bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water relations of winter wheat: 3. Components of leaf water potential and the soil-plant water potential gradient
Authors: Wallace J. S. , Clark J. A. , McGowan M. 
Published: March 2009

SUMMARYDiurnal and seasonal changes in the total, osmotic and turgor potentials of winter wheat leaves are compared in two seasons of mild and severe soil water stress. Gradients of total water potential in the soil-plant system are also presented. In both seasons the total water potential of the leaves decreased in parallel with the soil water potential, concurrently leaf osmotic potential also decreased sufficiently to maintain positive leaf turgor potential. Eventually, under severe water stress, soil water potential approached –1·5 MPa and leaf turgor potential tended to zero during the middle of the day.The potential drop across the soil-root system was twice that along the stem. Estimates of the water potential at the root surface varied diurnally and were often lower than the bulk soil water potential. In dry soil plants were unable to equilibrate with the soil water potential overnight. These results are consistent with the existence of significant resistance to water flow across the rhizosphere.
Rice bran as a supplement to elephant grass for cattle and buffalo in Indonesia: 1. Feed intake, utilization and growth rates
Authors: Moran J. B. 
Published: March 2009

SUMMARYIndonesian Ongole and swamp buffalo bulls were fed ad libitum a diet of elephant grass (Pennisetum purpureum) with five levels of rice bran (0, 1·2, 2·4, 3·6 and 4·8 kg/head/ day) in a study lasting 161 days. Measurements were made of the digestibility of the diet, the balances of nitrogen, phosphorus, calcium and water and the metabolizability of the gross energy. Using multiple regressions, the daily intakes of metabolizable energy were partitioned between maintenance and growth.Feeding rice bran stimulated appetite, initially improved feed conversion efficiency and increased growth rates. Each additional kilogram of rice bran fed depressed grass dry-matter intake by 0·8 kg in the buffaloes and 0·6 kg in Ongoles. Rice bran had little effect on digestibility of dry matter, organic matter and energy. Metabolizable energy contents of rice bran and elephant grass were calculated to be, respectively, 9·5 and 8·2 MJ/kg dry matter. Nitrogen and phosphorus status was improved in the supplemented animals but the balance of calcium was adversely affected. Voluntary feed intake was always higher in the buffaloes but the differences were reduced with increasing rice-bran supplementation.Metabolizable energy requirements for maintenance and growth did not differ significantly between Ongole and buffaloes and were similar to values calculated for British animals.
Investigations into the use of plant growth regulators in oil-seed sunflower (Helianthus annuusL.) husbandry
Authors: Baylis A. D. , Dickst J. W. 
Published: March 2009

SUMMARYThe effects of some plant growth regulators on the growth and development of two cultivars of oil-seed sunflower (cvs Flambeau and Luciole) were examined in 1977 and 1978. Sunflower is a marginal crop for the United Kingdom, being late maturing and susceptible to infection by grey mould (Botrytis cinerea) during the seed-filling period.An experiment in 1977 indicated that suitable growth regulators might improve sunflower husbandry principally by shortening the stem, allowing late applications of fungicide and insuring against lodging. A mixture of mepiquat chloride and ethephon (BAS 098 OOW) was the most effective stem shortener. Daminozide gave variable effects on yield depending on the rate and time of treatment. The number of seeds per m2 was the major determinant of yield; 1000-seed weights and oil contents were similar for all treatments. The proportion of linoleic acid in the oil was very high in all experiments.In 1978 a second experiment involving daminozide and two sunflower cultivars revealed seasonal and varietal differences in response. The timing of growth regulator application seemed critical to affect seed yield. The third experiment, in 1978, investigated the results of applying BAS 098 OOW to four plant population densities varying from 40000 plants/ha to 160000 plants/ha. High plant population density advanced maturation by 2 weeks, but in these plots the crop lodged in the absence of growth regulator treatment.
Environmental temperature, energy metabolism and heat regulation in sheep. I. Energy metabolism in closely clipped sheep
Authors: Graham N. McC. , Wainman F. W. , Blaxter K. L. , Armstrong D. G. 
Published: March 2009

1. The energy exchange of two sheep closely clipped at weekly intervals was determined at three feeding levels and seven environmental temperatures, using a respiration apparatus in which radiant temperature was equal to ambient temperature. All measurements were made under conditions in which the animal was in equilibrium with its environment and heat storage was zero.2. Body weight and fleece growth were both markedly reduced at the lowest feeding level. Weight losses were most marked at the lowest temperatures.3. The energy lost in faeces decreased slightly as environmental temperature increased from 8 to 38° C. Urine energy losses also fell. Losses of energy as methane were maximal in the temperature range 23–28° C. As a result of these changes, the metabolizable energy of food increased with environmental temperature by 7 Cal./24 hr./° C.4. The environmental temperature of the sheep at which their heat production was minimal, i.e. the ‘critical’ temperature was 39–40° C. for the lowest feeding level, 33° C. for the medium feeding level and 24–27° C. for the highest feeding level.
Sweating in cattle. III. Mechanism of water transportation through the skin
Authors: Taneja G. C. 
Published: March 2009

Two calves (Zebu × Australian Illawara Shorthorn and Shorthorn) of about 7–8 months of age were exposed to controlled atmospheric conditions. Cutaneous evaporation from the belly area of these calves was measured by the capsule method. Records of the temperature of the skin under test and that of the air passed over the skin was also maintained.The amount of water passing through the cattle skin was proportional to the difference between the saturated water-vapour pressure at skin temperature and the water-vapour pressure in the air. Tests were made for the water-vapour pressure difference varying from 9 to 25 mm. Hg.
Post-natal growth changes in the skin follicle population of the New Zealand Romney and N-type sheep
Authors: Carter H. B. , Tibbits Janet P. 
Published: March 2009

Quantitative aspects of skin follicle population growth and maturation in post-natal life from birth to 16 months have been studied in four groups of N-type and non-N New Zealand Romneys. The following characters were observed on skin biopsy specimens from a standard position on the mid-side in all cases: total and primary follicle population density; ratio of secondary to primary follicles ; primary and secondary fibre diameter; primary/secondary fibre diameter ratio ; and the incidence and degree of primary and secondary fibre medullation.No important differences were found between the genotypes examined in any of these characters except primary fibre diameter , the primary/ secondary fibre diameter ratio ; and the incidence and degree of primary and secondary fibre medullation. These characters individually, but especially in combination, appear of great diagnostic value at all post-natal ages in discriminating N-type from non-N genotypes, in terms which reduce the number of assumptions necessary on the relations between the fibre types of the staple and the follicles of origin in the skin.
The relative performance of inbreds and open-pollinated populations of spring-sown onions
Authors: Dowker B. D. , Fennell J. F. M. 
Published: March 2009

SUMMARYFirst (I1), second (I2) and third-generation (I3) inbreds were compared with openpollinated spring-sown onion populations in field trials at five sites over 2 years. The open-pollinated populations were earlier maturing and gave higher yields and a lower proportion of bullnecked plants than the inbreds but the latter had a lower proportion of unmarketable double bulbs. The mean level of expression of each character differed considerably between individual trials. The effect on sprouting within each year resulted from factors operating prior to storage; bulbs from all sites were stored at Wellesbourne in a common environment yet large differences in the proportion of sprouted bulbs from different sites occurred by the following spring.Interactions were found between the type of population (inbred and open-pollinated) and the macro-environment. Inbred populations showed a greater linear response to environment for yield, skin colour and proportion of bullnecked plants, but were less responsive for percentage of double bulbs.The results are discussed in relation to the evaluation procedures for inbreds.
The voluntary intake of oat straw by adult cattle as affected by the method of dietary presentation of a concentrated solution of urea, minerals and vitamins
Authors: Bass Jean M. , Hemingway R. G. , Fishwick G. , Parkins J. J. 
Published: March 2009

SUMMARYThree experiments were conducted to assess the effects of several methods of dietary presentation of 250 g/day of a fully soluble liquid supplement (LS) on the voluntary intake of oat straw by non-productive cows fitted with a rumen fistula (Expt 1), pregnant beef cows (Expt 2) and lactating beef cows (Expt 3). In each case the cows received fixed daily amounts of barley (2 kg for Expts 1 and 2; 3 kg for Expt 3). LS contained (g/kg) about 1100 crude protein (as urea), 30 calcium, 15 phosphorus and 50 salt plus trace elements and vitamins. In Expt 1, provision of LS in either the drinking water, or via the rumen fistula or sprayed on to the straw increased voluntary straw intake by about 12%. In Expt 2, provision of LS, whether by spraying on the straw or in a molasses lick, increased straw consumption, but giving LS in the drinking water did not. In both Expts 1 and 2 the digestibility of the oat straw was not significantly affected by the dietary supplement, any increases in metabolizable energy intake being reflexions of increased intakes. In Expt 3 there was no difference in the voluntary intake of oat straw by group-fed lactating beef cows offered LS in either the drinking water or as a molasses lick.Giving LS sprayed on the straw, or incorporating it into a molasses lick to housed animals, are convenient and practical methods of supplementing ruminant diets to increase their voluntary straw consumption. Inclusion of LS in drinking water gave inconsistent results, but the method warrants further investigation.
Methods of analysing yield from trials in which the produce is graded according to diameter
Authors: Chapman Elizabeth A. 
Published: March 2009

SUMMARYA study was made of the relationship between yields in particular size grades of carrots and onions and the number of plants per unit area with a view to providing adjustments to yields for differences in plant densities. It is concluded that the relationship for individual small grades cannot be fitted consistently by a single mathematical equation but that estimates of yields in small grades are best obtained by fitting a common equation to the accumulated yield at the limits of the grade and obtaining the yield by difference. Eleven previously published equations which have been shown to fit the relationship between total yield and plant density for a number of crops are compared with one newly developed for graded produce. It was found that the latter,where y = yield/ha, ρ = number of plants/m2 and A, B and C are constants, generally leads to the best fits when a large range of densities is present, but it is argued that, for adjustment of yields for small differences in densities such as are obtained in variety trials, a simpler equation such as a second degree polynomial is equally effective.
Tolerance of lentil, barley and oats to boron in irrigation water
Authors: Chauhan R. P. S. , Asthana A. K. 
Published: March 2009

SUMMARYAn experiment to determine the effect of concentration of boron in irrigation water on tissue Ca/B ratio and yield of lentil, barley and oats is described and the results discussed. Tissue Ca/B ratio is a better index for detecting B toxicity in plants. The grain and straw yield of lentil and barley decreased on and beyond 3 and 6, and 6 and 8 mg B/1 in irrigation water, respectively, but there was no effect on green fodder yield of oats.
Relation of shape of canopy to interception of radiation and yield of wheat
Authors: Dhillon G. S. , Kler D. S. 
Published: March 2009

SUMMARYField experiments were made at the Punjab Agricultural University, Ludhiana, during 1974–5 to 1978–9 to study the possibility of improving wheat yield by more efficient use of radiant energy through modification of the shape of the canopy under varying levels of fertilizers, irrigation and seed rates. The results showed substantial yield increase by sowing half the seed and fertilizers in one direction and half in rows at right angles, giving a spacing of 22·5 × 22·5 cm, thereby intercepting more light, which showed a significant direct relationship with yield, but there were negative correlations with soil temperature. The increase in row spacing decreased the yield. With 33% extra fertilizer than the local recommendation, sowing the crop in two directions gave 0·96 t/ha (33·4%) higher yield, whereas none of the other sowing methods showed significant increase. Mixing varieties to form a prismatic canopy gave higher yield than the mean of the varieties sown alone. Irrigating the crop more than thrice did not prove beneficial. North-south row direction tended to improve yield compared with east-west rows. Seed rates varying from 50 to 200 kg/ha showed neither significant effect, nor interaction with canopy shape except in 1978–9 when 150 kg seed/ha showed yield improvement over 100 kg/ha.
A study of subclinical worm infestation in sheep: Part II. The ‘tolerance’ level of infestation
Authors: Spedding C. R. W. , Brown T. H. 
Published: March 2009

1. The live-weight gain of lambs initially infected at five different levels was compared with that of similar but worm-free animals, under conditions of set-stocking at a high rate per acre.2. Over a period of 9 months the worm-free controls gained 67·7% more weight than the total infected group, but the live-weight gains of the five levels did not appear to be related to their original infection or to their egg counts.3. Although a few nematode eggs were detected in the faeces of some control lambs, reinfection was negligible under the conditions of this experiment.4. It was concluded that a marked depression of productivity may be associated with an egg count as low as 114 e.p.g. in sheep 4–7 months of age.
Soil and plant factors limiting the availability of copper to a beef suckler herd
Authors: Jarvis S. C. , Austin A. R. 
Published: March 2009

SUMMARYHypocuprosis has been diagnosed for 4 years in calves of a beef suckler herd at Warren Farm, Berkshire. The copper (Cu) contents and distribution in the soil at that site, as well as changes in herbage Cu throughout the 1979 grazing season, were examined. The herbage Cu concentration was always less than 7·5 μg/g and decreased markedly to 3·0 μg/g during July. Serum Cu contents of both untreated cows and untreated calves also decreased markedly, but at a much earlier stage than the decrease in herbage concentration. One untreated calf developed severe anaemia, but recovered when treated with Cu Ca EDTA. Although changes in the coefficient of absorption of dietary Cu were caused by changes in S and Mo contents, the calculated availability of Cu was dominated by the Cu content per se. Thus the calculated availability remained relatively high during the period when serum concentration decreased.The decrease in serum Cu may have occurred as the result of a differing availability of Cu in ensiled and grazed herbages. However, coincident with the decrease in serum Cu was a high concentration of Fe in the grazed herbage which was largely associated with the surfaces of the leaves. It is therefore possible that the development of Cu deficiency immediately after the animals started to graze was precipitated either through an interaction between Cu and Fe in the animal, or because of a reduced availability of Cu through an interaction with ingested soil.
Volatile fatty acid proportions and lactic acid metabolism in the rumen in sheep and cattle receiving silage diets
Authors: Chamberlain D. G. , Thomas P. C. , Anderson Fiona J. 
Published: March 2009

SUMMARYA total of 21 rumen-cannulated wether sheep and six rumen-cannulated Ayrshire cows were used in a series of experiments to investigate fermentation in the rumen in animals given silage diets and the nominal metabolism of silage lactic acid. Dietary experiments with sheep (three experiments) and cows (two experiments) given diets consisting of formic acid–preserved perennial ryegrass (Lolium perenne) silages, in some cases with supplements of rolled barley, were conducted to investigate the ruminal concentrations of lactic acid and of volatile fatty acids (VFA) after feeding. Ingestion of silage was followed by a short-lived peak in lactic acid concentration in the rumen and by a subsequent increase in the concentration of propionate or propionate and butyrate. Butyrate production was more evident in cattle than in sheep. Taken as an average over a 6 h period of sampling the proportions (m-mol/mol total VFA) of acetate, propionate and butyrate in the rumen in animals given silage alone were typically 590–600, 210–250 and 70–150 respectively. When silage was supplemented with barley, in both sheep and cattle, the proportion of propionate was reduced and the proportion of butyrate was increased. In one experiment with sheep these changes in fermentation pattern were shown to be accompanied by an increase in the number of rumen protozoa from 2·78×105/ml to 18·66·105/ml (P<0·01). However, in a subsequent experiment it was shown that defaunation led to an increase in the proportion of butyrate in the rumen.Twelve estimates were also made with sheep of the metabolism of lactic acid infused into the rumen in a single dose of 20–50 g. These experiments showed that both (L+) and DL-lactio acid were metabolized equally rapidly with a half-life of approximately 25 min. In faunated animals the major products of fermentation were propionate with a small amount of butyrate. In defaunated animals lactate metabolism was slowed and the major product of fermentation was butyrate.In vitrostudies of lactate fermentation were carried out using strained liquor and isolated bacterial and protozoal fractions from the rumen of sheep receiving silage diets. The rates of lactate disappearance (μg/mg protein/h) were 50 and 22·2 for the rumen liquor and bacterial fraction, respectively, which were significantly (P<0·05,n= 5) less than the rate of 294·7 for the protozoal fraction. Rumen liquor, bacterial and protozoal fractions yielded a similar mixture of fermentation end-products, propionate accounting for approximately 60% of the VFA produced.The results are discussed in relation to the metabolism of silage lactic acid in the rumen, the production of VFA and the yield of ATP for microbial cell synthesis. It is concluded that the pathways of lactate fermentation are regulated by the rumen microbial population and that protozoa may have an important role in the regulation of lactate fermentation.
Relationships between a P-sorption index, extractable Fe and Al and fluoride reactivity in the soils of an area of mid-Wales
Authors: Loveland P. J. , Wright P. S. , Dight R. J. 
Published: March 2009

SUMMARYThe soils of on area around Llangadog (mid-Wales) have been systematically sampled on a grid basis at 0–8 cm and 30–35 cm depths.A P-sorption index was determined for these samples as were Fe and Al extractable by both 0·1 M K-pyrophosphate solution and 0·2 M-NH4-oxalate solution at pH 3. The reactivities of the soils with 1 M-NaF solution at pH 6·8 and pH 8 were also measured.The results were stratified in terms of parent material, soil classification at subgroup level and soil series, and correlation coefficients calculated between the P-sorption index and the other variables (singly and in combination).Only pyrophosphate-extractable Fe, i.e. ‘organically bound’, correlated reasonably well with the P-sorption index. However, the correlation was such that tolerably good estimates of P-sorption in an agronomic context could be made from pyrophosphate-extractable Fe values only for previously uncultivated brown podzolic soils (Manod series).Fluoride reactivities at both pH values were poor predictors of P-sorption in these soils. Fluoride reactivity at pH 6·8 and oxalate-extractable Al, which have both been proposed as indices of the amounts of ‘poorly-ordered’ Al compounds in soils, failed to group these soils in similar ways. Doubt exists therefore as to whether these variables are measures of the same (or similar) property in these soils.
Determination of fixed ammonium in soil
Authors: Bremner J. M. 
Published: March 2009

1. A method of determining fixed ammonium in soil based on estimation of the difference in the amounts of ammonium released on treatment with N-HF:N-HC1 and with N-KCI has been investigated and compared with the hydrofluoric acid method of Rodrigues and the alkaline distillation method of Barshad.2. Results obtained by the N-HF:N-HCl procedure with profile samples of various soils indicated that 3–8% (average, 5·6%) of the nitrogen in the surface soils and 9–44% (average, 21·5%) of the nitrogen in the subsoils examined was in the form of fixed ammonium. Rodrigues's method gave much higher values and Barshad's method gave much lower values.3. Studies on the forms of nitrogen in soil profiles showed that the proportion of soil nitrogen released by acid hydrolysis as total-N and α-amino-N decreased with depth in the profile, whereas the proportion liberated as ammonium by acid hydrolysis increased with depth. They also showed that a considerable amount of the ammonium released by acid hydrolysis was derived from fixed ammonium in clay minerals.4. It was found that the proportion of soil nitrogen dissolved by N-HF:N-HCl increased with depth in the profile, whereas the proportion dissolved by neutral and alkaline reagents used to extract soil organic matter decreased with depth. On the average, 23·2% of the nitrogen in the surface soils and 47·4% of the nitrogen in the subsoils was dissolved by a single treatment with N-HF:N-HCl at room temperature for 24 hr.5. The reliability and significance of the results obtained by the N-HF:N-HCl method are discussed.
Relation of diurnal temperature and humidity ranges to egg production and feed efficiency of New Hampshire hens
Authors: Squibb Robert L. 
Published: March 2009

The effect of environment on the production and size of eggs, feed efficiency and mortality of New Hampshire hens in individual cages was studied simultaneously in five areas of Guatemala having temperatures covering a range of 0°–45° C. with variable humidities.While birds housed in the tropical lowlands did show visible signs of thermo-stress, there were no significant differences in egg size, production, feed consumption, mortality and body weight between areas or between groups within areas. The inconsistency of these data with other published reports is explained on the basis of the observed extremely wide diurnal range for temperatures and humidities. An attempt is made to present accepted physiological phenomena in the form of a working hypothesis wherein the diurnal temperature range is related to the fowl's tolerance to thermo-stress.