bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the phosphorus status of some coconut-growing soils of Sri Lanka
Authors: Loganathan P. , Dayaratne P. M. N. , Shanmuganathan R. T. 
Published: March 2009

SUMMARYThe phosphorus status of 58 soil samples representing 15 soil series and four soil Orders (Ultisol, Entisol, Alfisol and Oxisol) in the major coconut-growing regions of Sri Lanka was evaluated by determining the available P extracted by the methods of Olsen, Bray & Kurtz No. 1, Bray & Kurtz No. 2 and NH4OAc (pH 4·8) and the various P forms. Total P in the soils ranged from 37 to 338 mg/kg with organic P and active P constituting only about 20 and 50% of the total P respectively. In general the sandy soils of the Entisols and Oxisols had lower total and organic P but higher active and available P than the rest. The relative abundance of the various inorganic P forms was generally in the decreasing order of inactive P, Fe-P, Al-P and Ca-P. Al-P and Ca-P were positively correlated with percentage sand and negatively correlated with percentage silt and percentage clay whereas total P and organic P had the opposite trend. Available P extracted by the four methods was very low in almost all soils except some of the sandy soils (Entisols) which had marginal to moderate P contents. They were positively correlated with Al-P, Ca-P, percentage sand and negatively correlated with percentages of silt, clay and organic carbon.Phosphorus concentrations (0·074–0·116%) in the 14th leaf of coconut at the soil sites were all lower than the critical leaf-P concentration (0·120%). Leaf-P correlations with Bray & Kurtz No. 2-P and NH40Ac-P were significant (P < 0·05) and with Al-P and Ca-P were close to significant.The study revealed that the coconut-growing soils of Sri Lanka were deficient in total as well as the active and available forms of P except perhaps some of the sandy soils of the Entisol. This was confirmed by coconut leaf P analysis.
Free amino-nitrogen exchange across the hindquarters of fed and fasted sheep and pigs
Authors: Chalmers Margaret I. , Grant I. , White F. 
Published: March 2009

SUMMARYFree amino·N estimations were used to monitor the movement of free amino acids in blood passing through the hindquarters of sheep and growing pigs. The net uptakeor release of free amino·N was calculated from arterio-venous differences in the concentration of free amino·N measured in whole blood and plasma at short intervals of time.In both species the net change was an apparent release of free amino·N into venous blood. The release increased on fasting. Net uptake of free amino·N from blood was occasionally found at single sampling times due to loss from the cell compartment in sheep and from the plasma compartment in pigs. The uptake measured in whole blood was always less than in a single compartment of blood. The greatest fluctuation in free amino·N concentration occurred in the cells of aorta blood.It is concluded that both blood cells and plasma have independent roles in the net flux of free amino·N requiring determinations of amino acids in both whole blood and plasma to describe the exchange of blood free amino acids with tissue. A negative arteriovenous difference of free amino·N in blood across skeletal muscle is normal for healthy well-fed animals. Fasting increases the negativity.
A comparison of growing wheat continuously with growing wheat in a four-course rotation
Authors: Ridgman W. J. , Walters D. E. 
Published: March 2009

SUMMARYThe design and analysis of an experiment to compare the yield of wheat grown continuously with that of wheat grown in two phases of a four-course rotation is described and the results discussed. A method of analysis which avoids making assumptions about the covariance structure of the errors derived from repeated observations on the same plots, which could be appropriate to other sorts of rotation experiments, is given.There were no differences between yields of the first and second wheat crops which followed oats after beans in a four-course rotation, but the average of these two crops was 0·75 t/ha greater than the yield of wheat grown continuously. The response to N was the same in the two systems of cropping. The only yield component affected by the system of cropping was grain mass.
An attempt to improve the yield and quality of direct-drilled winter wheat grown continuously
Authors: Holbrook J. R. , Osborne J. D. , Ridgman W. J. 
Published: March 2009

SUMMARYSix field experiments on the effects of rate and time of application of nitrogen, three variety trials and one trial combining varieties with rates of application of nitrogen, all on winter wheat grown continuously and direct-drilled on a single farm, are described and the results discussed.The experiments showed that worthwhile yield responses could be obtained to very high rates of N application and that percentage protein in the grain increased linearly with amount of N supplied even to the highest rate (350 kg N/ha) applied. The effects of time of application were variable but there was a suggestion that applying the nitrogen in two doses in the spring gave more yield than a single dose, in one experiment. Applying some N in the autumn gave no more yield than applying it all in the spring.The variety trials gave results reasonably consistent with those of the National Institute of Agricultural Botany but the variety x nitrogen trial showed clear differences between varieties in response to nitrogen; the oldest variety, Maris Huntsman, showed a maximum at about 240 kg N/ha whereas none of the new varieties had reached their maximum by 270 kg N/ha.It is argued that field trials devoted to improving crop yields for a particular farm are worthwhile if site x treatment interaction is large and season x treatment interaction is small.
Microbiological and chemical changes in the rumen during the stepwise adaptation of sheep to high concentrate diets
Authors: Mackie R. I. , Gilchrist Frances M. C. , Robberts Anna M. , Hannah P. E. , Schwartz Helen M. 
Published: March 2009

SummaryA stepwise adaptation was carried out on eight sheep through diets containing 10, 24, 44, 60 to a final diet containing 71% maize meal and molasses. The numbers of protozoa in the rumen increased in proportion to amount of readily fermentable carbohydrate fed, up to and including the 60% grain and molasses diet, while the numbers of total culturable bacteria remained essentially constant. However, the proportions of amylolytic and lactate-utilizing bacteria increased, and there was an orderly shift from acid-sensitive to more acid-tolerant species, particularly amongst the lactate-utilizers in response to the gradual decrease in the ruminal pH. Up to this stage the protozoa probably controlled the rate of fermentation by engulfing starch grains and bacteria and were thus able to maintain the pH of the rumen above 5·5. Lactic acid appeared only transiently and the peak values tended to diminish as adptation progressed.The first day the final diet was fed the ruminal pH decreased to 5·4 or below for several hours. Within 7 days the number of protozoa had decreased by 50–80% and the number of total culturable bacteria increased sharply. Conditions in the rumen became unstable: peak values of D- and L- laotic acid increased by ca. 0·5 HIM, the acetate/propionate ratio decreased to ca. 2 and peak glucose concentration increased t o 3·2–9·5 mM. One animal refused all food for 1 day. Acid-tolerant species of lactate-utilizing bacteria multiplied rapidly in response to the increased production of ruminal lactic acid and the ratio of amylolytics to lactate-utilizers decreased from a mean of 10·7 to 3·6. This controlled the increase in lactic acid and the decrease in ruminal pH, allowing the ciliate protozoa to proliferate and regain control of the fermentation.The types of cellulolytic bacteria did not change during the experiment. Despite their acid sensitivity, the number of cellulolytic bacteria per gram of ingesta was of the same order after 54 days on the 71% grain and molasses diet (0·5–13·3 × 107) as on the initial high roughage diet (3·2–7·6 × 107).Three sheep which bloated showed no marked chemical or microbiological differences from the non-bloating animals.
Studies on the breeding season of Icelandic ewes and ewe lambs
Authors: Dýrmundsson Ø. R. 
Published: March 2009

SummaryThe paper reports on a study, conducted in four successive seasons, of sexual development and breeding activity in females of the Iceland breed, the only breed of sheep kept in the country. The ewe lambs normally attained puberty in their first year of life, on average at 7 months of age, with marked individual variation in both age and body weight at first oestrus. Ewe lambs always showed oestrus on average slightly later than mature ewes (2–9 years), the mean date of onset of the breeding season of the latter being 8 December, however, with considerable individual variation. Furthermore, ewe lambs had a shorter breeding season (1–4 months) than ewes (4–6 months) and they appeared to experience more silent heats resulting in less regular cyclic activity. There seemed to be a minor increase in the duration of the oestrous cycle with age and ewe lambs clearly exhibited shorter oestrus (heat) than ewes. With seasonal breeding activity ranging from November to May the mid-breeding season occurs some 4–7 weeks after the shortest day.
Coating and modified atmosphere effects on potato tuber greening
Authors: Banks N. H. 
Published: March 2009

SUMMARYCoating and modified atmosphere treatments reduced light-induced greening of King Edward potatoes. Although ‘Pro-long’ coating and 5% O2 treatments gave more complete inhibition of greening in some tubers, the variability of response was greater and the mean response less than for treatment with 15% CO2, 21% O2. The pattern of greening in the different treatments suggested the presence of O2 gradients within the tuber flesh. Coating caused small internal atmosphere changes, with CO2 content being negatively correlated with chlorophyll content. Larger changes achieved by modifying the external atmosphere of such tubers increased greening suppression. However, the magnitude of response to coating and to the low O2 treatment varied with maturity and growing conditions. The success of coating for inhibition of greening in potatoes will depend upon the physiological variability of the tubers to which it is applied.
Virus infection: a host dependent reaction reversible phenomenon
Authors: Ghosh S. K. 
Published: March 2009

SUMMARYRice necrosis mosaic virus infection induced different reactions on monocotyledonous and dicotyledonous plants under field conditions. Under identical conditions virus infection reduced the grain yield of rice by inhibiting plant growth, whereas in dicotyledonous plants likeLudwigiaand four fibre crops (including jute infection with sap from rice necrosis mosaic virus-infected rice plants, but not with sap from healthy plants) markedly increased yield, plant height, leaf size, stem diameter, seed weight and number of seeds per capsule.
The effects of frequency of defoliation on the yield response of a perennial ryegrass sward to a wide range of nitrogen application rates
Authors: Reid D. 
Published: March 2009

SummaryIn a 3-year experiment on a sward of S. 23 perennial ryegrass 21 rates of nitrogen fertilizer ranging from 0 to 897 kg/ha were applied annually on plots cut three, five or ten times per year. The cutting dates within each frequency were decided on the basis of herbage growth stage. Four-parameter exponential curves fitted to the herbage yield data show that the pattern of response to nitrogen application in the five cuts per year treatment was markedly similar to that reported for a previous experiment (Reid, 1970). Alterations in the cutting frequency affected the pattern of dry-matter yield response to nitrogen, but not that of crude-protein yield response. The combined effects of cutting frequency and nitrogen rate are illustrated by response surfaces fitted to the dry-matter yield results using an extension of the equation for the curves fitted to the individual frequency results. These surfaces show that as the number of cuts per year was increased the total yield and the response to nitrogen decreased, but the response was maintained to an increasingly high nitrogen rate. The practical implications of the results are discussed in relation to intensive grazing managements for dairy cows.
The digestion of spring and autumn harvested perennial ryegrass by sheep
Authors: Beever D. E. , Terry R. A. , Cammell S. B. , Wallace Annie S. 
Published: March 2009

SummaryS. 24 perennial ryegrass harvested in June, and subsequently in September from the same sward was conserved by rapid freezing. The digestion of the carbohydrate and protein components of the two diets was investigated, using sheep fitted with re-entrant cannulae at the proximal duodenum and terminal ileum and consuming daily 950 g of herbage dry matter.The higher content of soluble carbohydrate and the lower content of protein in the spring-cut herbage compared with the autumn cut, led to a more efficient fermentation in the rumen with a higher yield of volatile fatty acids per mole of substrate degraded, a proportionately higher yield of propionic acid and a substantially greater net gain of protein between mouth and duodenum on the spring cut herbage. Consequently, the quantity and composition of the amino acids entering the small intestine, or being absorbed therein, were not significantly different, despite the higher protein content noted on the autumn herbage.The total energy absorbed was markedly higher for the spring herbage (11·2 MJ/kg D.M.) compared with the autumn herbage (9·5) and the energy absorbed as protein from the two diets comprised 20 and 26% of total energy absorbed respectively.The possible causal mechanisms within the rumen, and the subsequent effect of these on nutrient supply are discussed in relation to the well-established higher efficiency of use of metabolizable energy (ME) of spring-cut herbage compared with autumn cut herbage of similar apparent energy digestibility.
Dry deposition of atmospheric ammonia at Rothamsted in 1976 and 1977
Authors: Rodgers G. A. 
Published: March 2009

SummarySoils at Rothamsted receive approximately 4 kg NH3-N/ha/year through dry deposition of atmospheric ammonia. The value is low compared with other nitrogen input processes and reflects the low concentrations of ammonia in the atmosphere. Rainfall is a major factor limiting dry deposition as it removes large amounts of ammonia from the atmosphere. Dry deposition of ammonia is a relatively unimportant source of combined soil nitrogen compared with other natural and artificial sources.
Effects of variety and date of harvest on the tuber dry-matter percentage of potatoes
Authors: Wurr D. C. E. , Bean J. N. , Allen E. J. 
Published: March 2009

SummaryUsing data from four field experiments, comparisons were made between the drymatter percentages of several varieties harvested at different times during the growing season.There were negative quadratic relationships between tuber dry-matter percentage and tuber size in all varieties except Pentland Marble. The dry-matter percentage of particular tuber sizes varied according to the variety and the time of harvest. Failure to recognize the importance of tuber size and the time of harvest may easily distort differences in dry-matter percentage between varieties.There were significant positive correlations between the number of tubers produced by each variety on 25 June and four different variables representing the dry-matter percentage of tubers harvested on 10 September. Varietal maturity, assessed as persistence of the foliage, was not significantly correlated with any tuber dry-matter percentage variable in September.
The amino acid, collagen and mineral composition of preruminant calves
Authors: Williams A. P. 
Published: March 2009

SummaryThe amino acid, mineral and collagen composition of certain different components of the bodies of preruminant calves was determined. The amino acid composition (g/kg crude protein) of the empty bodies of preruminant calves was: hydroxyproline, 40; aspartic acid, 81; threonine, 40; serine, 44; glutamic acid, 129; proline, 81; glycine, 113; alanine, 71; cystine, 13; valine, 39; methionine, 17; isoleucine, 28; leucine, 69; tyrosine, 25; phenylalanine, 36; lysine, 64; histidine, 25; arginine, 70; tryptophan, 8. The hydroxyproline, proline and glycine contents were much higher than in bovine muscle because about one-third of the total protein of the calves was collagen, a protein particularly rich in these amino acids. The collagen content of the individual body components varied considerably as did their amino acid contents. There were also some marked differences in the contents of some of the major constituents and minerals in the individual components. In particular the internal organs and blood (component (6)) contained significantly lower concentrations of crude protein, ash, Ca, Mg and P but significantly higher concentrations of Cu and Fe.
Efficiency of fallow as a store for fertilizer nitrogen in a semi-arid region
Authors: Seligman N. G. , Feigenbaum Sala , Benjamin R. W. , Feinerman Dvora 
Published: March 2009

SUMMARYFertilizer nitrogen recovery under fallow and under a wheat crop (Triticum aestivumL., cv. Miriam) grown on a deep loessial silty loam (Calcixerollic Xerochrept), was studied with15N labelled KNO3. The labelled nitrogen was applied (at a rate of 180kg/ha) to 30 cm diameter microplots enclosed in hard plastic tubes that protruded 5 cm above the soil surface. In the 1st year of the experiment there was a long dry spell during the main part of the growing season and plant dry-matter yields were low. The 2nd year was wet, with heavy rain early in the season. About one-third of the fertilizer N applied to the fallow was lost from the top 60 cm layer in the 1st year. Most of the fertilizer N remaining in the soil as mineral N at the end of the first season was lost in the 2nd year. The possible reasons for such low N-conservation efficiency are discussed.
The reaction of lettuce (Lactuca sativaL.) cultivars to cucumber mosaic virus
Authors: Walkey D. G. A. , Ward C. M. , Phelps K. 
Published: March 2009

SUMMARYAll 53 lettuce cultivars inoculated with cucumber mosaic virus became infected. Leaf mosaic symptoms were generally mild and unreliable for distinguishing degrees of resistance between cultivars. Yield reduction was the most satisfactory criterion for evaluating resistance, with reductions in individual cultivars ranging from 8 to 50%.
The effect of artificial light, hormones, and rams on the reproductive performance of Finn-cross ewes during the seasonal anoestrus in Israel
Authors: Amir D. , Gacitua H. 
Published: March 2009

SUMMARYAdult Finn-cross ewes, pregnant from September matings, were kept under natural (control) or artificial photoperiod (experimental). The artificial photoperiod consisted of an abrupt increase in daylength to 18 h for 30 days in November, followed by a step wise decrease of 30 min every 10 days until May.The ewes of the two groups were either exposed daily to rams after lambing in January-February or after weaning in March, or were kept isolated from the males until mating in April. Time of mating in the latter animals was determined by measuring the intra-vaginal electrical impedance. Hormone treatment for oestrus induction was given after weaning to a portion of the control and experimental ewes. The ovarian activity of the animals was determined by examining their plasma progesterone changes.Daily teasing of the ewes from lambing to weaning and/or treatment with artificially decreasing daylength did not influence the ovarian activity during this period. All the ewes which were examined for ovulation, from both the control and experimental groups, ovulated 40–60 days after lambing, and 96% of the animals of the two groups which were not treated with hormones for oestrus induction exhibited spontaneous oestrus in March–May.The lambing–first ovulation and the lambing–first spontaneous oestrus intervals were longer in the light-treated than in the control ewes, and in the animals kept isolated from the rams until mating than in those exposed to the males after lambing or weaning.A conception rate of 70–100% and a high rate of cycle activity were obtained during the two consecutive years of the experiment in both control and experimental animals, treated or not with hormones and exposed or not to rams. In view of these results, no conclusions could be drawn about the effectiveness of the artificial photoperiod, ram effect and hormone treatment, alone or in combination, in inducing cycling activity and to increase the fertility of Finn-cross ewes during the seasonal anoestrus in Israel.
Some effects of rate of application of nitrogenous fertilizer to wheat grown continuously compared with wheat in a four-course rotation
Authors: Ridgman W. J. , Walters D. E. , Wedgwood R. B. , Müller-Wilmes U. 
Published: March 2009

SUMMARYAn experiment comparing continuous winter wheat with the two wheat crops in a rotation of beans, oats, wheat, wheat, with four rates of application of N fertilizer, is described and the results discussed.The wheat following wheat in the rotation consistently outyielded the wheat following oats, but the continuous wheat yielded on average less. Response to N fertilizer was not affected by sequence of cropping and since there was practically no response to the highest increment of N, it is clear that additional N could not have brought the yield of the continuous wheat up to the level of the wheat in rotation.
Effects of restricted water on feed intake, nutrient utilization and nitrogen metabolism in Zebu cattle
Authors: Ikhatua U. J. , Ehoche O. W. , Umoh J. E. 
Published: March 2009

SUMMARYEighteen growing cattle with a mean live weight of 180 kg were used to study the influence of restricted water on feed intake, nutrient utilization and nitrogen metabolism in Zebu cattle in the Sudano–Sahelian ecological zone of Nigeria.Feed intake and water consumption were negatively correlated (r= 0·63). As the amount of water intake was reduced from 15·8 to 11·91/day, the mean feed intake increased from 5·6 to 6·8 kg D.M./day; water to feed ratios decreased from 2·83 to 1·75 and average daily live-weight gain as well as apparent feed utilization efficiency improved significantly from free-choice water to 50% of free-choice water treatments respectively.Apparent digestibility coefficients of almost all the nutrients from the 75 and 50% of free-choice water treatments indicated progressively higher (though not significant) values than those of the free-choice water treatment. Nitrogen metabolism did not indicate any difference in the nitrogen intake in any of the three treatments; however, nitrogen balance and nitrogen retained as a percentage of nitrogen intake were significantly (P< 0·05) higher on the 50% of free-choice water treatment.The survival ability of these Zebu breeds of cattle under water stress during the acute water scarcity of the protracted dry period of the Sudan–Sahelian zone of Nigeria could probably be attributed to increased recycling of nitrogen as well as a reduction in nitrogen loss during the period.