bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of drought on barley: soil and plant water relations
Authors: Day W. , Lawlor D. W. , Legg B. J.
Published: March 2009

In a field experiment on the effects of drought on spring barley, the crop was protected from rainfall by automatic rain shelters; a range of drought treatments was achieved by irrigating various plots according to a predetermined schedule. There were 12 treatments which ranged from no irrigation to full irrigation from emergence to harvest; results from seven treatments are discussed in this paper.

The rate of water uptake was determined for four soil horizons centred at 0·15, 0·50, 0·80 and 1·10 m. For all treatments, the rate of uptake in each horizon decreased as the soil dried, and although there were large differences in root density between horizons, maximum rates of uptake were similar in all horizons down to 0·80 m. Treatment effects showed that prolonged drought decreased the rate of uptake from the 0·80 and 1·10 m horizons: root density at and below 1·0 m probably differed between treatments.

Differences between treatments in leaf water potential (ψL) and osmotic potential (πL) were small, and there was no evidence that osmotic adjustment contributed to the drought response of this crop. Near anthesis, pre-dawn ψL was near zero for irrigated treatments and between – 3 and – 5 bar for unirrigated. During the day, ψL decreased to a minimum of – 15 to – 18 bar for irrigated plants, and was generally 3 bar lower for unirrigated. For all treatments, ψL was greater than π for the major part of the day, i.e. positive turgor was maintained; however, turgor was usually greater for irrigated than for unirrigated plants. The relationship, for leaf 8, between ψL and transpiration flux density was markedly non-linear, and was of a similar form for irrigated and vinirrigated plants. As the form of this relationship was independent of treatment, the non-linearity could not have been caused by variations in soil water potential through the profile.

Stomatal resistance differed markedly between treatments. A detailed analysis is presented, relating measured resistance for leaf 8 to ψL and to environmental variables: irradiance (I), water vapour pressure deficit (vpd), and temperature (T). The analysis showed no significant dependence of resistance on ψL or T, but marked dependence on I and vpd; a mathematical model combining a hyperbolic response function for I and an exponential function for vpd fitted the data well. The responses of abaxial and adaxial surface resistances to vpd were similar, but their light responses differed because of their different exposures to incident irradiance.
The effects of irrigation, nitrogen fertilizer and the control of pests and pathogens on spring-sown field beans (Vicia fabaL.) and residual effects on two following winter wheat crops
Authors: McEwen J. , Bardner R. , Briggs G. G. , Bromilow R. H. , Cockbain A. J. , Day J. M. , Fletcher K. E. , Legg B. J. , Roughley R. J. , Salt G. A. , Simpson H. R. , Webb R. M. , Witty J. F. , Yeoman D. P.
Published: March 2009

Experiments started in 1976, 1977 and 1978 on Clay-with-Flints soil at Rothamsted tested the effects of combinations of eight two-level factors on spring-sown field beans. Factors tested, presencev. absence, were irrigation, nitrogen fertilizer, aldicarb, fonofos (dieldrin in 1976), benomyl to the seed bed, permethrin (fenitrothion in 1976), pirimicarb, benomyl foliar spray (not tested in 1976).

The main pests and diseases present were nematodes of the genusPratylenchus, the pea aphidAcyrthosiphon pisum, the pea and bean weevilSitona lineatus, root blackening associated with the fungal generaPythiumandFusarium, the foliar diseases chocolate spot,Botrytisspp., rust,Uromyces fabaeand bean leaf roll virus.

Incidence of these pests and diseases varied between years. Controlling those present increased yield by about 0·7 t grain/ha each year. The difficulty of apportioning this increase to particular pests and diseases is discussed.

Irrigation increased total dry-matter production and grain yield in 1976 and 1978 but only total dry-matter production in 1977, when grain yield was lost because of lodging. Nitrogen fertilizer had little or no effect.

The most favourable combinations of treatments gave yields of 3·4, 5·0 and 6·4 t grain/ha in the 3 years respectively. Small yields in 1976, despite irrigation, were attributed to premature senescence caused by exceptionally high temperatures. It is suggested that with good control of pests and diseases yields of at least 5 t/ha should be attainable on Clay-with-Flints soil without irrigation in years of average temperature and rainfall and yields in excess of 6 t/ha when the soil-moisture deficit is lessened by either above-average rainfall or irrigation.

Treatments applied to the beans had little or no effect on two following crops of winter wheat.
Effects of nitrogen and its carriers with different topping heights on growth, yield and quality of tobacco
Authors: Mahadik S. R.
Published: March 2009

In this investigation the largest amount of nitrogen used, 44 kg per hectare, increased leaf size, yield and amount of nicotine in the leaf. The three carriers of N had similar effects on growth and yield at each amount applied but calcium ammonium nitrate produced tobacco inferior in quality to that with ammonium sulphate and urea. Increasing topping height from 8 to 10 and to 12 leaves increased the total leaf area per plant and yields, delayed maturity and lowered the quality of the tobacco. The greatest yield was produced by using 44 kg of N and topping at 12 leaves, but the best quality resulted from using 44 kg of N and topping at 8 leaves.
Ryegrass populations from intensively managed leys III. Reaction to management, nitrogen application and Poa trivialisL. in field trials
Authors: Charles A. H.
Published: March 2009

Populations of Lolium perenneL. derived from fields where the management was paddock grazing were compared with plants from breeder's seed of the cultivars originally sown at the collection sites. In the first trial the ‘survivor’ population derived from an S. 24 ley was better adapted to withstand intensive sheep grazing and high nitrogen application (672 kg/ha/ annum) than either S. 24 or Stormont Zephyr. Extra treading by sheep in addition to that involved in the high stock density (1186sheep/ha) used at the time of grazing produced only a small reduction in yield of dry matter. In the second trial, the ‘survivor’ population derived from an S. 23 ley had a higher yield of dry matter than S. 23 at the high level of N application (672 kg/ha/annum). There was no difference in the yields when 168 kg N/ha/annum was applied. In both field trials yield in the year of sowing was high for all swards, although the survivor populations were slower to establish than the original cultivars. The evaluation of the ryegrass populations in terms of dry-matter yield was affected by the small quantity of Poa trivialispresent when this grass was sown with the ryegrasses. In the second trial this conclusion also applied to yield of nitrogen in the herbage.
Ripening of grain maize in England: varietal differences in ripening patterns
Authors: Bunting E. S.
Published: March 2009

Changes occurring during ripening in dry weight and percentage dry-matter content of grain and rachis (cob) have been studied in Inra 200, and comparable data obtained for a U.S.A. dent hybrid, Minnesota 803, a Canadian flint × dent hybrid, OX 302, and a range of European flint × dent hybrids (Prior, Kelvedon 59A, De Kalb 202, Maris Carmine, Pioneer 131 and Anjou 210).

In Minnesota 803, OX 302 and, to a lesser extent, Prior, loss of water from the grain was more rapid than in Inra 200 during later stages of ripening. OX 302 reached a harvestable stage (40% grain water content) 10–12 weeks after silking, about 7 days earlier than Inra 200 in favourable seasons, and nearly 14 days earlier when conditions for ripening were less satisfactory. The patterns of changes occurring in the cob were quite different from those in ripening grain. Maximum dry weight of cob was reached when the grain was in the milk stage, and then declined throughout the period of rapid grain development; in the ripe ear, cob dry weight was 15–20% below its earlier maximum. At comparable grain water contents, the cob in Inra 200 was wetter than in Prior, Minnesota 803 and, even more markedly, OX 302. In contrast, water content in the cob of Maris Carmine and Anjou 210 was slightly higher than in Inra 200. The possible relationship between the differing varietal trends in ripening grain (and cob) and resistance to stalk rot is discussed.

The dry weight of the cob in ripe ears of Inra 200 was barely half that found in OX 302 and Minnesota 803, and lower than in other European flint × dent hybrids. Shelling percentage in ripe ears of Inra 200 was 88–90; it was 84–86 in other European flint × dent hybrids, about 80 in Minnesota 803 and 75 in OX 302. Mention is made of the relevance of this information to choice of variety for production of ground ear maize.
Oil content, yield and morphological response of rape (Brassica campestris L.) to irrigation and fertilizer treatment
Authors: Joarder O. I.
Published: March 2009

Rape (Brassica campestris L.) is well adapted to the Bangladesh climate and is an important oil crop of the northern part of Bangladesh. It requires a shorter growing season than any other crop of this kind but is less resistant to drought, which causes considerable damage to the crop by reducing total green area during late December and January and results in a poor yield. Considerable increase of rape-seed production will be possible through the elimination of drought by irrigation, the right supply of nutrients and application of proper cultural practices. We report here on studies of the effect of fertilizer under irrigated and non-irrigated conditions on the seed yield, oil content and some seed yield associated characters of rape and the importance of irrigation in rape cultivation in Bangladesh.
Reproduction in the buffalo-cow: pH of the vaginal secretions
Authors: Shalash M. R.
Published: March 2009

1. Fifty buffalo-cows were used for studying the pH of the vaginal secretion at different stages of the sex cycle.

2. Highly significant differences were found in the pH value of the vaginal secretions during the different stages of the sex cycle. The average was 7·3 during oestrus, 8·1 during dioestrus and 8·3 during pregnancy.
Studies on forage cell walls: 4. Flow and degradation of alkali-treated rice hull digesta in the ruminant digestive tract
Authors: McManus W. R. , Choung C. C. , Robinson V. N. E.
Published: March 2009

Sheep weighing 27 kg live weight were fed ad libitum three pelleted diets containing alkali-treated ground rice hulls (0, 5 and 15 g NaOH/100 g rice hull dry matter) in a 1:1 ratio with ground non-alkali-treated lucerne and were fed a fourth diet comprising the above control pellet fed ad libitum with a wheat grain supplement to determine the effects of alkali treatment and of energy supplementation on the digestion of cell walls and to assess the dynamics of flow of digesta through the gastrointestinal tract.

Flows of organic matter (OM) and nitrogen (N) to the duodenum were not different for the four diets, but daily whole digesta flow past the duodenum was greater (P < 0·01) for the two alkali-treated diets. Alkali treatment of rice hulls increased the percentage of total digestion of OM that occurred in the foregut (68%) compared with non-alkali-treated diets (52%), did not increase total volatile fatty acid concentration in rumen liquor, or adversely increase rumen pH. The capability of rumen microbiota to synthesize ammo acids was not adversely affected by alkali treatment. The percentage unit digestibility of cell wall constituent OM in the whole tract was increased approximately 1·6-fold by alkali treatment. Grain supplementation increased diet digestibility.

Scanning electron microscope studies revealed confirmatory visual evidence of enhanced degradation of alkali-treated rice hulls in the tract. It is clear from these studies that alkali treatment has caused sheets of silicified cuticle on the outside of rice hulls to dissolve and to lift away from the underlying lignocellulosic (palisade) matrix. It is also clear that this matrix material is itself heavily mineralized. Disappearance of silica across the gut wall was greatest for animals fed alkali-treated diets. No clinical signs of urolithiasis were seen. Sheep readily coped with the sodium intake (33 g/day) associated with alkali-treated diets, partially by an increased water consumption and a greater ruminal and intestinal absorption of this electrolyte.

It is calculated that the OM intakes recorded and nutrients released from alkalitreated rice hull diets provided between 500 and 600 kcal net energy/day.
Evaporative water loss in domestic fowls and its partition in relation to ambient temperature
Authors: Richards S. A.
Published: March 2009

The rate of evaporative water loss has been studied in domestic fowls in the ambient temperature range from 0 to 40°C.

Results for whole-body evaporation were similar when obtained by the open-flow and direct-weighing methods. At low levels of absolute humidity the rate increased by 0·03 mg/(g.h.°C) from 0 to 22 °C and by 0·17 mg/(g.h.°C) from 23 to 40 °C. Wholebody evaporation decreased with rising ambient water vapour pressure by 0·7 mg/(g.h.kPa).

Cutaneous water loss was greater than respiratory water loss below 21 °C; it accounted for 78% of whole-body evaporation at 0 °C, falling to 25% at 40 °C.

The rates of respiratory and whole-body evaporation could both be expressed as linear functions of respiratory frequency.
The nutritive value of diets containing different proportions of grass and heather (Calluna vulgaris L. Hull) to sheep
Authors: Milne J. A. , Bagley L.
Published: March 2009

Five levels of frozen grass and heather (Calluna vulgaris, L. Hull) which contained 85% of the current season's shoots, were offered to five castrated male Scottish Blackface sheep per level. The levels of grass were 0, 200, 400, 600 and 800 g D.M./day, and heather was offered ad libitum after the grass had been eaten. Both the grass and heather were harvested in September. Voluntary intakes of heather increased by 0·46 g/g of additional organic matter intake (OMI) of grass between the two lowest levels of grass, but at higher levels of grass there was a highly significant (P < 0·001) linear decrease in OMI of heather of 0·57 g/g additional OMI of grass.

No associative effects of grass (OM digestibility 70%) and heather (OM digestibility 44%) on OM or neutral-detergent fibre digestibility could be demonstrated. Intakes of digestible OM and nitrogen balance increased in a positive and linear manner with the proportion of grass in the diet. To meet the nitrogen and energy requirements for maintenance of the sheep the diet would require to contain 50% of grass. These findings are discussed in relation to the nutrition of sheep grazing heather-dominant moorlands.
A comparison of the sown swards of perennial ryegrass S. 24 and Italian ryegrass RvP in a two-year lamb production system, with different breeds of sheep
Authors: Newton J. E. , Young N. E. , Orr R. J.
Published: March 2009

A comparison was made between an intensive system of lamb production based on Italian ryegrass RvP and one based on perennial ryegrass S. 24, over 2 years, each at three stocking rates (14, 17, 20 ewes/ha). More grass was grown in the first year than in the second when the yield of RvP was particularly reduced. The ewes and lambs ate more RvP than S. 24 but there was no difference in lamb growth rate. The lambs grew faster at the low stocking rate from 0 to 18 weeks and from 0 to slaughter than at the medium and high stocking rates, in both years. Ewe intake and lamb growth rate were higher in the second year than the first. The Masham ewes with two lambs ate significantly more grass per unit of body weight than the Finnish Landrace × Scottish Halfbred and Finnish Landrace × Scottish Blackface ewes, and their lambs grew significantly faster. It was concluded that for an intensive system of lamb production from grass, S. 24 was more suitable than RvP.
Fat deposition in Hereford and Friesian steers: 3. Growth efficiency and fat mobilization
Authors: Truscott T. G. , Wood J. D. , Gregory N. G. , Hart I. C.
Published: March 2009

Food utilization in relation to growth of body components, and fat mobilization and its hormonal control in vivo, were examined in 15 Hereford and 15 Friesian steers which were slaughtered at 20 months of age. Changes in body composition between 6 and 20 months were calculated from the body composition of these animals and from an additional four and two steers from each breed slaughtered at 6 and 13 months of age, respectively.

The Friesians consumed more food overall (14%) and grew more rapidly (14%), but their intake in relation to metabolic body weight was not different from that of the Herefords. Although the Friesians deposited more protein in relation to lipid there was no breed difference in food conversion ratio, and maintenance requirement relative to empty-body weight0·75 was estimated to be 7% greater in the Friesians than the Herefords. Friesians therefore had a lower efficiency of conversion of food energy to body energy. It is speculated that the higher maintenance requirement of the Friesians was due to a faster rate of protein deposition and a higher proportion of visceral organs with an associated higher rate of protein turnover.

Changes in plasma concentrations of free fatty acids (FFA), insulin, growth hormone (GH), adrenaline and noradrenaline were examined in response to fasting at 12 and 20 months of age. Inaddition plasma concentrations of glucose, thyroxine (T4) and triiodothyronine (T3) were measured at 20 months of age.

At both ages, FFA concentration increased almost linearly with duration of fasting and was not different between breeds. It was therefore unrelated to fat partitioning and a poor index of breed differences in metabolic and body type. Within breeds, the rate at which FFA concentration increased during fasting was correlated with estimated maintenance requirement (r = 0·53). This suggests a different relationship between FFA utilization and maintenance requirement in the two breeds.

During fasting at 12 months of age, Friesians had higher concentrations of plasma GH and noradrenaline. At 20 months of age they had higher concentiations of glucose, insulin and catecholamines. There was no obvious hormonal explanation for the observed differences in body composition or growth efficiency. Correlations between indices of fat partitioning and maintenance requirement were low, suggesting no direct link between the two traits.
Effects of eight factors on the growth and nutrient uptake of winter wheat and on the incidence of pests and diseases
Authors: Prew R. D. , Church B. M. , Dewar A. M. , Lacey J. , Penny A. , Plumb R. T. , Thorne Gillian N. , Todd A. D. , Williams T. D.
Published: March 2009

A multifactorial experiment sown to winter wheat cv. Hustler in autumn 1978 tested the effects of combinations of the following eight factors, each at two levels: drill type, sowing date, amount of nitrogen, division of nitrogen, irrigation, autumn pesticide (aldicarb), summer aphicide (pirimicarb), and fungicide (carbendazim, maneb and tridemorph).

The mean grain yield of all plots was 9·7 t/ha and the best eight-plot treatment mean was 11·3 t/ha. The factors that had the greatest effect on yield were aphicide and fungicide, mainly from the control of Metopolophium dirhodum and Septoria spp. respectively. Both factors increased grain size and their effects were more than additive and greater with 250 than with 160 kg N/ha. Aphicide and fungicide also temporarily decreased the numbers of microbes on the developing ears. Autumn pesticide gave good control of aphids in the winter and some control in the summer: it also decreased nematode populations and slightly increased yields.

Precision sowing compared with random distribution of seeds along the row had little effect on growth or yield. Sowing on 21 September compared with 13 October greatly increased growth early in the season but had less effect after anthesis; it was the only factor that increased yield when aphicide and fungicide were applied. There was negligible infection by barley yellow dwarf virus in crops sown on either date. The amount and division of N fertilizer affected N uptake early in the season and had small effects on the production and survival of tillers. Three N applications instead of one slightly increased grain yields but did not affect total N uptake by grains plus straw, which averaged 190 kg N/ha. The larger amount of N always increased N uptake but decreased yield in the absence of aphicide and fungicide. Irrigation slightly decreased yield despite prolonging the duration of green leaf area.
N, P and K fertilizer studies in pyrethrum (Chrysanthemum cinerariifolium)
Authors: Rao B. R. Rajeswara , Singh S. P. , Rao E. V. S. Prakasa
Published: March 2009

Pyrethrum is a small bushy perennial crop cultivated for its flowers which have insecticidal properties. Pyrethrins, the active principles in the flowers, are contact insecticides causing nervous breakdown leading to paralysis and death of insects. Kroll (1963) and Parlevliet, Muturi & Brewer (1968) have shown that the flower yields of pyrethrum could be improved by applying P fertilizer whereas N and K fertilizers did not increase the yields. On the other hand, Mwakha (1979a, b) showed that pyrethrum responds to N fertilizer on soils deficient in N. The present investigation was carried out to study the response of pyrethrum to various rates of application of N, P and K and sources of phosphorus.
Comparative analysis of the growth, development and yield of three soya-bean varieties (Glycine max L.)
Authors: Tayo T. O.
Published: March 2009

The growth, development and yield of three soya-bean varieties, Hampton, Kent and CNS, were compared in two field experiments during 1974 and 1975 in Nigeria. The results, which were similar for both years, showed that the varieties differed significantly in the order Hampton > Kent > CNS for the development per plant of leaf area, number of branches, number of nodes, number of mature pods, number of seeds, pod and seed yields, husk dry weight and seed to husk ratio as well as seed yield per hectare. The differences between the varieties in seed yield could be genetic but leaf area development seems important as well. Hampton therefore appears to have the potential for high seed yield under the prevailing local conditions.
Performance of growing pigs fed dried microbial cells (Methylomonas methylotropha)
Authors: Whittemore C. T. , Moffat I. W.
Published: March 2009

In two experiments, 192 individually penned pigs were given diets containing 900 g barley/kg together with either 100 g dried microbial cells (DMC)/kg or 100 g white fish meal (WFM)/kg, and grown from 23 to 60 kg live weight. In Expt 1 rationing was by live weight and there was no difference between diets for feed used or live weight gained. In Expt 2, pigs were rationed by time and those fed diet DMC grew 15 g/day slower than those fed diet WFM, and their carcasses were of lower specific gravity.
Magnesium metabolism in the dairy cow. I. Metabolism on stall rations
Authors: Rook J. A. F. , Balch C. C. , Line C.
Published: March 2009

1. The results are reported of a series of 8-day magnesium metabolism trials carried out with milking cows fed a variety of typical winter stall rations.

2. Twelve cows fed a standard ration of 15 lb. hay plus 12 lb. of a concentrate mixture containing 3 parts dredge corn, 1 part bran, 1 part decorticated groundnut meal and 1 lb./cwt. Churn 105 minerals, showed variations in the proportion of the feed magnesium excreted in the faeces of from 66·53 to 76·98%, probably reflecting individual differences in the capacity of animals to absorb magnesium.

3. Wide differences in the utilization of the magnesium in typical winter rations were observed. Mean values, with a standard error, obtained for the proportion of the feed magnesium excreted in the faeces with various types of ration were as follows: hay plus concentrates, 71·48 ± 0·94; hay plus proprietary dairy cubes, 62·15 ± 2·73%; hay, proprietary dairy cubes plus decorticated groundnut meal, 91·98 ± 1·93%; hay, silage (1) plus concentrates, 79·53 ± 0·99%; hay, silage (2) plus concentrates, 74·07 ± 4·24%; hay, mangolds plus concentrates, 74·28 ± 5·91%.
Hairiness in wool and a method for selection based on the nature of the fibres and the distribution of halo hairs of the lamb's tail
Authors: Labban F. M.
Published: March 2009

Hairiness in wool of Suffolk sheep as a fault was found to be associated with other defects like coarseness of wool fibres, hairiness of the britch, and the occurrence of pigmented fibres. The presence of these various defects was studied in the lamb's tail at docking time, and subsequently evaluated and correlated with the fleece.

The tails were graded according to the nature of the fibres and the spread of halo hairs from the tip to the base into four principal grades which by further subgrading could be made into seven grades. The results were as follows:

(1) There was wide variability in grades of tails within each flock.

(2) Average grade of tails followed in general the mean quality of the adult fleece.

(3) When Border Leicester were crossed with Welsh Mountain the tails of the two reciprocal crosses were found to be of hairy type of tail and nearly like the Welsh Mountain type.

(4) The percentage of coloured tails in the least hairy grades was found to be inversely related to the quality of the tail grade and indirectly to the fleece quality.

(5) The diameter of the wool fibres on the base of the tail is highly correlated with the diameter of fibres from the britch regions or mean fibre diameter from four regions of the body (mid-shoulder, midside, hip and britch).

(6) The mean diameter of the wool fibres obtained from four different parts of the tail was correlated with those of the britch regions only.

(7) The diameter and variability of fibres increased from shoulder to britch in the body and from base to tip in the tails.

(8) The britch and tails of two groups of sheep, one group characterized by coarse and the other by fine britch and tail wool, were studied histologically. There were significant or highly significant differences in the following characteristics in the britch of the two groups: (a) total number of follicles, (b) primary follicles with no medulla, (c) total number of secondary follicles, (d) secondaries with no medulla, (e) secondaries with large medulla. The only type of follicle where a significant difference was found in the tail was in the number of secondary follicles with no medulla.
The value of mid-season top-dressings of nitrogen fertilizer for main-crop potatoes
Authors: Cooke G. W. , Widdowson F. V. , Wilcox J. C.
Published: March 2009

Twenty-one field experiments were carried out from 1953 to 1955 on main-crop potatoes to compare dressings of nitrogen applied wholly to the seedbed (as ammonium sulphate), with equivalent dressings applied partly to the seedbed (as ammonium sulphate) and partly as a top-dressing (of ‘Nitro-Chalk’) just before the final ridges were set up.
The critical relationship between soil moisture content in the region of wilting point and the mineralization of natural soil nitrogen
Authors: Robinson J. B. D.
Published: March 2009

1. Laboratory incubation studies with topsoil samples of the Kikuyu red loam coffee soil have shown that active nitrification of the natural soil nitrogen stops at a soil moisture level just below the permanent wilting percentage. Ammonification of natural nitrogen in this soil does not cease at this moisture level and ammonia nitrogen accumulates substantially, although the values found at the end of the 32-day incubation period, and the rate of ammonification are significantly lower as the moisture level is decreased from ⅚ to of the permanent wilting percentage.
Milking sows by machine
Authors: Lodge G. A.
Published: March 2009

Equipment for milking sows by machine and the technique employed are described.

The writer wishes to express thanks to Mr H. S. Hall, of the National Institute for Research in Dairying, for assistance in the selection of suitable teat cups, and to the Avon India Rubber Co. Ltd, for kindly supplying the liner tubing.
Nutrient relations of winter wheat:3. Nitrogen uptake, photosynthesis of flag leaves and translocation of nitrogen to grain
Authors: Gregory P. J. , Marshall B. , Biscoe P. V.
Published: March 2009

Two years with contrasting weather, 1976 and 1977, were used to investigate the effects of nitrogen fertilizer on the uptake of nitrogen by crops of winter wheat and on the rate of photosynthesis of flag leaves. The studies involved a number of crops which received various amounts of nitrogen fertilizer at various stages of growth. Weekly measurements were made of the amount of nitrogen in the crops and its distribution within the plant, while a mobile gas exchange system measured the photosynthesis of individual flag leaves.

While the treatments imposed in 1976 resulted in different concentrations of nitrogen in the flag leaves, the maximum rate of photosynthesis and its efficiency in dull light were both unaffected when leaves of the same age were compared. The 2 years gave contrasting results in terms of the amounts of nitrogen taken up during grain growth: in the very dry summer of 1976 it could account for only 25% of the nitrogen in the ear at harvest while in 1977 it could account for almost 50%. These different amounts of translocation to the grain were accompanied by different photosynthetic behaviours of the flag leaves and our analysis shows that, in all treatments, the maximum rate of photosynthesis after anthesis was related to the fractional loss of nitrogen from the leaves.

The implications of these results for farming practice and for techniques used to investigate the effects of nitrogen on photosynthesis are discussed.
The relations between the main shoot and tillers in barley plants
Authors: Kirby E. J. M. , Jones H. G.
Published: March 2009

Barley plants normally produce some tillers which die at an early stage, without bearing an ear. To investigate the proposition that these non-ear-bearing tillers may be wasteful of plant resources, two experiments were made in which the effect of tiller growth on the growth and final size of the main shoot was assessed. In one experiment, tillers were removed at a very early stage when they were a few mm long, or later when they were just emerging from the subtending leaf sheath. In the other experiment the main shoot was removed from the embryo and the size of the coleoptile tiller which grew in its absence was measured.

Tiller removal affected the growth and final size of the main shoot. Leaves emerged more quickly on the main shoot of the detillered plants and were bigger and sometimes more in number. The main shoot of the detillered plants was heavier and it bore a greater weight of grain because the ear had more and heavier grains. In the experiments where the main shoot was removed the coleoptile tiller produced more leaves, which emerged more rapidly and it bore more grains than the coleoptile tiller of the intact plants.

It is concluded that tillers, during their initiation and early growth, compete with the main shoot for a limited supply of resources, thus reducing the size of the main shoot. As some of the resources of the plant are used to produce tillers which die at an early stage and make no contribution to the final grain yield, it appears that they should be regarded as wasteful and that their production may reduce the final grain yield. The physiology of the initiation, growth and early death of these non-ear-bearing tillers requires further investigation.
Competition studies in diploid and tetraploid varieties of Lolium perenne: 1. The influence of density and proportion of sowing
Authors: Norrington-Davies J. , Harries J. H.
Published: March 2009

Two varieties of Lolium perenne, the diploid Hora and the tetraploid Terhoy were sown either as a pure stand or as a binary mixture on to the surface of multipots filled with a standard John Innes compost. Density of sowing was varied over the range of 16, 24, 36, 50 and 100 seeds/pot. There were four replicates. The pattern of germination was followed over a period of 14 days when it was found that (i) the varieties did not differ in their germination when grown alone, but in mixtures the diploid was slower to germinate than the tetraploid, (ii) as the density of sowing per pot was increased, the mean germination time (MGT) was increased, and (iii) the final germination of both verities decreased with increasing density.

In a second experiment the same procedures were followed as before but seed of each variety was sown either as a pure stand or in a mixture of varying proportion as follows: 100:0, 75:25, 50:50, 25:75, 0:100.

The results showed that (i) the diploid had the fastest MGT whilst the mixture values showed no significant variation, and (ii) the final germination percentage of the diploid decreased relative to its pure stand value as its proportion in mixtures decreased, whilst the tetraploid under the same circumstances increased relative to its pure stand value.

It is suggested that differences such as those found could be explained by the presence of germination inhibitors in the seed coats of the two ryegrass varieties.
Studies on the Breeding System of Alexandrian Senna (Cassia Acutifolia Del.)
Authors: Khalifa M. A.
Published: March 2009

Cassia acutifolia Del., known in the Sudan as ‘Senna Makka’ and in commerce as ‘Alexandrian Senna’ (Tothill, 1948), is indigenous to the Sudan and grows wild in the Northern and Central Provinces. It is used locally as a laxative and itsactive ingredient senoside is extracted for pharmaceutical purposes in England, U.S.A. and Germany. The Sudan has been exporting pods and leaves of Senna for many years and the crop has been steadily growing in economic importance. The exported produce is obtained from wild or cultivated Senna plants. Recently a breeding programme has been initiated to provide improved varieties that can both meet the growers’ need for high yield and satisfy the market's demand for uniform high quality produce. Before a proper plant breeding programme can be established, the mode of reproduction must be known since crop breeding procedures are largely determined by the reproductive system. This paper reports on studies made to determine the breeding system in Alexandrian Senna.
Food-intake level in some Romney Marsh ewes and follicle-group development in their progeny
Authors: Wildman A. B.
Published: March 2009

1. An experiment was carried out in which twelve Romney Marsh ewes were separated into two groups, one kept on a high plane of food intake and one on a low plane during pregnancy and lactation. Skin and wool samples were taken from the progeny at birth and weaning; the ratio Sf/Pf was determined for these ages as well as the proportion of follicles of various kinds and in different phases of activity. The results are compared with those of Ryder from an earlier experiment with Cheviots.

2. Differences in food intake of ewes of the order described affected live weight at weaning, but did not significantly affect the differentiation and development of secondary follicles in the foetus nor their number at weaning.

3. Lambs in the low-plane group shed secondary fibres at 12 months old much more than those which had been in the high-plane group.

4. A partial association of variation in birth Sf/Pf with variation in birth weight was demonstrated, but more than half the variation in this ratio is not accounted for in this way, and the same applies to the variation in birth S/P of the Cheviots in Ryder's earlier experiment. It is suggested that variations in foetal environment and in the early post-natal period affect the rate at which the secondary follicle population in a lamb develops towards its mature genetic maximum.
The performance of sheep with differing haemoglobin and potassium blood types
Authors: King J. W. B. , Evans J. V. , Harris H. , Warren F. L.
Published: March 2009

1. Records of sheep with differing haemoglobin and potassium blood types were examined in a large flock of Scottish Blackface sheep.

2. Differences in reproductive performance, which would be subject to natural selection, and in growth rate, fleece characteristics, etc., which would be subject to artificial selection, were sought as an explanation for the gene frequencies observed in different breeds.

3. No significant differences were found in any weights or measurements.

4. The number of lambs produced by different types of ewe did not differ significantly, although there was some suggestion that haemoglobin heterozygotes produce a larger number of lambs at weaning.

5. Study of the equilibrium of the population, however, showed that any heterozygote advantage, if it exists at all, can only be small.
A study of growth in swards of timothy and meadow fescue. I. Uninterrupted growth
Authors: Langer R. H. M.
Published: March 2009

1. Swards of S. 48 timothy and S. 215 meadow fescue growing alone or together were sampled at intervals of 3 weeks throughout the season. The number and weight of leaves, stems and ears were determined, and leaf area was estimated.

2. Despite high rainfall, the total number of tillers in both species declined from the beginning of the experiment until early July, but increased again from then onwards until the original complement had been approximately restored. The number of leaves failed to show a corresponding increase in the autumn because each tiller carried fewer leaves than earlier in the year.

3. In the spring total dry weight increased more rapidly in meadow fescue than in timothy which in turn out-yielded meadow fescue later in the season. Both species attained their greatest dry weight soon after ear emergence, a period which was marked by considerable crop growth and relative growth rates.

4. Leaf area index reached a maximum before total dry weight had increased to its highest level, but then declined in both species. Meadow fescue differed from timothy by producing a second crop of foliage after the summer with a leaf area index of about 7. This second rise appeared to be due mainly to increased leaf size in contrast to timothy whose leaves became progressively smaller towards the end of the season.

5. The differences in growth between the species discussed with reference to their dates of ear emergence which in this experiment differed by about 6 weeks.
Variability of yields in cereal variety × fungicide trials
Authors: Mycroft Hilary
Published: March 2009

Yield variability of spring barley and winter wheat varieties is investigated in National Institute of Agricultural Botany trials sown to assess the influence on varieties of fungicide treatment. The extent of the variation in relative variety performance due to years and centres is estimated for untreated and treated yields and for yield response to fungicide. The consequences for the design of future trials systems are considered.
The effects of breed, breeding system and other factors on lamb mortality: 2. Factors influencing the incidence of delayed birth, dystokia, congenital defects and miscellaneous causes of early death
Authors: Woolliams Carol , Wiener G. , Macleod N. S. M.
Published: March 2009

The incidence of a number of causes of death of lambs around the time of birth was examined in relation to breed, inbreeding, birth weight, birth type, sex of lamb, week of birth and parity. Data were from a grazing flock on an upland farm over a 6-year period. The breeds were the Scottish Blackface, Cheviot, and Welsh Mountain and the crosses among them. Each breed and cross was maintained at five levels of inbreeding ranging from zero to 59% inbreeding coefficient.

The incidence of delayed birth varied significantly among the breeds and crosses with the Welsh having the lowest incidence. Compared with the pure breeds the crosses showed a lower incidence of both delayed birth and preparturient deaths, but significantly only for the latter.

Dystokia was classified according to whether it arose from the relative dimensions of lamb and dam or from malpresentation. For both types the heaviest lambs had the highest incidence but the association with birth weight was much stronger for dystokia involving dimensions. Breed variation was not significant, but cross-breds had the highest frequency for the dimensions category and the lowest for malpresentation. Singles were at greater risk than twins as were lambs born to a first parity.

Congenital defects as a cause of death were divided into six categories. Only skeletal defects varied significantly among breeds and the incidence increased with inbreeding, but crosses of inbred lines did not have the lowest frequency. For congenital defects overall and for hydrocephalus and hydronephrosis in particular, line crosses (noninbred) had the lowest incidence and 25% inbred lambs the highest, the frequency declining with further inbreeding. None of the other factors considered affected variation in the incidence of any of these defects to a significant extent.

Liver rupture and brain haemorrhage were most frequent in heavy lambs, singles and lambs born to a first parity dam.
Water relations of winter wheat: 3. Components of leaf water potential and the soil-plant water potential gradient
Authors: Wallace J. S. , Clark J. A. , McGowan M.
Published: March 2009

Diurnal and seasonal changes in the total, osmotic and turgor potentials of winter wheat leaves are compared in two seasons of mild and severe soil water stress. Gradients of total water potential in the soil-plant system are also presented. In both seasons the total water potential of the leaves decreased in parallel with the soil water potential, concurrently leaf osmotic potential also decreased sufficiently to maintain positive leaf turgor potential. Eventually, under severe water stress, soil water potential approached –1·5 MPa and leaf turgor potential tended to zero during the middle of the day.

The potential drop across the soil-root system was twice that along the stem. Estimates of the water potential at the root surface varied diurnally and were often lower than the bulk soil water potential. In dry soil plants were unable to equilibrate with the soil water potential overnight. These results are consistent with the existence of significant resistance to water flow across the rhizosphere.
Rice bran as a supplement to elephant grass for cattle and buffalo in Indonesia: 1. Feed intake, utilization and growth rates
Authors: Moran J. B.
Published: March 2009

Indonesian Ongole and swamp buffalo bulls were fed ad libitum a diet of elephant grass (Pennisetum purpureum) with five levels of rice bran (0, 1·2, 2·4, 3·6 and 4·8 kg/head/ day) in a study lasting 161 days. Measurements were made of the digestibility of the diet, the balances of nitrogen, phosphorus, calcium and water and the metabolizability of the gross energy. Using multiple regressions, the daily intakes of metabolizable energy were partitioned between maintenance and growth.

Feeding rice bran stimulated appetite, initially improved feed conversion efficiency and increased growth rates. Each additional kilogram of rice bran fed depressed grass dry-matter intake by 0·8 kg in the buffaloes and 0·6 kg in Ongoles. Rice bran had little effect on digestibility of dry matter, organic matter and energy. Metabolizable energy contents of rice bran and elephant grass were calculated to be, respectively, 9·5 and 8·2 MJ/kg dry matter. Nitrogen and phosphorus status was improved in the supplemented animals but the balance of calcium was adversely affected. Voluntary feed intake was always higher in the buffaloes but the differences were reduced with increasing rice-bran supplementation.

Metabolizable energy requirements for maintenance and growth did not differ significantly between Ongole and buffaloes and were similar to values calculated for British animals.
Investigations into the use of plant growth regulators in oil-seed sunflower (Helianthus annuusL.) husbandry
Authors: Baylis A. D. , Dickst J. W.
Published: March 2009

The effects of some plant growth regulators on the growth and development of two cultivars of oil-seed sunflower (cvs Flambeau and Luciole) were examined in 1977 and 1978. Sunflower is a marginal crop for the United Kingdom, being late maturing and susceptible to infection by grey mould (Botrytis cinerea) during the seed-filling period.

An experiment in 1977 indicated that suitable growth regulators might improve sunflower husbandry principally by shortening the stem, allowing late applications of fungicide and insuring against lodging. A mixture of mepiquat chloride and ethephon (BAS 098 OOW) was the most effective stem shortener. Daminozide gave variable effects on yield depending on the rate and time of treatment. The number of seeds per m2 was the major determinant of yield; 1000-seed weights and oil contents were similar for all treatments. The proportion of linoleic acid in the oil was very high in all experiments.

In 1978 a second experiment involving daminozide and two sunflower cultivars revealed seasonal and varietal differences in response. The timing of growth regulator application seemed critical to affect seed yield. The third experiment, in 1978, investigated the results of applying BAS 098 OOW to four plant population densities varying from 40000 plants/ha to 160000 plants/ha. High plant population density advanced maturation by 2 weeks, but in these plots the crop lodged in the absence of growth regulator treatment.
Environmental temperature, energy metabolism and heat regulation in sheep. I. Energy metabolism in closely clipped sheep
Authors: Graham N. McC. , Wainman F. W. , Blaxter K. L. , Armstrong D. G.
Published: March 2009

1. The energy exchange of two sheep closely clipped at weekly intervals was determined at three feeding levels and seven environmental temperatures, using a respiration apparatus in which radiant temperature was equal to ambient temperature. All measurements were made under conditions in which the animal was in equilibrium with its environment and heat storage was zero.

2. Body weight and fleece growth were both markedly reduced at the lowest feeding level. Weight losses were most marked at the lowest temperatures.

3. The energy lost in faeces decreased slightly as environmental temperature increased from 8 to 38° C. Urine energy losses also fell. Losses of energy as methane were maximal in the temperature range 23–28° C. As a result of these changes, the metabolizable energy of food increased with environmental temperature by 7 Cal./24 hr./° C.

4. The environmental temperature of the sheep at which their heat production was minimal, i.e. the ‘critical’ temperature was 39–40° C. for the lowest feeding level, 33° C. for the medium feeding level and 24–27° C. for the highest feeding level.
Sweating in cattle. III. Mechanism of water transportation through the skin
Authors: Taneja G. C.
Published: March 2009

Two calves (Zebu × Australian Illawara Shorthorn and Shorthorn) of about 7–8 months of age were exposed to controlled atmospheric conditions. Cutaneous evaporation from the belly area of these calves was measured by the capsule method. Records of the temperature of the skin under test and that of the air passed over the skin was also maintained.

The amount of water passing through the cattle skin was proportional to the difference between the saturated water-vapour pressure at skin temperature and the water-vapour pressure in the air. Tests were made for the water-vapour pressure difference varying from 9 to 25 mm. Hg.