, and it was found that floral differentiation had not been inhibited by the shortened photoperiods, but that the full elongation of the internodes, especially the upper internodes, had been suppressed.5. Selection experiments with progenies of the cross Wintok × A.fatna form Cc 3872 grown under different photoperiods confirmed a highly selective response to daylength, thus indicating that this response is under genetic control.
The effect of a submaintenance diet on the composition of the pig
Authors: Pomeroy R. W. 
Published: March 2009

Five inbred Large Whites from the same strain as used by McMeekan (1940) were reared on a High Plane of nutrition to approximately 330 lb. live weight at which one was killed as a control. The rest were put on to a submaintenance diet of straw and water and killed successively at roughly equal intervals in live weight between 330 and 200 lb. The weights of blood, organs and offals were determined and the carcasses were jointed and completely dissected into their constituent tissues. The total weights of each and the weights within the various joints were recorded.(1)Organs. The early-maturing organs, brain, eyes, etc., continued to grow. Other organs like the heart, liver, lungs, etc., suffered a greater or less degree of atrophy which was probably determined by a suspension of their functions.(2)Carcass composition. The tissues of the carcass were affected in reverse order to their development, i.e. fat most, muscle less and bone least. Bone continued to grow in the earlier stages of submaintenance.
Drainage and evaporation from fallow soil at Rothamsted
Authors: Penman H. L. , Schofield R. K. 
Published: March 2009

1. Study of the automatic records shows:(a) There is a seasonal change in the drainage response after rain which can be almost wholly ascribed to viscosity changes arising from seasonal changes of soil temperature (p. 77).(b) Evaporation occurring after a fall of rain has no measurable effect on the drainage response to that rain (pp. 78, 87).(c) The maximum drainage rates for the 20 in. gauge are much larger than those for the deeper gauges. The maxima change seasonally and are again primarily dependent on viscosity (p. 78).(d) There is no marked change in the field capacity of the gauge during the year. The air-filled pore space at field capacity may change by about 15% of its average value (p. 81).
The relation of drainage to rainfall and other meteorological factors
Authors: Sahni P. N. 
Published: March 2009

Natural drainage periods, i.e. periods between consecutive cessations of flow of the Rothamsted 20 in. drain gauge, were selected for the months of June, July and August. All periods of from 2 to 13 days were taken.A curvilinear relationship between the difference of rainfall and drainage (deficit) and rainfall was established.Residuals from this curve showed no appreciable correlation with the mean air temperature, but there was some slight evidence that the deficit was increased by a decrease in relative humidity or an increase in wind velocity.The residuals showed little correlation with drainage during the previous 3 weeks.
Population studies with wheat: III. Seed rates in nursery trials and field plots
Authors: Hudson H. G. 
Published: March 2009

The discrepancies between nursery plots and field plots, found by previous workers when investigating yield problems with wheat, are discussed. The reason for these differences is given, and the true optimum plant density identified.It is shown that the intensity of competition for water and soil nutriments influences the optimum plant density, and that a high intensity of competition is associated with a low optimum plant density. A summary of literature is given, and the varying values for the optimum seed rates in different parts of the world interpreted in the light of water and soil nutriment supplies.
Studies on the excretion of copper in the rabbit
Authors: Eden A. 
Published: March 2009

1. In metabolism experiments undertaken to study the channels of elimination of copper under varying conditions, the rabbit was chosen as experimental animal for convenience of manipulation. This choice, although not defeating the main objects of the work, accidentally added valuable informationon the little-known habit of “physiological faecal refection”in this animal.2. On a normal diet of bran and oats, containing the usual traces of copper, the rabbit is in copper equilibrium, excreting as much in faeces and urine as is taken in the food. Urinary elimination is of the order of 0·07–0·38 mg. per litre, but this is very subsidiary to faecal elimination of about 2·5 mg. per 100 g. of dry matter, which may account for even more than 96 % of the total food copper.3. Increase of food copper is not reflected by material increase of urinary output, the higher quantities appearing almost entirely in the faeces. Of 50 mg. of copper or nearly 200 times the normal food intake, as the dissolved sulphate dried on to the food, only 0·1 mg. appeared in the urine, the remainder being slowly excreted in the faeces over the unexpectedly long period of 4 or 5 weeks.
Dissolved organic and inorganic phosphorus compounds in pig slurry: effect of drying
Authors: Gerritse R. G. , Eksteen R. 
Published: March 2009

SUMMARYFrom gel filtration studies it has been found that more than 50% of organic phosphorus dissolved in pig slurry is contained in compounds of high molecular weight. Various ions, e.g. calcium, copper, orthophosphate, are bound by these compounds. From the purine and pyrimidine base composition and resistance to acid and alkali treatment it follows that these organic compounds probably are complexes derived from polydeoxyribonucleotides (DNA).The effect of drying pig slurry at various temperatures (0–100 °C) on the solubility of phosphorus, calcium and copper after redispersion of the dried slurry was investigated. The solubility of organic phosphorus was not affected by drying and redispersion in water, but the amount of phosphorus contained in dissolved organic molecules of high molecular weight decreased on drying at higher temperatures. The solubility of copper was also not affected by heat treatment. The solubility of inorganic phosphorus is mainly related to the solubility constants of mineral phosphates. On the other hand the total solubility of the cations involved is determined by complex formation.
Using Suffolk sheep for improving lamb production from sub-tropical Egyptian sheep:2. Lamb and fattening performance
Authors: El-Shobokshy A. S. , Aboul-Naga A. M. 
Published: March 2009

SUMMARYLamb and fattening performance and carcass quality of Suffolk x local Ossimi cross-bred lambs are discussed. 1369 cross-bred lamb records over the period from 1957 to 1970 were available for the study. The lambs of 50–59% Suffolk were the best cross-bred group with an advantage of 7–7, 14–2 and 17–1% over the native Ossimi lambs in birth weight, 120-day and yearling body weights, respectively. Generally, lamb performance declined as the Suffolk breeding was increased. However, breed groups variation was not statistically significant, except for birth weight.Seventy-one weaned male lambs, 4 months of age, from three breed groups: 70–90% Suffolk, 35–45% Suffolk and local Ossimi, were fattened for 16 weeks using two levels of feeding. The two Suffolk cross-bred groups gained slightly more body weight than the local Ossimi. After 8 weeks of fattening, the 35–45% Suffolk lambs gained significantly more weight than the local lambs. However, the local lambs were more efficient in converting food to live-weight gain.The carcass quality of the Suffolk cross-bred lambs was better than the local lambs, and the advantage was greater for the high Suffolk breeding group.
A field study of coat shedding in cattle under conditions of equal day-length but different temperatures
Authors: Murray D. M. 
Published: March 2009

A comparison has been made over 2 years of spring shedding in cattle maintained in two environments experiencing a similar photoperiod but vastly different seasonal temperatures. At each location (Walcha and Narrabi, N.S.W.) experimental animals were divided into two nutritional groups, namely a Feed group and a Pasture group.2. In 1961-62 both the Feed and Pasture groups in the warmer climate of Narrabri shed their winter coats in October, while animals maintained under the cooler conditions of Walcha did not acquire their summer coats until January of the following year. The Narrabri groups, however, also displayed superior live-weight gains than the corresponding groups exposed to the more severe winter conditions prevailing at Walcha.3. The following year (1962-63) a differential feeding programme was adopted for the two Feed groups which resulted in their live-weight gains for the experiment being similar. Although the low ration of hay fed to the Narrabri Feed group to achieve this parity of weight gains introduced a nutritional stress factor in the group, these animals displayed a slightly superior shedding ability than did those in the Walcha Feed group.
The response of a rye-grass/white clover sward to various irrigation régimes
Authors: Stiles W. , Williams T. E. 
Published: March 2009

A variety of irrigation régimes were applied to a rye-grass/white clover sward, at several nitrogen levels, in small-plot field experiments.Herbage yields increased with decreasing soil moisture deficit.No outstandingly good irrigation régime was found, but some distinctly poor practices were identified, by reference to the yield per unit of irrigation water and to the shape of the annual growth curve. The significance of the results for irrigation practice is discussed.Tho authors wish to thank Dr William Davies for the provision of facilities, Mr R. J. Canaway and his staff who made the irrigation apparatus, many past and present colleagues who helped with the field work, and members of the Biometrics Department who analysed the data.
Autumn nitrogen for winter wheat
Authors: Widdowson F. V. , Penny A. , Williams R. J. B. 
Published: March 2009

1. Fourteen experiments with winter wheat on heavy-land farms from 1958–60 compared autumn dressings of sulphate of ammonia with equivalent early (March) or late (May) spring top-dressings. Dressings applied on two or all three dates of application were also compared.2. Consistent and significant gains in yield from low (0·5 or 0·6 cwt. N/acre) and high (1·0 or 1·2 cwt. N/acre) levels were obtained at most centres, which were on fields under arable rotation.3. With the low level of N, gains in yield were greatest from a single May top-dressing. There was no gain from dividing the dressing.4. With the high level of N, dressings divided between autumn-May or March-May were best. March-May was the most consistently satisfactory treatment and gave the highest mean increases in yield in 1959 and 1960, but in 1958 autumn-May was better. Single May dressings gave slightly lower yields. There was no advantage from dividing N between all three dates of application.5. Single applications of N in autumn gave lower yields than single applications in spring; supplementing autumn N with a late spring top-dressing gave almost the same yield as giving all the N in spring. Dividing the dressing in this way may be convenient on many heavy-land farms.6. The percentage of N in the grain was highest with a late top-dressing of fertilizer-N, lowest with autumn N and intermediate with March top-dressings.
Visual judgements of quality in meat III. Assessments of bacon qualities by naïve and experienced judges using photographic reference standards
Authors: Gatherum D. P. , Harrington G. , Pomeroy R. W. 
Published: March 2009

1. Two panels of eight students, with no previous experience in scoring bacon sides for eye-muscle qualities or for fatness, co-operated in an experiment involving thirty-five photographs of back rashers of bacon presented to them in batches of twenty at a time. The members of the first panel made their assessments without any guide, whereas those of the second were provided with sets of photographic reference standards showing a graded sequence of rashers scoring from 0 to 10 for each of the two characteristics involved.2. Those provided with the reference standards spread out their scores over the available range more than those who judged without them.3. Judging discrimination between markedly different groups of rashers was improved when the reference standards were available. This was not true of discrimination between similar rashers since repeatability of scoring was to some extent decreased when the standards were used.4. When the reference standards were not available, these inexperienced judges tended to adjust their level of scoring according to the quality of the batch of rashers being assessed. This adaptive effect was eliminated when reference standards were available although apparently random fluctuations of level of scoring from batch to batch still occurred.5. Differences between judges due to their different uses of the available range of scores were less marked, although not entirely eliminated, when reference standards were used by the naive judges. Systematic differences between the scores awarded by various judges remained, as did a few differences of opinion on the relative quality of certain examples.
Analysis of honey farmers' records on queen rearing and queen introduction
Authors: Free J. B. , Spencer-Booth Yvette 
Published: March 2009

1. Queen-rearing and queen-introduction records of two honey farmers have been analysed.2. Cells with newly grafted larvae were sometimes more readily accepted by queenless and broodless colonies than by queenless colonies with brood, or queenright colonies, and sometimes more readily accepted and built by queenless colonies with brood than by queenright colonies. Giving larval food with the larvae made little difference to acceptance.3. Sealed cells and virgin queens wero more readily accepted by colonies dequeened for 3 days or more than by more recently dequeened colonies, particularly when the former had queen cells. Queen cells were the least successfully introduced to colonies which had been dequeened 3 hr. or less. Younger cells were better accepted than older cells in recently dequeened colonies, but not in colonies dequeened 3 days or more. Cell protectors did not increase the percentage of mated laying queens produced.4. Mated laying queens were less successfully introduced to colonies with virgin queens, cells, or laying queens and cells, than to colonies with laying queens only.5. In June and July cells and virgins were more successfully introduced, and mated laying queens less successfully introduced, than in other months. The acceptance of grafted cells did not vary with the time of the year.6. The success obtained with cell building, and cell and queen introduction differed greatly in different years.