bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation in methane production by sheep fed every two hours
Authors: Mathers J. C. , Walters D. E.
Published: March 2009

Four sheep were maintained on a pelleted diet based on barley straw, sunflower-seed meal and barley which was offered at 2 h intervals by mechanical feeders. In each of two periods approximately 3 weeks apart, methane production was measured continuously for 6 h in each animal. Despite the frequent feeding regime, methane output varied markedly with time increasing after feeding and then declining. Serial correlation analysis indicated a rhythmical variation of period 2 h which was confirmed by Fourier series analysis for all but one data set. The observations suggest that even with frequent feeding, there is considerable deviation from steady state in the rate of carbohydrate fermentation in the rumen.
The effects of cattle slurry and inorganic nitrogen fertilizer on the yield and quality of spring barley
Authors: Pain B. F. , Richardsonf S. J. , Fulford Rosemary J.
Published: March 2009

In experiments over 3 years (1974–6) cow slurry in the range 0–112·5 t/ha and ammonium nitrate in the range 0–120 kg N/ha were applied to field plots factorially to test the effects on the yield and quality of spring barley grain.

In 1974 slurry application markedly improved the grain yield (cv. Golden Promise) at each rate of inorganic N and increased grain size. Applying N fertilizer with more than 37·5 t slurry/ha reduced grain yield below the maximum. Grain with the highest crude protein content (15·1 %) was obtained from a combination of slurry and inorganic N. The residual effects of the slurry treatments gave satisfactory grain yields in 1975 without additional fertilizer.

Grain yields (cvs Julia and Abacus) in other experiments carried out on a different soil type in 1975 and 1976 were approximately half those obtained in 1974, due in part to drought conditions. The pattern of the results was similar. Heaviest grain yields were harvested from plots receiving 70 t slurry/ha with no additional N.
Relationship between bacteria and ciliate protozoa in the rumen of sheep fed on a purified diet
Authors: Kurihara Y. , Takechi T. , Shibata F.
Published: March 2009

Two sheep, with and without ciliate protozoa, were fed on a wood-pulp cellulose, corn starch, soya-bean protein diet and the microbiological and chemical characteristics of the rumen ingesta of both sheep were studied. The purified diet led to a simplified rumen flora enabling some deductions to be made about the interactions of the principal bacterial species and their interactions with the protozoa in relationship to the biochemical analysis of the rumen. Ammonia concentrations were similarly low in each animal. Total volatile fatty acid concentrations were higher in the faunated sheep though the proportion of propionic acid was highest in the unfaunated sheep. Cellulose digestion in the faunated rumen was about twice that in the unfaunated one. Total bacterial concentrations in the unfaunated rumen were over twice those in the faunated rumen, but the numbers of cellulolytic bacteria were higher in the latter while the numbers of amylolytic bacteria were higher in the unfaunated rumen. The principal species of bacteria differed in the two rumens.
Block designs for variety trials
Authors: Patterson H. D. , Williams E. R. , Hunter E. A.
Published: March 2009

In this paper we present a series of resolvable incomplete block designs suitable for variety trials with any number of varieties v in the range 20 ≤v ≤ 100. These designs usefully supplement existing square and rectangular lattices. They are not necessarily optimal in the sense of having smallest possible variances but their efficiencies are known to be high.
A study of gene effects in three wheat crosses
Authors: Singh S. , Singh R. B.
Published: March 2009

The joint scaling test of Cavalli (1952) and the six-parameter procedure of Jinks & Jones (1958) were applied to test the adequacy of the additive-dominance model and to estimate various main and interaction gene effects for five characters, namely, final plant height, ear length, number of spikelets per spike, number of grains per spike and yield per plant, in three wheat crosses (Kalyan Sona × Norteno 67, Norteno 67 × WL 212 and K. Sona × Moti). Goodness of fit of the model varied from cross to cross for the same character except for number of grains per spike and yield per plant for which the model was inadequate for all three crosses. The two methods were in complete agreement regarding the presence of epistasis in the material. Among the interaction parameters, the component [1] showed the greatest effect for most of the characters in all three crosses where there was evidence of epistasis.
A method of assessing cutaneous pigmentation in bovine skin
Authors: Yang S. H.
Published: March 2009

1. Since the pigmentation of the skin cannot be assessed by visual examination of the hair or hide, a simple and convenient method of grading the cutaneous pigmentation of cattle based on the microscopic examination of skin sections has been described.

2. The degree of cutaneous pigmentation of the skin of twenty body regions of three Ayrshire cows, two Ayrshire bull calves, two Sudanese Zebu bulls, one Sudanese Zebu cow and one Jamaican Zebu cow have been assessed by this method.

3. The skin of the Zebu cattle was found to be much more heavily pigmented than that of the Ayrshire cattle.

4. The dorsal and lateral regions of both the Zebu and the Ayrshire cattle were more pigmented than the ventral and leg regions.
Phenotypic and genetic associations between production characters and blood characters in sheep. Erythrocyte potassium levels and haemoglobin types in Peppin Merinos genetically different for clean fleece weight and crimp frequency
Authors: Evans J. V. , Moodie E. W. , Burr E. J. , Roberts J. , McGuirk B. J. , Barlow R.
Published: March 2009

Red blood cell electrolyte levels and haemoglobin types have been determined in flocks of Peppin Merino sheep genetically different for clean fleece weight and crimp frequency. The flocks selected for high clean fleece weight or low crimp frequency had significantly higher mean erythrocyte potassium levels than did those flocks selected for low clean fleece weight or high crimp frequency, this difference was apparent in both haemoglobin AB and BB types. Erythrocyte potassium concentration was not correlated with either clean fleece weight or crimp frequency within flocks. The high clean fleece weight flock had a significantly higher gene frequency for high potassium than did the low clean fleece weight flock, while the high crimp frequency flock had a lower haemoglobin B gene frequency than the low crimp frequency flock.
Restricted randomization for blocks of sixteen plots
Authors: Dyke G. V.
Published: March 2009

Grundy & Healy (1950) developed a method of ‘restricted randomization’ applicable to factorial experiments of 2nor 3ntype laid out either in quasi-Latin squares of size 8 × 8 or 9 × 9, or in blocks of 8 or 9 plots. This method of randomization, while in no way affecting the validity of the normal analysis, prevents the appearance of designs with obviously undesirable features. Grundy & Healy gave an example of a quasi-Latin square inwhich the main effect of one factor corresponded to the pattern:
Plasma concentrations of glucose and non-esterified fatty acids (N.E.F.A.) in the pregnant and lactating ewe and the effect of dietary restriction
Authors: Patterson D. S. P. , Burns K. N. , Cunningham N. F. , Hebert C. Nancy , Saba N.
Published: March 2009

1. The effect of undernutrition on the levels of plasma glucose, N.E.F.A. and ketone bodies was observed in fourteen Suffolk-cross ewes late in pregnancy by comparing with data obtained on seven control ewes of comparable pregnancy status. An attempt is made to relate these changes with plasma triglyceride levels, liver fat deposition and plasma pigmentation.

2. Evidence is presented which shows that while plasma glucose values are normally distributed, plasma N.E.F.A. levels show a positively skew distribution. This abnormality is corrected by transforming plasma N.E.F.A. values to their logarithms.
Ramularia beticola in sugar-beet seed crops in England
Authors: Byford W. J.
Published: March 2009

Ramularia beticola was prevalent in sugar-beet seed crops in Oxfordshire, Gloucestershire and Lincolnshire in July each year from 1966 to 1971, and defoliated some crops prematurely. It was scarce in Bedfordshire, Huntingdonshire and Essex, and this distribution could not be related to method of growing the crop or density of plant stand. A method is described for assessing leaf spot incidence in beet seed crops after bolting is complete. Fungicide sprays delayed disease development by ca. 2½ weeks.
Marginal sulphur supplies for grassland herbage in south-east Scotland
Authors: McLaren R. G.
Published: March 2009

Sulphur deficiency in agricultural crops has never been regarded as a significant problem in Great Britain. However, the widespread use of sulphurfree fertilizers and the introduction of Clean Air Acts together with increased crop yields necessitate a reappraisal of the situation. S.E. Scotland is an area where atmospheric sulphur dioxide levels are considerably lower than most other regions of Britain (Junge, 1972). The concentration of sulphur in precipitation is also relatively low (Stevenson, 1968) and therefore the area is likely to be affected by restricted sulphur supplies. A survey of the sulphur content of soils and corresponding herbage was carried out in this area during 1972 and 1973.
Studies on feed intake and feed utilization by sheep I. Voluntary feed intake of dry, pregnant and lactating ewes
Authors: Hadjipieris G. , Holmes W.
Published: March 2009

1. The feed intake of four dry and of twenty pregnant and lactating ewes has been measured. Hay and dried grass cubes alone or in combination were studied on indoor conditions by direct measurement of intake and digestibility while the intake on grazing was measured by the chromic oxide-faecal nitrogen method.

2. For dry sheep, hay (61% O.M. digestibility) limited intake to 780 g. D.O.M./day and with added grass cubes there was a steady increase so that intake with cubes alone (although their apparent O.M. digestibility was 56%) was 1140 g. B.O.M./day. Pregnant ewes showed similar intakes and only with ewes carrying twins and triplets was there a slight decline in intake with advancing pregnancy.

3. The digestibilities of the diets were similar for pregnant, and lactating ewes.
Digesta flow and mineral absorption in lambs before and after weaning
Authors: Dillon Jane , Scott D.
Published: March 2009

Four young lambs fitted with cannulas at the pylorus and at the ileo-caecal junction were used to study the effects of weaning on digesta flow and mineral absorption. Prior to weaning when milk alone was fed the small intestine was the major site for dry matter disappearance and for the absorption of Ca, P, Na and K. Both the small and the large intestine were, however, important sites for Mg absorption at this time.

After weaning, when the lambs were fed a concentrate diet, at least two-thirds of the digested dry matter disappeared within the reticulo-rumen. The small intestine, however, still remained the major site for the absorption of Ca, P, Na and K. Most Mg absorption, in contrast, now occurred anterior to the pylorus and it would appear that the move from hindgut to foregut as a site for Mg absorption was directly associated with the introduction of dry feed and the development of fermentative digestion within the reticulo-rumen.

Both before and after weaning the faeces was the major route for the excretion of Ca surplus to requirement and the faeces also became increasingly important as a pathway for P and Mg excretion once dry feed was given. The urine, in contrast, was consistently the major pathway for the excretion of Na and K.
Influence of environment and heredity on the shape of lactation curves in Sahiwal cows
Authors: Rao M. K. , Sundaresan D.
Published: March 2009

The shape of the lactation curve of Sahiwal cows was estimated by fitting a gamma function to 2034 lactations made by 681 cows at two farms in Indo-Gangetic plains of Northern India. The persistency of lactation yield was estimated by three methods: P1, the coefficient of variation among weekly yields; P2, ratio of lactation yield to peak yield, and P3, from the gamma function.

The gamma function fitted to the weekly yields explained 75·9% of the variation. A least-squares analysis of different traits associated with lactation curve shape indicated significant influence of parity, period and season of calving on the lactation curve. The lactation yield, peak yield and daily yield up to the peak were highest for winter calvers, while persistency was highest for monsoon calvers. The milk yield traits showed an increase up to the second or third lactation, while the persistency decreased from the first to eighth lactation with increase in parity order. The lactation curve was also more flat in the first lactation than later. The lactation yield and persistency increased with increase in age at calving independent of parity order. The lactation yield, peak yield, persistency and daily yield up to the peak were positively correlated with service period, lactation length and calving interval.

The heritability and repeatability estimates of different traits, genetic and phenotypic correlations of lactation milk yield with different persistency measures indicated that P2 is a better measure of persistency. The peak yield could be used as a criterion of selection in early lactation to bring about improvement in lactation yield and persistency.
The effect of triamcinolone on glucose metabolism in ketotic sheep
Authors: Ford E. J. H. , Evans Joan
Published: March 2009

The withdrawal of food from Clun Forest ewes pregnant with twins produced signs of pregnancy toxaemia accompanied by a significant decrease in the concentration of glucose, a significant increase in the concentration of ketones, non-esterified fatty acids (NEFA) and 3-hydroxybutyrate in plasma and a significant decrease in total entry rate and irreversible loss of glucose. A single intramuscular injection of 0·05 or 0·2 mg/kg of triamcinolone acetonide had no significant effect on the concentration of glucose, ketones or 3-hydroxybutyrate in plasma or on the total entry, irreversible loss or recycling of glucose in ketotic or in normal pregnant sheep. The low dose had a significant effect on the concentration of NEFA in plasma. Recovery from the clinical signs was slow after either dose of steroid but appeared to be hastened by the onset of parturition which was more rapid after the higher dose.
Influence of phosphorus and potassium on forage yields in relation to fertilization and stage of harvest of an oat companion crop
Authors: Hamilton Herman A.
Published: March 2009

1. The effects on forage yields as a result of the interaction between fertilizer management and stage of harvesting an oat companion crop were studied under the climatic conditions of northern Ontario.

2. Grain yields as well as silage yields were increased on the application of 400 lb. 4–24–12 per acre. Fertilization of the corffipanion crop seeded with a- hay mixture resulted in first- and secondyear yields that were significantly greater than those obtained without fertilization of the companion crop.

3. By harvesting oats at the silage stage rather than as mature grain only the succeeding firstyear hay yields were significantly greater on the application of additional phosphorus and potassium.
Relating the nitrogen fertilizer needs of winter wheat crops to the soil's mineral nitrogen. Influence of the downward movement of nitrate during winter and spring
Authors: Addiscott T. M. , Darby R. J.
Published: March 2009

Optimum applications of N fertilizer, Nopt have been related successfully to the amount of mineral N in the soil, Nmin in some parts of Europe but not always in the UK. If there is a body of mineral N, QN, that ultimately lessens the need for N fertilizer, it will not remain constant in its amount or its position. Mineralization will add to QN, while the nitrate component of QN will be leached downwards.Also, part of QN will be taken up into the crop where it will continue to lessen the need for fertilizer N but will be safe from leaching. A computer model was used to simulate these processes for 23 experiments, covering five sites and five years, in which N opt had been estimated. From these simulations we derived trial values of QN that took account of mineral N to a series of depths on a series of dates. For each date we used the trial values to find the depth for which Nopt was best correlated with QN andassumed that this was the depth, dL, of the lower boundary of QN on that date. Thus dL was a collective value for all 23 experiments. The value of dLincreased throughout the winter and the spring and was very closely related to the cumulative average drainage through 0·5 m soil at Rothamsted. By 15 April, dL, was 1·66 m, a depth that was compatible with observations by others that winter wheat can remove mineral N to a depth of at least 1·5 m. We inferred two likely reasons why Nmin may fail as a predictor of Nopt in the UK: insufficient depth of sampling, and too wide a spread of sampling dates. The values of Nopt were shown to be related satisfactorily to the values of QN computed, without any measurements of mineral N, for appropriate depths on single dates.
Effect of cocoa pod ash on the growth of maize
Authors: Adu-Dapaah H. K. , Cobbina J. , Asare E. O.
Published: March 2009

Pot and field experiments were conducted at the Faculty of Agriculture Arable Crops Farm, Kumasi, Ghana during the major rainy season to compare the agronomic efficiency of potassium in cocoa pod ash with that of muriate of potash and to determine the optimum rate of application of cocoa pod ash to maize (Zea mays L. cv. La Posta). Results from the two experiments indicated that the application of 90 kg N/ha and 67 kg P2 O5/ha did not increase shoot dry matter (DM) yield over the control. However, significant increases in DM yield over the control were obtained when N and P were applied together with 56 kg K2O/ha, demonstrating the complementarity of the major nutrient elements N, P and K. Shoot and root DM increased with increasing application of cocoa pod ash. Application of 140 kg/ha cocoa pod as (equivalent to 56 kg K2O/ha) produced the same DM and shoot potassium yields as 56 kg K2O/ha as muriate of potash. The optimum rate of application of cocoa pod ash was 280 kg/ha (112 kg K2O/ha).
Natural sucking performance and age of weaning in zebu cattle (Bos indicus)
Authors: Reinhardt V. , Reinhardt Annie
Published: March 2009

Sucking behaviour and age of weaning were investigated in a herd of East African zebu cattle in which all calves born had been retained for several years. Suckling rates were compared at different periods of the 24 h cycle and found to be less at night than during any day-time period. The highest rates of suckling took place in the early morning and in the late afternoon. The early morning suckling was triggered by the dawn. During both night and day, suckling was irregular and bouts were presumably due to sympathetic induction because a high proportion of the calves was suckled on each occasion. The total sucking time and the number of bouts varied significantly in inverse relation to age of the calf but the duration of a sucking bout was constant at 8 min and independent of age. There was an average of 4·8 sucking bouts within 24 h giving a total duration of 38 min. Sucking behaviour did not exhibit sex-specific differences. The average age of natural weaning was 10 months but there was a marked sex difference. Female calves were prevented by their mothers from sucking after an average age of 8·8 months but male calves continued to be suckled for a further 2·5 months and were weaned at an average age of 11·3 months.
Effect of leaf position and plant age on the translocation of 14C-assimilates in onion
Authors: Khan A. A.
Published: March 2009

Individual leaf blades of onion plants were treated with 14CO2 57, 71, 93 and 112 days after transplanting. The distribution of labelled translocates was determined 24 h after labelling. The older the plant the more of 14C-assimilate left the source leaf; 112 days after transplanting, leaves 1–7 all exported more than 70% with leaf 7 showing a maximum export of 93 % of the fixed carbon. In the early stages of the development, the leaves, pseudostem and the bulbs were the major sinks in decreasing order. But the bulbs became the dominant sink at 71 days and at 112 days the bulbs almost monopolized the import of the radiocarbon, with 90 % of the exported 14carbon being recovered from them. The bulbs received their 14carbon supply from all the leaves but particularly the basal and middle region leaves. Roots were a weak sink and received their 14carbon supply only from basal leaves. The stem and mature leaf blades were unimportant sinks throughout the life of the plant.
Controlled environment composting for mushroom cultivation: substrates based on wheat and barley straw and deep litter poultry manure
Authors: Noble R. , Gaze R. H.
Published: March 2009

Substrates for mushroom cultivation were prepared, following a 2 day mixing and blending process, in bulk tunnels under a controlled temperature regime using forced ventilation. The temperature regime was based on a conventional bulk tunnel composting process, i.e. pasteurization at 60 °C for 6 h, followed by a conditioning phase at 47 °C until the substrate was clear of ammonia. With the exception of ammonia, which increased with increasing compost nitrogen content, this process did not result in strong odours. The substrates were ready for inoculation with mushroom ‘spawn’ 7–12 days after the initial mixing of the compost ingredients. Increasing the compost nitrogen content from 1·1 to 2·5% of the dry matter by increasing the quantity of deep litter poultry manure added to straw in the ingredients resulted in a greater subsequent yield of mushrooms. Further increases in the substrate nitrogen content resulted in prolonged tunnel processing times, substrate desiccation, incomplete clearance of ammonia from the substrate and subsequently low or no mushroom yields. Substrate bulk density at the time of spawning decreased with increasing nitrogen content, but was increased by chopping the straw ingredient. Mushroom yields from composts prepared with barley straw were significantly lower than those from wheat straw composts, at equivalent nitrogen contents. Supplementation of prepared substrates with the proprietary protein-rich ingredient, Betamyl 1000, increased yields by 13·6%.
Effects of condensed tannins inLotus pedunculatuson its nutritive value for sheep. 2. Nitrogenous aspects
Authors: Waghorn G. C. , Shelton I. D. , McNabb W. C. , McCutcheon S. N.
Published: March 2009

Fourteen young wether sheep were fed freshly cutLotus pedunculatusas a sole diet to examine the effects of condensed tannins (CT; 55 g/kg lotus DM) on nitrogenous aspects of digestion. The experiment was carried out indoors at Palmerston North, New Zealand over 32 days with one group of sheep receiving an intraruminal infusion of polyethylene glycol (PEG; 100 g/day) to preferentially bind CT (PEG group) so that the lotus was essentially ‘CT-free'. The other sheep, not given PEG, were termed the ‘Tannin’ group.

The principal effects of CT were to increase the flow of feed nitrogen (N) to the abomasum despite a 12% reduction in DM intake of the Tannin sheep. Rumen microbial N turnover rate was slower in Tannin animals than in those receiving PEG (1·86v. 2·63/day) but microbial N flux to the abomasum was similar in both treatments. The proportion of N intake disappearing from the rumen was lower in Tannin (0·13) than in PEG sheep (0·26) and the N digestibility was 0·67 and 0·81 for the respective treatments (P <0·001).

The beneficial effects of CT in reducing rumen degradation of feed protein were negated in part by a reduction in fractional absorption of amino acids (AA) from the small intestine. Fractional absorption of essential AA was 0·66 in Tannin and 0·79 in PEG sheep; values for non-essential AA were 0'59 in Tannin and 0·73 in PEG groups. Amino acid concentrations in blood were similar for both groups, but Tannin sheep had lower plasma urea concentrations, a more rapid plasma urea turnover rate and a higher irreversible loss than those receiving PEG. Growth hormone concentrations in plasma were similar for both treatments.
Effects on Nutritive Value for Growing Pigs of Pelleting Diets Containing Low Glucosinolate Rapeseed Meals
Authors: Rowan T. G. , Lawrence T. L. J.
Published: March 2009

Many pigs are given their diets in cubed or pelleted form and the process of pelleting has been shown to increase nutritive value. The reasons for increases in nutritive value following pelleting of a diet are uncertain but reductions in crude fibre and improved apparent digestibility of gross energy and dry matter (D.M.) may be involved (Lawrence, 1971, 1976, 1979). As rapeseed meal (RSM) is higher in crude fibre and, in general, of lower digestible energy value than soya-bean meal (SBM), it was thought possible that the beneficial effect of pelleting could be greater in RSM than in SBM diets.
Soil-plant nitrogen dynamics following incorporation of a mature rye cover crop in a lettuce production system
Authors: Wyland L. J. , Jackson L. E. , Schulbach K. F.
Published: March 2009

Winter non-leguminous cover crops are included in crop rotations to decrease nitrate (NO3-N) leaching and increase soil organic matter. This study examined the effect of incorporating a mature cover crop on subsequent N transformations. A field trial containing a winter cover crop of Merced rye and a fallow control was established in December 1991 in Salinas, California. The rye was grown for 16 weeks, so that plants had headed and were senescing, resulting in residue which was difficult to incorporate and slow to decompose. Frequent sampling of the surface soil (0–15 cm) showed that net mineralizable N (anaerobic incubation) rapidly increased, then decreased shortly after tillage in both treatments, but that sustained increases in net mineralizable N and microbial biomass N in the cover-cropped soils did not occur until after irrigation, 20 days after incorporation. Soil NO3-N was significantly reduced compared to winter-fallow soil at that time. A15N experiment examined the fate of N fertilizer, applied in cylinders at a rate of 12 kg15N/ha at lettuce planting, and measured in the soil, microbial biomass and lettuce plants after 32 days. In the cover-cropped soil, 59% of the15N was recovered in the microbial biomass, compared to 21% in the winter-bare soil. The dry weight, total N and15N content of the lettuce in the cover-cropped cylinders were significantly lower; 28 v. 39% of applied15N was recovered in the lettuce in the cover-cropped and winter-bare soils, respectively. At harvest, the N content of the lettuce in the cover-cropped soil remained lower, and microbial biomass N was higher than in winter-bare soils. These data indicate that delayed cover crop incorporation resulted in net microbial immobilization which extended into the period of high crop demand and reduced N availability to the crop.
Growth, morphology and nutritive quality of shaded Stenotaphrum secundatum, Axonopus compressus and Pennisetum clandestinum
Authors: Samarakoon S. P. , Wilson J. R. , Shelton H. M.
Published: March 2009

The response to shade in growth and nutritive quality of buffalo grass (Stenotaphrum secundatum) was compared with that of two other stoloniferous grasses, mat grass (Axonopus compressus) and kikuyu grass (Pennisetum clandestinum). The grasses were grown outdoors in Brisbane, Australia, in soil in pots over two growing seasons in 1985/86. Treatments in the first season (Expt 1) were shading at 0 (full sun), 42, 59 and 68% with moderate N (two spaced applications of 50 kg/ha) and, in the second season (Expt 2), 0 and 59% shade with high (50 kg/ha every 2 weeks) and low (5 kg/ha every 2 weeks) N.

Unusually for tropical grasses, the top yield of all species was higher under shade than in full sun, except for S. secundatum at high N in Expt 2. S. secundatum and A. compressusshowed an increase in top yield up to 68% shading whereas P. clandestinum reached a maximum at 42% shading. Shade increased shoot:root ratio and specific leaf area in all species but had little effect on leaf:stem ratio and the proportion of dead material in the tops. Stubble yield (stem bases and stolons) was reduced under shade but to a much smaller extent than root yield. S. secundatum and A. compressus had similar morphological characteristics. Their yield was lower than that of P. clandestinum in Expt 1 (autumn growth) but was similar to that of P. clandestinum in Expt 2 (summer growth). These grasses had a higher leaf:stem ratio and lower proportion of dead material in tops than P. clandestinum.

Shade generally increased herbage nutritive value through an increase in N concentration and drymatter digestibility. The latter response was somewhat variable and mostly small (1–3% units). Under shade, the general trend was towards a decrease in total nonstructural carbohydrates, cell-wall content and insoluble ash, and an increase in lignin content. A. compressus was higher in digestibility and soluble carbohydrates than the other grasses.

S. secundatum was not clearly superior in response to shade and its nutritive quality was lower than that of A. compressus.
Effect of nitrogen fertilizer rate on soil nitrate nitrogen content after harvesting winter wheat
Authors: Chaney K.
Published: March 2009

The nitrate nitrogen content of the soil (0–90 cm) was measured immediately after the harvest of winter wheat at eight sites in central and eastern England in 1987 and 1988. On average, 50% of the total nitrate detected was in the 0–30 cm, 30% in the 30–60 cm and 20% in the 60–90 cm soil horizon. Although soil nitrate N increased with the amount of N fertilizer applied, it was not a linear relationship. There were small nonsignificant increases in soil nitrate up to the optimum fertilizer rate for yield but, once the optimum was reached, further addition of fertilizer increased nitrate contents significantly.

Therefore, applying the correct quantity of N for high grain yield did not significantly increase soil nitrate residues after harvest compared with the no-fertilizer treatment. This emphasizes the importance of applying the appropriate rate of N for each crop, because applying too much is not only uneconomic but also significantly increases the amount of mineral N which could be subsequently leached over the winter.
Variation among wheat cultivars in the response of leaf gas exchange to light
Authors: Blum A.
Published: March 2009

This research was done in order to explore genetic variation in carbon exchange rate (CER) of spring wheat (Triticum aestivum) leaves in response to variable photosynthetically active radiation (PAR) and to compare old and new Israeli cultivarsin this respect. Leaf gas exchange was measured in detached turgid leaves of 17 cultivars inan open system at 25 °C when PAR was reduced from c. 1200 to 200 μmol/m2 per s. Linear regressions of CER, stomatal conductance, transpirationand leaf internal CO2 concentration (Ci) on log PAR were fitted for each leaf(regression r2 was never <0·79) and the regressions were compared among cultivars by analysis of variance.

Genotypes differed significantly for the slope (b) but not the intercept (a) of the regression of CER on log PAR, indicating that genotypic differences for CER increased with increasing PAR. Photosynthetic capacity, as expressed by the ratio of CER/Ci, differed significantly among cultivars only at high PAR. Stomatal conductanceand transpiration increased in a linear or a nonlinear fashion with log PAR and differences among cultivars for both were greatest at medium to low PAR. Photosynthetic water–use efficiency (WUE) and its variation among cultivars were greatest at the highest PAR. Genotypic variation in CER athigh PAR was confirmed by repeated results for 11 cultivars intwo independent experiments.

The recently developed high-yielding cultivar V652 had a higher maximum CER, higher photosynthetic capacity and greater WUE at high PAR than older and lower-yielding cultivars. The results suggest an upward genetic shift in photosynthetic capacity andin CER at high PAR when selection for yield was performed under the high-irradiation conditions of Israel.
The effects of weather, seed rate and cultivar on lodging and yield in winter wheat
Authors: Easson D. L. , White E. M. , Pickles S. J.
Published: March 2009

Winter wheat cultivars Apollo, Hornet, Longbow and Norman were each sown at 50, 100, 200, 400, 800 and 1600 seeds/m2in a field experiment conducted in Northern Ireland over the 1989/90 crop year. No growth regulators were applied and the wheat received 178 kgN/ha top-dressing in the spring. Hourly rainfall, windspeed and wind direction data were recorded and lodging was visually assessed from the end of May to harvest. Lodging first occurred in the 1600 seed-rate plots as the ears were emerging in early June and then progressively increased in the 800, 400 and 200 plots during June, July and August. Lodging did not occur suddenly but took several hours, with the stems first lying at an angle before lodging completely. Stem buckling or breakage did not appear to be the principal form of structural failure. The longest strawed cultivar, Longbow, lodged most severely. The shorter-strawed Norman also lodged badly in contrast with Hornet which had a similar straw length. Apollo, which was taller than Norman and Hornet and produced more ears per square metre than the other cultivars, lodged least but tended to lean atc.30° from the vertical. Lodging occurred during or within 24 h of periods of rainfall which, in many cases, coincided with windspeeds at crop height averaging > 25 km/h and occasionally > 50 km/h. Lodging also occurred following rainfall when the windspeed did not exceed 16 km/h. The grain yield was negatively correlated with the average lodging from ear emergence to harvest, there being a 1 t/ha decline in yield for each 10% increase in average area lodged. The 50 and 100 seed-rate plots yielded 10 t/ha and had little or no lodging. The decline in yield with increased lodging and seed rate was attributed to the effect of lodging rather than to seed rate and was associated with a fall in the number of grains/ear and 1000-grain weight from 56 and 53·5 g at the lowest seed rate to 15 and 42·7 g at the highest, respectively. A comparison of the plants from lodged and unlodged plots of the 1600 and 800 seed rates, and subsequently of the 800 and 400 seed rates, indicated that at the higher seed rate, lodged plots had less fresh weight per unit area, basal internodes with smaller diameters, fewer support roots per stem, and a lower root dry weight per stem.
Amide nitrogen transformation in waterlogged soil
Authors: Magid H. M. Abdel , Tabatabai M. A.
Published: March 2009

In laboratory studies, the amount of N mineralized under waterlogged conditions during 14 days at 30°C was significantly correlated (P< 0·001) with the activities of amidase, glutaminase and asparaginase in soil when these enzymes were assayed by either a nonbuffer or a buffer method using appropriate substrates. N mineralization under waterlogged conditions was also significantly positively correlated with N mineralization under aerobic conditions, especially at 25 and 35 °C (P< 0·001). Generally, the results indicate that the use of amidase, glutaminase and asparaginase activities in predicting plant-available N in soils deserves more attention.
Effect of nitrogen, phosphorus and potassium application on yield of potato tubers (Solatium tuberosum L.)
Authors: Sharma U. C. , Arora B. R.
Published: March 2009

Six field experiments, three each during 1982–3 and 1983–4, were conducted on a sandy loam soil to study the effect of varying levels of nitrogen, phosphorus and potassium, in the absence and presence of farmyard manure (FYM) (30 t/ha), on the number of tubers and yield of potato in three grades. Increase in nitrogen, phosphorus and potassium application, in the absence or presence of FYM, did not significantly affect the total number of tubers/m2 but did affect the number of tubers in different grades. An increase in nitrogen and potassium significantly decreased the number of tubers/m2 in small (< 25 g) and increased in medium (25–75 g) and large (> 75 g) grades at 45, 60, 75 and 90 days after planting. Increase in the application of phosphorus increased the number of tubers/m2 in the small grade and decreased it in the large grade but did not affect the number in the medium grade. Increase in nitrogen and potassium application decreased the tuber yield in the small grade and increased it in the medium and large grades. Applied phosphorus increased the yield in the small and medium grades and decreased it in the large grade. The increase in the yield of tubers with increase in nitrogen and potassium application was found to be caused by an increase in the number of tubers in the medium and large grades at the expense of the small grade; however, with applied phosphorus the increase in yield was due to increase in the weight of individual tubers within the small and medium grades. FYM application decreased the number of tubers in the small grade and increased it in the medium and large grades. The response of potato to nitrogen increased and to phosphorus and potassium decreased with the application of FYM.
Effect of the duration of the vegetative phase on crop growth, development and yield in two contrasting pearl millet hybrids
Authors: Craufurd P. Q. , Bidinger F. R.
Published: March 2009

The phenotype of medium duration pearl millet varieties grown in West Africa differs from that of the shorter duration millets grown in India. African varieties are usually much taller, have longer panicles, fewer productive tillers, and a lower ratio of grain to above-ground dry-matter (harvest index). The effect of crop duration on plant phenotype was investigated in two hybrids using extended daylengths to increase the duration of the vegetative phase (GSl: sowing to panicle initiation). The two hybrids, 841A × J104 and 81A × Souna B, were considered to represent the Indian and African phenotype, respectively. Tiller production and survival, leaf area, and dry-matter accumulation and partition, were monitored over the season. Grain yield and its components were determined at maturity.

The two hybrids responded similarly to the short and long daylength treatments. The duration of GSl was increased from 20 to 30 days, resulting in increased number of leaves, leaf area, and stem and total dry-matter accumulation; there was no effect on tiller production and survival, or on panicle growth rate. Grain yield was, therefore, the same in both GSl treatments, and harvest index (HI) was much reduced in the long GSl treatment owing to the increased stem growth. One evident effect of a longer GSl was on dry-matter partitioning between shoots; partitioning to the main stem (MS) was increased, whereas partitioning to the tillers was reduced.

There was no difference in crop development, growth or yield between the two hybrids in either GSl treatment. The only significant differences were in the efficiency with which intercepted radiation was converted to dry matter, which was greater in 841A × J104 than in 81A × Souna B, and in the balance between MS and tillers; the grain yield of the MS was significantly greater in 81A x Souna B than in 841A × J104, but at the expense of number of productive tillers.

The results demonstrate that both African and Indian phenotypes are equally productive under good agronomic conditions. The lower HI in longer duration African millets is a consequence of a much extended stem growth phase and therefore increased competition between stem and panicle during grain filling. Possible ways to increase grain yield in the medium duration African millets are considered.
Effects of acute heat stress on changes in the rate of liquid flow from the rumen and turnover of body water of swamp buffalo
Authors: Chaiyabutr N. , Buranakarl C. , Muangcharoen V. , Loypetjra P. , Pichaicharnarong A.
Published: March 2009

During 5 h of acute heat exposure (41 °C), there were increases in the heart rate from 43±2 (S.E.) to 51 ± 1 beats/min, respiratory rate from 26±4 to 86± 16 breaths/min and rectal temperature from 38·5 ± 0·1 °C to 39·7 ± 0·2 °C. The flow rate of liquid from the rumen and body water turnover significantly increased while biological half life of chromium-51 ethylenediaminetetra-acetate in the rumen and tritiated water decreased from 12·9 ± 2·5 and 87·7 ± 6·8 h to 9·3 ± 2·0 and 49·2 ± 5·7 h respectively. An increase in blood volume during acute heat stress occurred with an increase of both plasma and cell volume. An elevation of plasma water coincided with an increase in plasma protein and glucose. There is evidence that the increase in plasma water during heat exposure came from extravascular tissue space and/or from the digestive tract.
Nitrogen fixation as influenced by pesticides and rice straw in paddy soils
Authors: Jena P. K. , Rao V. Rajaramamohan
Published: March 2009

The effect of three herbicides and an insecticide combination on nitrogen fixation in three paddy soils was investigated in a laboratory incubation study. The influence of pesticide combination on N2 fixation was evaluated in the presence and absence of rice straw under flooded and non-flooded conditions. In a non-flooded alluvial soil single or combined application of butachlor and carbofuran significantly stimulated N2 fixation. There was no effect on N2 fixation when thiobencarb was applied alone; but with thiobencarb in combination with carbofuran higher N2 fixation occurred. Both oxadiazone and thiobencarb had no effect on N2 fixation under flooded conditions, but in combination with carbofuran the N2 fixation was high. In acid sulphate saline Pokkali soil, rice straw application stimulated N2 fixation; the stimulatory effect of carbofuran either alone or in combination became more pronounced under flooded conditions. N2 fixation was low in a laterite Sukinda soil and the effect of pesticides was not changed by rice straw amendment. A uniform stimulation of N2 fixation occurred in soils when carbofuran was applied either singly or in combination with other herbicides tested. Results indicate that the effect of pesticides on N2 fixation varied with the rice straw application and water regime.
Metabolic adaptation during pregnancy in winter-shorn sheep
Authors: Symonds M. E. , Bryant M. J. , Lomax M. A.
Published: March 2009

The effects of winter shearing on ewe live weight, body condition score (BCS) and the concentrations of glucose, non-esterified fatty acids (NEFA), 3-hydroxybutyrate, growth hormone (GH), cortisol, insulin and the thyroid hormones in plasma plus that of oxygen and carbon dioxide in jugular vein blood and packed cell volume (PCV) were measured at weekly intervals over the final 7 weeks of pregnancy in two groups of multiple-bearing shorn and unshorn pregnant ewes.

Shorn ewes lost 47% more live weight than unshorn controls over the period from the day of being shorn to immediately after lambing. There was a significant decrease in BCS in both groups between 45 and 9 days before lambing. Three days after shearing the plasma NEFA concentration was higher in the shorn group but there were no other significant differences between shorn and unshorn groups in the plasma concentrations of NEFA, cortisol or insulin over the remaining 7 weeks of pregnancy. Both the PCV and concentration of carbon dioxide in blood were higher in shorn sheep throughout the final 6 weeks of pregnancy indicating they were making metabolic adaptations to long-term cold exposure. This response may have been mediated via an increase in thyroid hormone concentrations which were higher throughout the 7-week sampling period in shorn animals compared with unshorn controls. A decrease in ambient temperature was associated with a significant increase in the plasma concentration of GH and glucose in shorn animals. At 2 weeks before lambing there was a decrease in the plasma glucose concentration and an increase in 3-hydroxybutyrate concentration in the unshorn ewes, but these changes were not observed in the shorn animals. It is concluded that winter shearing of the pregnant ewe results in an increased loss of maternal body tissues and metabolic adaptations to long-term cold exposure without any of the changes associated with an increase in energy expenditure during the final third of pregnancy.
Response of lactating goats to low phosphorus intake 2. Nitrogen transfer from rumen ammonia to rumen microbes and proportion of milk protein derived from microbial amino acids
Authors: Petri A. , Müschen H. , Breves G. , Richter O. , Pfeffer E.
Published: March 2009

Five rumen-cannulated dairy goats were fed diets supplying 2·8 g P/day plus 1·4 g P/kg milk (adequate P) for weeks 1–6 of lactation. Two goats then continued to receive this adequate P supply while three goats were fed deficient diets supplying only 0·8 g P/day plus 0·4 g P/kg milk. Solutions containing CrEDTA and (15NH4)2SO4 were infused into the rumen continuously for 96 h during weeks 5–6 and 11–12, respectively. At intervals following the intraruminal infusion, 15N enrichments of rumen ammonia-N, rumen bacteria-N and milk protein-N were determined. Cr concentration was measured in particle-free rumen fluid.

P deficiency did not significantly affect rumen fluid kinetics. It caused a significant increase in pH and reduced the size of the rumen ammonia pool and its outflow rate. Digestibility of organic matter as well as efficiency of microbial protein synthesis were decreased significantly and thus net microbial yield was reduced from 34·1 to 13·7 g N/day. The transfer of N of microbial origin to milk protein decreased from 5·3 to 2·7 g/day, whereas secretion of N in milk protein not originating from rumen microbes remained unchanged at 5·6–5·8 g/day.
Effect of pod removal and plant growth regulators on the growth, development and carbon assimilate distribution in oilseed rape (Brassica napusL.)
Authors: Keiller D. R. , Morgan D. G.
Published: March 2009

Removal of basally positioned pods on the terminal inflorescence at anthesis and 6 days thereafter increased the duration of flowering and resulted in the formation of a larger number of smaller pods.

Removal at 12 days after anthesis did not affect flower production but increased the number of flowers setting pods. Application of benzyladenine to the apices of intact plants from 8 days but not 14 days after anthesis greatly extended flower but not pod production. Liquid scintillation counting showed that the benzyladenine treatment led to more14C-labelled assimilates moving to the apices.