bluuebunny/crossref_metadata_2025_split huggingface dataset:
Volatilization of ammonia from solid and liquid urea surface-applied to perennial ryegrass
Authors: Watson C. J. , Stevens R. J. , Laughlin R. J. , Poland P. 
Published: March 2009

SUMMARYA field experiment compared the effects of urea, surface-applied either as a solid or liquid, at a rate of 100 kg N/ha, on ammonia volatilization from an established perennial ryegrass sward on three separate occasions during 1990 at the Agricultural Research Institute, Hillsborough, Northern Ireland. Total NH3 loss over 10 days from prilled urea for each of the three study periods was equivalent to 3.4, 9.1 and 4.4% of N applied. On two occasions, applying urea as a liquid significantly increased NH3 loss compared to prills, whereas on the third occasion there was no significant effect. Increasing the spray volume from 80 to 640 ml/m2 had no significant effect on NH3 volatilization.Surface application of urea as a liquid compared to the prilled form did not lower NH3 volatilization and therefore is not a strategy that would improve the efficiency of urea as a nitrogen source for temperate grassland.
Intake and digestion in swamp buffaloes and cattle. 1. The digestion of rice straw (Oryza sativa)
Authors: Kennedy P. M. , McSweeney C. S. , Ffoulkes D. , John A. , Schlink A. C. , LeFeuvre R. P. , Kerr J. D. 
Published: March 2009

SUMMARYFour swamp buffaloes (Bubalus bubalis) and four crossbredBos indicusxB. tauruscattle, fistulated at the rumen and abomasum or duodenum, were offered rice straw with mineral supplements in two experiments. In Expt 1, the straw was supplemented with 5% of leaf ofLeucaena leucocephala, and in Expt 2 with either urea or urea with sunflower meal and rice grain. Intake of supplements of urea or urea/sunflower/rice respectively was 935 and 681 g/kg offered in buffaloes and 566 and 789 in cattle.Buffaloes ruminated longer than cattle (Expt 1, 635v. 452 min/day; Expt 2, 626v. 466 min/day,P< 0·01). In Expt 1, voluntary intake and frequency of ‘A’ sequence forestomach contractions of both species was not affected by species, but buffaloes had a greater (P< 0·05) contraction force in the rumen and omasum, lower rate of ‘B’ sequence rumen contractions, and faster (P< 0·001) rate of gastrointestinal passage than cattle. In Expt 2, voluntary intake of both species was similar, and addition of concentrates did not affect voluntary roughage consumption, norin siturate of digestion of rice straw. Rate and predicted extent of digestion of dietary materials did not differ between species in Expt 1, despite lower concentrations of ammonia in rumen fluid in cattle than buffaloes; however in Expt 2, the rate of digestion of rice straw was higher (p< 0·05) and predicted extent of digestion was 14–20% (P< 0·05) lower in buffaloes. Digestibility of cell wall constituents was lower (P< 0·05) in buffaloes than in cattle in both experiments, but in Expt 2, provision of concentrates reduced (P< 0·01) the proportion of digestible cell wall constituents digested in the forestomach of buffaloes, but not of cattle.
Intake and digestion in swamp buffaloes and cattle. 2. The comparative response to urea supplements in animals fed tropical grasses
Authors: Kennedy P. M. , Boniface A. N. , Liang Z. J. , Muller D. , Murray R. M. 
Published: March 2009

SUMMARYSwamp buffaloes (Bubalus bubalis) and crossbred cattle (B. indicusxB. taurus) were offered two forages in two experiments. In Expt 1, four animals of each species were offered mature Rhodes grass hay (Chloris gayana) with a mineral supplement or with a supplement of minerals and urea (17·6 gN/d). In Expt 2, another group of four buffaloes and four cattle were offered mature spear grass hay(Heteropogon contortus) with mineral supplementation at intervals of 3 h. Four levels of urea (0, 5, 21 and 97 g/day) and35S-sulphate were continuously infused in four periods.Rhodes grass was consumed in greater amounts by cattle, whereas buffaloes ate more spear grass. Urea supplements increased intake of Rhodes grass by 12% in buffaloes and 22% in cattle, and of spear grass by 34% in buffaloes and 41 % in cattle. Digestibility of cell wall constituents and acid-detergent fibre of spear grass was lower (P< 0·05) in buffaloes than in cattle (417v. 499; 471v. 560 g/kg respectively). In Expt 2, dry matter digestibility progressively increased (P< 0·05) from 364 to 408 g/kg with increased urea infusion. Rumen dry matter pool increased by 11–21 % on infusion of 97 g urea/day, compared with no urea. Digestion of ground forages incubatedin situin the rumen was depressed below rumen ammonia levels of 30–60 mg N/l, while digestion of cotton thread was depressed below 60–80 mg N/l (Expt 1) or 150–200 mg N/l (Expt 2).Patterns of N content in cotton thread suggested that more microbes attached in buffaloes and there was subsequently faster detachment than in cattle, particularly with increased urea infusion.
Casting of the fleece in sheep. Estimation of experimentally induced fibre shedding rate
Authors: Doney J. M. , Smith W. F. 
Published: March 2009

SUMMARYA simple and rapid technique for estimating changes in fibre brush-end formation rate is described. The technique was used to give a quantitative estimate of the extent of brush-end formation induced by exogenous hormonal treatment of normal sheep and to establish the time relationship between treatment, fibre brush-end formation and the subsequent casting of the fleece.
Efficiency of water use by irrigated wheat in the Sudan
Authors: El Nadi A. H. 
Published: March 2009

SUMMARYField experiments were conducted to study the differential responses of a wheat crop to water stress during different stages of its growth. Evidence was produced to show that both the flowering phase and the stage of grain filling and maturation were more sensitive to drought than the vegetative period of growth. Yield of wheat was not reduced when the crop suffered from cycles of water stress induced during the vegetative period, if the crop received favourable water regimes thereafter. Efficiency of water utilization from different water treatments was assessed. There was no relation between the protein and starch contents of the grain and the type of water treatment.The effects of different water treatments on crop development and on components of yield were studied.
The artificial rearing of calves and their growth on grass diets: I. The effect of type and temperature of milk substitute given ad libitum
Authors: Tayler J. C. , Lonsdale C. R. 
Published: March 2009

SUMMARYTwo experiments were carried out to study the effect of the ad libitum feeding of whole-milk substitutes, either warm or cold, and the availability of drinking water, on the level of food intake and live-weight gain of calves. Freshly cut grass or pasture was the sole source of solid feed.In Exp. 1 forty Hereford x Friesian male calves were reared individually indoors in a 2x2x2 factorial design experiment. The treatments were full-cream milk powder υ milk substitute, temperature at which the milk was offered, and drinking water υ no drinking water available to the calves. Fresh grass was cut daily and fed ad libitum to all animals from the sixth day of treatment.In Exp. 2, twelve Hereford x Friesian male calves were reared at pasture on warm or cold full-cream milk during weeks 1–7, and on milk substitute during weeks 8–15.During both experiments calves receiving warm milk drank slightly more than calves receiving cold milk; this difference was significant in Exp. 1 only. There was a tendency for calves receiving cold milk to make higher live-weight gains (0·05 < P < 0·1) when drinking water was available than when it was not. In Exp. 1, the rates of live-weight gain of calves receiving warm or cold milk substitute with drinking water available were 0·99 and 0·89 kg/head/day, respectively: for calves receiving full-cream milk powder the corresponding rates were 0·86 and 0·80 kg/head/day. When drinking water was not available the rates of gain of calves on warm or cold milk substitute were respectively 0·93 and 0·82 kg/head/day, and on full-cream milk powder, 0·94 and 0·55 kg/head/day.In Exp. 2 the rate of live-weight gain measured during the first 7 weeks, whilst calves were receiving full-cream milk powder, was 0·88 kg/head/day irrespective of the temperature at which the milk was given. During weeks 8–14 milk substitute was given, which resulted in rates of live-weight gain of 1·05 kg/head/day for calves receiving warm milk and 0–92 kg/head/day for calves receiving cold.The rates of gain attained on cold milk are considered adequate for rearing calves intended for an intensive system of production. It is also suggested that the use of cold milk could facilitate a marked decrease in the daily labour requirements associated with the artificial rearing of calves.
Aqueous ammonia compared with other nitrogenous fertilizers as solids and solutions on grass
Authors: Hodgson D. R. , Draycott A. P. 
Published: March 2009

SUMMARYField experiments with Italian ryegrass cut four times a year compared aqueous ammonia with ammonium sulphate and with a mixture of ammonium nitrate and urea (equal parts by weight). In 1963 four rates of nitrogen, 224, 448, 672 and 896 lb/acre, were applied as single and split dressings of injected aqueous ammonia, as solid ammonium sulphate and as injected solution of ammonium sulphate. There was little difference in total dry-matter yield between a single injection of aqueous ammonia and the split dressing of solid. Injecting ammonium sulphate solution eliminated scorch caused by single applications of solid supplying 448 lb N/acre or more and gave significantly greater dry-matter yields. A single application of 448 lb N/acre provided enough nitrogen to sustain the response of the grass to the end of the season.In 1964 a single injection of aqueous ammonia was compared with ammonium nitrate/urea applied as solid or solution at 280, 560 and 840 lb N/acre. There was no difference in total dry-matter yield between aqueous ammonia and ammonium nitrate/urea at rates of 560 and 840 lb/acre. At 280 lb/acre a split dressing of solid produced most dry matter. More than 280 lb N/acre was required, therefore, as a single application in spring to last the whole season, but this rate of nitrogen applied as a split dressing was almost sufficient to give maximum yield.In both experiments the seasonal distribution of dry matter was similar for single and split applications except in 1963 when large single injections of ammonium sulphate produced greater yields at the third cut than the split applications. The percentage of nitrogen recovered in the harvested grass decreased as nitrogen rate was increased and was greater from single than split applications. Recovery of nitrogen from aqueous ammonia was less efficient from four injections than one, and was greater in 1964 than 1963 due to better penetration of the sward by injector tines. Least nitrogen was recovered from surface-applied solutions of ammonium nitrate/urea. Regressions of dry-matter yield on nitrogen yield showed that single injections of aqueous ammonia were as efficient as other fertilizers tested.
Diallel analysis of competition between grass species
Authors: Norrington-Davies J. 
Published: March 2009

SUMMARYTimothy [S. 50], meadow fescue [S. 53], perennial ryegrass [S. 23], Italian ryegrass [S. 22] and cocksfoot [S. 143] were grown together in all possible pair combinations at two levels of fertility, in a pot experiment. Dry weight of herbage and tiller counts were determined at 136 and 198 days from sowing. The data were analysed for competitive effects by the application of the diallel analysis technique of Durrant (1965). The competitive effects were largely compensatory in type with dominant species such as Italian ryegrass and perennial ryegrass increasing in mixtures, relative to their pure stand values, more than species such as timothy and meadow fescue declined. This resulted in a tendency for the mixture means to exceed their mid-constituent values.The competitive effects on the reciprocal differences were seen to be predominantly of the alpha type; that is, there was a constant increase or decrease in one or more species when grown with others. The alpha values were found to be correlated with the unmixed species values so that ƀ, the mean effect, wasappropriately calculated from alpha. The over-all value of ƀ was –1.216, which means that for each gram difference in weight between the species when grown by themselves there was 2.452 g increase in difference between the species when grown in mixtures, the larger species increasing and/or the smaller species decreasing. There were significant differences in ƀ values between harvests, the ƀ competitive effects being approximately twice as large in the more mature plants. Although the alpha competitive effects increased in magnitude with time the species order remained relatively constant, and in terms of competitive ability the species could be placed in the ascending order, meadow fescue, timothy, cocksfoot, perennial ryegrass and Italian ryegrass.Tiller number showed a similar pattern, but the ƀ values were smaller, and not significant. Nevertheless competition had differential effects upon the plant weight/ tillering relationship and it is possible that the resultant morphological changes would influence the re-growth quality of the species.The conclusions derived from the analysis of reciprocal differences in this work is compared with earlier examples.
The assessment of herbage legume varieties: III. Annual variation in chemical composition of eight varieties
Authors: Davies W. Ellis , Thomas T. A. , Young Norman R. 
Published: March 2009

SUMMARYThe primary growth of eight varieties from three species—white clover (3), red clover (4) and lucerne (1)—was sampled at fortnightly intervals during 2 years and the percentage N, P, K, Ca, Mg, Na and in vitro dry-matter digestibility (IVD) were determined.Differences between species, date of sampling and years were highly significant for all constituents. Clover was significantly different from lucerne for all constituents except P, and white from red clover with the exception of Ca. There was a steady decrease in N, P, K, Na and IVD with advance of date of cutting but no marked trend in Ca and Mg. Some constituents changed considerably from first to second year, decreasingin the case of Ca, and increasing for N, P andNa; the remainder K, Mg, and IVD changed only 4–8%.The varieties did not give the same relative results in the 2 years for P, K and Ca content, but there was no interaction for N, Na, Mg, IVD content. Species differences accounted for mostof these interactions.Percentage composition is discussed in relation to the needs of cattle and it is concluded that these herbage legumes provided sufficient Ca, Mg, N, K, and Na (white clover, and the firsttwo cuts of S. 123 red clover and lucerne only) for milk production and growth. The level of P fell below the quoted needs of a 20 kg/day milking cow but was adequate for growth.
The effects on winter wheat of ammonium sulphate, with and without a nitrification inhibitor, and of calcium nitrate
Authors: Gasser J. K. R. , Hamlyn F. G. 
Published: March 2009

SUMMARYWinter wheat grown on a sandy-loam and on a clay-loam soil was given ammonium sulphate alone or treated with the nitrification inhibitor, 2-chloro-6-(trichloromethyl)- pyridine, drilled with seed, in autumn. In spring, dressings of treated or untreated ammonium sulphate or of calcium nitrate, were broadcast. 75 or 150 lb N/acre were given on the sandy loam and 50 or 100 lb on the clay loam. Plants were sampled during growth and grain yield was measured.Without fertilizer-N, the wheat yielded 17 cwt/acre on the sandy-loam and 46 cwt on the clay, and with the double dressings given in spring yields were 52 and 56 cwt/ acre. On the light soil, treated ammonium sulphate given in autumn increased yield by 3–5 cwt/acre with the single dressing and by 5–4 cwt/acre with the double one.On the heavy soil the inhibitor had no effect on yield. Dressings of 50 lb N/acre in autumn or spring increased yields equally, but with 100 lb N/acre the spring dressing increased yield slightly more than autumn dressings. Calcium nitrate at 75 lb N/acre was significantly better than ammonium sulphate on the light soil.The inhibitor did not affect the speed with which N was taken up, or the total uptake, from fertilizer given in spring.
The relationship between yield and digestibility in spring varieties of barley, oats and wheat after ear emergence
Authors: Cannell R. Q. , Jobson H. T. 
Published: March 2009

SUMMARYThe pattern of dry matter (D.M.) yield, digestibility and nitrogen (N) content of two contrasted grain:straw (G/S) ratio varieties each of barley, oats and wheat grown at three levels of nitrogen was measured over the 30 days after ear emergence, D.M. yield rose with time, while digestibilityand N content declined. Although the D.M. yield was highest in the oat variety, Maelor, one barley variety, Deba Abed, had the highest digestibility and a similar yield of digestible dry matter. Wheat was lowest yielding. The low G/S varieties of wheat and oats had higher yields of digestible D.M., but the high G/S variety, Deba Abed, was the higher yielding barley. Yield of digestible D.M. increased with increasing N fertilizer, due to the increased D.M. yield.
Growth of broilers on diets containing field beans (Vicia faba L.)
Authors: Blair R. , Bolton W. 
Published: March 2009

SUMMARYDuring the 4· to 9·week stage Ross Chunky H broilers were fed on diets containing two varieties of field beans at 0, 10, 20 and 30 % rates of inclusion. No significant treatment effects were observed on live-weight gains, amounts of food eaten or food-conversion ratios.
Potassium reserves in British soils: II. Soils from different parent materials
Authors: Talibudeen O. , Dey S. K. 
Published: March 2009

SUMMARYTwenty-six soils from different parent materials were exhaustively cropped with ryegrass in the glasshouse. Soil and crop measurements revealed inter-relationships similar to those observed with Rothamsted soils (Part I) generally, except that 12 of 20 soils, ‘poor’ in K (as defined by the K intensity of the uncropped soil and the change in soil K intensity with cropping), gave patterns of K uptake by the ryegrass crop similar to those of soils ‘rich’ in K. This indicates that these soils contain some K reserves not differentiated from those accumulated by K-manuring in Rothamsted by laboratory measurements.The cumulative K yield of ryegrass was very significantly related to the K intensity of the uncropped soil. The relationships were improved slightly by allowing for differences in soil pH and organic carbon content. The cumulative K yields at 16 weeks and at 60 weeks were better related to the total clay (<2 µ) content than to the fine clay (< 0·2 µ) content of the soil. The K intensities of the cropped soils decreased to nearly 10–3 (AR) units after 16 weeks cropping (except the Harwell soil which took 3 years to do so), although large differences in K yield persisted until much later.Potassium-buffer capacity per unit clay content of the soil (by a laboratory method) was inversely related to the K intensity of the uncropped soil and to K uptakes at 16 and 60 weeks. The rea⋅ons for this apparent anomaly are discussed and a more correct basis for the units for K-buffering capacity is suggested. The buffer capacities of ‘rich’ soils in the laboratory and glasshouse experiments were significantly related but not of ‘ poor ’ soils.Soils exhausted by cropping released more K to ryegrass after a. drying-and-wetting cycle in amounts proportional to the clay content of the soil. This points to the need for caution in measurements to assess status after air-drying soils.
Studies on the production of beef from zebu cattle in East Africa IV. Variation in blood haemoglobin and its response to the feeding of dicalcium phosphate
Authors: Lampkin K. , Howard D. A. 
Published: March 2009

Lactating Boran type zebu cows had high haemoglobin levels during the week after calving, after which these levels dropped sharply and then continued to decline more gradually until their calves were weaned. Some recovery was made during the subsequent dry period.Cows fed 1 oz. dicalcium phosphate daily were constantly lower in blood haemoglobin level than their controls, and significantly so between the 14th and 20th weeks of the lactation. No differences were observed in weekly weight changes or in estimated milk yields.Calf haemoglobins decreased gradually with age until relatively adult levels were reached at about a year of age. Initial content during the week of birth was lower than at a few weeks old. There was no difference in the blood haemoglobins of calves suckling on treated and untreated cows.Individual variation was high in all groups. Some implications of seasonal effects and altitude are discussed.
Mineral nitrogen in tropical forest soils
Authors: Cunningham R. K. 
Published: March 2009

1. Δmin-Nad is the most satisfactory measurement for assessing mineralizable-N in the tropical forest soils used; values are treble those for Δmin-Nf and then increase even further on storage. Comparisons of Δmin-Nad are pointless unless methods of sampling, drying, storing and incubating are standardized.2. Δmin-Nad is correlated with total N and organic C but not pH.3. Undisturbed tropical forest soils can produce very large quantities of mineral N, particularly in their surface layers. This probably accounts for the lack of N responses in these soils. More intensive cultivation of these soils is only possible when organic matter is preserved by protecting cleared soils.4. Added nitrogen was leached more rapidly in these soils than in comparable temperate soils but was not fast enough to prevent absorption by plants.
Measuring soluble phosphorus in soils, comparisons of methods, and interpretation of results
Authors: Williams R. J. B. , Cooke G. W. 
Published: March 2009

Soil samples from 179 field experiments testing phosphate fertilizers on potatoes, swedes and grass were analysed for total phosphorus, and for phosphorus soluble in the following solutions: 0·3 N-HCl, 0·002 N-H2SO4, 1% citric acid (H3Ci), 0·5 N acetic acid (HAc), acetic acid-sodium acetate buffer (HAc-NaAc) at pH 4·8, 0·5 M-NaHCO3, and 0·01 M CaCl2.Average values for soluble P were closely related to average crop responses to superphosphate in the experiments on swedes, but not in the grass and potato experiments. The extractants that differentiated best between responsive and unresponsive groups of experiments were HAc, HAc-NaAc, and NaHCO3 for potatoes, and HCl, H2S04, HAc–NaAc, NaHCO3 and CaCl2 for grass.For the experiments as a whole 0·5 M-NaHCO3 was the ‘best’ extractant. The HCl, H2SO4, and HAc-NaAc buffer solution methods were roughly equally effective, though inferior to NaHCO3; the other three extractants (HAc, H3Ci, CaCl2) were of little general use. Total P in soil was also related to response to superphosphate, though less well than values for soluble P obtained by the better methods.Estimates of soluble P by different solvents were often related. Estimates by HCl and H2SO4 methods were most closely related; values for P soluble in H2SO4 and in HAc-NaAc were also often significantly correlated, as were estimates by HAc–NaAc and CaCl2. The H3Ci and CaCl2 methods gave results that were least related to those with other methods.The use of soil analyses in advising on P-manuring is discussed and a tentative method is proposed of establishing the analytical limits for soluble P that define ‘deficient’ soils. If the confidence attached to the limiting values that separate ‘deficient’ and ‘non-deficient’ soils is stated, farmers will be able to assess the risk entailed in accepting advice based on soil analysis.