bluuebunny/crossref_metadata_2025_split huggingface dataset:
The nitrogen cycle in grassland soils: with especial reference to the Rothamsted Park grass experiment
Authors: Richardson H. L. 
Published: March 2009

1. In an examination of Park Grass soils extending over 3 years, and in shorter studies of other grassland soils, the fresh soil always contained more ammonia than nitrate nitrogen. The levels of both were low, and in spite of minor fluctuations were sufficiently constant to suggest the existence of equilibrium conditions in the nitrogen cycle. Climatic factors had no appreciable influence except on one very acid plot; here frost or drought, severe enough to kill the herbage, allowed ammonia to accumulate. Otherwise, treatment had little effect, but liming tended to give higher ammonia and lower nitrate levels. The equilibrium levels of both ammonia and nitrate were higher in old grassland soils than in land newly put down to grass.2. “Mineralizable” nitrogen, produced by incubating the fresh soils under standard conditions, showed a seasonal rhythm the opposite of the annual temperature rhythm, tending to a maximum in winter and early spring and a minimum in summer and early autumn. This was related to the addition and decay of organic residues in the soil. An abnormally dry summer caused a temporary rise, especially on the more acid plots. An extremely acid plot, on which a mat accumulated in the field, produced as much mineralizable nitrogen on incubation as more normal soils.3. Ammonia and nitrate production on incubation differed greatly with different treatments, apparently as a result of the influence of treatment on soil reaction. The more acid soils, withpH less than 6.0, produced chiefly ammonia, while the less acid soils produced chiefly nitrate. There was a significant correlation between reaction and percentage nitrification.
The proximate analysis of the organic constituents in north-east scottish soils, with some notes on the methods
Authors: Shewan James M. 
Published: March 2009

1. The proximate analysis has been made of several profiles from the north-east of Scotland, these including Scots pine, beech, birch andCallunaheath.2. The system of proximate analysis proposed by Waksman has been used as a basis for the investigation, but various modifications have been introduced, e.g. sugar and cellulose determinations, with a view to obtaining greater accuracy.3. Although a restricted number of profiles has been investigated, the results indicate that these may be divided into two groups, viz. raw humus and mull types, according to the manner in which the various fractions have been decomposed.
Seed disinfection: II. Large-scale field trials on the disinfection of seed corn with mercury dust disinfectants
Authors: Weston W. A. R. Dillon , Hanley F. , Booer J. R. 
Published: March 2009

1. Treatment in bulk of the grain of wheat, barley, winter oats and spring oats with a proprietary dust, and two experimental dusts A and B which contained organic compounds of mercury, had no harmful effect on germination when drilling followed shortly after treatment. In the case of spring oats, drilling was delayed 7½ weeks after treatment without any harmful effects on germination.2. The proprietary and experimental dusts both proved effective in controlling bunt disease of wheat, and the leaf-stripe and net-blotch diseases of barley.3. In the case of barley, the proprietary and experimental dusts both increased the speed of “brairding” but not the final plant population. This hastening of seedling growth did not lead to a higher yield.4. In the case of winter oats, only the experimental dust A gave a significant increase in plant population and a satisfactory control of the loose smut disease.
The vitamin A content of the colostrum of dairy cows
Authors: Stewart James , McCallum Jennie Whitelaw 
Published: March 2009

1. The vitamin A content of the colostrum of one hundred cows, kept under the same conditions of dietary and management, was found to range from 1181 to 35 I.U. per 100 ml.2. It has been established that this wide range was not due to any differences in dietary, breed or date of calving in animals kept under the same conditions of management.3. It is suggested that the vitamin A content of the colostrum may be materially affected by the length of the non-lactating period between successive calvings.
Nitrogen metabolism in the ovine stomach: 1. The transfer of urea from the blood to the rumen
Authors: Harrop C. J. F. , Phillipson A. T. 
Published: March 2009

SUMMARYThe effect of single, intravenous injections of urea on the concentration of ammonia in the rumen has been examined in conscious and anaesthetized sheep.In conscious sheep maintained on a diet providing 11·4 g nitrogen/day, the net increase in concentration of rumen ammonia after the injection of urea showed negative correlations with the pre-injection concentrations of rumen ammonia and of plasma urea. The maximum concentration of ammonia attained in the rumen after the injection wasx 16·6 ± 0·28 mg NH3-N/100 ml. No such correlations were found in conscious sheep given a diet providing 20·7 g N/day. In addition, the maximum concentration of ammonia attained in the rumen after the injection of urea was significantly lower at 10·7 ± 0·91 mg NH3-N/100 ml, and the net increases in concentration were smaller.Starvation for one day reduced the net increment in rumen ammonia concentration after urea injection in animals given the lower-N diet, to the same low level observed in fed or starved sheep maintained on the higher-N diet.Differences were observed in the transfer of blood urea to the rumen in experiments with anaesthetized sheep which had been maintained on the lower-N diet for long or short periods beforehand. Animals which had been left to graze, and then housed indoors and given the lower-N diet for a short period before the experiment, showed much smaller increases in rumen urea plus ammonia concentration after the injection of urea than sheep which had been given the same diet for a long period. There was no difference in the response of the salivary secretions to the urea injections.
Permeability of saturated sands, soils and clays
Authors: Carman P. C. 
Published: March 2009

It is shown that the permeability of a water-saturated sand or fine powder can be calculated with considerable accuracy, if the porosity and the specific surface are known. In particular, the Kozeny theory here discussed leads to a very useful relationship between permeability and porosity. It is shown that clays do not conform to the theory in its simple form, but that it may be modified to give a satisfactory representation of the data available. The physical grounds for this modified theory are discussed in some detail, and it is shown that, while it is open to criticism, it is at least in harmony with our present knowledge of clays.An important deduction which follows from the modified theory is that clays may have zero permeability at quite considerable porosities, e.g. at ∈ = 0·207 for a clay soil, and ∈ = 0·355 for a plastic clay.
The incorporation of radioactively labelled amino acids into skeletal muscle protein by Pietrain and Large White pigs
Authors: Perry B. N. 
Published: March 2009

SUMMARYThe changes in muscle protein and plasma radioactivity with time have been observed in anaesthetized pigs receiving constant infusions of [14C]glycine and [3H]tyrosine. The specific radioactivity of muscle protein was found to increase linearly with time. However, it was not possible to calculate absolute rates of muscle protein synthesis for the plasma radioactivity had not reached a plateau after 8 h infusion.The specific radioactivities of Pietrain muscle protein increased more rapidly than those of Large Whites when animals of the same lean mass, receiving the same dietary amino acid supply per unit of lean mass, were compared. However, when considered with respect to published biochemical data, these results support the hypothesis that the differences arise from inequalities in plasma specific radioactivities; which appeared to be related to differences in blood volumes, between pigs of the two breeds, at the same age. When plasma specific radioactivity/time relationships were adjusted so as to account for this variation no significant differences were found, indicating that muscle protein synthesis and muscle growth proceed at similar rates in the two breeds.
Response of cotton to water and nitrogen in a tropical environment: I. Frequency of watering and method of application of nitrogen
Authors: Hearn A. B. 
Published: March 2009

SUMMARYTwo experiments were made in successive years in which three frequencies of watering were combined factorially with several rates and methods of applying nitrogen. Soil water content and leaf water potential were measured. The least frequent watering treatment decreased yield and nitrogen applications increased yield. All of the effect of water and most of the effect of nitrogen were associated with changes in the number rather than the weight of bolls. Although the combination of heavy nitrogen with frequent watering caused the crop initially to set fruit more slowly than did heavy nitrogen with infrequent watering, it prolonged flowering and increased the number of fruit ultimately set. Thus yield and the potential duration and cost of insect control were also increased. There were no differences in yield nor rate of setting between the following methods of application of the nitrogen: all applied to the seed bed; split application between the seed bed and side dressing 2 months later; and split application between the seed bed, side dressing, and irrigation water. However, when application was split so that most was applied in the water, the response was not as great. Application of nitrogen combined with frequent watering decreased the weight of the early bolls by decreasing fibre per seed. Nitrogen increased the weight of later bolls by increasing the number and weight of seeds. The practical and physiological implications of these results are discussed and a crop nutritional hypothesis for cotton developed further.
The rate of decay in relation to soil types and vegetative covering in Glamorgan
Authors: Isaac W. E. 
Published: March 2009

Summary1. The object of this investigation was to determine the extent to which the decomposing power of soils within a climatic region is influenced by:(a) the geological character of the rocks from which the soils are derived,(b) the nature of the vegetative covering.2. A short account is given of the geography, climatology, geology and pedology of Glamorgan. The soils of South Glamorgan appear in general to be Brown Earth types.3. In studying the rate of decay it is necessary to obtain an index of the intensity of the total biochemical processes taking place. One of the best and most suitable of indices for this purpose is CO2evolution.4. A type of apparatus used by a previous investigator (Neller) to measure the CO2 evolved from soil was tested and found to be unsatisfactory. Thus a suitable apparatus had to be evolved. This apparatus is described in detail.
Growth and Yield in Pure and Mixed Crops of Potato Cultivars
Authors: Chowdhury A. R. , Hodgson D. R. 
Published: March 2009

SUMMARYExperiments were made between 1977 and 1979 to investigate the possibility of raising potato yields by mixing together cultivars having different growth patterns. The experiments also included mixtures of unsprouted and sprouted seed of the same or different cultivars. In the first experiment (1977) Pentland Crown was mixed with Arran Pilot, Red Craig's Royal or Désirée and the binary mixtures (1:1) compared with the pure stands of each. Yield of tubers from the mixtures did not differ significantly from the mean of two components planted alone at wide or narrow spacing of the seed tubers. Two experiments with identical treatments (1978) included mixtures of Majestic and Désirée and of each cultivar with unsprouted and sprouted seed. Mixtures (1:1) yielded more tubers than the mean of the two components planted alone and at final harvest in one experiment unsprouted and sprouted Majesties gave 7·6 t/ha more than the mean of these and 6·9 t/ha more than the more productive culture (P < 0·05). Similar differences were obtained in the second experiment.In the final experiment (1979) the degree of sprout development at planting time was varied in the cultivar Majestic. Short or long sprouted seed was mixed with unsprouted seed and long sprouted Désirée was also mixed with unsprouted Majestic. Mixtures of the unsprouted cultivar with either long sprouted Majestic or Désiré exceeded, significantly, the mean yield of components planted alone by 4·1 and 5·8 t/ha, respectively, at a high level of fertilizer. As a mean of three experiments the mixture of sprouted and unsprouted Majesties yielded 6·26 t/ha more tubers than the mean of the components and 4·27 t/ha more than the higher yielding component in pure culture. Better light interception due to higher leaf area duration and a more persistent leaf canopy appeared to produce these effects.
Comparative growth of maize cultivars with different leaf orientation
Authors: Remison S. U. , Fajemisinf J. M. 
Published: March 2009

SUMMARYTwo maize hybrids, NHYB-1 and NHYB-2 with upright leaf orientation, and two composites, FARZ 27 and 34 with lax leaf orientation, were compared. The crops were grown at three levels of nitrogen (0, 75 and 150 kg N/ha) at Ibadan in the rain forest zone of Nigeria in 1979 and 1980.N application increased leaf area index (LAI) and hastened flowering. The composites had greater LAI than the hybrids. Lodging was greater at harvest than at mid-silk and severer in the hybrids than in the composites. Grain, stover and total dry-matter yields were greater for the composites.The hybrids were more responsive to N application in 1979 but the pattern was not consistent in 1980. More dry matter was partitioned to the grain in the hybrids as shown by their higher harvest index, especially in 1979. The concentration of N in ear leaf and stover increased with increase in N application, but P and K concentrations in the stover were highest in the control treatment.
An evaluation of the use of dihaploids and unreduced gametes in breeding for quantitative resistance to potato pathogens
Authors: Maine M. J. De 
Published: March 2009

SUMMARYIn a breeding programme to combine quantitative resistance to two important potato pathogens, Phytophthora infestans causing late blight in foliage and Qlobodera pallida (the cream potato cyst-nematode), tetraploid (4 ×) off spring were obtained by crossing dihaploids, mainly as females, with tetraploids. Glasshouse and field tests in the first and second tuber-years showed that most of the off spring of highly blight-resistant dihaploids had high resistance to P. infestans. Two such dihaploids, PDH 182 and PDH 247, crossed with a tetraploid selected for high general combining ability for potato cyst-nematode (PCN) resistance, gave off spring all of which were highly blight resistant. About one third also had high PCN resistance.Detached leaflet tests were used for rapid blight resistance screening of other progenies from dihaploid × 4 × crosses in their seedling year. Differences were found in the effects of 4 × parents on the mean resistances of progenies from blight-resistant dihaploids.The results also showed differences between dihaploids in their effectiveness in transmitting blight resistance to 4 × offspring. This could be due to differences in the mode of unreduced female gamete formation, i.e. first division restitution or second division restitution (SDR). If all the unreduced gametes were produced by SDR, the differences could be due to differences in homozygosity between dihaploids with respect to blight resistance genes.The dihaploid × 4 × crosses gave few offspring per pollination. The few seedlings obtained may be offset by a higher frequency with the required characters. Since fewer seedlings would have to be grown in order to find the required combination of characters, savings could be made in planting and resistance-testing facilities over those required in conventional breeding.The tetraploid hybrids obtained can be used in a second cycle of breeding in three ways simultaneously: by crossing with other tetraploids, by crossing with dihaploids selected for complementary characters and to produce dihaploids with combined resistances.
Growth, mineral composition and grain yield of irrigated and rainfed millets and sorghum
Authors: Muldoon D. K. 
Published: March 2009

SUMMARYSorghum bicolor, Pennisetum americanum, Echinochloa utilis, Panicum miliaceum, Setaria italica and Eleusine coracana were grown with and without full irrigation on an alkaline clay soil at Trangie, Australia. Dry-matter yields and forage quality changes with time were measured in the 1st year. Grain yield was recorded over 2 years.Dry-matter accumulation was initially most rapid in sorghum and Japanese barnyard millet. Sorghum, pearl millet and finger millet produced the most dry matter; these were the latest to reach head emergence. The early-maturing proso millet and foxtail millet produced only 7 and l i t dry matter/ha respectively. These two millets, like sorghum and pearl millet, had a high nitrogen: sulphur ratio and low sodium concentration in the forage. Finger millet had a lower nitrogen: sulphur ratio and a sodium concentration that was surpassed only by Japanese barnyard millet.Irrigated sorghum consistently produced the highest grain yields: over 9 t/ha. Yields from the millets were: foxtail 6·0, finger 5·0, proso 3·5, pearl and Japanese barnyard millet 2·8–2·9 t/ha. Special features of the millets are discussed.
Interactions between fungicides, insecticides and spraying regimes in the control of fungal diseases, insect pests and yield of cow pea Vigna unguiculata (L.) Walp.
Authors: Oladiran A. O. , Oso B. A. 
Published: March 2009

SUMMARYThe fungicides benomyl and captafol separately were tank mixed with each of the insecticides decis (decamethrin), permethrin, and cypermethrin (synthetic pyrethroids) and nuvacron (monocrotophos). The mixtures were tested as foliar sprays at three spraying regimes to protect cow-pea plants against pod and foliar diseases and insect pod borers.Two sprays, 1·5 kg a. i. /ha of benomyl mixed with 0·75 kg a. i. /tia of monocrotophos at 35 and 49 days after planting, gave the best control of brown blotch, web blight, Cercospora leaf spot and the pod borer, Maruca testulalis. This regime also gave the highest grain yield for two consecutive years. The mixtures were not phytotoxic. Interactions between the test fungicides, insecticides and spraying regimes in relation to disease and pest control and yields are discussed.
The effects of fasting on the concentrations of intermediate metabolites in the blood and hepatic tissues of pregnant and non-pregnant ewes
Authors: Herriman I. D. , Heitzman R. J. 
Published: March 2009

SummaryBlood and liver samples were taken from four fasted pregnant and five fasted non-pregnant Finnish Landrace × Dorset Horn ewes. The following metabolites were measured: adenine monophosphate (AMP), adenine diphosphate (ADP), adenine triphosphate (ATP), citrate, 2-oxoglutarate, phosphoenolpyruvate, pyruvate, lactate, 2-phosphoglycerate, 3-phosphoglycerate, α-glycerophosphate, malate, β-hydroxybutyrate, acetoacetate, glutamate, alanine and NAD+.The effects of a 6-day fast on non-pregnant ewes were shown as significant reductions in the hepatic concentrations of 2-phosphoglycerate, alanine, NAD+ and ADP, together with significant increases in the hepatic concentrations of 3-hydroxybutyrate, malate and the ratio of 3-hydroxybutyrate:acetoacetate. In the blood there were significant reductions in the concentrations of urea, citrate and in the ratio of 3-hydroxybutyrate: acetoacetate.Similar but more marked changes occurred in the late pregnant ewes, with additional significant reductions in the hepatic concentrations of citrate, ATP and the level of cell energy, and additional increases in the blood of the ratio of lactate: pyruvate and the concentrations of 3-hydroxybutyrate and 2-oxoglutarate. However, unlike the non-pregnant ewes no significant changes in either the plasma concentration of urea or the hepatic concentration of ADP were observed in the late pregnant ewes.
The induction and synchronization of parturition in sows treated with I.C.I. 79,939, an analogue of prostaglandin F2x
Authors: Ash R. W. , Heap R. B. 
Published: March 2009

SummaryI.C.I. 79,939, a potent analogue of prostaglandin F2a, was used to induce and synchronize parturition in seven gilts and three sows. A total dose of up to 750 μg injected intra-muscularly during a treatment period of about 24 h on days 109–111 of gestation induced parturition approximately 26 h after the start of treatment. The length of gestation, which was 114 ± 0·2 days in 147 normal untreated pigs, was significantly reduced to 111 ± 0·2 days (P < 0·01) in ten pigs in the same herd treated with I.C.I. 79,939. In this trial, no side-effects were detected, the average birth and 3-week weights of piglets were within the normal range, and sows usually returned to normal oestrus within a week after weaning.
Some effects of planting density and variety on the relationship between tuber size and tuber dry-matter percentage in potatoes
Authors: Wurr D. C. E. , Allen E. J. 
Published: March 2009

SummaryThree experiments are reported which investigated the effects of planting density and variety on the relationship between tuber dry-matter percentage and tuber size. In the first experiment dry-matter determinations were made on samples of tubers less than 3·8 cm and greater than 3·8 cm from different planting densities obtained at eight fortnightly harvests. Standard analysis of variance was used for each harvest date and apart from Maris Piper giving consistently higher dry-matter percentages than Pentland Crown for the same tuber sizes, effects were small and difficult to interpret. The reasons for the problems in interpretation, which were mainly due to differences in tuber size distribution, are discussed.In the second and third experiments the effects of tuber-size distribution were removed by regression analyses of tuber dry-matter percentage on tuber size in definable grades and curves were fitted to the data. These curves revealed that tuber dry-matter percentage tends to show a quadratic response to increasing tuber size and is affected by variety and stem density. The significance of these results is discussed.
Pollination and fertilization in commercial crops of field beans (Vicia faba L.)
Authors: Stoddard F. L. 
Published: March 2009

SUMMARYIncidences of pollination and fertilization were surveyed in 21 commercial crops of field beans (16 of winter, 5 of spring) in southern Cambridgeshire (England) in 1982 and 1983. During the first part of the flowering season of winter beans, from 30 to 75% of flowers were not pollinated, and thus could not set pods. Where the pollination was largely spontaneous, relatively few pollinated flowers were fertilized and within them, relatively few ovules were fertilized. Later in the season and through most of the spring-bean flowering season, over 90% of flowers were pollinated and over 75% of ovules were fertilized. Incidences of pollination and fertilization varied greatly among the fields, and provision of hives of honeybees in fields of winter beans was associated with an improvement in the incidence of pollination from poor to moderate in 1983 but not in 1982. It is concluded that the incidence of pollination in many fields of winter beans is too low early in the season for an optimum distribution of yield along the stems.