bluuebunny/crossref_metadata_2025_split huggingface dataset:
The evaluation of potassium metaphosphate as a source of potassium for potatoes with special references to foliar diagnosis, yield and quality of tubers
Authors: Lachover D. , Feldhay Helena 
Published: March 2009

1. The availability of K in potassium metaphosphate was investigated in an experiment with large pots using a red sandy soil, low in exchangeable potassium. Potatoes were grown. The effects of potassium metaphosphate in three different granule sizes, applied at two rates, were compared with those of equivalent potassium chloride and potassium sulphate.2. Characteristic deficiency symptoms appeared in plants receiving no K and the crop responded to K fertilizer in potassium concentration, yields of tubers, and dry matter, and starch concentrations.3. Potassium metaphosphate, regardless of granule size and of application rate, was as effective as potassium chloride and potassium sulphate in giving normal development of potato plants, high potassium uptake in the foliage, and yield of tubers.
Differentiation of the effects of protein status and acid-base balance on the appetite of sheep for lucerne silage
Authors: Phillip L. E. , Simpson M. V. 
Published: March 2009

SUMMARYFive cross-bred Suffolk lambs (liveweight 24–29 kg) were fed lucerne silage and made acidotic or offered supplemental protein with the objective of determining the effects of acidosis and amino acid undersupply on food intake from silage. In this study, at McGill University, Quebec, Canada in January 1989, lucerne silage (25% DM) was supplemented with equimolar amounts (450 mmol/kg DM) of ammonium chloride, ammonium bicarbonate and sodium bicarbonate; fishmeal was added at 100 g/kg silage DM. The lambs were fedad libitumaccording to a 5 × 5 Latin square with 21-day periods.Digestibility of organic matter (OM) from silage ranged from 78 to 82% and was not significantly affected by diet (P> 0·05). Voluntary intake of digestible organic matter (DOM) from silage was. Fishmeal supplementation of lucerne silage improved nitrogen retention (P> 0·05) but not intake of DOM. The addition of ammonium chloride to silage reduced blood concentration (p< 0·05) and urinary output of HCO3, increased ammonia excretion in urine (P< 0·05), and depressed intake of DOM (P< 0·05). Ammonium bicarbonate also reduced voluntary intake of DOM (P< 0·05) but had no significant effect (P> 0·05) on the acid-base status of the lambs. Sodium bicarbonate depressed food intake but had no significant effect on measures of acid-base balance.The results suggest that metabolic acidosis is not an underlying mechanism restricting food intake by sheep and that neither acid-base imbalance nor inadequate protein status is likely to explain the limitation in food intake from ensiled lucerne.
Studies on ewe's milk:V. The effect of high cereal diets on ewes and on the yield of milk and milk constituents
Authors: Poulton S. G. , Ashton W. M. 
Published: March 2009

SUMMARYMilk yields determined by a lamb-suckling and an oxytocin technique were compared using a control group of four ewes. Both methods showed a similar linear decrease in yield with advancing lactation, but the oxytocin method gave 23% more milk presumably because residual milk was included.When the diet of lactating ewes was changed so that the amounts of hay and commercial concentrates were reduced in favour of flaked maize, such severe acidosis developed when 39·5% of this food was introduced abruptly or 53% more gradually over one week, that the trials were discontinued.Rolled barley, which probably ferments more slowly, was therefore used instead of flaked maize. Levels up to 62·9%, gradually introduced over a period of 3 weeks, also produced acidosis whose severity varied greatly in individual ewes.Milk yield was also determined by the oxytocin technique for ewes receiving normal diets followed by those rich in rolled barley, and the milk was analysed for fat, protein and lactose. The composition of the milk was extremely variable during rolled barley feeding, but there was an indication of an increase in the percentage of crude protein and also fat, after a marked fall in the latter in the milk of two ewes with the change to the low-fibre diet.Diet had little effect on yields of milk and its components but, on the rolled barley diets, the rate of decrease of these yields was arrested (or even reversed in the case of fat), with a high degree of significance (milk yieldP< 0·05, fat yieldP <0·01, protein yieldP< 0·01). These observations are discussed, in the light of knowledge on the effect of diet on molar proportions of volatile fatty acids in the rumen.
The effect of plant population and irrigation on sugar beet
Authors: Harris P. M. 
Published: March 2009

SUMMARYFour experiments are described in which the response of sugar beet to irrigation was measured over a range of approximately 30000–150000 plants per hectare, and one experiment where the effects of plant population and spatial arrangement were studied. The experiments were carried out on a sandy soil in the south-east of England and extended from 1960 to 1965. The response of sugar beet to irrigation was affected by plant density. It is suggested that some explanation for the modified responses may be provided by considering effects of plant population on (i) the rate at which the soil surface is covered by leaves, and (ii) effects on the volume of soil exploited for water.
The residual effect of phosphate and potash fertilizers applied to cut or grazed grassland
Authors: Brockman J. S. , Shaw P. G. , Wolton K. M. 
Published: March 2009

SUMMARYP and K fertilizers were applied over a 5-year period to plots that were either cut, individually grazed or communally grazed. Residual effects were assessed in the sixth year when the sward was ploughed and sown with Italian ryegrass. The residual study supported the earlier published inference that (a) P returned to the sward in sheep dung is not an effective P source under field conditions, (b) communal grazing can lead to appreciable transfer of K from one plot to another.
The transport of potassium to ryegrass roots in soils with and without added potassium
Authors: Addiscott T. M. , Talibudeen O. 
Published: March 2009

SUMMARYThe mechanisms responsible for moving K from soil to root were studied by growing perennial ryegrass in pots containing a flinty silt loam from Rothamsted and a sandy Woburn soil, with and without added K, at 0.75 water-holding capacity. More water was taken up from the Rothamsted soil than from the Woburn soil, and less was taken up when K was added without affecting dry-matter production. After 25, 52, 83, 122, 194 and 276 days, K uptake, water uptake and the K concentration in the soil solution were measured and the mass-flow contributionto K uptake calculated.Without added K, mass-flow accounted for only about one-sixth of the K taken up from the Rothamsted soil and about one-third from the Woburn soil. Except at first, diffusion probably accounted for the remainder of uptake but was the rate-controlling step for uptake from the Woburn soil only. With added K, mass-flow became much more important relative to diffusion in both soils, and transported more than enough K to account for the measured K uptake. Root interception probably did not contribute to K uptake after the early part of the experiment, because the pots used were small.
Polysaccharide synthesis and degradation by rumen micro-organismsin vitro
Authors: Thompson J. K. , Hobson P. N. 
Published: March 2009

SUMMARYMicro-organisms from the rumen of a hay-fed sheep rapidly synthesized an intracellular polysaccharide (starch) when growing or resting suspensions of cells were incubatedin vitrowith easily metabolized sugars.In 30 min incubation periods the optimum pH for the synthesis of starch by resting cultures was about 6·0 when glucose or fructose were substrates. Relative to glucose (as 100%) in ability to form the polysaccharide were, fructose, 75%; sucrose, 80%; soluble starch, 18·6%; maltose, 6·9%; cellobiose, 4%; and xylose, 2·1%. No starch was formed from galacturonic, acetic, propionic, butyric, lactic or succinic acids. A bacterial fraction of the microbes was reponsible for about 80% of the starch formed from glucose, fructose or sucrose.In incubations of 24 h, resting cultures formed more starch per unit of microbial protein than growing cultures. The utilization of microbial starch and lactic acid, formation of which often accompanied starch synthesis, gave rise to volatile fatty acids. Acid production was maintained from these substrates at rates similar to those obtained from the fermentation of glucose. The acids were in molar proportions of 65–70% acetic, 20–27% propionic and 8–15% butyric. The maximum starch calculated to be synthesized by the microbes from 100 ml of rumen liquor, in media containing excess sugar, amounted to over 250 mg from glucose, 200 mg from fructose, 200 mg from cellobiose and 50 mg from xylose. It is calculated that under optimum conditions for synthesis about 25 g of starch would pass daily from the rumen of a sheep.
The development of some digestive enzymes in the intestines of pigs reared artificially
Authors: Campbell Rosa M. , Brough Helen , Fell B. F. 
Published: March 2009

SUMMARYA comparison was made of the development of acid and alkaline phosphatase, invertase, lactase and leucine aminopeptidase specific activities in the small intestines of two groups of neonatal pigs. The groups consisted of two litters of suckling pigs and two litters of pigs that were delivered by hysterectomy and reared in incubators on a diet based on cow's milk. In the unsuckled pigs there was retardation of the development of invertase and leucine aminopeptidase. The unsuckled animals grew slowly and were affected by diarrhoea, and it is possible that enteric disease may have affected the development of the brush border of the intestinal epithelial cells, or enzymes specifically associated with the microvilli.
Potassium in soils under different cropping systems:2. The effects of cropping systems on the retention by the soils of added K not used by crops
Authors: Addiscott T. M. , Johnston A. E. 
Published: March 2009

SUMMARYThe K balance, the difference between K added as fertilizer or farmyard manure (FYM) and K removed by the crops, was calculated for soils from the Classical and Ley-Arable experiments at Rothamsted and for the Woburn Ley-Arable experiment, for the duration of each experiment. Linear regressions on K balance accounted for 78% of the variation in exchangeable K (Ke) and for 83% in K uptake by ryegrass (KP) in the Classical experiments, for 56 and60% respectively in the Ley-Arable experiments at Rothamsted, and for 39 and 6% in the Woburn Ley-Arable experiment.Regressions of Ke and Kp on K balance suggested that, in the Rothamsted Ley-Arable experiments, rather more than half of the K balance remained extractable by ryegrass from the plots with a rotation of crops, and apparently all of the K balance from those under continuous grass. About one-fifth of the K balance remained extractable by ryegrass from the soils in the Rothamsted Classical experiments and soils given FYM retained K slightly better than other soils. With all soils about half the K extractable by ryegrass was exchangeable to ammonium acetate.The plots with FYM or under continuous grass contain more organic matter than other plots in the same experiments. The following possible effects of increasing the organic matter content of the soils were investigated by calculating the multiple regressions of K, and KB on K balance with either percentage of organic C, total CEC, or organic CEC:(1) loss of K decreased by increasing the water retention and lessening leaching;(2) improved K retention by increasing the total cation exchange capacity (CEC) available for K absorption;(3) improved K retention by a mechanism arising from the different selectivities of clay and organic matter for K relative to Ca.In the Classical experiments, where organic matter usually increases because of FYM additions, effect (2) seems the most probable, perhaps because the K given in the FYM was already absorbed by organic exchange sites. In the Ley–Arable experiments, where the K was given mainly as soluble K fertilizer and the organic matter develops mainly under grass, effects (1) or (3) seemed to operate, probably simultaneously.The Woburn Ley-Arable experiment had no continuous grass plots, the soils differed little in organic matter content and no deductions could be made.
Field drainage experiments and design on former opencast coal mining land
Authors: Scullion J. , Mohammed A. R. A. 
Published: March 2009

SUMMARYA series of drainage trials was set up to investigate various aspects of drainage design on former opencast coal mining land. The drainage problem was characterized. Subsoiling, subsoiling direction with respect to slope and drain spacing were assessed as factors affecting drainage performance. The persistence of subsoiling effectiveness was also monitored. Drainage performances were evaluated statistically (Scullion, Mohammed & Ramshaw, 1986).Surface wetness was the predominant feature of drainage conditions on opencast land and the effectiveness of drainage treatments was limited to the control of this superficial water. Secondary drainage, in this case subsoiling, was found to be an essential feature of field drainage, reducing surface wetness and runoff. The effectiveness of subsoiling was dependent on there being sufficient gradient (4–5%) along channels for intercepted water to clear. For this reason, adoption of appropriate minimum reinstatement gradients and the arrangement of field drains to accommodate preferred directions of secondary treatments would assist drainage effectiveness.There was a gradual deterioration in drainage performance as spacing increased. Spacings in the range 20–30 m appeared to offer a reasonable compromise between cost and benefit. The persistence of subsoiling treatments, which deteriorated markedly after 2–4 years, was not affected by drain spacing. Performance at the widest spacings tested was, however, generally poor regardless of time since subsoiling.A basis for calculating design rates on individual sites and the implications for drainage theory of soil air-water interactions are briefly considered.
The effects of energy intake during pregnancy in doe rabbits on pup birth weight, milk output and maternal body composition change in the ensuing lactation
Authors: Partridge G. G. , Daniels Y. , Fordyce R. A. 
Published: March 2009

SUMMARYA study was made in rabbits on the effects of energy intake during pregnanoy on pup birth weight and survival, and on doe body composition and milk output in the ensuing lactation. In addition the experiment examined the effects of varying crudeprotein intakes during lactation on the rate of fat loss of does and the resultant energetic efficiency of milk production.Forty-seven multiparous cross-bred does were used. They were offered one of two diets in pregnancy, either diet HE (14·8 MJ digestible energy (DE)/kg D.M.) to appetite or diet LE (12·9 MJ DE/kg D.M.) at maintenance levels. After parturition seven does on each treatment were slaughtered and their body composition analysed (control groups). In lactation the remaining does were evenly allocated to receive either diet LE (195 g crude protein (CP)/kg D.M.) or diet HP (240 g CP/kg D.M.) to appetite. Litter sizes were standardized to six pups and litter growth rates were used as an indirect estimate of milk production. Does were then killed, at random, on day 9 or day 18 of lactation to give an estimate of changes in body composition as lactation progressed.Does offered diet HE during pregnancy had higher carcass fat levels at parturition than their counterparts offered diet LE (496 cf. 370 g/kg carcass D.M. respectively). Litter size was unaffected by dietary treatment during pregnancy but litter weights at birth were significantly greater in HE does (442 cf. 398 g respectively). Pup mortality at birth, however, was also much higher in these animals (28 cf. 9% respectively). Voluntary food intake in early lactation (day 1—9) was depressed by feeding diet HE during pregnanoy. Milk composition was affected by pregnancy diet, with does offered diet HE producing milk containing significantly higher fat levels (HE 123 g fat/kg milk cf. LE 105 g fat/kg milk).Doe carcass composition changes revealed that fat was usually mobilized in early lactation and gained as lactation progressed independent of dietary treatment. The protein content of the fat-free dry matter appeared to be relatively unaffected by the dietary treatments imposed. The data were used to derive an estimate of the partial efficiency of dietary energy utilization (fc) for milk output and maternal tissue gain. The line of best fit was described by the equation ER = 0·65 (±0·17) MEI-1–25, where ER = milk energy output + carcass energy change and MEI = metabolizable energy intake in MJ.
Temperature-induced changes in cold tolerance of Lolium perenne
Authors: Eagles C. F. 
Published: March 2009

SUMMARYResponses of cultivars of Lolium perenne with contrasting winter hardiness to hardening and dehardening at different temperatures were studied in controlled-environment experiments in 1984/85. After hardening at 2 °C, the hardy cultivars Premo and S23 had faster initial rates of change of LT50 (lethal temperature at which 50% of plants were killed), measured on seedlings in an artificial freezing test, and achieved a greater degree of cold tolerance than the susceptible cultivar Grasslands Ruanui. When acclimated at higher temperatures (4–10 °C), the hardier cultivars were better able to develop increased cold tolerance than Grasslands Ruanui. Plants of Premo and S23, previously hardened at 2 °C, maintained their cold tolerance when transferred to warmer temperatures (4–12 °C) better than Grasslands Ruanui, which dehardened even at 4 °C.The responses of the cultivars to hardening and dehardening temperatures under controlled-environment conditions were reflected in seasonal changes in hardiness, measured as cold tolerance of tillers sampled during fluctuating temperatures of a typical maritime winter (1977/78) at Aberystwyth, UK.
Nutritional availability of amino acids from the rumen anaerobic fungusNeocallimastixsp. LM1 in sheep
Authors: Gulati S. K. , Ashes J. R. , Gordon G. L. R. , Connell P. J. , Rogers P. L. 
Published: March 2009

SUMMARYThe rumen anaerobic fungusNeocallimastixsp. LM1 was specifically labelled in batch culture with either [14C]lysine, [14C]lysine + [3H] tyrosine, [14C] methionine, or [35S] sulphide. Fractionation of acid hydrolysates of fungal biomass on an amino acid analyser showed that the labelled amino acids were directly incorporated into fungal protein with little or no degradation. [35S] Sulphide was incorporated into cysteine and methionine.Absorption of amino acids from the small intestine was measured in sheep with permanent fistulae in the abomasum and terminal ileum, by introducing radiolabelled fungal biomass into the abomasum together with Cr-EDTA as the marker for digesta flow. The proportions of [14C] lysine (Expt 1), [14C] lysine + [3H] tyrosine (Expt 2), [14C] methionine (Expt 3) and the sulphur amino acids from [35S] sulphide (Expt 4) which appeared unabsorbed at the terminal ileum averaged 0·13, 0·07 + 0·08, 0·13 and 0·02, respectively. These proportions reflect the high digestibility of certain essential amino acids and the sulphur amino acids of fungal proteins. The results indicate that the true fractional digestibility of fungal proteins isc. 0·9. Consequently, a large biomass of anaerobic fungi in rumen digesta would be expected to provide a valuable source of digestible amino acids to ruminants.
Determination of optimum tuber planting density for production of tubers in processing ware grades in the potato variety Record
Authors: Wurr D. C. E. , Fellows J. R. , Sutherland R. A. , Allen E. J. 
Published: March 2009

SUMMARYA series of experiments examining the influences of size and spacing of planted potato tubers (‘seed’ tubers) on tuber yields was conducted at four sites in the UK in 1982–84. A new approach to data analysis was used to estimate the optimum tuber planting density for different ware grades. The optimum density, which maximized returns, decreased with increasing seed tuber weight and ratio of seed-tuber cost to ware value and with lower than average total tuber yields. Changing the required ware grade from 40–65 mm to 40–80 mm had a minimal effect on the optimum tuber planting density.Optimum tuber planting densities were lower than in published recommendations but this disparity appeared to be accounted for by differences in the number of stems produced by each planted tuber. There was some evidence that, with lower seed-tuber weights, the optimum planting density differed with site and that at optimum economic densities small and medium seed tubers outyielded large seed tubers.
Effects of the infusion of amino acids into the abomasum of sheep, with emphasis on the relative value of methionine, cysteine and homocysteine for wool growth
Authors: Reis P. J. , Tunks D. A. , Munro S. G. 
Published: March 2009

SUMMARYMerino sheep were given abomasal infusions of various amino acids or mixtures of amino acids. Effects on wool growth were measured using autoradiography or a clipping procedure and changes in the concentration of amino acids in plasma were measured in some experiments.Mixtures of five (28 g/day) or ten (45 g/day) essential amino acids (both mixtures containing 3 g methionine) stimulated wool growth of sheep receiving a maintenance ration; on average, the volume of wool grown increased 48% and 86%, respectively. When cysteine completely replaced methionine in these mixtures, wool growth was markedly reduced, but two-thirds of the methionine could be replaced by cysteine without affecting wool growth. Homocysteine was partially effective in replacing methionine and, when supplemented with betaine, folic acid and vitamin B12, the mixture was still significantly inferior to that containing methionine. In contrast, abomasal supplements of methionine or homocysteine alone were equivalent as supplements for wool growth. The results indicated a specific role for methionine in the control of wool growth, other than the provision of cysteine. This role was postulated to be related to some function of S-adenosylmethionine.Infusion often essential amino acids caused appreciable increases in the concentrations of cystine, methionine, cystathionine and taurine in plasma; total essential amino acids increased threefold whereas nonessential amino acids decreased in concentration. The replacement of methionine in the infusion by cysteine or homocysteine significantly altered the concentration of cystine, methionine and cystathionine in plasma.Evidence was obtained that the adverse effects on wool growth of high abomasal doses of methionine (10g/day) could not be reduced or prevented by provision of additional glycine and were not related to the supposed toxic effects of 3-methylthiopropionic acid, a metabolite of the transamination pathway.