bluuebunny/crossref_metadata_2025 huggingface dataset:
Take-all, Gaeumannomyces graminis var. tritici, and yield of wheat grown after ley and arable rotations in relation to the occurrence of Phialophora radicicola var. graminicola
Authors: Slope D. B. , Prew R. D. , Gutteridge R. J. , Etheridge Judith
Published: March 2009

The Rothamsted ley–arable experiments were on two fields with similar soils but with contrasting previous cropping: old grass on Highfield, old arable on Fosters field. Damage by take-all (Qaeumannomyces graminis var. tritici) occurred sooner in successive wheat crops grown after a lucerne ley and arable sequence (LU) than after a grass-clover ley and arable sequence (LC). On Highfield the difference was consistent and large, it occurred as soon as a second wheat crop was grown and resulted in wheat yielding 1 t/ha less after the LU than after the LC sequence. This difference did not persist in the next wheat crop where take-all was prevalent after both sequences. On Fosters field take-all developed more slowly and differences between sequences were mostly smaller.

Wheat seedling bio-assay of soil cores from the LU and LC sequences showed that little take-all fungus persisted through the leys and that soils were much infested after a first wheat crop in the LU sequence on Highfield, but not in the LC sequence on Highfield or in either sequence on Fosters field. Microscopic examination of roots from assay seedlings and from field plants showed that Phialophora radicicola var. graminicola (PRG) was most common in soils where take-all developed slowly, but our results did not show if this was a causal relationship. The occurrence of much PRG in the LU sequence on Fosters conflicts with previous reports which associate large populations of this fungus only with grassland soils.
Studies on the digestibility of the cellulose fraction of grassland products. Part I. The relation between the digestibility of silage cellulose as determinedin vitroand silage crude fibre digestibility determined by feeding trial
Authors: Barnett A. John G.
Published: March 2009

1. Anin vitromethod is described whereby it is possible to obtain the digestibility coefficient of silage cellulose. The apparatus and techniques used are described in detail and the reproducibility of the results obtainable is stressed.

2. The results so obtained on twenty-seven samples of silage of diverse nature, with regard to composition and method of production, show a reasonable degree of correlation with the corresponding figures for the digestibility coefficients of crude fibre obtained by feeding trial.
The effect of level and pattern of feeding on the yield of milk constituents from cows of different yield potential
Authors: Johnson C. L.
Published: March 2009

Data from three dairy-cow nutrition experiments have been analysed in terms of the yields of milk, lactose, fat and protein. Yields of the three constituents varied linearly with milk yield. However, yields of fat from individual cows were much more variable at high milk yields than were the other two constituents. Patterns of feeding had relatively little effect on the pattern of protein yield in cows fed to their production potential but could be important in influencing yields of fat.

Predicted responses of protein and fat yields to increments of feed were generally small in cows being fed according to their predicted yield potential and the conversion of metabolizable energy to milk constituents was of a low biological efficiency.
The effects of winter and spring defoliation on the subsequent yield of grain and straw of S.147 oats
Authors: Davies G. M.
Published: March 2009

1. An investigation to compare winter and spring defoliation of S.147 oats, and incorporating an application of nitrogen, was carried out during the seasons 1950/1, 1951/2 and 1952/3.

2. Forage available in the spring was considerably greater than that available in the winter, but it had a lower crude-protein content.

3. Compared with the undefoliated oats, both spring and winter defoliation reduced the number of productive tillers by significant amounts, but nitrogen had no effect on tiller numbers under defoliated and undefoliated conditions.

4. Spring and winter defoliation caused significant reductions in grain yields; with winter defoliation the decline in yields was substantial. On the undefoliated and spring-defoliated oats nitrogen increased yields by significant amounts.

5. Spring and winter defoliation reduced straw yields, but nitrogen on both treatments and on the undefoliated oats gave significant yield increases.
Effects of nitrogen applied at different dates, and of other cultural treatments on eyespot, lodging and yield of winter wheat. Field experiment 1952
Authors: Salt G. A.
Published: March 2009

Lodging and yield of winter wheat were studied in a factorial experiment on land infested with the fungus Cercosporella herpotrichoides Fron. causing Eyespot. Two varieties, Squareheads Master 13/4 with long, and Bersée with short, straw, were compared at two seed rates; sulphate of ammonia was applied at 0, 2, and 4 cwt./acre at four different dates; four of the 8 blocks of 10 plots were sprayed in March with sulphuric acid to control eyespot.

Lowering the seed rate from 3 to 1½ bushels/acre decreased eyespot and the area lodged and increased the mean yield of the 2 varieties by 4·9 cwt. in unsprayed and 2·1 cwt./acre in sprayed plots. Spraying the variety Squareheads Master decreased the straws with severe lesions from 66 to 17%, decreased the area lodged from 95 to 36%, and increased grain from 22·4 to 32·4 cwt./acre; spraying Bersée decreased severe lesions from 56 to 15%, decreased lodging from 54 to 1% and increased yield from 32·6 to 43·5 cwt./acre.

The mean percentage infection at harvest was little affected by nitrogen applied in March, April or May, but was decreased by nitrogen applied in October. In contrast, the time of applying nitrogen greatly affected the weight of straw and the extent of lodging, both of which were increased more by top dressings in March and April than by those in May. Plots that received nitrogen in March and October had similar weights of straw, but the latter, with less eyespot, lodged less. Where lodging was slight, grain yields were increased equally by nitrogen applied at each date; where lodging was extensive, yields were depressed by dressings in March and April, and increased by those in October and May. Sulphate of ammonia, applied at 0, 2 and 4 cwt./acre to sprayed (upright) plots of Bersée, yielded respectively 36·8, 42·9 and 47·3 cwt. of grain, whereas applied to unsprayed (completely lodged) plots of Squareheads Master yielded only 22·4, 22·0 and 22·9 cwt./acre respectively.
Studies of the skeleton of the sheep I. The effect of different levels of dietary calcium during pregnancy and lactation on individual bones
Authors: Benzie D. , Boyne A. W. , Dalgarno A. C. , Duckworth J. , Hill R. , Walker D. M.
Published: March 2009

1. Three groups of mature ewes were fed during pregnancy and lactation on rations differing in their calcium content. The mean daily intakes of calcium were 1·4 g. (group A), 4·5 g. (group B), and 7·4 g. (group C). Blood samples were analysed monthly for calcium and inorganic phosphorus. The ewes were killed at approximately 100 days after parturition and the skeletons isolated. Individual bones, either whole or divided into definite fractions, were analysed.

2. The level of calcium intake was without effect on the number of lambs born, birth weight, or growth while milk fed.

3. Blood calcium was significantly lower in group A than in groups B and C, but blood inorganic phosphorus was unaltered.

4. The resorption of bone substance was greater in group A than in groups B and C.

5. The severity of resorption varied between bones, and in regions within certain bones. Resorption was most severe in the vertebrae and pelvis, and only slight in the metacarpal, the metatarsal and the shafts of other long bones. Resorption of intermediate magnitude was found for the remainder of the skeleton.

6. Resorption was accompanied by reductions in the percentages of ash in bones, but this effect was proportionately less than the ash weight reduction.

7. Radiological observations made on flesh-free bones at the end of the experiment gave a picture of resorption similar to that presented by the data for ash weights and percentages of ash, namely that resorption was much greater in group A than in groups B and C.
Relation between body size and muscle fibre diameter in the newborn lamb
Authors: Joubert D. M.
Published: March 2009

1. An investigation is reported in which the relationship was examined between body size and muscle fibre size of nineteen newborn lambs and including twelve males and seven females. Body size was measured in terms of the dead body weight and that of the dressed carcass, while muscle fibre size was estimated on the basis of the mean crossdiameter of 150 fibres per lamb.

2. It was shown that the dressing (or carcass) percentage tends to increase with an increase in body weight, from 42·26% at a body weight of 2000 g. to 49·04% at 7000 g.

3. Of the 2850 cross-diameters recorded, the majority (33·8%) of the fibres measured between 8·0 and 9·6 μ, while individual fibres varied in size from 1·6 to 22·4 μ.

4. Highly significant, positive correlations were shown to exist between both body (r = 0·996) and carcass (r = 0·946) weight, and mean muscle fibre diameter, indicating that differences in size between the lambs may be accounted for largely by corresponding variations in the size of individual muscle fibres.

5. Of the three muscles sampled m. gastrocnemius had the largest mean fibre diameter (10·38μ), followed in decreasing order by m. rectus femoris (9·72 μ) and m. longissimus dorsi (9·09 μ). These inter-muscle differences were significant at the 1% level of probability.

6. Ram lambs had significantly thicker muscle fibres (10·32 μ) than ewe lambs (8·72 μ), but also weighed the heavier and produced heavier dressed carcasses. Some evidence was produced, however, in support of the theory that at comparable weights males possess thinner individual, and therefore a greater number of fibres than females.
Grazing studies on the Guadalcanal Plains, Solomon Islands. 1. Climate, soils, and soil fertility assessment
Authors: Watson S. E. , Whiteman P. C.
Published: March 2009

The Guadalcanal Plains encompass approximately 460 km2 with both forest and grassland phases. Mean annual rainfall is 2160 mm, with a drier season from June to October, but soil moisture deficits seldom occur. Soils are freely to imperfectly drained brown loam to clays (Ustropepts). Soil analyses show available P concentrations of 15–17 μg/g, adequate K, Cu, Zn and Mn, and high Ca and Mg, but sulphate sulphur is low. A nutrient omission trial gave significant negative responses to the omission of P, K, S and Mo. However, responses to P applications were not obtained in the field with Centrosema pubescens, but significant responses to K and S were found under a cut and remove system. Yield response in the grasses Brachiaria decumbens and B. mutica to applied N was markedly limited in the absence of applied S, even though B. mutica was able to maintain S concentrations in herbage at 2–3 times those of B. decumbens. Without applied S, S contents and N:S ratios in B. decumbens were inadequate for beef cattle, but adequate in B. mutica except at high N inputs (300 kg/ha/year). Application of 40 kg S/ha to the legume C. pubescens increased yields by approximately 50%, reduced incidence of Cercospera leaf spot, and gave increased N concentrations. For establishment of sown mixed pastures on the Guadalcanal Plains we recommend the basal application of 20 kg P/ha, 50 kg K/ha, 30 kg S/ha and 0·15 kg Mo/ha, with 30 kg S/ha applied every 2 years.
The effect of age at which spring-born calves are introduced to pasture
Authors: Poole D. A.
Published: March 2009

Spring-born Friesian heifer calves were turned out to grass at either 3 or 4 months of age. In the summer of 1976 the experiment had 20 calves per treatment and in 1977 there were 22 calves per treatment. The calves remained outside for both day and night. They were the leaders in a leader–follower rotational grazing system based on nine paddocks. The followers were yearling heifers and sheep. Each calf was offered a daily grazing supplement of 1·8 kg concentrates. Housing was in mid-September.

There were no management problems and summer growth rates were within the range 0·55–0·74 kg/day. Calves turned out at 3 months of age grew slightly better than calves turned out at 4 months. This difference was not statistically significant, but it does suggest there is no harm in turning calves out at an early age. From a practical viewpoint the result indicates that all spring-born calves could be turned out in one batch in early summer.
The effects of dazomet and nitrogen fertilizer on successive crops of maize (Zea mays L.) grown for either grain or forage
Authors: Barnard A. J. , Hornby D.
Published: March 2009

Maize was grown for grain or forage on the same site at Woburn for 7 consecutive years. Yields were satisfactory and there were no serious pest or disease problems, provided the small plots were netted until young plants were established. Different rates of nitrogen fertilizer were tested with and without annual applications of a soil sterilant, dazomet. Average yields of grain (85% dry matter) and forage (dry matter) were respectively 4·5 and 8·8 t/ha with 50 kg N/ha and 5·0 and 9·5 t/ha with 100 kg N/ha. Without dazomet there was a further increase with 150 kg N/ha. Weather influenced the response to nitrogen, and the response to a split dressing of the highest rate was variable. Except for plots receiving the split dressing of N in 1973 and 1974 dazomet always increased yields: grain yields were increased on average by 1 t/ha and forage by 1·6 t/ha. Dazomet-treated plots had taller and heavier plants with more stems, leaves and nodal roots, but fewer seminal roots than untreated plots. Dazomet-treated plots also had fewer migratory nematodes and smaller and less varied root myoofloras. Most of these differences were greatest in the young crop and possible reasons for this ‘early boost’ are discussed.
An assessment of accumulation of Cd, Cr, Gu, Ni and Zn in the tissues of British Friesian steers fed on the products of land which has received heavy applications of sewage sludge
Authors: Rundle H. L. , Calcroft Marian , Holt C.
Published: March 2009

Fifteen British Friesian steers were reared using grain and forages which had been grown on land which has had a long history of use for disposal of sewage sludges. The food consumption was recorded and samples of feedingstuffs analysed for Cd, Cr, Cu, Ni and Zn. The various components used in compounding the feedingstuffs were also analysed. After about 13 months the animals were slaughtered and samples of various organs and tissues obtained for analysis.

The majority of the Cd, Cr, Cu and Zn came from sources other than uptake into plants. The largest single contributor was the high phosphate mineral supplement. No animal health problem due to the feed regime was encountered. Concentrations of cadmium in liver and kidney were slightly higher than average. Muscle cadmium concentrations of Cr, Cu, Pb, Ni and Zn were within the range of published values.
The effect of level of concentrate supplementation given with grass silage during the winter on the total lactation performance of autumn-calving dairy cows
Authors: Gordon F. J.
Published: March 2009

A total of 140 British Friesian cows in their second or later lactation and with a mean calving date of 27 October (s.D. 18 days) were used in a randomized-block experiment over a 3-year period. The experiment was designed to examine the effects of level of concentrate given during the winter period, in addition to ad libitum access to grass silage, on total lactation performance. The silage had a mean dry-matter content and digestible organic matter in the dry matter of 206 and 698 g/kg respectively and the mean inputs of concentrates on the five treatments were 0–64, 0–89, 1–14, 1–38 and 1·59 t/cow (treatments 1–5 respectively). Sixteen replicates per treatment were housed in individual stalls during the winter period in order to facilitate the measurement of silage intake and the remaining animals in each year were maintained as a single group.

All animals in each year grazed together as a single group at pasture at a mean stocking rate of 6–0 cows/ha and without supplementary concentrates.

Level of concentrate supplementation had a significant linear effect on the intake of silage dry matter with the relationship between total intake of silage dry matter over the winter period (kg, y) and concentrate dry matter input (kg, x) being described by equation (1)
The incidence and effect of poisoning with Lantana camara in different cattle breeds
Authors: Frisch J. E. , O'Neill C. J. , Burrow H. M.
Published: March 2009

The incidence of lantana poisoning and its effect on mortality, growth rate and fertility were recorded from 1975 to 1982 in seven lines of Bos taurus and Bos indicus cattle and their crosses.

Two Bos taurus Hereford × Shorthorn (HS) lines had higher incidences of poisoning and higher mortalities after poisoning than the Bos indicus based breeds.

During the period of poisoning, live–weight gains of affected animals of all breeds were reduced but subsequent recovery was rapid. Lantana poisoning had no detectable effect on the fertility of animals affected at least 10 months prior to their first mating, irrespective of breed.

Parasite control influenced the incidence of poisoning and mortality in genetically similar groups of HS cattle. This observation, when combined with the between-breed relationships between the incidence of lantana poisoning and susceptibility to environmental stresses suggests that the marked breed differences in susceptibility to lantana poisoning stem from differences in resistance to other environmental stresses, including cattle ticks. This offers little scope for selection of animals that are resistant to lantana poisoning per se but has practical significance in lantanainfested regions.
Effect of postnatal development and weaning upon the capacity of pig intestinal villi to transport alanine
Authors: Smith M. W.
Published: March 2009

The relationship between structure and the ability of piglet intestine to transport alanine has been determined during the first few weeks of postnatal life.

Villus length halved without change in crypt depth during the 3rd week of postnatal life. A similar shortening of villi, accompanied by an increase in crypt depth, took place when 2-week-old piglets were weaned on to a solid diet. Weaning piglets at 3 weeks increased crypt depth without causing further shortening of villi.

Alanine transport was shown, by quantitative autoradiography, to be largely confined to enterocytes in the region of the villus tip. The way in which this transport function developed was analysed further by fitting logistic growth curves to measurements of intra-enterocyte alanine concentration. The ability of enterocytes to transport alanine occurred earlier and alanine was accumulated to higher concentrations in enterocytes studied in 21- compared with 15-day-old unweaned piglets. Weaning piglets on day15 or 21 and measuring alanine transport 5 days later produced a pattern of development similar to that reported previously for adult animals.

Transport of alanine throughout postnatal development showed sodium dependency. Effects of alanine on intestinal short-circuit current of weaned piglets were again similar to those recorded in adult animals.

These results are discussed in terms of intestinal adaptation to a changing environment and in relation to the ‘notional capacity’ of a pig villus to transport amino acids during the early postnatal period of development.
The effect of variety and harvesting stage on forage production of barley in a low-rainfall environment
Authors: Droushiotis D. N.
Published: March 2009

Three cutting stages, the boot stage, 50% heading and the milk stage of grain, were imposed on eight barley varieties at four sites, two in each of two successive cropping seasons. Dry-matter and digestible yield increased significantly when harvest was delayed from the boot to the milk stage but crude-protein content and digestibility declined with advanced maturity. A similar pattern of response was obtained in most cases when varieties were examined individually. Variety 628 produced the highest yield, 8·34 t D.M./ha, while the most digestible variety was Athenais with 61·9% digestibility. In low-rainfall regions harvesting at the later stages of maturity is recommended, to take advantage of the higher D.M. yields.
Quantitative digestion by sheep of carbohydrates, nitrogen and S-methyl-L-cysteine sulphoxide in diets of fresh kale (Brassica oleracea)
Authors: Barry T. N. , Manley T. R. , Duncan S. J.
Published: March 2009

Apparent digestibility of forage kale (cv. Maris Kestrel) was compared with that of mixed perennial ryegrass (0·85) and clover (0·15) herbage in two experiments. In a third experiment measurements were made of the partition of digestion between the reticulo-rumen and post-ruminal regions of the digestive tract in sheep fed kale, using intra-ruminal infusion of inert ruthenium phenanthroline and chromium-EDTA markers and time sequence sampling from the duodenum. Results in Expt 3 were compared with predicted values for a range of ruminant diets, including digestion of fresh perennial ryegrass and white clover.

In Expts 1 and 2 the ratio of readily fermentable to structural carbohydrate (CHO) was much higher in kale (2·6–3·2) than in mixed ryegrass and clover herbage (0·6), and showed little difference between kale leaf and stem components. Apparent digestibilities of organic matter (OM), cellulose and hemicellulose were 80–90% for kale diets, varied little with changes in leaf/stem ratio, and were generally slightly higher than for mixed ryegrass and clover herbage. Calculated metabolizable energy (ME) concentrations were 12·0 and 11·7 MJ ME/kg D.M. for kale and mixed ryegrass and clover respectively.

Despite large intakes of water-soluble CHO and pectins in kale-fed sheep in Expt 3, duodenal flows were small and respectively 92 and 98% of the total amounts digested were digested in the rumen. Ruminal cellulose digestion (95% total digested) was as predicted for normal ruminant diets, but less hemicellulose was digested in the rumen (71% total digested) than predicted. Total N flow at the duodenum was 5 g/day less than N intake, and respectively 27 and 66% of the N apparently digested was accounted for as total N absorption from the rumen and post-ruminal absorption of NAN. Calculated absorption of amino acids from the small intestine was less for the kale diet (14% ME intake) than for diets of fresh perennial ryegrass and white clover (20% ME intake). Possible reasons are that 10% more of the OM ingested was digested in the rumens of sheep fed kale than was predicted, that the ratio of dietary total N/100 g digestible OM was much less for kale (3·7) than for perennial ryegrass and white clover (5·6) diets, and that protein formed a lower proportion of the total N in kale diets (75%) than in diets of ryegrass and clover (90%). Despite 3·3 g of S-methyl-L-cysteine sulphoxide (SMCO) being consumed per day, none was detected in either rumen or duodenal contents or in faeces.

In was concluded that complete conversion of SMCO to dimethyl disulphide occurred in the rumen, that dimethyl disulphide may have caused the depression in ruminal digestion of hemicellulose, and that the digestion products of kale are deficient in absorbed amino acids relative to other forms of energy, thus explaining responses to essential amino acid supplementation in lambs grazing kale.
A comparison of sample preparation and calibration techniques for the estimation of nitrogen, oil and glucosinolate content of rapeseed by near infrared spectroscopy
Authors: Starr Carol , Suttle Janet , Morgan A. G. , Smith D. B.
Published: March 2009

Predictions of nitrogen, oil and glucosinolate concentration in rapeseed samples were made by near infrared reflectance analysis after various grinding treatments. Also examined were the effects of normalizing reflectance data and the possible advantage of using all combinations of two and three wavelengths in the calibration regression analysis over forward stepwise regression. The main conclusion was that drying the samples prior to a controlled grinding treatment gave the best results, although acceptable results for selection purposes could be obtained using whole seeds to predict nitrogen and oil. None of the treatments of the seed or reflectance data allowed acceptable prediction of glucosinolate content.
Effect of temperature and light intensity on resistance in marrow (Cucurbita pepo) to cucumber mosaic virus
Authors: Pink D. A. C. , Walkey D. G. A.
Published: March 2009

Plants of Cucurbita pepoL. cvs Cinderella, Cobham Bush Green and Goldrush were inoculated with cucumber mosaic virus (CMV) and some grown at each of three temperatures (15, 20 and 25 °C) and three light intensities (13, 40 and 120 W/ma). Symptom severity in all three cultivars decreased with increased temperature but only for ovs Cinderella and Cobham Bush Green when the light intensity was raised. In general ov. Cinderella was most resistant and cv. Goldrush most susceptible, except at 25 °C, when most plants were symptomless.
The rates of nitrification of peat soils in British Guiana
Authors: Paul H. , Shariff M. A. A.
Published: March 2009

A study has been made of some of the nitrogen fractions of the pegasse soils of British Guiana in virgin and exhausted conditions, that is, before and after cropping.

1. Preliminary field experiments on the virgin and exhausted soils adduced strong evidence in support of the complaints made by farmers that the productivity in yields of the pegasse soils after continuous cropping for a comparatively short period is considerably impaired.

2. The virgin soil showed an appreciable amount of nitrate nitrogen, while the exhausted sample indicated no nitrate. The latter soil, on the other hand, contained a higher amount of ammonia nitrogen measured by KCl extraction than the former soil.

3. Nitrification studies with added ammonium salts indicated that under optimum conditions the nitrifying power of the exhausted soil was extremely low. Additions of sodium nitrate indicated that the nitrate was partially reduced to ammonia by the worn-out pegasse soil. The virgin pegasse, on the other hand, showed an appreciable rate of nitrification.
Studies on the oxalate contents of the leaves of certain varieties of Beta vulgaris
Authors: Baker C. J. L. , Eden A.
Published: March 2009

1. Studies were made during the 1951 and 1952 seasons of the oxalate contents of the leaves of mangolds, sugar mangolds and fodder sugar beet.

2. In all varieties greater concentrations of total oxalates were found during the summer months, the amounts diminishing gradually as the season advanced. Up to 12% was found in the dry-matter of mangold leaves and 9% in fodder sugar-beet leaves in July, these levels falling to 3% by mid-winter. There is some evidence that these changes are due in part to loss of outer leaves.

3. Roughly one-third of the oxalates are present in water-soluble form. The addition of 1 part of chalk to 1000 parts of leaves, as has been generally recommended, is theoretically sufficient to render unavailable the soluble oxalates present during winter, but insufficient for leaves fed earlier hi the season.

4. A number of observations showed small reductions in the soluble oxalate contents of the leaves due to wilting, but there were exceptions to this, and these appear to be related to sampling periods rather than to varieties.

5. Insoluble oxalates appear to be unaffected by wilting and may show apparent increases in amount due to respiration losses of labile leaf constituents. The insoluble/soluble oxalate ratio is thus changed by wilting.

6. It is suggested that the undesirable effects sometimes resulting from the feeding of beet leaves to livestock may not be due to oxalates, but that other factors present, which are labile during wilting, may be involved.
The assessment of structure in tropical soils
Authors: Pereira H. C.
Published: March 2009

A comparison of methods of measuring the structural condition of cultivated surface soil was made for two important East African soil types.

The soil samples were drawn from two field experiments: (i) a tillage trial in coffee on a porous red lateritic clay soil of recent volcanic origin; (ii) a rotation trial for cotton, on a red sandy lateritic loam of granitic origin.

Of the measurements on soil cores, total porespace and field capacity (⅓ atmosphere) showed little change, while percolation rates, free-draining pore-space and a new rainfall acceptance test all reflected the observed field behaviour of the soils, and showed fairly close and highly significant correlation. Field sieving of dry clods gave highly significant differences in the lateritic clay, the stronger clods indicating the poorer soil condition. Drysieving for ½ mm. crumb was ineffective, as was wet-sieving after wetting under vacuum. Wetting by immersion gave some differences between treatments, but higher variability and no significant correlation with free-draining pore-space. Wetting by rainfall impact on dry crumbs gave the best wet-sieving tests on the clay soil. Different sieving techniques gave inconsistent results on the sandy soil. Crumb structure measurements are not efficient indications of structural conditions on these soil types, which are of wide occurrence in tropical countries.
Nitrogen transformations during the biological decomposition of straw composted with inorganic nitrogen
Authors: Bremner J. M.
Published: March 2009

1. Nitrogen transformations during the decomposition of straw composted with ammonium carbonate have been studied by following the changes in (a) the amounts of inorganic and organic nitrogen; (b) the amounts of ammonia-, volatile base-, α-amino- and amino sugar-N liberated by acid hydrolysis of the organic nitrogen complexes; and (c) the amino acid composition of acid hydrolysates of the composts.

2. Synthesis of organic nitrogen during the biological decomposition of straw composted with ammonium carbonate is not accompanied by any gross change in the distribution of the forms of organic nitrogen. A large fraction of the organic nitrogen synthesized is in the form of protein; a smaller fraction is in the form of amino sugar.
Effects of row width and planting density on growth and yield of two maincrop potato varieties. 2. Number of tubers, total and graded yields and their relationships with above-ground stem densities
Authors: Ifenkwe O. P. , Allen E. J.
Published: March 2009

Data are reported from three experiments from 1972 to 1974 which examined the effects of two row widths (66 cm and 132 cm) and five planting densities on number of tubers, tuber yields and tuber saleability of two maincrop potato varieties (Désirée and Maris Piper). Fewer tubers were generally found in 132 cm rows than in 66 cm rows; in 1972 reductions were most marked at high densities in both varieties and in 1974 effects were most pronounced in Maris Piper. Row width had little effect on total tuber yield at any stage of growth in either variety. The use of 132 cm rows reduced tuber greening, so that yields of saleable ware tubers at final harvest were not reduced by 132 cm rows in any year and in 1973 were higher in Désirée from 132 cm rows than from 66 cm rows. These results suggest that wider rows than are currently used in practice should be considered for maincrop potatoes, especially where water is not limiting.

Increasing planting density increased total yields in both varieties although the responsesto the final increments in planting density were small. Yields > 38 and > 57 mm declinedat the higher planting densities in Maris Piper and the optimum above-ground stem densities for ware grades differed markedly in the two varieties. Good relationships between tuber yieldsand number of above-ground stems were found in all years and support the use of stems as thebasic unit of density in this crop.
Studies on reproduction in prolific ewes. 4. Sequential changes in the maternal body during pregnancy
Authors: Robinson J. J. , McDonald I. , McHattie I. , Pennie K.
Published: March 2009

Seventy-eight Finnish Landrace × Dorset Horn ewes in lamb to Suffolk rams were slaughtered serially between 50 and 145 days of gestation. The mean litter size was 2·7. The daily feeding regime aimed to provide each ewe with 15 MJ of metabolizable energy (ME) in the first month of gestation and 9·4 MJ in the second and third. Thereafter the ewes were provided with a basal intake of either 9·6 MJ (low plane, LP) or 13·4 MJ (high plane, HP) plus 1·3 MJ for each foetus.

For ewes with 2, 3 and 4 foetuses the mean percentage changes in maternal body weight over pregnancy were respectively — 5, — 10 and — 14 (LP) or + 3, — 2 and — 6 (HP). Changes in weights of blood, liver and the empty gastro-intestinal tract through gestation varied with the plane of nutrition but not with number of foetuses. In contrast, udder weight at parturition was dependent on number of foetuses but not on plane of nutrition.

Increased hydration of the maternal tissues in late pregnancy tended to mask concurrent losses of body fat. For example, over the last 2 months, HP ewes carrying quadruplets lost on average 1·0 kg in body weight but 5·5 kg of (chemically determined) fat. The latter was lost at a rate which increased up to an average of 170 g/day over the last 2 weeks of pregnancy. Net changes in body protein were estimated to be relatively small, but there was some redistribution, including loss from muscle and gain by the udder. There was no evidence of any demineralization of the maternal skeleton.

The practical significance of the changes in body composition is discussed, in particular that of the increasing rates of loss of body fat with increasing litter size. It is suggested that the dangers implicit in these rates of fat loss must be taken into consideration when deciding on dietary regimes and the timing of breeding cycles for highly prolific ewes, or indeed when embarking on a programme of increased prolificacy.
Composition of beef carcasses:I. Material, measurements, jointing and tissue separation
Authors: Pomeroy R. W. , Williams D. R. , Harries J. M. , Ryan P. O.
Published: March 2009

One side of the carcasses from 145 beef animals was weighed, measured and quartered. Measurements were made in the exposed eye muscle region which was then photographed. Measurements were made from the photographs and the quarters were jointed. Each joint was separated into lean, bone, intermuscular fat, subcutaneous fat and ‘other tissues’. The material is described in terms of breed, sex and side weight. Details of the measurements made are given and the methods of jointing and tissue separation are described. The latter was different in three groups of 30, 72 and 43 animals. The overall carcass composition in terms of lean, bone, intermuscular fat plus ‘other tissues’, and subcutaneous fat for the three groups is summarized and the reasons for including ‘other tissues’ with intermuscular fat are given.
Effect of soil type and depth on crop production
Authors: Reith J. W. S. , Inkson R. H. E. , Caldwell K. S. , Simpson W. E. , Ross J. A. M.
Published: March 2009

Topsoils from eight different soil series were substituted for the local soil in three arrangements involving two depths of topsoil and either local or sand subsoils. A rotation of crops was grown with uniform annual N, P and K treatments for 24 years. A peaty soil produced the highest yields of grain, straw and grass, presumably because it released more N than the mineral soils, but an average yield of swedes. No mineral soil consistently produced higher yields of all crops and, although there were some significant differences, the variations in yield were generally relatively small. The deep topsoil consistently produced the highest yields. Topsoil with sand subsoil gave the lowest yields of grain, straw and swedes but not of grass.

All the crops on the peaty soil had higher concentrations of P in the dry matter than those from the seven mineral soils. Crops and herbage on the Laurencekirk and Foud-land soils had consistently slightly higher P concentrations than those on the other five mineral soils. Compared with the amounts applied, the crops removed considerably more K but only 45–68% of the P. There were large differences in the proportion of the P residues extractable by acetic acid from the different soil series.

The depth of topsoil was at least as important as soil type in determining yield, and the results support the use of soil depth as one of the main factors used in the Land Capability Classification for Agriculture.
The measurement of leaf colour in grasses
Authors: Hamill Madeline , Camlin M. S.
Published: March 2009

A method of assessing colour of grass leaves was developed to distinguish between cultivars. Leaves from a representative population of 60 plants of each cultivar were measured. To eliminate subjective judgment a colour difference meter was used, giving tristimulus values X, Y and Z (approximating to red, green and blue respectively), from which the colour co-ordinates L, a and b of the Commission Internationale de L'Eclairage system were calculated.

In a pilot study two visually distinguishable perennial ryegrass cultivars were easily separated (P <0·01) using the colour measurements. In a further examination comparing 23 cultivars, 68% of all possible cultivar pairs were separated (P <0·01).
The value of potato peelings in the nutrition of the bacon pig
Authors: Woodman H. E. , Evans R. E.
Published: March 2009

Mechanical peeling of potatoes removes an exceedingly thin skin that is notably richer in ether extract, fibre and lime, but much poorer in N-free extractives, than the thicker parings obtained by ordinary hand peeling. The latter, in respect of their general composition, do not differ to any marked extent from whole potatoes.

The results of digestion trials with pigs have shown that potato peelings, after cooking, are highly digestible when included in the rations of bacon pigs. The N-free extractives, which form about 80% of the dry matter of the hand peelings, have a digestion coefficient of 96·2%. An allowance of 5 lb. of such peelings supplies as much digestible organic matter as 4 lb. of whole potatoes, and it is concluded that 1 lb. of barley meal in the rations of bacon pigs may be replaced by 4 lb. of potatoes or by 5 lb. of potato peelings. Both the potatoes and the potato peelings should be cooked before feeding.

In conclusion, the writers take this opportunity of expressing their thanks to Messrs V. Thurlbourn and C. Bendall, in whose experienced hands the care of the experimental animals was placed during the digestion trials.
The effect of Beckmann's treatment by sodium hydroxide on the digestibility and feeding value of barley straw for horses
Authors: Williamson Grahame
Published: March 2009

The digestibility coefficients of old barley straw fed with a basal ration of oats, bran and maize to two adult horses and of the same straw after treatment by Beckmann's method were ascertained. The coefficients of the nitrogen-free extractives and the crude fibre of the untreated straw were 33·23 and 38·24 respectively and of the treated straw 54·14 and 63·71. There was a reduction in the digestibility of the small quantity of protein and fat.

Taking into account the 14·5% of dry matter lost during treatment, the starch equivalent value of the treated material was somewhat higher than that of poor quality meadow hay.

The digestibility coefficients were considerably lower for an immature horse previously maintained entirely on fresh grass.
The course and magnitude of water stress in Lolium perenne and Dactylis glomerata
Authors: Jackson D. K.
Published: March 2009

Simulated swards of Dactylis glomerata (var. S.37) and Lolium perenne (var. S.23) were grown in large lysimeters or vertical pipes of 15 cm diameter, both sufficiently deep to allow largely unrestricted root development.

Rainfall was excluded, and the effect of a drying cycle on the plant water balance was compared with irrigated controls in a sequence of sampling harvests at increasing soil water deficits.

Leaf water potential (ΨL) fell during the day, both in treatments and controls, to levels which might be expected to reduce extension growth and, frequently, stomatal diffusion. Rapid recovery occurred in the evening to levels which might allow normal functioning of growth processes not dependent on sunlight. Defoliation reduced plant stress and stomatal restriction.

The amelioration of plant water stress appeared to require a reduction in atmospheric evaporative demand, and irrigation had relatively little effect. The possibility is discussed that the major benefits of irrigation are other than through the relief of water stress within the plant. The significance of this is considered in relation to conventional irrigation techniques.

The leaf water status was more sensitive to drought, transpiration was reduced more, and the root system extended more slowly in Dactylis than in Lolium. Consequently, the onset of permanent wilting due to exhaustion of water from the profile was delayed compared with Lolium. It is deduced that this characteristic might enhance the survival of Dactylis in prolonged drought, but prove disadvantageous in terms of growth during short droughts, when reduced stomatal opening might limit CO2 uptake. This would not be an impediment, however, if investigations suggesting that partial closure has a minor effect on CO2 uptake compared with that on transpiration were to be confirmed.
Investigations on the root-nodule bacteria of leguminous plants: XXI. The growth of the root-nodule organisms and inoculated peas at low temperatures
Authors: Vartiovaara Unto
Published: March 2009

The present paper records some investigations on the growth of the clover- and pea-nodule organisms (Rhizobium trifolii Dangeard and Rh. leguminosarum Frank), and the nitrogen fixation of the pea, at low temperatures. Growth of the bacteria was studied with pure culture experiments in large flasks, in which the bacteria were grown on a solid gelatine medium. The amount of nitrogen in the bacterial mass thus obtained was used as the basis of comparison. The fixation of nitrogen by peas was studied with a pot-culture experiment in a relatively cold greenhouse. Inoculated plants were grown in quartz sand, and were supplied at an early stage with mineral nitrogen either as Ca(NO3)2 or (NH4)2SO4. The plants were harvested after flowering and analysed. The main results of these experiments were the following:

(1) Pure-culture experiments with five strains of clover-nodule bacteria and four strains of pea-nodule bacteria showed that at 6–13° C. the strains imported from more temperate climates grew distinctly less well than did the northern European strains. Even between the Swedish and Finnish strains there were clear differences: the latter formed the more bacterial matter in the cold. It may be appropriate to consider such differences when selecting cultures for inoculating leguminous crops.

(2) In the pot-culture experiment, the application of mineral nitrogen (30 mg. N per plant) to inoculated peas kept at relatively low temperatures had very little effect on the amount of dry matter produced. The slightness of this effect was similar to what has been previously observed in experiments at more favourable temperatures. Nitrogenous fertilization slightly lowered the amounts and percentages of total N present as protein and amino nitrogen, in the crop; but nitrate application somewhat increased the nitrate content of the crop. Hence, it may be concluded that, even under these low-temperature conditions, the application of artificial nitrogen has not had a favourable effect on the size or quality of the crop.
An accurate wet-combustion method for the determination of carbon in soils
Authors: Alper Pauline
Published: March 2009

1. Inaccurate results previously obtained with wet-combustion methods for the determination of carbon in soils have probably been due to: (a) incomplete oxidation of carbon; (b) incomplete absorption of carbon dioxide. The method described herein ensures complete oxidation and complete absorption. The oxidizing agent employed consists of a mixture of sulphuric acid and potassium bichromate; the absorption takes place in a closed system.

2. When highly accurate results are required, a combustion tube is a necessary adjunct to the wet-combustion method, as appreciable amounts of carbon escape complete oxidation in reaction flask.

3. The soil should be moistened with water before adding the oxidizing mixture, to avoid the formation of complexes, which may protect part of the carbon from oxidation by the acid.

4. Within limits, the concentrations of sulphuric acid and potassium bichromate do not affect the results.

5. While it is necessary to use catalysts (selenium and potassium sulphate) for the complete oxidation of the resistant carbon of coal, catalysts were found to be unnecessary for the determination of carbon in soils.

6. For soils rich in chloride, it is necessary to absorb the chlorine evolved by means of sodium bisulphite solution.
Field experiments of factorial design
Authors: Wishart John
Published: March 2009

A recent paper by A. E. Brandt (1937) goes into the details of a type of design in field experimental procedure, where two or more factors are under examination, which has been much elaborated since 1928, when the first 2 × 2 × 2 experiment, involving two levels of each of three factors, nitrogen, potash and phosphate, was carried out at Woburn (Rothamst. Rep. 1927–8) with four-fold replication. Similar experiments, of the 3 × 2 × 2 type, had in fact been conducted at Rothamsted (Rep. 1925–6) two years earlier, but there was here the further complication that no differentiation was possible for two of the factors at one level (no manure) of the third. Details have been given by Fisher (1937) and Yates (1937) of, among others, experiments of the 2n and 3 × 2n types, and it may be said that the recent work has been in the direction of systematizing the lay-out and analysis of such experiments. Further features have been the device of confounding, which dates back to 1927 (Rothamst. Rep. 1927–8), i.e. it is almost contemporaneous with the first introduction by Fisher of randomized blocks and Latin square experiments, and the suggestion that replication may even be dispensed with entirely, a much more recent innovation. Confounding is a method of enlarging the number of blocks between which elimination of soil heterogeneity is possible by sacrificing information on certain of the higher-order interactions, which are considered unlikely to be real effects; with absence of replication an estimate of the experimental error is found by grouping together a number of these higher-order interactions.
On the influence of protein on the fattening of fowls
Authors: Halnan E. T.
Published: March 2009

1. The principal change in the composition of adult fowls during fattening is an increase in the fat content of the body, the protein increase being subordinate in amount.

2. Within the limits studied, the efficiency of conversion of food energy to carcase energy is not affected by variation in the protein content of the ration.

3. A food mixture consisting of 5% dried skim milk of 95% Sussex ground oats proved as efficient for fattening fowls as a food mixture consisting of 20% dried skim milk, and 80% Sussex ground oats.

4. The food mixtures used gave satisfactory results in fattening when used in pellet form in a dry state.
Artificial insemination of sheep: I. Preliminary investigation on its application to sheep in Kenya
Authors: Anderson James
Published: March 2009

An account is given of a preliminary experiment on artificial insemination of cross-bred Merino sheep in Kenya. 202 ewes were inseminated and 74·3 per cent conceived. The practical application of artificial insemination to sheep breeding in Kenya is discussed.