bluuebunny/crossref_metadata_2025_split huggingface dataset:
The determination of nitrogen in heavy clay soils
Authors: Bal D. V. 
Published: March 2009

In determining the nitrogen content of the heavy black cotton soil of the Central Provinces, India, by the Kjeldahl process it is important that the determinations be carried out on moist and not on air-dried soil. These soils apparently contain a cementing material probably containing iron which is insoluble in concentrated sulphuric acid and protects organic matter in the interior of the compound particles from the action of the acid.It may be that these soils are peculiar in this respect, but it would seem of importance that other workers should take into account the possibility of error in the estimation of nitrogen when using air-dry soils.In conclusion it is with great pleasure that I acknowledge my indebtedness to Mr F. J. Plymen and Dr H. E. Annett for their valuable suggestions and advice during the course of this work.
Studies in the physical properties of soils: III. Observations on the electrical conductivity of soils
Authors: Hanies William B. 
Published: March 2009

1. An improved and simplified laboratory method of measuring the electrical conductivity of soils is described and measurements recorded for diverse soil samples.2. The results for ignited soil lead to certain interesting confirmations of the capillary theory of an ideal soil.3. The results for soils generally indicate a sufficiently simple connection between conductivity and moisture for this property to be made the basis of soil moisture determinations.4. Certain clays were found to form a class apart, and must be regarded as exceptions to the general statement in (3) owing to the more complex nature of the moisture-conductivity relationship.
The chemical evaluation of pyrethrum flowers (Chrysanthemum cinerariifolium). The extraction of the flowers for analysis and the preparation of colourless concentrates of the pyrethrins
Authors: Martin J. T. 
Published: March 2009

1. Biological trials have been carried out to determine the efficacy of petroleum ether as solvent for the extraction of pyrethrum flowers for analysis. 95% of the toxic material was extracted from flowers one year old after only 3 hr. percolation. An extraction period of 8 hr. with petroleum ether is suggested.2. A method of preparing colourless extracts of pyrethrum and analytical data for such extracts are given. They are shown to be of value for the preparation of concentrates of the pyrethrins. The preparation of a colourless concentrate containing 93% of total pyrethrins, as determined by a modified Seil method, is described.
The storage of artificially dried grass
Authors: Wright Norman C. 
Published: March 2009

1. Experiments have been carried out to determine the relation between the moisture content of artificially dried grass and the relative humidity of the surrounding atmosphere. This relation is given by a smooth curve. At relative humidities which are typical of outdoor winter conditions in the British Isles (80–90%) the equilibrium moisture content lies between 18 and 30%.2. The rate of moulding is directly related to the relative humidity and therefore to the moisture content of the dried grass. For reasonably safe storage a relative humidity of 67 % should not be exceeded. This corresponds to a moisture content of roughly 13 %. Even this low value does not confer absolute immunity from mould growth.3. The importance of extending storage trials over long periods is stressed. In one instance storage for 300 days was required before mould growth occurred. Neglect of this fact may account for the widely held view that a relative humidity of 70–75 % provides safe storage conditions.4. Attempts to detect mould growth at an early stage by plating methods proved unsuccessful. It is shown that the two earliest and most reliable indications of mould growth are (i) the appearance of visible mycelium when the product is examined under a low-power objective, and (ii) the detection of a musty smell.
The fate of nitrate in cattle slurries acidified with nitric acid
Authors: Stevens R. J. , Laughlin R. J. , O'Bric C. J. 
Published: March 2009

SUMMARYThe fate of NO3-in raw and anaerobically-digested cattle slurries acidified with HNO3was studied in a laboratory incubation experiment at the Agriculture and Food Science Centre, Belfast, in 1992. Four amounts (20, 30, 40 and 50 g) of each slurry type were acidified with five rates of HNO3supplying 0·7, 1·4, 2·1, 2·8 and 3·5 mg N/g enriched to 10 atom%15N. The slurries were stored in 500 ml glass jars for 7 days at 20 °C. The jars were left open to allow O2supply by diffusion through the slurry surface to create varying degrees of aeration depending on slurry depth. Fluxes of N2and N2O were measured from each jar for 2 h each day. The pH was measured after each gas flux measurement and HNO3--N recovery as NO3--N measured at the end of the incubation.For raw cattle slurry, almost none of the HNO3--N was recovered as NO3--N at the 0·7 or 1·4 mg HNO3-N/g rates, but recovery was not significantly different (P >0·05) from 100% at the 2·8 and 3·5 mg HNO3-N/g rates. At the 21 mg HNO3-N/g rate, recovery was higher when larger amounts of slurry were incubated, indicating that O2could promote NO3-loss. Average pH during the incubation period had to be < 5·5 for recovery of HNO3-N as NO3-N to be > 90%. For digested cattle slurry, recovery was > 87% at the 0·7 mg HNO3-N/g rate and not significantly different (P >0·05) from 100% at all other acid rates.Fluxes of N2and N2O were not detected from any digested slurry treatment but were measured in all raw slurry treatments. Gaseous losses occurred after incubation for 1 day, and maximum flux rates occurred after incubation for 2 days. Fluxes were highest from incubations with the intermediate amounts of slurry containing 1·4 mg HNO3-N/g. The largest observed flux from an individual jar was 322 μg N2-N/g/2 h with 40 g of slurry containing 1·4 mg HNO3-N/g, which would have accounted for a loss of 23% of the added HNO3-N during this period. Nitrous oxide and N2were always evolved simultaneously and when the pH was between 7 and 9. On average, 90% of the total loss of N-gases was as N2.The raw slurry contained much higher concentrations of volatile fatty acids than the digested slurry. If HNO3is added to slurries containing such readily decomposable substrates, the NO3-is susceptible to loss as N2and N2O by denitrification. Oxygen supply, pH and substrate availability control the rate of denitrification.
Ammonia volatilization following surface-applied pig and cattle slurry in France
Authors: Moal J.-F. , Martinez J. , Guiziou F. , Coste C.-M. 
Published: March 2009

SUMMARYField experiments were carried out in Brittany (Western France) in 1993 to measure ammonia losses from surface-applied pig and cattle slurry. Experiments were conducted on grass, stubble (wheat and maize) and arable land using a wind tunnel system. Ammonia losses were followed during periods ranging from 20 to 96 h after slurry application. Rates of slurry applied varied from 40 to 200 m3/ha. In two experiments, losses from cattle slurry were respectively 75 and 54% of the ammoniacal nitrogen applied in the slurry. Ammonia emissions from pig slurry applied at a rate of 40 m3/ha, during spring and summer experiments, were higher on grass (45–63% of the total ammoniacal nitrogen applied) than on wheat stubble (37–45%). On average, 75% of the total loss in all experiments occurred within the first 15 h after spreading. Significant correlations were found between ammonia losses (kg N/ha) and mean soil temperature and slurry dry matter content (%) using simple linear regressions and stepwise procedures. The time of application was also found to influence the magnitude of ammonia loss: 83% of the total loss occurred within 6 h when the slurry was applied at midday compared with 42% when it was applied in the evening.
Response of broilers to dietary levels of thevetia cake
Authors: Atteh J. O. , Ibiyemi S. A. , Ojo A. O. 
Published: March 2009

SUMMARYTwo experiments done at the University of Ilorin, Nigeria, in 1992/93 investigated the effects of dietary levels of thevetia cake on the performance and nutrient retention of broilers. In Expt 1, dayold broiler chicks were fed either a control diet or diets containing 5, 10 or 15% thevetia cake during a 4-week period. In Expt 2, day-old broiler chicks were fed a standard diet until 4 weeks of age and were then switched to diets containing 0, 5, 10 or 15% thevetia cake. Inclusion of thevetia cake in broiler diets, irrespective of level of inclusion, drastically reduced feed intake and weight gain (p < 0·01) at both the starter and finisher stages. Dietary thevetia cake also caused a significant increase in mortality rate (P < 0·01). There was a reduction in protein and fibre retention and dietary ME with increases in the dietary level of thevetia cake at both the starter and finisher stages (P < 0·05). It is concluded that thevetia cake is toxic to broilers and needs further processing before it can effectively be used as an ingredient in broiler feed.
The quantum yield of photosynthetic electron transport evaluated by chlorophyll fluorescence as an indicator of drought tolerance in durum wheat
Authors: Flagella Z. , Pastore D. , Campanile R. G. , Fonzo N. Di 
Published: March 2009

SUMMARYThe chlorophyll fluorescence parameters ΔF/Fm′ and Fv′/Fm′, related respectively to the quantum yield of photosynthetic electron transport and to the efficiency of excitation capture by the open centres of photosystem II, have been evaluated as possible indicators of drought tolerance in durum wheat. ΔF/Fm′ and Fv′/Fm′ measurements were carried out on excised leaves, both control and dehydrated, of 25 cultivars. ΔF/Fm′ and Fv′/Fm′ values were obtained at two times after the start of fluorescence measurement: at 14 s, i.e. during the induction curve (ΔF/Fm′14s and Fv′/Fm′14s) and at 200s, i.e. at steady state fluorescence (ΔF/Fm′200s and Fv′/Fm′200s).In dehydrated leaves a mean significant decrease of 20% (P < 0·001) was observed in ΔF/Fm′14s values. In contrast, no great differences were observed between control and dehydrated leaves with regard to ΔF/Fm′200s, Fv′/Fm′14s and Fv′/Fm′200s.The percentage decrease of ΔF/Fm′14s after dehydration was correlated with the drought susceptibility index (DSI) of the cultivars, evaluated on a yield basis and a significant correlation (r = 0·72, P < 0·001) was found.
Appearance and growth of individual leaves in the canopies of several potato cultivars
Authors: Firman D. M. , O'Brien P. J. , Allen E. J. 
Published: March 2009

SUMMARYLeaf appearance of contrasting potato cultivars was examined in field experiments at Cambridge, UK, between 1985 and 1990. Three experiments examined the effects of N fertilizer on the appearance and growth of leaves. Four experiments examined leaf appearance over a wide range of planting dates and in two of these experiments different physiological ages of seed were compared.Linear regression of rate of appearance of main-stem leaves on air temperature indicated a strong dependence of rate of leaf appearance on temperature in the cultivar Maris Piper with a phyllochron of c. 31 K d/leaf but in Estima variation in rate of leaf appearance was only partly explained by differences in air temperature. The phyllochron of main-stem leaves in Estima and Home Guard was shorter for old seed than young seed but there was little effect of seed age in four other cultivars. The phyllochron of main-stem leaves was longer without N fertilizer than with N but the difference in the phyllochron between rates of applied N was small. Leaf appearance on sympodial branches was slower and more variable than on the main-stem. Growth of branches differed between cultivars, particularly with no N fertilizer. In the determinate cultivars Estima and Diana there was restricted growth of branches but in the indeterminate cultivar Cara, significant leaf area was contributed by branches. The duration of leaf appearance and longevity of individual leaves is discussed in relation to N, temperature and cultivar.
The sprouting process in yam (Dioscorea spp.) tuber pieces
Authors: Onwueme I. C. 
Published: March 2009

SUMMARYThe progression of sprouting was observed in water-yam (Dioscorea alata) and whiteyam (D. rotundata) tuber pieces planted in moist sawdust. Soon after planting, white callus-like protuberances (sprouting loci) were seen on the tuber surface, followed by the appearance of one or more differentiated shoot buds on the sprouting locus. Sprouting loci appeared more readily on the upper and lower parts of each tuber piece than on the sides. Large tuber pieces sprouted more rapidly, had larger and more numerous sprouting loci, and gave rise to more shoot buds than small tuber pieces.Anatomical examination showed that the shoot bud resulted from the activity of a layer of meristematic cells lying close to the tuber surface. Extensive cell divisions commenced in this layer after planting, and some of the resulting cells soon differentiated into the shoot bud.
Allometry of food intake and grazing behaviour with body size in cattle
Authors: Illius A. W. 
Published: March 2009

SUMMARYIn 2 years two groups of 32 grazing cattle were used to examine the effects of previous grazing treatment and of body size on grazing behaviour and herbage organic matter intake (HOMI). Compensatory intake resulted from differences in grazing time only in the first year. There were no sex differences in intake when account was taken of differences in mature size raised to the power 0·73. Bite weight was related to the degree of maturity by the allometric coefficient of 0·46, and HOMI was similarly related by the coefficient of 0·36. This accords with the predicted effects of restricted grazing conditions on animals of different weight, and with allometric changes with weight in incisor breadth. Decreases in intake under grazing were similar in animals differing in maturity and weight. It is suggested that under constant grazing conditions the change in grazed herbage intake as animals mature reflects the allometric change in bite weight and a corresponding decline in bite numbers, resulting in consumption of a constant proportion of ad libitum intake.
Flavour differences in meat from lambs grazed on lucerne (Medicago sativa) or phalaris (Phalaris tuberosa) pastures
Authors: Park R. J. , Corbett J. L. , Furnival E. P. 
Published: March 2009

SUMMARYSignificant differences were found in the flavour characteristics of stewed minces from lambs raised on either lucerne or phalaris pastures. The meat from lambs raised on lucerne had a more intense ‘sharp’ and ‘sickly’ aroma and flavour and a significantly lower flavour acceptability. These characteristics were not significantly alter when the lambs were starved for up to 3 days before slaughter. However, the flavour of meat from lambs transferred from lucerne to phalaris 7 or 14 days before slaughter was not significantly different from that of lambs grazed solely on phalaris.
Length of oestrus, duration of phenomena related to oestrus, and ovulation time in the local fat-tailed Awassi ewe
Authors: Schindler H. , Amir D. 
Published: March 2009

SUMMARYOestrous cycle and phenomena accompanying oestrus were studied in the local fattailed Awassi ewe. By heat detections at 4 h intervals, the average period of oestrous was found to be 35·5 h and the mean duration of the oestrous cycle, 17·5 days. The repeatability of length of oestrus and of cycle length was 0·60 and 0·41, respectively. The appearance of a transparent or cloudy fluid secretion indicated that the ewe was still at least in the first half of the oestrous period, while that of a viscous creamy secretion indicated the approaching end of oestrus as well as the approaching ovulation; the latter events generally coincided. The onset of oestrus was not centred around any particular time of day.
The genetics of resistance to two strains of bean common mosaic virus in three cultivars of Phaseolus vulgaris L.
Authors: Innes N. L. , Walkey D. G. A. 
Published: March 2009

SUMMARYA high level of resistance to the bean common mosaic virus strains NL3 and NL4 when inoculated separately or together was confirmed in the cultivars Turkish Brown, Valja and 1750–73. Following crosses between the susceptible cv. The Prince and all three resistant cultivars, inoculation of F2 and F3 populations revealed that the cvs Turkish Brown and Valja each differed from The Prince in being homozygous for a major recessive gene conferring resistance to both NL3 and NL4. Homology tests indicated that the same gene was present in both Turkish Brown and Valja. Polygenes in Turkish Brown and Valja also appeared to confer some resistance to NL3, or environmental variation led to continuous distribution patterns in the F2's of resistant parents crossed with The Prince. Although a major recessive gene controlled resistance to NL3 in cv. 1750–73, it differed from that in the two other resistant cultivars. In addition, cv. 1750–73 carried a dominant gene determining reaction to the virus; probably the I gene originally found in Corbett Refugee. An attempt is made to relate these results to Drijfhout's (1978) gene-for-gene model. Using Drijfhout's gene nomenclature all the cultivars tested appear to carry the strain nonspecific gene bc-u. Further genetical tests will be necessary to determine with certainty which, if any, of Drijfhout's strain-specific resistant bc-genes are present in the three resistant cultivars studied here.
Influence of drying method and ageing on chemical and physical properties andin vitrodegradation characteristics of grass and maize samples
Authors: Cone J. W. , Van Gelder A. H. , Marvin H. J. P. 
Published: March 2009

SUMMARYThe influence of different drying conditions on the chemical composition, physical properties,in vitroorganic matter degradability and fermentation kinetics of forages was investigated using young and old grass (Lolium perenne) samples (harvested on 15 June and 9 July 1992 at Lelystad, The Netherlands) and young and old maize (Zea mayscv. Scana) stem samples (harvested on 19 August and 30 September 1991 at Lelystad). The samples were either freeze-dried with a maximum sample temperature of 10 °C, dried in a vacuum at 20 °C or air-dried at 30, 50, 70 and 105 °C. The different drying methods had little effect on ash, acid detergent fibre (ADF), acid detergent lignin (ADL), crude fibre and crude protein (CP) contents andin vitrodegradation of the forage samples. However, some effects were found for sugars and phenolic acids. The neutral detergent fibre (NDF) content in protein-rich samples and the fermentation kinetics in rumen fluid differed significantly according to drying method. In samples dried other than by freeze-drying, proteins were bound to the NDF content and in some cases an effect on the amount of soluble sugars was also seen. Physical properties of the samples were determined by differential scanning calorimetry (DSC) and differences were found between freeze-dried materials and those dried at 70 °C. The influence of age on the maize samples was very pronounced, whereas it had little effect on the characteristics of the grass samples, with the exception of a decreased CP content and an increased sugar content after acid hydrolysis.
Seasonal variation in the morphology of perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata) plants and populations in pastures under intensive sheep grazing
Authors: Brock J. L. , Hume D. E. , Fletcher R. H. 
Published: March 2009

SUMMARYThe morphology of independent plants of ‘Grasslands Ruanui’ perennial ryegrass (Lolium perenneL.) and three cultivars of cocksfoot (Dactylis glomerataL.) (‘Grasslands Apanui’, ‘Grasslands Kara’ and ‘Grasslands Wana’) in mixed pastures under intensive sheep grazing was studied at Palmerston North, New Zealand during 1991/92.Both perennial ryegrass and cocksfoot exhibited a similar pattern of clonal growth and population structure. Distribution of plants among various orders of branching showed a relatively stable pattern through most of the year except in spring, when stem decay and plant fragmentation exceeded apical growth and regeneration, causing an increase in the proportion of small plants and a corresponding decrease of larger plants. This pattern was similar to that previously reported for white clover (Trifolium repensL.). Nevertheless, seasonal variation in plant structure (number of leaves, tillers and stems per plant) was small, but variation in organ size (DW or length) was greater. Stolon formation through elongation of internodes occurred throughout the year, but was associated primarily with flowering.Grazing management caused no differences in plant structure between species or among the cocksfoot cultivars, but did affect the size of organs, and hence plants. Cocksfoot plants were 50–60% heavier than perennial ryegrass under rotational grazing. Under set stocking, only perennial ryegrass and Wana cocksfoot exhibited sufficient phenotypic plasticity to survive, both Kara and Apanui cocksfoot failed to persist. The only consistent difference between the species was greater flowering in perennial ryegrass than in cocksfoot, in both the proportion of plants flowering, and the number of flowering tillers per plant. Both species produced stolons throughout the year, although perennial ryegrass and Wana cocksfoot had a higher proportion of plants with stolons than Apanui and Kara cocksfoot. Length and DW of stolons per plant were similar in both species.As there was little variation in plant structure and plant density, length of stolons per unit area tended to parallel seasonal changes in pasture tiller density. The role of grazing management in the survival of tillers and plants, and subsequent performance of grass species in pastures is discussed.
Radiation-attenuated schistosome vaccination – a brief historical perspective
Authors: BICKLE Q. D. 
Published: March 2009

SUMMARYThe high level of protection which can be induced by vaccination of a range of hosts, from rodents to primates, with live radiation-attenuated schistosome larvae offers great promise for development of a human schistosome vaccine. Studies of the irradiated vaccine models benefitted from significant funding during the 1970–90s and much was learned concerning the inducers, targets and mechanisms of immunity. Less progress was made in definition of the protective antigens involved. The application of new techniques for identifying membrane and secreted antigens has recently provided new vaccine candidates and a new impetus for schistosome vaccine development. This article is intended as an overview of some of the main lessons learned from the studies of the irradiated vaccines as a backdrop to renewed interest in schistosome vaccine development.
Christ, creation and the drama of redemption: ‘The play's the thing . . .’
Authors: Bender Kimlyn J. 
Published: March 2009

AbstractThe Christian doctrine of creation is predicated upon two convictions: the transcendence of God and the creative activity of God in the world. While recent studies have shown the compatibility of these two seemingly conflicting convictions, the grounding for them has received less attention. This paper argues that a proper Christian understanding of these convictions and their relationship is dependent upon seeing their basis in christology and trinitarian doctrine. It thus traces the close relationship between Christ and creation and that between creation and redemption in scripture, the patristic period and their more recent retrieval in Schleiermacher and Barth, comparing such conceptions to pagan and neo-pagan alternatives for understanding the God–world relation.