bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology and position of the shoot apex in some temperate grasses
Authors: Wilman D. , Gao Y. , Michaud P. J.
Published: March 2009

The morphology and position of the shoot apex in field swards was studied in 12 grasses for 12 months, in eight related grasses in 2 years, and in seedlings, young tillers and older tillers of Lolium perenne.

Lolium multiflorum had relatively large numbers of primordia, long apices, which were above ground or near ground level, and a small length of apex per primordium. Festuca arundinacea had few primordia, a large length of apex per primordium, and apices which were well below ground or near ground level. Lolium perenne, Festuca pratensis and Lolium × Festuca hybrids were intermediate between Lolium multiflorum and Festuca arundinacea in numbers of primordia and length of apex per primordium. Festuca rubra and Dactylis glomerata had rather small numbers of primordia, whereas Phleum pratense had relatively large numbers of primordia and of unemerged and emerged leaves.

The numbers of leaf primordia in Lolium perenne increased as the seedling main shoots or the tillers grew older, while the numbers of unemerged leaves per shoot remained more constant.

The morphology, position and protection of shoot apices are discussed in relation to differences between species in rate of establishment and persistence.
Effects of number and siting of single-space feeders on performance and feeding behaviour of growing pigs
Authors: Morrow A. T. S. , Walker N.
Published: March 2009

Two experiments of randomized block design were carried out at the Agricultural Research Institute of Northern Ireland in 1991/92 involving groups of 20 pigs fed ad libitum from single-space feeders with built-in water supply from 37 kg to slaughter at 91 kg liveweight.Treatments were replicated 16 and 6 times respectively in Experiments 1 and 2. In the first experiment, one feeder perpen was compared with two feeders per pen positioned side by side. Two feeders increased feed intake (P < 0·05) but had no significant effects on growth rate or feed conversion. With two feeders, the total time that feeders were occupied and the number of visits to feeders were both increased, while the number of enforced withdrawals from feeders and the amount of queuing were both decreased compared with the single feeder. In the second experiment, placing two feeders 2 m or more apart instead of side by side had no significant effects on feed intake or growth rate but improved feed conversion efficiency by 4%. This improvement was associated with fewer and longer visits to feeders but no difference in enforced withdrawals or queuing. In both experiments all treatments showed broadly similar patterns of diurnal feeding behaviour with two peaks of activity daily, a smaller peak pre-midday and a larger one in the afternoon. This pattern was influenced more by number of visits to feeders than by the mean duration of each visit. It is recommended that two single-space feeders are used in pens of 20 finishing pigs when non-pelleted diets are offered ad libitum and that feeders are sited some distance apart, not side by side.
Effect of sward surface height on herbage intake and performance of lactating ewes lambed in winter and continuously stocked on pasture
Authors: Morris S. T. , McCutcheon S. N. , Parker W. J. , Blair H. T.
Published: March 2009

Thirty-six 4-year-old Border Leicester × Romney (BR), Poll Dorset × BR (PBR) and Suffolk × BR (SBR) ewes balanced for litter size were assigned, 6 days after the mid-point of lambing (29 June 1989), to one of three sward surface height (SSH) treatments replicated twice (six ewes/1 ha paddock). The mean SSH during the 54 days of the trial were 2·6, 4·4 and 7·8 cm. Herbage organic matter intake (OMI) was measured using intraruminal chromium controlled release capsules during weeks 3, 4, 7 and 8 of lactation. Ewe OMI was not influenced by SSH during week 3 of lactation. During weeks 4 and 7 of lactation, ewe OMI increased with SSH up to a SSH of 7·8 cm. In week 8 of lactation there was no significant difference in OMI between ewes grazing the 4·4 or 7·8 cm SSH treatments, suggesting maximum intake at this stage of lactation is reached at 4·4 cm SSH. A maximum OMI of 2·6±0·1 and 3·0±0·1 kg OM/ewe per day (P< 0·05) was reached in week 4 of lactation on the 4·4and 7·8 cm SSH treatments, respectively. Ewes grazing the 2·6 cm swards had a relatively constant OMI throughout the experiment (range 1·8±0·1 to 2·0±0·1 kg OM/ewe per day). However, these ewes lost 10·5 kg of liveweight while those on the 4·4 and 7·8 cm SSH treatments maintained a constant liveweight. Sward surface height had no effect on ewe midside wool growth rate or mean fibre diameter (measured at day 60 of lactation) or on lamb liveweight gain. Ewe breed cross had no effect on ewe OMI or midside wool growth. Lambs reared by SBR ewes were heavier (20·4±0·5 kg) at day 60 of lactation than lambs reared by PBR (18·7±0·6 kg) or BR (18·4±0·6 kg) ewes (P< 0·05). These results suggest that for Winter(June)-lambing ewes in good condition a SSH of 4·0 cm under continuous stocking should ensure near to maximum ewe and lamb performance. However, ewes in good body condition at lambing stocked on a SSH down to 3 cm will rear lambs to acceptable weaning weights but at the expense of ewe liveweight loss and possible long-term carry-over effects on future productionif compensatory weight gains are not achieved during the spring pasture growth period.
The health and performance of the grazing animal in relation to fertilizer nitrogen usage. II. Weaned lambs
Authors: Large R. V. , Speeding C. R. W.
Published: March 2009

1. Experiments were carried out in 1961 and 1962 to study the effect of high levels of nitrogenous fertilizer on the health and performance of early weaned lambs. The lambs were artificially reared and grazed in a ‘worm-free’ area. In 1961, levels of Nitro-chalk were applied at 22 and 110 kg. N/hectare/month and in 1962 an intermediate level of 66 kg. N/hectare/month was added; the actual totals applied per hectare were 220,660 and 1100 kg. to treatments N1, N2 and N3 respectively. All nitrogen treatments were carried out with and without irrigation (applied to maintain a soil moisture deficit of less than 2.5 cm.).

2. Lambs were introduced to the experimental plots when 8-10 weeks of age and grazed in rotation a series of four paddocks on each treatment; a low grazing pressure was maintained at all times.
An experiment measuring effects of N, P and K fertilizers on yield and N, P and K contents of grazed grass
Authors: Widdowson F. V. , Penny A. , Williams R. J. B.
Published: March 2009

1. An experiment was started in 1959 to measure effects on grazed permanent grass of ammonium sulphate, calcium nitrate, superphosphate and muriate of potash; yields and N, P and K contents of the herbage were measured from 1961 to 1964.

2. Applying 1.5 cwt. N/acre per year (in four bi-monthly doses) consistently increased yields. The first and fourth cuttings yielded less with 3.0 cwt. N/acre per year (also in four bi-monthly doses) than with 1.5 cwt. N/acre, but the second and third cuttings yielded more; the total additional yield from 3.0 cwt. N was small. Yields were increased equally by ammonium sulphate (providing that lime was also applied) and calcium nitrate.

3. Yields were increased more by P than by K; the increase from P was greater when N was also applied.
Influence of tree growth on spray chemical deposits on peach leaves
Authors: Hogmire H. W. , Wimmer M. J. , Crim V. L. , Welker R. M. , Wentz E. , Smith R. R.
Published: March 2009

A 50–fold increase in peach tree growth over a 98-day spraying season resulted in a 64 and 96% reduction in nigrosine dye deposit in the periphery and centre of the tree, respectively. Drift from spraying of adjacent rows made a significant contribution (18–39%) to the total chemical deposit in the tree periphery in four of six applications. Drift between rows was not a factor in centre tree deposit, except for a 38% contribution in the initial application. A variable reduced application rate of methyl parathion, calculated using a regression equation, resulted in a more uniform deposit throughout the season than a full application rate, providing comparable control of Oriental fruit moth withc. 50% less insecticide.
Factors affecting birth weights of Awassi lambs
Authors: Juma K. H. , Faraj M.
Published: March 2009

The Awassi flock raised at the Abu-Ghraib Experiment Station over the years 1960-64 produced 923 single and 88 twin births. The environmental factors affecting birth weight, and the repeatability of birth weight were investigated.

Sex of lamb, type of birth, weight of dam, time and year of lambing were found to have significant effects on the birth weight of Awassi lambs. Male and single lambs were heavier at birth than female and twin lambs respectively. Ewes weighing between 126 and 135 lb. produced the heaviest lambs at birth. Lambs born earlier and later in the lambing season were heavier than lambs dropped in midseason.
Teat-seeking activity in new-born lambs: the effects of cold
Authors: Alexander G. , Williams D.
Published: March 2009

Behaviour of lambs was studied in three separate physiological states resulting from planned exposure to cold, i.e. energy reserves depleted, discomfort during the experience of cold, and hypothermia.

When lambs were observed under mild conditions, prior depletion of about 20 % of the energy reserves, due to exposure to cold conditions for 4 hr., was without marked effect on teat-seeking activity. However, when the lambs were observed under cold, wet conditions, there was a marked depression of this activity. The activity in lambs which had been kept warm to conserve energy also tended to be depressed under conditions of discomfort due to cold.
Grazed pasture parameters. I. Pasture dry-matter production and availability in a stocking rate and grazing management experiment with dairy cows
Authors: Campbell A.G.
Published: March 2009

1. Net pasture dry matter production and available pasture dry matter were measured over 3 years in a small-scale replica of the study of the effects of dairy cow grazing management and stocking rate reported by McMeekan & Walshe (1963).

2. The four treatments were

(i) Controlled rotational grazing, light stocking rate (0.95 cows/acre).

(ii) Controlled rotational grazing, heavy stocking rate (1.19 cows/acre).

(iii) Uncontrolled, set stocked grazing, light stocking rate (0.95 cows/acre).

(iv) Uncontrolled, set stocked grazing, heavy stocking rate (1.19 cows/acre).

3. The pasture measurement technique employed measured net pasture production (gains through new growth minus losses from all sources). It is argued that this parameter, rather than absolute pasture production, governs the changes in the dry matter feed supply to the grazing animal.
Grazed pasture parameters. III. Relationships of pasture and animal parameters in, and general discussion of a stocking rate and grazing management experiment with dairy cows
Authors: Campbell A. G.
Published: March 2009

1. Pasture parameters have been correlated with animal production parameters from a trial in which two management systems (‘controlled’ and ‘uncontrolled’ grazing), each at two stocking rates (0.95 and 1.19 cows/acre), were compared.

2. Per acre butterfat production was positively related to percentage utilization of available D.M., but negatively related to yield of available D.M.

3. Per cow butterfat production was significantly and positively correlated with yield of available D.M. in the two months after calving (August and September) and in the penultimate month of lacta-tion (April), but this correlation was not significant in other months.

4. It is concluded that management system was as important as stocking rate in increasing the utilization of pasture and animal production from pasture.
Experiments on the direct, cumulative and residual effects of town refuse manures and sewage sludge at Rothamsted and other centres 1940–1947
Authors: Garner H. V.
Published: March 2009

Several town-refuse manures were compared with farmyard manure at Rothamsted and five other places between 1940 and 1947. The organic manures were used at 8 and 16 tons/acre with and without fertilizer nitrogen and potash. Direct and residual effects were measured on agricultural and horticultural crops.

All organic manures improved yields in the year of application, FYM most and consistently. The average percentage increases in yield produced by the pulverized refuses tested, in relation to the increase from an equal weight of FYM, were: sugar beet 22, mangolds 83, carrots, 85, potatoes 51. The corresponding figures for screened dust were: sugar beet 40, mangolds 28, carrots 41; the dust slightly depressed potato yields. Averaging all sixteen experiments on root crops, the pulverized refuses had 64% of the first-year effect of FYM and the screened dust 25%.
Stem and root characteristics associated with lodging resistance in four winter wheat cultivars
Authors: Crook M. J. , Ennos A. R.
Published: March 2009

The effects of root and shoot characteristics on the lodging resistance of four cultivars of winter wheat were investigated by combining results from a field trial (set up at Manchester University's Experimental Grounds, Jodrell Bank, in mid-September 1991) with morphological and mechanical measurements on their stems and anchorage systems. Cultivars showed contrasting lodging resistance: Widgeon was most susceptible, followed by Galahad, Riband and Hereward which, alone, did not lodge. Lodging resistance was not related to the strength and stiffness of the stems, which were usually adequate to withstand the forces to which they were subjected. Most plants instead failed in their root system which rotated through the soil. Resistance was associated with short and light stems (and hence on the force applied to the plants by wind and gravity) and with high values of the anchorage strength of the root system (and hence on the force resisting lodging). Lodging occurred during grain filling when the ears were heaviest and when the soil was wet. The anchorage strength of a plant depended on two characteristics of the root system: the bending strength and the angle of spread of the basal coronal roots. Plants with stronger, more widely spread coronal roots produced larger soil cones during anchorage failure and resisted larger forces. Future breeding for lodging resistance, therefore, should continue to select for plants with shorter stems and with stiffer, more widely spread, coronal roots.
Effects of straw incorporation on the yield, nitrogen fertilizer and insecticide requirements of sugarbeet (Beta vulgaris)
Authors: Allison M. F. , Jaggard K. W. , Last P. J.
Published: March 2009

Incorporation of large amounts of straw (8–15 t/ha dry matter) into the soil had no effect on the incidence of soil pests and diseases or sugarbeet seedling population densities in experiments performed over three seasons (1984/85 to 1986/87) in Suffolk. Straw incorporation had no effect on sugar yield at the recommended rate of nitrogen fertilizer application, but the sugar yield and nitrogen uptake were reduced in one year by the incorporation of straw when the rate of applied nitrogen was low. It is probable that incorporating straw reduced the amount of nitrogen leached over the winter; however, the longer-term implications of straw incorporation remain to be assessed.
Effect of Haemonchus contortus on productivity of ewes, lambs and weaners in a semi-arid environment
Authors: Cobon D. H. , O'Sullivan B. M.
Published: March 2009

Lactating ewes, ewes that had lambed but subsequently lost their lambs (dry) and weaners were either artificially infested with 2000–3000 third-stage Haemonchus contortus larvae (parasitized) or drenched with levamisole (treated) and run under extensive grazing conditions in north-west Queensland. Worm egg counts in parasitized lactating, dry and weaner sheep ranged from 860–2830 eggs per gram of faeces. These levels of infestation significantly (P < 0·01) reduced liveweight gain of all three sheep classes, milk yield of ewes and wool growth of weaners compared to their treated counterparts. The lower milk yield of the parasitized ewes significantly (P < 0·01) reduced lamb growth rate. Survival of lambs to weaning was 26% higher in the treated group. The experiments showed that moderate levels of H. contortus, that did not produce clinical signs of infestation, reduce productivity of sheep in this semi-arid environment.
Factors affecting body weight at birth and at 90 days of age in pure-bred and cross-bred cattle in a tropical environment
Authors: Willis M. B. , Wood P. D. P. , Kaspar A.
Published: March 2009

Live weights of 8764 calves born in seven herds in Cuba during the years 1966–8 were measured at birth and at approximately 3 months of age. Over 2600 were pure bred: Zebu (2002), Santa Gertrudis (435) and Charolais (212); the remainder were crossbred Holstein x Zebu (4955) and Brown Swiss x Zebu (1160).

Year, season of birth, herd and sex were associated with variation in mean birth weight in all breeds and crosses except Charolais in which no seasonal effect was apparent and in Brown Swiss x Zebu cross-breeds in which herd and sex effects were absent.

At 90 days there was a general tendency for calves born in late spring and summer to be heavier than those bom at other times. By this age, herd variation had subsided among Brown Swiss x Zebu cross-breds, and variation due to sex had ceased to be important among Charolais calves.

Estimates of heritability of birth weight ranged from 0·09 in Holstein crosses to 0·62 in Brown Swiss crosses, and of weight at 90 days from 0·05 in Brown Swiss crosses to 0·44 in the Charolais breed. Phenotypic correlations between birth and 90 days weights were of the order of + 0·25 while genetic correlations were positive for pure breeds and negative for cross-breeds.
Leys and soil organic matter:III. The accumulation of macro-organic matter in the soil under different swards
Authors: Garwood E. A. , Clement C. R. , Williams T. E.
Published: March 2009

Macro-organic matter (roots and partially decomposed plant debris retained on a 0·25 mm mesh sieve) was measured in soils under various swards. Under a grazed perennial ryegrass/white clover sward, sown on arable land, macro-organic matter in the top 15 cm of soil rose steadily in the first 8 years to 15·8 t/ha, but subsequently declined. Under arable cropping there was great variation with crop and season. Under grass, most of the macro-organic matter accumulated in the top 2 cm of soil, particularly during the first 3 or 4 years. More macro-organic matter was found under perennial ryegrass/white clover than under cocksfoot/white clover swards.

After 3 years under grass macro-organic matter accounted for 10% of the total soil carbon, and represented about half the increase in soil carbon.

Half, or less, of the nitrogen which accumulated in soil under grass was in the macroorganic matter fraction. The differences between swards which received no N fertilizer and those which received 940 kg/ha over 3 years was small, 16–40 kg N/ha respectively for cut and frequently grazed swards. The ratio of C:N in macro-organic matter under different swards averaged 22:1.
Culture and fertilization of sheep ovarian oocytes:III. Evidence on fertilization in the sheep oviduct based on pronucleate and cleaved eggs
Authors: Quirke J. F. , Gordon I.
Published: March 2009

Four hundred and fifteen oocytes cultured in growth medium for 24·5–28·5 h were transferred to the oviducts of 23 oestrous ewes. Twenty ewes were bred prior to transfer; three remained unbred as a control. After intervals of 24–73 h oocytes were recovered. In 179 oocytes from 19 bred recipients, 19 pronucleateand 26 cleaved eggs were recovered; one apparent 4-cell egg was found in 37 oocytes recovered from unbred ewes.
The effect of breed on the composition of blood
Authors: Heyns H.
Published: March 2009

The blood of 12 Afrikaner cows and their calves and 12 Friesland cows and their calves were analysed for 12 constituents to study the effect of breed on the composition. Breed had a significant effect on the composition of blood. The haemoglobin, erythrocyte, alkaline phosphatase, potassium and calcium content of the blood of the Afrikaner cows were statistically significantly higher, and the glucose and globulin significantly lower, than those of Friesland cows. In respect of the calves, differences were statistically significant for haemoglobin, erythrocytes, alkaline phosphatase, glucose, calcium, albumin and non-protein nitrogen.
Statistical evaluation of drainage treatments in simple field trials with special reference to former opencast coal mining land
Authors: Scullion J. , Mohammed A. R. A. , Ramshaw G. A.
Published: March 2009

Drainage trials frequently lack any statistical evaluation of treatment differences, often because of practical difficulties in setting up randomized field experiments. Also, where detailed moisture measurements are carried out the usefulness of such data is small in relation to the workload involved. Procedures are described here which seek to rectify, in part, the above limitations.

Routine drain and surface condition data were analysed. Parallel regression analysis was used to compare drainage response patterns based on linear relationships between rainfall and peak drain flow. A point scoring system allowed treatment effects on surface conditions to be evaluated by x2analysis.

Artificial drainage seeks to simulate naturally free-draining conditions. In line with this objective, soil moisture contents in the field, on a ‘Field Capacity Day’ (Stewart & Adams, 1968), were related to those at a standard (– 10 KPa) moisture tension typical of free-draining reference sites. Effectiveness of drainage performance was indicated by proximity of field and reference tension moisture contents.

Worked examples of each of the above procedures are provided. The procedures were found to be both sensitive and complementary. The value of the overall approach and its application under more normal agricultural conditions are discussed.
Effects of inflorescence removal on seed yield performance of field beans (Vicia faba) under different shading treatments
Authors: Aufhammer W. , Götz-Lee I.
Published: March 2009

Effects of inflorescence removal under different plant densities and degrees of shading on seed yield of field beans (Vicia fabaL.) were investigated. Two indeterminate cultivars were used in field experiments for two seasons (1985 and 1986). The hierarchy within the generative storage system of field bean plants was manipulated by removal of inflorescences at various growth stages and nodes.

Removal of the inflorescences of nodes 1–3 (counted from the base upwards) caused about 30% loss of seed yield potential compared with the control but compensatory increases in seed yield were found, differing with plant density and duration of shading. Under favourable growing conditions (no shading, 20 plants/m2), overcompensation occurred, giving a mean seed yield up to 40% more than in controls.

Removal of all inflorescences above the ninth flowering node did not significantly reduce seed yield as plants completely compensated for the restriction on yield imposed.
Effect of timing of injection with pregnant mare's serum gonadotrophin on fixed-time artificial insemination of seasonally anoestrous ewes
Authors: Fukui Y. , Akaike M. , Anzai H. , Ono H.
Published: March 2009

Effect of timing of pregnant mares's serum gonadotrophin (PMSG) injection combined with a progestagen-impregnated vaginal sponge on fixed-time artificial insemination with fresh, undiluted semen during the nonbreeding season was investigated. PMSG injection 2 days before sponge removal (group A) caused significantly earlier oestrus than injection at the time of sponge removal (group B). Lambing percentages in a total of 320 ewes after fixed-time insemination at 36 h (64·1%) and 48 h (47·2%) in group A, and 48 h (59·5%) and 60 h (39·5%) in group B were not significantly different from those resulting from ‘at oestrus’ insemination (500% and 511% in groups A and B, respectively). The present results indicate that the optimum time for fixed insemination may depend upon the time of PMSG injection associated with progestagen treatment.
Nitrogen immobilization in decomposing litter contributes to productivity decline in ageing pastures of green panic (Panicum maximum var. trichoglume)
Authors: Robbins G. B. , Bushell J. J. , McKeon G. M.
Published: March 2009

The extent and rate of N release from nylon bags containing green panic (Panicum maximumvar.trichoglume)litter was measured for up to 319 days (long-term studies) in 1978/79 and 1979/80 in Gayndah, Australia. Dry matter (DM) decomposition rates were measured in 41 periods of 39 days and related to environmental variables and initial litter N concentrations (short-term study).

About half of litter DM decomposed during the long-term studies, while N concentration in the remaining litter increased from an initial average of 0–57 % N, to 0–95 % N. Net release of N from bags began when its concentration in the residue increased to c.0–65% N (or when the C:N ratio decreased to 75:1). Only a net 20–30 % of the initial N was released for potential plant uptake by the end of the study. The short-term study showed that DM decomposition was rapid and independent of pasture age. Decomposition rate increased with soil moisture and average daily temperature but was unaffected by initial litter N concentration. Release of N from decomposing litter was slow, despite rapid DM decomposition. It was concluded that a major cause of declining productivity in sown grass pastures is the immobilization of N in decomposing grass litter.
Phenological development in bambara groundnut (Vigna subterranea) at alternate exposure to 12 and 14 h photoperiods
Authors: Linnemann A. R.
Published: March 2009

The developmental phase in which photoperiod sensitivity for podding occurs was determined for two bambara groundnut genotypes grown in 1987 and 1990 in glasshouse experiments in the Netherlands, namely genotypes ‘Tiga Nicuru’ from Mali (day-neutral for flowering and photoperiod-sensitive for podding) and ‘Ankpa 4’ from Nigeria (photoperiod-sensitive for both flowering and podding). Eighteen photoperiod treatments were given to each genotype. Two treatments consisted of a constant 12 or 14 h photoperiod and started 21 days after sowing for ‘Tiga Nicuru’ and 18 days after sowing for ‘Ankpa 4’. Eight treatments were introduced by transferring plants with at least 20 flower buds (33-day-old plants of ‘Tiga Nicuru’ and 35-day-old plants of ‘Ankpa 4’) from a 12 to a 14 h photoperiod or vice versa. In ‘Tiga Nicuru’ transference was for 4, 8, 12 days or until harvest, and in ‘Ankpa 4’ it was for 8, 12, 16 days or until harvest. Another eight similar treatments were given to plants transferred after having had at least 20 open flowers (48-day-old plants of ‘Tiga Nicuru’ and 62-day-old plants of ‘Ankpa 4’). Transferring plants of ‘Tiga Nicuru’ to the 12 h photoperiod for at least 8 days induced podding. Plants were susceptible to podding induction for nearly 4 weeks: podding was induced in plants which had been in the natural photoperiod (≥ 15·5 h) for 21 days, followed by 12 days in the 12 h photoperiod and subsequently in the 14 h photoperiod until harvest, and it could still be induced in 48-day-old plants that had had > 20 open flowers. However, transference to the 12 h photoperiod for 16 days did not induce podding in ‘Ankpa 4’. Transferring plants from the 12 to the 14 h photoperiod or vice versa caused differences in the number of flowers and pods/plant, petiole length and leaf area. The influence of photoperiod was most obvious on the number of pods/plant. Leaf area and number of pods/plant seem suitable parameters for modelling crop growth under different photoperiods. Leaf area development correlated with the number of developing pods/plant, but was also more directly influenced by the prevailing photoperiod.
Effect of the absence of condensed tannins in faba beans (Vicia faba) on resistance to foot rot, Ascochyta blight and chocolate spot
Authors: Helsper J. P. F. G. , Norel A. Van , Burger-Meyer K. , Hoogendijk J. M.
Published: March 2009

The effect of breeding for the absence of condensed tannins in the testa ofVicia fabaL. on resistance to foot rot, Ascochyta blight and chocolate spot diseases was investigated in 1988–92 at Wageningen, The Netherlands. For this purpose the disease development in tannin-free and tannin-containing partners of six near-isogenic pairs was compared after exposure to causative pathogens. Except for one near-isogenic pair, in which both partner lines showed a relatively high resistance, the tannin-free lines were more susceptible to foot rot than the tannin-containing partners of the same pair. This observation indicates that the presence of condensed tannins in the testa prevents infection of the plant by the causative pathogens.Fusarium oxysporumandF. solani, isolated from faba bean tissues showing foot rot symptoms, were shown to be primary foot rot pathogens, whileF. avenaceumcaused wilting of young plantlets. No pathogenic isolates were obtained fromF. tabacinum. Resistance toBotrytis fabae(chocolate spot disease), scored on leaves and stems under glasshouse and field conditions in 1992, was not influenced by selection for the absence of condensed tannins which occur in the testa of mature seeds. Under the same environmental conditions, leaves, stems, pods and seeds of tannin-free lines showed similar levels of damage due toAscochyta fabae(Ascochyta blight) as the tannin-containing partner lines of the same near-isogenic pair. These results indicate that condensed tannins do not play a role in resistance to bothB. fabaeandA. fabae, probably because, except for the seeds, these polyphenols do not accumulate in the tissues affected by these pathogens.
Varietal differences in the chemical composition and in vitro digestibility of rice straw
Authors: Vadiveloo J.
Published: March 2009

Four varieties of rice straw, MRl, MR71, MR84 and MR27, were separated into the following botanical fractions; inflorescence, stem, leaf blade and leaf sheath. The relative proportion of each fraction in whole straw was estimated and analysed for its chemical composition and in vitro digestibility (IVD). The composition and IVD of whole straw was then calculated. Cluster analysis showed that MRl was distinct from the other varieties. This could be attributed to a high proportion of stem (32·3%), high IVD (36·9%), low insoluble ash (4·0%) and a low silica content (2·7%) in the whole straw. The genetic distance between any two varieties ranged from 5·4 × 10-3 to 47·8 × 10-3 and was largest between MRl and the other varieties. Cluster analysis also showed that within a variety, the chemical composition and IVD of the stem, leaf blade and leaf sheath were similar, suggesting that sampling errors may be reduced if the inflorescence, which comprises 7–13% of the whole straw, is excluded when the material is analysed. Stepwise and canonical discriminant analyses indicated that the important variables to be measured when comparing straw varieties were IVD, crude protein and insoluble ash.
The effect of age, sex and season on sebum output of Ayrshire calves
Authors: Smith Miranda E. , Jenkinson D. McEwan
Published: March 2009

Sebum was collected from pre-cleaned areas on the skin of Ayrshire calves at a fixed time using a cup and solvent technique, extracted and weighed. The rate of sebum output decreased with time and after 18 h there was very little increase in the weight of sebum on the skin surface. Sebum output over a period of 3 h was not statistically different between animals of different ages but tended to be higher in castrated males than in females and was lower in winter than throughout the remainder of the year.
A new gene, developed through mutagenesis, for resistance of rice to bacterial leaf blight (Xanthomonas campestris pv. oryzae)
Authors: Nakai H. , Nakamura K. , Kuwahara S. , Saito M.
Published: March 2009

An induced mutant of rice, designated M41, resistant to several races of bacterial leaf blight, obtained after irradiation with thermal neutrons, was crossed with the original variety, Harebare. Test crosses revealed that the resistance of M41 to the Japanese races I, II, III and IV is controlled by a single recessive gene, considered to be different from four previously identified dominant resistance genes of japonica-type varieties and from three recessive genes in indica-type varieties for resistance to Philippine races. The gene in M41 was tentatively designated xa-nm(t).
Effects of incorporating straw, using different cultivation systems, and of burning it, on diseases of winter barley
Authors: Jenkyn J. F. , Gutteridge R. J. , Todd A. D.
Published: March 2009

An experiment at Rothamsted in 1985–89 and another at Whaddon in 1986 studied the effects of incorporating straw on diseases of winter barley. Net blotch (Pyrenophora teres) and leaf blotch (Rhynchosporium secalis) were initially less severe where straw was burnt or incorporated by ploughing than where cultivations only partially buried it. However, by summer both diseases were usually more severe where straw had been burnt than where it had been incorporated. At Whaddon, eyespot (Pseudocercosporella herpotrichoides) tended to be less severe in tine-cultivated plots where straw was incorporated than where it was burnt, but at Rothamsted, where the straw treatments were confounded with cultivations, there was no consistent effect. The disease was usually more severe where straw was incorporated by ploughing than where it was incorporated using other methods. In contrast, the severity of take-all was generally decreased by ploughing. Seedlings usually grew better where straw had been burnt rather than incorporated and grain yields were often larger. However, yields at Rothamsted in 1987 were unusually, and inexplicably, smaller after burning the straw so that the 5-year mean yields showed no significant differences between treatments.
Seed yield in caraway (Carum carvi). 2. Role of assimilate availability
Authors: Bouwmeester H. J. , Smid H. G. , Loman E.
Published: March 2009

Assimilate availability may determine seed yield of caraway during three periods: (i) beforeflowering it may determine dry matter allocation to flowers and thereby the number of ovaries; (ii) during flowering it may determine seed set; and (iii) after flowering it may determine seed filling. From 1990 to 1992 in the vicinity of Wageningen, field experiments were performed in which growth, assimilate storage and partitioning, and the effects of shading during various growth stages on seed set and filling, were studied to determine the importance of these three phases. Dry matter production before flowering was correlated with dry mass of flowers, but there was no relationship between the dry mass of flowers and seed yield. Assimilate availability after flowering only slightly affected seed yield, but during flowering it had a strong effect. Shading 50% (during c. 3 weeks of flowering only) reduced yield by 30% whereas 50% shading (after flowering for > 1 month) reduced yield by only 6%. In addition, the main flowering period of biennial caraway over a number of years was estimated and the daily amount of photosynthetically active radiation (PAR) for that period calculated. There was a close linear relationship between light intensity during flowering and yield. The possibilities for yield improvement using these results are discussed.
Digestion, rumen fermentation and chewing behaviour of red deer fed fresh chicory and perennial ryegrass
Authors: Hoskin S. O. , Stafford K. J. , Barry T. N.
Published: March 2009

Pure chicory (Cichorium intybus) and perennial ryegrass (Lolium perenne) forages were cut and fed fresh at Palmerston North, New Zealand, during March 1993 to castrated male red deer kept indoors in metabolism crates. Chicory contained lower levels of dry matter, higher levels of ash, and had a higher ratio of readily fermentable: structural carbohydrate than perennial ryegrass. Apparent digestibility of organic matter was highest for chicory (0·81 v. 0·72), but cellulose apparent digestibility was highest for perennial ryegrass (0·71 v. 0·59). Relative to perennial ryegrass, the rumen fluid of deer fed chicory contained higher concentrations of protozoa, ammonia and total volatile fatty acids (VFA) but had a lower pH at 15.00 h. Chicory-fed deer had higher rumen VFA molar proportions of n-butyrate and a higher acetate: propionate ratio. Total eating time and chews during feeding/g dry matter intake were similar for deer fed the two forages, but deer fed chicory spent much less time ruminating (33 v. 270 min/day) and had fewer rumination boluses (38 v. 305/day). It was concluded that the low rumination time may indicate rapid disintegration of chicory in the rumen to < 1 mm critical particle size, and that particle breakdown and rumen fractional outflow rate should be measured in future experiments with deer fed on chicory.
Performance of conventional and alternative cropping systems in cryoboreal subhumid central Alberta
Authors: Izaurralde R. C. , Juma N. G. , McGill W. B. , Chanasyk D. S. , Pawluk S. , Dudas M. J.
Published: March 2009

A 3-year field study (1986–88) was conducted in central Alberta to discover how diverse soil-plant systems function under cryoboreal subhumid conditions. Barley, fescue, faba (field) bean and a barley/field pea intercrop were grown continuously on different soils at Ellerslie and Breton using two distinct tillage methods. The agronomic performance, weed-crop interactions and below-ground productivity of these cropping systems were examined. The main findings were as follows: different soil properties did not affect yields of barley, barley/field pea and fescue fertilized with N and P; silage yield of faba bean at Breton was greater than at Ellerslie; barley/field pea and faba bean could be grown without tillage at Ellerslie; barley/field pea plots had the lowest weed counts; fescue root biomass was greatest at all depths followed by faba bean and barley; and soil properties appeared not to induce differences in root production of a cereal, an annual forage legume and a perennial grass. Increasing the use of annual legumes into rotations, either as sole crops or as intercrops with cereals, may be a viable alternative to continuous cereal cropping because annual legumes contribute N through biological N fixation, reduce weed competition and increase the input of root mass in soil.
Intake, by sheep, and digestibility of chickweed, dandelion, dock, ribwort and spurrey, compared with perennial ryegrass
Authors: Derrick R. W. , Moseley G. , Wilman D.
Published: March 2009

Six plant species were compared as food for sheep: chickweed (Stellaria media (L.) Vill.), dandelion (Taraxacum officinale Weber), dock (Rumex obtusifolius L.), ribwort (Plantago lanceolata L.), spurrey (Spergula arvensis L.) and perennial ryegrass (Lolium perenne L.). In two experiments at Aberystwyth in 1985 and 1986, the species were fed to lambs as the total diet, after artificial drying. In another experiment in 1987, they were fed fresh, in 1·5 minute meals, to yearling sheep.

The dicotyledonous species had a lower proportion of cell wall (neutral detergent fibre) in dry matter than perennial ryegrass. The true dry matter digestibility of chickweed, dandelion, dock and leafy ribwort was as high as that of ryegrass, but the in vivo digestibility of all five dicotyledonous species was lower than that of ryegrass. The voluntary intake of the dicotyledonous species was higher than might have been predicted from their digestibility. The voluntary intake of spurrey was > 20% higher than that of ryegrass.

When the species were fed fresh, spurrey had the highest rate of intake as a consequence of a high chewing rate and a low requirement for number of chews/g of dry matter consumed. Chewing rate was higher on all the dicotyledonous diets than on ryegrass. The rate of intake of dandelion was above average, but that of dock was low and variable, particularly when the plants had been chopped.
Nitrogen transformations in calcareous soils amended with pig slurry under aerobic incubation
Authors: Bernal M. P. , Roig A.
Published: March 2009

The mineralization and nitrification processes in pig slurry were investigated in Spain in 1990 in three calcareous soils, differing mainly in content and type of clay, two classified as Typic Calciorthids and one as a Xerollic Calciorthid. Two different amounts of slurry were mixed with the soils, one equivalent to 273 mg N/kg soil and the other equivalent to 546 mg N/kg soil. The mixtures of soil and slurry were aerobically incubated for 16 weeks at 28 °C. A mean initial immobilization of 22·19% of the total-N added was detected in soils treated with the lower rate of slurry. The amount of mineralized N after 112 days of incubation was between 36 and 47% of the total-N added with the lower slurry application to the three soils. The net amount of N mineralized throughout the experiment was therefore within the range 14–23% of the total-N added. The nitrification of the NH4-N added to the soil began after 7 days of incubation, and followed a first-order kinetic model. The mean values of potential nitrate formation were 61 and 51% of the total-N added in soils amended with 273 and 546 mg N as pig slurry per kg soil respectively. The rate constants were higher in the treatments with the lower slurry application (0·043–0·083 per day). Therefore, in these treatments, the nitrification process was faster and total nitrate levels were higher than in soils receiving double that amount of slurry. The NO3-N evolution was parallel to the total-N evolution from the 14th day of incubation onwards. The N-mineralization process was limited by the transformation of the organic-N into ammonium (ammonification).
Effects of prolonged administration of a β-agonist drug, ritodrine, on cardiovascular, metabolic and endocrine responses to adrenaline in growing ram lambs
Authors: Bassett J. M.
Published: March 2009

Five Suffolk crossbred ram lambs were administered ritodrine, a β2-agonist drug, by continuous intravenous infusion at 0·5 μg/kg per min for 9 days to determine effects of prolonged β-agonist infusion on metabolism and on the responsiveness of the animals to short-term infusions of adrenaline. Consistent with other investigations, this study showed that initially the drug caused rapid increases in heart rate and plasma concentrations of free fatty acids (FFA), lactate and insulin, but decreased plasma growth hormone. There was no effect on plasma glucose or pancreatic glucagon concentrations. After 24 h of ritodrine infusion, these effects were attenuated as tachyphylaxis to the drug developed. On days 2–9 of the infusion, heart rate remained significantly higher than preinfusion values, but plasma glucose concentration was significantly lower than before infusion. Despite the rapid disappearance of these ‘side-effects’ of the drug and the apparent normality of most metabolic parameters, short-term infusion of adrenaline (50 ng/kg per min for 60 min then 500 ng/kg per min for a further 60 min) after 9 days of ritodrine infusion showed that the responses of lactate, FFA and heart rate to adrenaline were significantly attenuated in comparison with the responses determined before β-agonist infusion. This result, together with similar earlier observations on fetal lambs, implies that selective attenuation of β-receptor mediated cardiovascular, metabolic and endocrine responses to the endogenous catecholamines could play an important role in determining how β-agonist drugs act to modify carcass development.
Efficiency of nitrogen use by dryland wheat in a subhumid region in relation to optimizing the amount of available water
Authors: Benbi D. K.
Published: March 2009

The effect of soil water supply on efficiency of N use in wheat and NO3-N accumulation in the soil profile was studied in a field experiment on loamy sand soil at Boothgarh in Hoshiarpur, Punjab, India in 1980/81. As the water supply increased from 509 to 548 mm, the response to N application increased by 11·5 kg grain/kg N and apparent N recovery by 11% at optimum N application rates. The increase in N recovery with additional water supply was related to the NO3-N use from the profile. The accumulation of NO3-N in the profile was related linearly to rate of N application but inversely to water supply up to an optimum value of 580 mm. Further increase in water supply did not increase fertilizer N use. If both the amount of moisture stored in the profile at sowing and the probable rainfall during the crop season are known, the efficiency of fertilizer N use can be predicted.
Response of Pure Stands and Mixtures of Cereals and Legumes to Nitrogen Fertilization and residual effect on subsequent barley
Authors: Papastylianou I.
Published: March 2009

Two rotation field experiments of a single forage–cereal cycle each were conducted on a clay loam soil (Vertic Cambisols) in Cyprus in 1982–85. The forages in the first cycle (1982–84) were pure stands of vetch (Vicia saliva L.), peas (Pisum sativum L.) and oats (Avena sativa L.) and mixtures of each of the two legumes with oats at sowing ratios of 90:10, 75:25, 50:50 and 25:75 grown with 15, 30, 60, and 90 kg fertilizer N/ha. For the second cycle (1983–85) the same crops were used but with only two mixture ratios (legume:oats 90:10 and 75:25), and with 0, 15, 45 and 90 kg N/ha. Barley (Hordeum vulgare L.) was the test crop after the forages in both cycles. Legumes did not respond to N fertilization, whereas the yields of the pure stand of oats and the mixtures increased. The legumes yielded more N but less dry matter than the cereals. The grain and N yields of barley were higher after legumes than after oats, with intermediate yields after the mixtures. Barley responded to residual N fertilizer, irrespective of whether it was applied on legumes, oats or mixtures in the previous year. When choosing the forage to be grown, farmers should consider (a) the need for roughage and protein, (b) the costs of N fertilizer for crops and of protein for animal feed stuff and (c) the rotational role of the crop.
Comparison of crop yields and soil conditions during 30 years under annual tillage or grazed pasture
Authors: Tyson K. C. , Roberts D. H. , Clement C. R. , Garwood E. A.
Published: March 2009

Crop yields and soil properties of grazed grass–clover pasture and arable plots at the Grasslands Research Institute, Hurley, UK. were measured over 30 years (1955–84). Yields of herbage declined from 9·6 t DM/ha in the first harvest year to 4–6 t in years 5 to 8 but subseque8tly increased (after liming) to give a mean yield of 8·2 t for 1963–84. Yields of barley in plots receiving a seed-bed application of 45 kg N/ha averaged (1962–80) 3·1 t/ha and, in plots top dressed with an additional 100 kg N/ha, 4·1 t/ha but after 1969, response to additional N and yield under both N treatments showed a marked decline.

Soil carbon increased during the first 10 years under pasture from 1·2 to 1·8% and soil N from 0·13 to 0·17%. These increases, equivalent to 1 t C and 75 kg N/ha per year, occurred at the same time as the initial decline in herbage yield noted above. During the subsequent 20 years, C and N remained relatively constant and herbage yields increased. Soil C and N decreased under 30 years' arable management to 0·8% C and 0·1% N, equivalent to a loss of 290 kg C and 25 kg N/ha per year.

Major factors that appear to have influenced herbage yields were (i) soil moisture, (ii) accumulation of N in the soil organic matter during the first 8 years and the subsequent increase in the rate of mineralization, and (iii) the action of the earthworm population in creating a stone-free, fertile layer of top soil. As for barley, it was concluded that yields could not be maintained indefinitely on this soil series, as a result of the loss of soil structure and the development of a compact layer of soil at plough depth.