bluuebunny/crossref_metadata_2025_split huggingface dataset:
The nutrient requirements of herbage on deep acid peat
Authors: Reith J. W. S. , Robertson R. A. , Inkson R. H. E. 
Published: March 2009

SummaryA mixed sward of grasses and clovers, previously established with adequate Ca, N, P and K on deep acid peat, was used for a factorial experiment to determine the amounts of nutrients required to produce herbage for conservation. The treatments consisted of all combinations of 0, 117and 234 kg N, 0, 29 and 58 kg P and 0, 156 and 312 kg K/ha, and their effects on the botanical composition of the sward, the yield and mineral composition of the herbage, and the nutrient status of the peat were measured over a period of five years. Three cuts were taken annually, one third of the N dressings being applied for each cut.Tall fescue became the dominant grass species while cocksfoot persisted much better than either ryegrass or timothy. The proportion of clover in the sward was reduced to practically zero by applying N, but without N it was maintained at about 20% by applying K.Yields of dry matter were greatly increased both by N and by K and there was a marked positive interaction between these two nutrients. Due to the marked suppression of clover by applied N there was no response to the first increment of N in 1959, but with this exception, 1 kg N/ha with adequate P and K produced between 15 and 30 kg dry matter/ha. The effect of K increased from 1958 to 1962, the first increment consistently producing most of the response. Applying P had little effect on yield until the fifth year when a significant response was obtained.The mineral composition of the herbage varied during the season; the percentages of N, Ca, Na and Mg were generally higher in autumn than in early summer whereas the percentage of K showed the opposite effect.The N, P and K treatments had large effects on the percentages of N, P, K, Na, Ca and Mg in the herbage and on the amounts removed in the crop. Without applied N, but with adequate P and K, percentage of N varied according to the amount of clover in the sward. With applied N there was less variation and the average percentage of N was about 1·7 with 39 kg N and 2·0 with 78 kg N/ha/cut. Percentage of P ranged from 0·14 to 0·54 and percentage of K from 0·5 to 3·5. Apparent recoveries up to 74, 65 and 96 % were obtained from the N, P and K treatments, respectively.For continuous production by cutting and removing the herbage, a mixed sward containing clovers appears to require, without applied N, about 120 kg K/ha/year. With applied N, an additional 0·3 to 0·5 kg K/kg N appears to be needed. The amount of P required will depend mainly on the concentration desired in the herbage and on the rate of N used. To produce herbage with 0·3 % P in the dry matter about 15 kg P/ha/year, plus approximately 0·1 kg P/kg N applied seems to be needed; for 0·4 %P the corresponding quantities are about 40 kg P/ha plus 0·3 kg P/kg N applied.
Studies on the agronomy, genetics and interrelationships of yield and its morphological components in a diallel set of families ofLolium perenneL.
Authors: Thomson A. J. , Wright A. J. , Rogers H. H. 
Published: March 2009

SummaryFive selected clones ofLolium perennewere selfed and diallel crossed without reciprocals to produce 15 families. These families were grown in a replicated field trial for 2 years at four rates of applied nitrogen – 0, 225, 450 and 675 kg N/ha – per annum. The data recorded included dry-matter yield, number of fertile and sterile tillers per plant, mean dry weight per fertile and sterile tiller and total dry weights of fertile and sterile tillers. Conventional analyses of variance and diallel analyses were applied to the data as well as path analyses, used to examine the interrelationships between yield and the tiller characters.The main effect ofyearswas significant only for mean dry weights per tiller and dry-matter yield. Increasing the rate of applied nitrogen increased the number of tillers and yields but decreased mean tiller dry weights. Differences betweenprogenieswere due to both general and specific combining ability for most characters. Relatively high narrow-sense heritabilities were obtained for the tiller characters although there were differences between the two years.The progenies achieved their yield through different combinations of tiller characters, some having large numbers of fertile tillers with medium dry weights and others having numerous sterile tillers with high dry weights. Although there was inconsistency in the interrelationships between characters, number of tillers was always more important in determining yield than mean dry weight per tiller.The results are discussed in relation to the predictive value of tiller characters on yields and the implications for breeding programmes.
Prospects for the development of F1hybrid varieties of perennial ryegrass (Lolium perenne) and other herbage grasses
Authors: Foster C. A. 
Published: March 2009

SummaryConsideration is given to the prospects of producingF1hybrid varieties of perennial ryegrass,Lolium perenne, and other herbage grass species for commercial use. In the light of the results of interpopulational hydridization in this and other crop species and of the technical and economic disadvantages inherent in other methods ofF1hybrid seed production, it is concluded that the development of interpopulationalF1hybrid varieties, by the field interpollination of parent populations, is a desirable and worthwhile breeding objective.
Associations among certain morphological traits of diallel cross progenies in Bromus inermis Leyss
Authors: Mishra S. N. , Drolsom P. N. 
Published: March 2009

SummaryA study of correlations among certain morphological traits of progenies from a 6 x 6 diallel cross was made. In general, genotypic correlations were similar in sign to the phenotypic correlations in all but two of the 21 cases, but there were differences in magnitude (nine differed by 0·40 and four of these by more than 0·70). Some estimates of the environmental correlations were large (1·57, 1·52, 0·78, 0·75, 0·73 and 0·54). Positive and significant correlations indicated that improvement in some characters related to forage and seed yield should be possible by selection among the diallel progenies.Path analysis was used as a means of analysing phenotypic correlation coefficients among seven contemporary variables. The method was employed to analyse the system of all possible correlations among certain plant measurements. By this technique one may find the maximum effect, compatible with the data, which can be assigned to a general size factor (common to all variables) and determine the nature and degree of influence of residual, group, and special factors. In most of these the influence of the general size factor predominated (minor in the case of leaf width, pCX = –0·31; and florets per spikelet, pGX = –0·09). Only two of the 21 correlations required factors in addition to the general size (florets per spikelet and spikelets per panicle, excess correlation –0·46; and leaf width and culm diameter, excess correlation +0·53). Special factors acting on each part separately from the other were present in all cases. The study indicated that the genetic differences in this study were largely in general size and to a small extent in group and special factors.
Energy utilization in the laying hen in relation to ambient temperature
Authors: Davis R. H. , Hassan O. E. M. , Sykes A. H. 
Published: March 2009

SummaryEnergy balances have been determined, using the comparative slaughter procedure, over 3-week periods on groups of laying hens kept at ambient temperatures of 7·2, 15·6, 23·9, 29·4 and 35 °C.Energy intake declined as the environment became warmer (kcal ME/kg¾/day = 203· 1·13°C); heat production, as measured by the difference between energy intake and energy retention, also declined with increasing ambient temperature (kcal/kg¾/day = 151 – 1·11°C). There was a linear relationship between heat production and ambient temperature with no thermoneutral zone or critical temperature.The energy available for egg production remained almost constant at 50 kcal/kg¾/day equivalent to a rate of egg production of 82% at each ambient temperature.
The intensive production of herbage for crop-drying III. The effect of the continued application of nitrogenous fertilizers to grassland
Authors: Holmes W. 
Published: March 2009

1. The experiment previously described (series 4, Holmes, 1949) on the effect of massive applications of nitrogenous fertilizers on the productivity of a ryegrass dominant pasture was continued for 3 years (1946, 1947, 1948). The manurial treatments ranged from none to the application of 312 lb. nitrogen per acre and this was applied with and without 135 lb. P2O5 and 168 lb. K2O per acre. Farmyard manure was applied to one block in 1948.2. With the heaviest nitrogen treatment plus phosphate and potash the average yield for 3 years was 8000 lb. dry matter and 1640 lb. crude protein (similar to the yield in 1946) compared with a control yield of 4720 lb. dry matter and 590 lb. crude protein. The yields declined from year to year when phosphate and potash were not applied, the decline being greatest with the heaviest application of nitrogen.3. The seasonal distribution of the yield of herbage was very considerably modified by the time when fertilizers were applied.4. The botanical composition of the swards was related to the yield, 70% of the grasses in the highest yielding sward being perennial ryegrass and cocksfoot while the lowest yielding sward contained only 35% of these grasses.5. The manurial treatments had no effect on the pH, loss on ignition or the content of readily soluble P2O5 in the soil, but in the first year there was some evidence of a general reduction of readily soluble K2O to a low level.
The intensive production of herbage for crop-drying IV. The effect of massive applications of nitrogen with and without phosphate and potash on the yield of grassland herbage
Authors: Holmes W. 
Published: March 2009

1. A small-scale plot experiment was carried out from 1947 till 1949 to study the effect of massive dressings of nitrogen with and without phosphate and potash on the yield of a ryegrass-dominant sward. A 4 × 4 Graeco-Latin square was used.The nitrogen treatments were: (1) no nitrogenous fertilizer, (2) 260 lb., (3) 520 lb., (4) 416 lb. nitrogen per acre per annum. These applications were divided into four or five equal dressings, the first being applied in March and the others after successive cuts.In 1948 and 1949 the following mineral treatments were also applied: (A) no mineral fertilizer, (B) 180 lb. K2O per acre, (C) 120 lb. P2O5 per acre, and (D) treatments B and C combined. These treatments were applied in two parts, half in spring and half in midsummer.2. Applications of phosphate did not affect the yields of herbage but yields were severely restricted in the absence of potash.3. Where potash was applied there was no significant change in the annual yield of herbage from 1947 to 1949 for any one of the treatments. The nitrogen treatments increased the yields from 4300 lb. dry matter and 600 lb. crude protein per acre with treatment 1 to 9000 lb. dry matter and 1900 lb. crude protein with treatment 3. The yield response of dry matter to nitrogen applications was curvilinear, but that for crude protein was rectilinear.4. Increasing the application of nitrogen per cut from 52 to 104 lb. per acre raised the protein content in the dry matter of the herbage from 15·20 to 18·25%.5. The plots receiving the nitrogen treatments gave earlier production and also produced a greater proportion of the total yield in July-September than the untreated control plots.6. Where potash was present the average net efficiency of recovery of nitrogen for 3 years was 47, 39 and 37% for treatments 2, 3 and 4 respectively.7. Where potash was present the content of vigorous grasses in the sward (perennial ryegrass and timothy) was increased in relation to the quantity of nitrogen applied, from approximately 40% in treatment 1 to 75% in treatment 3. The content of vigorous grasses in the sward was reduced in the absence of potash.8. The results and their practical implications are discussed.
Placement of fertilizers for sugar beet
Authors: Cooke G. W. 
Published: March 2009

Ten experiments on sugar beet in 1949 tested a phosphate-potash fertilizer applied in different ways. There was no damage to germination or plant establishment by fertilizer placed in bands 2 in. to the side and 2 in. below the level of the seed.There were no significant differences between the yields of sugar given by placed and broadcast fertilizer. Similar yields were given by broadcast applications applied early and worked deeply into the seed-bed and by dressings on the seed-bed which were worked in shallowly. Split dressings where half the fertilizer was broadcast and half was drilled beside the seed were not markedly superior to placing or broadcasting all the fertilizer. In most of the experiments placing gave more vigorous growth than broadcasting the fertilizer during late spring and early summer; at harvest this superiority had vanished.The results of these experiments confirm those carried out in 1947 and 1948. There is no advantage from placing the full dressing of fertilizer beside the seed in districts where the crop is normally grown, except that labour is saved in applying the fertilizer.
The self-selection of diet by pregnant ewes
Authors: Gordon J. G. , Tribe D. E. 
Published: March 2009

1. Eight Cheviot ewes, bearing twins, housed in individual pens, and given the choice of a protein concentrate, a carbohydrate concentrate, hay, minerals and water, failed to select a ration that allowed them to bear and rear strong healthy lambs.2. Three ewes maintained under these conditions developed a condition resembling pregnancy toxaemia.3. The amount of food eaten by each ewe decreased during the last few weeks of pregnancy, This is probably the reason for the disappointing performance of the ewes at lambing.4. The possible influence on the behaviour of the ewes of the constant presence of food is discussed.
Stocking intensity and pastoral production: II. Herbage intake of Merino sheep grazed at different stocking rates
Authors: Langlands J. P. , Bennett I. L. 
Published: March 2009

SummaryEstimates were made at monthly intervals between January and December 1965 of the intake and nutritive value of the diet of unmated Merino ewes grazed continuously at stocking rates ranging from 2·5 to 37·1 sheep/ha. Oesophageally fistulated sheep were used to estimate intake and nutritive value.Drought conditions existed during the experiment. Digestibility declined linearly with increasing stocking rate. The intercepts of the relationship between digestibility and stocking rate differed between months, being at a maximum in spring. Nitrogen content was also greatest in spring but did not change consistently with increasing stocking rate. Organic-matter intake declined linearly with stocking rate and increased asymptotically with total herbage available, the asymptotic relationship being the more precise. Neither relationship differed significantly between months. Organicmatter intake/ha increased continuously with increasing stocking rate and the maximum intake was predicted to occur at a stocking rate greater than that at which the sheep survived.
The chemical composition of British agricultural liming materials
Authors: Chater Margaret , Williams R. J. B. 
Published: March 2009

SummaryNinety-four British liming materials were examined. The contents of Ca, Mg, K, P, S, Sr, B, Fe, Mn, Zn, Cu, Co, Mo, Ni, Cd and Na in the acid-soluble fraction, and Mn, Cu, Co, Mo, Ni, Sr, Ti, Cr, Ga, Pb, Sn, V, Y, Zr and Ba in the acid-insoluble fraction were determined by chemical and spectrographic analysis. Water soluble nitrate was also determined.Only manganese, providing on average 3 kg Mn/ha for a 10 t/ha dressing, was found in agriculturally significant quantities in the acid-soluble fraction of the limestones or shell-sands analysed. Magnesium, present only in significant amounts in the dolomitic limestones, provided on average 27 kg Mg/ha from a 10 t/ha dressing.The acid-insoluble fraction of the limestones contained, on average, a twentieth of the concentration of Mn in the acid-soluble fraction. The concentration of K was much larger and depended on the amounts and nature of the insoluble fraction. The acidinsoluble fraction contained no significant amounts of other plant nutrients. The relative concentrations of Mn and K in both fractions emphasize that results based on the total amounts of elements in limestones could overestimate their potential value as sources of plant nutrients.
Potatoes for canning – design of growing systems
Authors: Thompson R. , Gray D. , Pascal J. A. 
Published: March 2009

SummaryEffects of set size, density of planting, harvest date and spatial arrangement on yield and size grading of potatoes were examined using the cultivar Maris Peer. The results indicate that highest economic returns would be obtained by growing crops at between 70 and 110 eyes/m2, using small sets for late season production and large ones only for very early production, with as near a square pattern of planting as possible.Based on these findings four growing systems were tested on a field scale, a 1·5 m raised bed with four rows, a 0·6 m ridge, a 0·9 m ridge containing two rows 0·3 m apart, and a 0·75 m ridge. Highest yields and returns were obtained from the two-row, 0·9 m, ridge system, which also had certain cultural advantages.
The effect of sulphur deficiency on the uptake and incorporation of nitrogen in ryegrass
Authors: Millard P. , Sharp G. S. , Scott N. M. 
Published: March 2009

SUMMARYSulphur deficiency reduced the yield and sulphur content of ryegrass at the fourth cut, while increasing the nitrogen content and N:S ratio. The distribution of the forms of nitrogen was also altered, with a decrease in the proportion of nitrogen recovered as amino acids and an increase in the concentration of asparagine. Amino acid analysis showed that the concentrations of the sulphur-containing amino acids cyst(e)ine and methionine were depressed by sulphur deficiency as well as those of arginine, histidine, lysine, glycine, leucine, serine and threonine. Sulphur deficiency, therefore, decreases the quality of crude protein found in grass, as well as reducing the yield.
The effect of paclobutrazol on plant height and seed yield of oil-seed rape (Brassica napus L.)
Authors: Scarisbrick D. H. , Addo-Quaye A. A. , Daniels R. W. , Mahamud S. 
Published: March 2009

SUMMARYThe effect of paclobutrazol (applied at several concentrations and timings) on stem length and the seed yield of oil-seed rape was explored in three field trials during 1981–4. Spring applications were most effective in reducing plant height, but they had an adverse influence on the yield components. Autumn applications increased seed yield in one season, but were less effective in the final trial when soil conditions were much drier at establishment. Data indicated that autumn treatments may increase the productivity of the uppermost racemes. Future studies must investigate the persistency of paclobutrazol in the soil, and its possible influence on subsequent arable cropping.
Regulation of water loss under moisture stress in sunflower genotypes: stomatal sensitivity in relation to stomatal frequency, diffusive resistances and transpiration rate, at different canopy positions
Authors: Prasad T. G. , Sashidhar V. R. , Chari Malathi , Rao S. Rama , Devendra R. , Kumar M. Udaya 
Published: March 2009

SUMMARYTranspiration rate, diffusive resistances, canopy conductances and water potentials were determined at three canopy positions in non·stressed and stressed plants of sunflower hybrid BSH·1 and five other cultivars of sunflower under field conditions. The leaf area (LA) and stomatal frequency (f) was determined at the three canopy positions in field·grown plants and the total number of stomata per plant was calculated as the product of LA and f. These variables were then related to the dry·matter accumulation and seed yield in these cultivars. Cultivars with either a high leaf area or high number of stomata per plant were more productive under non-stress conditions. Under stress conditions, cultivars differed in the extent of change in conductance (g) and transpiration rate at different canopy positions. In the hybrid BSH·1, g was low at all levels in the canopy associated with a higher (less negative) water potential and this hybrid had lower transpiration rates at all canopy levels under stress although the number of stomata per plant was high. Stomatal sensitivity associated with a higher threshold water potential for stomatal closure is discussed as a possible explanation for the higher dry·matter accumulation and productivity of hybrid sunflower BSH·1 under moisture stress conditions.
The effect on the rumen composition of feeding sheep diets supplying different starches. I. The variation in rumen composition of sheep fed lucerne or wheat as the sole diet
Authors: Chou K. C. , Walker D. M. 
Published: March 2009

1. Three fistulated and four unfistulated crossbred sheep were each fed once daily with diets of lucerne or wheat.2. A pre-feeding sample of the rumen liquid was examined for its content of protozoa, of various chemical components and for its enzymic activity on glucose and on soluble starch. Several samples were taken from each sheep at intervals over periods of up to 8 weeks, during which time the sheep were maintained solely on the single diet.3. Considerable variation occurred, both between sheep and between samples from the same sheep, in the concentrations of ciliate protozoa and of lactic acid, especially on the wheat diet.4. Analyses for nitrogen, pH, dissolved C02, volatile fatty acids and for the molar proportions of acetic and propionic acid showed differences due to diet.
The effect on the rumen composition of feeding sheep diets supplying different starches. II. The partition of nitrogen, pH, volatile fatty acids, protozoal numbers, enzymic activity and certain other chemical constituents
Authors: Chou K. C. , Walker D. M. 
Published: March 2009

1. Three fistulated cross-bred sheep were fed diets which consisted solely of lucerne, cereals or potatoes. Potatoes were fed both in the raw and in the cooked form.2. A pre-feeding sample of the rumen liquid was examined for its content of protozoa and various chemical components and for its enzymic activity on glucose and on soluble starch.
The effects of leys and their management on the yield of succeeding wheat crops on heavy land
Authors: Hanley F. , Ridgman W. J. , Jarvis R. H. 
Published: March 2009

1. One long-term experiment comparing the effects of leys and arable cropping on the yield of arable crops and three experiments on the effect of management of lucerne/grass leys on the following arable crops, all conducted on heavy clay land, are described and the results discussed.2. In the first two years after breaking a ley yields of wheat were higher than on plots which had had all-arable cropping and it is suggested that this effect could be due to a combination of disease and weed control and the nitrogen status of the soil.
The effect of potassium carbonate solution on the drying of lucerne: 1. Laboratory studies
Authors: Tullberg J. N. , Angus D. E. 
Published: March 2009

SummaryThe drying rate of fully exposed individual lucerne plants was substantially increased following brief immersion in 0·18 M potassium carbonate solution. The increase was maintained over a range of drying conditions, and at low moisture contents, but the use of more concentrated potassium carbonate solutions yielded no further increase. Changes in leaf:stem ratio had a smaller effect on the drying rate of potassium carbonate treated lucerne than on untreated lucerne.Tests with diffusive resistance and viscous flow porometers support the hypothesis that potassium carbonate solution changes the water transmitting properties of the cuticular waxes.