bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population studies with wheat: I. Sampling
Authors: Hudson H. G. 
Published: March 2009

The design and field technique of two large scale experiments, laid down to investigate the problems of sampling and “propinquity”, are described in detail. These experiments were designed so that the plant number, stem number, ear number, straw weight and grain weight for 7200 lengths of 6 in. of drill row, together with the position of each observation, might be obtained.The lowest sampling error, expressed as a percentage of the mean, is obtained by using the smallest sampling unit, but the large number of sampling units of this size that would have to be taken make it impracticable. The optimum sampling unit consists of 6 ft. of drill row, taken as 3 ft. of two adjacent rows. The size of the sampling unit is of greater importance than the shape in determining its accuracy, and little s lost by using sampling units of 18 in. of five adjacent rows.The nature of the observation affects the degree of sampling. In the experiments examined the plant number, stem number and ear number require very similar sampling, but grain weight requires a sample which is about twice as large as that required by the other observations.The percentage of the plot that must be taken as a sample (the sampling percentage) to obtain any given accuracy is related to the size of plot: the larger the plot, the lower the sampling percentage necessary. To obtain an error of 5% of the mean the sampling percentage for grain weight is approximately 5% in 1/20 acre plots, 15% in 1/100 acre plots and 43% in 1/600 acre plots if the plots are not subdivided. These percentages are similar to those calculated from various randomized block experiments in Cambridge.
Studies in the nutrition of vegetables: Phosphate deficiency and yield tests on sand cultures of May King lettuce
Authors: Woodman R. M. 
Published: March 2009

Media from which phosphate was absent finally caused bronzing of the leaves of the resulting stunted plants of May King lettuce grown in sand culture, and red or crimson stalks. Phosphate alone produced characteristic purple (and/or bronze) and apple-green, flat, stunted rosettes with broad, non-crinkly leaves, and red stalks. Water alone caused stunted, straggly, purple plants, with relatively long, crimson stalks.Where some phosphate was supplied in addition to the other essential elements, a plant of normal colour resulted at first. Later, purple blotches appeared on the plants receiving inadequate supplies; the intensity of this purple became greater as the amount of phosphate in the medium diminished, and it could be controlled by varying the concentration of phosphate in the medium or the frequency of application. Another deficiency symptom was the tougher leaf resulting from a lack of phosphate. A sufficiency of phosphate caused earlier maturity.The media which contained the two greatest concentrations of phosphate were the best of those used because they gave the best growth, lettuces of the best colour without purple blotches, earlier maturity, and tenderer leaves.The final yields of heads were statistically the same with the two heaviest phosphate treatments, and both were greater by about 40% of the lesser yields than the two statistically equal yields with the lower amounts of phosphate. All the phosphate treatments gave yields superior by about 40,000–60,000% to the non-phosphate and phosphatealone yields, but this second difference had no commercial significance. Similar results were obtained for the roots, and for the dry weights of the tops and roots.
Factors influencing the percentage of nitrogen in the barley grain of Hoosfield
Authors: Yates F. , Watson D. J. 
Published: March 2009

The effect of rainfall, sowing date and yield on the percentage of nitrogen in the barley grain of certain representative plots on Hoosfield is studied.All these factors are shown to have marked effects. The farmyard manure plot differs from the others, both in mean percentage and in the effects of rainfall and yield.Changes in variety appear to have had little apparent influence, but there is a progressive decrease in the percentage of nitrogen which cannot be accounted for by changes in any of the above factors, and which may well be due to varietal improvementComparison is made with the results of the similar study on the permanent barley plots at Woburn.
The identification of minerals in soil colloids
Authors: Nagelschmidt G. 
Published: March 2009

X-ray, optical, dehydration and chemical methods in use for the identification of minerals in soil colloids are discussed with special regard to their limitations. These are mainly due to uncertainties about the variation of physical properties of standard minerals with decreasing grain size and the possible existence and importance of amorphous material. The aggregate method in X-ray analysis, which is specially important for soil colloids, is described. Various techniques for dehydration and optical analysis are discussed, and it is concluded that they are useful only when used in combination with X-ray data. The advantages of combining various chemical methods with X-ray analysis are pointed out.Standard data are given for a number of minerals, and the evidence for their occurrence in soil colloids is reviewed. These minerals are quartz, cristobalite, oxides and hydroxides of iron and aluminium, minerals of the kaolinite, montmorillonite and mica groups.
The use of carcass measurements to predict the yield of ‘high-priced cuts’ in carcass of Holstein calves
Authors: Butterworth M. H. , Diaz J. A. , Hoystad E. 
Published: March 2009

SUMMARYMeasurements were made on 104 carcasses of Holstein or Holstein cross-bred calves in a commercial slaughterhouse and retail butchers in Monterrey, NL. Measurements were: chilled carcass weight, circumference of side, maximum depth of forequarter (three measurements), length of leg, length of side, and length of forearm. Carcasses were cut and the sum of the weights of round, rump, short loin and rib (all bone in) defined as ‘high-priced cuts’. Multiple regressions were computed for linear, semi-allometric and allometric equations using a CDC 3300 computer.The linear form of the equation accounted for more of the total variance than either the semi-allometric or allometric forms. In all equations cold carcass weight accounted for the greater part of total variance (98·9, 97·1 and 98·2% respectively for the three equations in the order as mentioned above). The incorporation of circumference of side slightly improved the goodness of fit in all cases as did the inclusion of length of side and length of leg in the semi-allometric form. The particularly high proportion of the total variation attributable to cold carcass weight in the present study was probably due to the sparse fat cover of the calves.
Factors modifying egg production with special reference to seasonal changes
Authors: Whetham Elizabeth O. 
Published: March 2009

Summary1. Sexual periodicity in many animals is largely conditioned by variations in the daily light period. That egg production in hens may be controlled by the use of artificial lights has long been known.2. The action of light is probably connected with the activity of the anterior lobe of the pituitary.3. The natural variation in daily light period at different latitudes has been used to study the effect of light on egg production throughout the world. Curves have been constructed of egg production grouped in 5° of latitude and the correlation with the hours of daylight at those latitudes studied.
Investigations into the Intensive System of Grassland Management. By the Agricultural Research Staff of Imperial Chemical Industries, Limited. VIII. The Comparative Digestibility and Feeding Value of Fresh and Artificially Dried Grass
Authors: Watson S. J. , Ferguson W. S. 
Published: March 2009

Two series of trials have been carried out to compare the digestibility of fresh grass with the material obtained by drying grass, from the same source and cut at the same time, in a band drier by heated air at an inlet temperature of 200° C.This process has not affected the digestibility of the various constituents with the possible exception of the crude protein which is slightly depressed.In the second series of trials a drier operating with air at an inlet temperature of 600° C. was also used. In this drier a depression of the digestibility of the constituents of the grass was noted. This was particularly so in the case of the protein which was depressed to a very marked degree.It would therefore appear that although the use of the higher temperature increases the output of the drier, it adversely affects the digestibility of the final product.
Nitrogen requirements of sugar beet in relation to harvesting date
Authors: Holmes M. R. J. , Devine J. R. , Dunnett F. W. 
Published: March 2009

SummarySeven field experiments were made on the effect of two harvesting dates on the nitrogen requirements of sugar beet. All were on Rauceby series soils overlying oolitic limestone in Lincolnshire.Nitrogen fertilizer increased sugar yield in all experiments, and yield was considerably higher at the mid-December harvest than in early October. On average, the sugar-yield response to nitrogen was greater at the late harvest, and the requirement for nitrogen was about 45 kg/ha higher then than at the early harvest. Sugar content was depressed less at the late harvest than at the early by increasing nitrogen rate.These results suggest that farmers should apply more nitrogen to fields that they plan to harvest late than to early-harvested fields; they also have implications for the conduct and interpretation of nitrogen response experiments on sugar beet.
Spring top-dressings of ‘Nitro-Chalk’ and late sprays of a liquid N-fertilizer and a broad spectrum fungicide for consecutive crops of winter wheat at Saxmundham, Suffolk
Authors: Penny A. , Widdowson F. V. , Jenkyn J. F. 
Published: March 2009

SummaryAn experiment at Saxmundham, Suffolk, during 1974–6, tested late sprays of a liquid N-fertilizer (ammonium nitrate/urea) supplying 50 kg N/ha, and a broad spectrum fungicide (benomyl and maneb with mancozeb) on winter wheat given, 0, 50, 100 or 150 kg N/ha as ‘Nitro-Chalk’ (ammonium nitrate/calcium carbonate) in springMildew (Erysiphe graminisf. sp. tritici) was most severe in 1974. It was increased by N and decreased by the fungicide in both 1974 and 1975, but was negligible in 1976. Septoria (S. nodorum) was very slight in 1974 and none was observed in 1976. It was much more severe in 1975, but was unaffected by the fungicide perhaps because this was applied too late.Yield and N content, number of ears and leaf area index were determined during summer on samples taken from all plots given 100 or 150 kg N/ha in spring; each was larger with 150 than with 100 kg N/ha. The effects of the liquid N-fertilizer on yield and N content varied, but leaf area index was consistently increased. None was affected consistently by the fungicide.Yields, percentages of N in, and amounts of N removed by grain and straw were greatly and consistently increased by each increment of ‘Nitro-Chalk’. Yields of grain were increased (average, 9%) by the liquid fertilizer in 1974 and 1975, and most where most ‘Nitro-Chalk’ had been given, but not in 1976 when the wheat ripened in July; however, both the percentage of N in and the amount of N removed by the grain were increased by the liquid fertilizer each year. The fungicide increased the response to the liquid N-fertilizer in 1974, but not in 1975 when Septoria was not controlled, nor in 1976 when leaf diseases were virtually absent.The weight of 1000 grains was increased by each increment of ‘Nitro-Chalk’ in 1975 but only by the first one (50 kg N/ha) in 1974 and 1976; it was very slightly increased by the liquid fertilizer and by fungicide each year.
Seasonal variation in the potential herbage production and response to nitrogen by kikuyu grass (Pennisetum clandestinum)
Authors: Colman R. L. , O'Neill G. H. 
Published: March 2009

SummaryThe herbage production and response to nitrogen fertilizer by kikuyu grass were measured in a field experiment conducted over a 12-month period. The experiment was designed to measure the growth of kikuyu grass at different rates of application of nitrogen fertilizer but without limitation due to mineral nutrient supply other than nitrogen, soil pH effects of nitrogen fertilizer, defoliation and pests and diseases.Growth rate and response to nitrogen were closely related to mean temperature and moisture supply. Relations were established between growth rate, nitrogen response and apparent nitrogen recovery and the climatic variables, mean temperature and mean available soil moisture in 14-day periods. With nitrogen applications of 224 kg N/ha the predicted growth rate at 13 and 23 °C mean temperature were 38 and 196 kg D.M./ha/day, respectively; with 112 kg N/ha growth rate at the higher temperature was 106 kg D.M./ha/day. Growth and response to nitrogen ceased at mean temperatures around 10 °C.Apparent recovery of nitrogen in harvested herbage over a 16-week growth period after nitrogen application was 51%; recovery in the first 4 weeks of growth varied from 1 to 56 % depending on temperature and moisture supply.Relations between growth rate and mean temperature were used to predict the seasonal growth pattern for a range of environments in which yield data for the species are available. The results indicate the potential for high annual dry-matter production from kikuyu grass when adequately supplied with nitrogen and moisture is nonlimiting. The grass is also adapted for growth and survival in areas ranging from moist sub-tropical to cool-temperate.
The relationship between productivity and some components of canopy structure in ryegrass (Lolium spp.)
Authors: Rhodes I. 
Published: March 2009

SummaryExperiments were carried out to measure the components of canopy structure (on young spaced seedlings), their heritabilities and relationship to sward yield in the F1 generation of a diallel cross between six ryegrass populations.Considerable differences existed between parent populations in both leaf length and tiller angle, but little difference existed in leaf angle. All the components of canopy structure were highly heritable, tiller angle, leaf length and leaf rigidity showing narrow sense heritabilities greater than 0·75.There were large differences in yield between F1 families, moreover, when (a) Lolium perenne families, (6) L. multiflorum families and (c) L. perenne x L. mvltiflorum families were considered separately, leaf length and a composite character derived from leaf length and tiller angle (all measured on young spaced seedlings) were closely related to yield under sward conditions.The plant breeding implications of these results are discussed.
Observations on mammary development in calves and lambs
Authors: Wallace C. 
Published: March 2009

The normal course of mammary development has been briefly described, in sheep from 2 months of foetal age to 4 months after birth; and in dairy cattle from the 3-month foetus to calves 6 months old. Observations were also made on a series of udders from ewes during their first pregnancy. A small group of beef calves and a number of freemartins of various ages were also examined.Development was found to be closely similar in the two species, and in both, sex differences were marked.Experimentally it was found that in males of either species castration at birth had little effect on mammary growth, while prolonged treatment with oestrogen gave rise to enlarged teats, dilated cisterns and ducts, and to a certain amount of secretion. Little gland tissue was formed in oestrogen-treated males, and there was no increase in the spreading of mammary tissue from the neighbourhood of the teat.Females of the two species showed a striking difference in their response to experimental treatment. In sheep, removal of the ovaries at birth had no apparent effect on mammary development up to 4 months, while treatment with oestrogen stimulated gland formation in both spayed and intact lambs and also restricted the normal spread of mammary tissue into the udder. In cattle, on the other hand, heifers spayed at birth showed almost complete cessation of mammary development, while implants of oestrogen, in addition to inducing gland formation, promoted the spreading of tissue into the udder pad of the spayed animal.Udder development of freemartins appeared to be similar to that of normal heifers from 5 months foetal age to about a month after birth, but thereafter was more like that of a spayed animal. Removal of the abnormal gonads shortly after birth had no effect, while oestrogen treatment induced development of teats, ducts and glands exactly as in a normal heifer.Comparing small numbers of calves of the two types, it was found that heifers of the beef breed in general showed slightly poorer mammary development than dairy heifers that had been treated in the same way, with more connective tissue and numerous leucocytes in the mammary zone.
Some chemical changes in the nitrogenous constituents of urine when voided on pasture
Authors: Doak B. W. 
Published: March 2009

1. The chemical changes which take place in a urine patch have been studied using urine from wethers and to a small extent from cows.2. The sizes of individual urine patches vary considerably, depending mainly on the volume of the urination. The average from wethers is about 45 sq.in.3. The volume of urine per wether per day averages 2880 ml. with a nitrogen content of 0·92%, of which about 75% was in the form of urea; 4·1% as allantoin; 2·6% as hippuric acid; 1·5% as creatine-creatinine; and 12·4% as amino-nitrogen.4. Improved herbage growth results in twice the area actually wetted with urine. The total area affected averaged 100 sq.in.5. The probable area wetted with urine from cow urinations was about 650 sq.in. with a further 200 sq.in. affected indirectly.6. With wethers the average rate of nitrogen application on a urine patch amounts to 432 lb. of nitrogen per acre.7. The rate of hydrolysis of urea in laboratory experiments is affected by temperature and is increased by small amounts of hippuric acid but not by the other urinary constituents tried. The hydrolysis rate is greater at soil moisture content of 24% than at higher moisture levels.8. Urea hydrolysis in soil (both in laboratory and in the field) is accompanied by pronounced increase in pH (up to pH 9·2 with urea equivalent to that applied to a urine patch).9. The rate of nitrification is greatly affected by the pH changes. At pH values in excess of 8 nitrites accumulate and nitrate formation is retarded.10. Heteroauxin and allantoin were both found to stimulate nitrification in laboratory experiments when used at levels found in urine. Other urinary constituents were without effect.11. The hold up of urine on leaf surfaces of pastures was shown to amount to as much as 12·5% of the green weight of herbage.12. Ammonia in considerable amounts may be lost to the air both from herbage and from soil.13. Field experiments are in complete agreement with laboratory experiments and no essential difference of wether and cow urine was noticed.14. The fate of the nitrogenous constituents is briefly considered and shown schematically.
The effect of treatment by prostaglandin analogue (ICI–80, 996) or progestagen (SC-9880) on ovulation and fertilization in cyclic ewes
Authors: Boland M. P. , Gordon I. , Kelleher D. L. 
Published: March 2009

SummaryMature cyclic ewes were treated intravaginally with sponges impregnated with 30 mg SC-9880 (G. D. Searle) or intramuscularly with 100 μg Cloprostenol (I.C.I. 80, 996) and examined subsequently for oestrus, ovulation and fertilization. At 70 h after the end of treatment, 90% of ewes treated with SC-9880 and 45% of those treated with Cloprostenol had ovulated. Of ewes yielding eggs at 100 h a significantly higher proportion of SC-9880 treated sheep showed evidence of fertilization (69% v. 7%).
The influence of sward characteristics on the herbage intake of grazing calves
Authors: Hodgson J. , Capriles J. M. Rodriguez , Fenlon J. S. 
Published: March 2009

SummaryExperiments were carried out at the Grassland Research Institute, U.K. (Expt 1) and the Universidad Central de Venezuela, Maracay (Expt 2), to study the influence of sward characteristics upon the herbage intake of young grazing cattle. In both studies the animals were strip-grazed in small groups on a series of plots, at a generous herbage allowance.The digestibility of the herbage ingested exerted a dominant influence on herbage organic matter (OM) intake, which increased at a constant rate as organic matter digestibility (OMD) increased throughout the range observed, 55–81% in Expt 1 and 53–63% in Expt 2. Intakes were similar in the two experiments at 60–65% OMD, but the rate of decline with decreasing digestibility was much greater in Expt 2 than in Expt 1.Intake was affected to a small extent in Expt 2 by the weight of herbage, the proportion of green material, and the extended height of the sward. In Expt 1 the intake from plots of primary growth was approximately 10% greater than that from secondary growths at equivalent digestibility and crop weight.The implications of these observations to techniques of grazing management are discussed.
The growth and activity of winter wheat roots in the field: nutrient uptakes of high-yielding crops
Authors: Barraclough P. B. 
Published: March 2009

SUMMARYRoot and shoot growth and nutrient uptake have been monitored for several winter wheat crops which gave a mean grain yield of 9·5 t/ha (85% D.M.) when grown on three soil types in 1980 and 1981. Averaged over all crops, maximum growth rates were 170 kg/ha/day for shoots and 14 kg/ha/day for roots; maximum nutrient uptake rates for N, P, K, Ca and Mg were 2·75, 0·47, 341, 0·60 and 0·18 kg/ha/day respectively. Maximum uptake of K and Ca occurred at anthesis with values of 239 and 38 kg/ha respectively, whilst for the other nutrients maximum uptake was at final harvest with values of 200, 39 and 14 kg/ha for N, P and Mg respectively. The grain contained 141 kg N, 27 kg P, 41 kg K, 3·2 kg Ca and 7·1 kg Mg/ha.The quantity of nutrients arriving at root surfaces by mass flow was calculated for one of the crops from measurements of soil solution concentration and potential evapotranspiration data. The potential supply of nutrients by mass flow, as a percentage of that actually taken up between 19 March and 29 June, was 25% for N, 4% for K, 800% for Ca and 32% for Mg.
Further studies on the response of maize to K fertilizer in the tropics
Authors: Kayode G. O. 
Published: March 2009

SUMMARYA study designed to investigate the effect of K nutrition on the yield, components of yield and on macro- and micronutrient concentration of maize showed no significant effect of K on yield in forest alfisols derived from basement complex rocks and in savannah alfisols derived from sandstones in the tropics. Potassium addition significantly decreased lodging, but had little influence on cob length, ear weight, shelling percentage or moisture content.Ear-leaf N and K were significantly increased, while Ca and Mg were decreased by K application. All the micronutrient concentrations (Zn, Fe, Mn, Cu) were significantly increased by K application in the forest and savannah zones. Yield was positively correlated with ear-leaf N on both soils.
A model of lysine deposition in cereal grains
Authors: Draper S. R. 
Published: March 2009

SUMMARYA general model of lysine deposition in cereal grains is presented. By inserting into the model values for the lysine contents of various individual protein fractions, equations have been derived which relate total lysine content to total nitrogen. The equation for barley has been used to predict the likely variation in lysine content for this species and the results are compared with published data.