bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the relation between cultivation implements, soil structure and the crop I. Some preliminary observations on the measurement of soil structure, with a description of an instrument for the measurement of soil resistance
Authors: Culpin Claude 
Published: March 2009

The need for physical measurements of soil structure to assist in studies of the relation between cultivation implements and plant growth is pressing.The nature and measurement of soil compactness and consolidation are briefly discussed. Measurements of soil resistance give an indication of consolidation rather than of compactness.An instrument used for the measurement of soil resistance is described, with some notes upon its performance.A brief outline is given of studies on soil structure in relation to gyrotilling. It is shown that the soil-resistance apparatus described gives results similar to those obtained by the use of the drawbar dynamometer in ploughing. A relation between soil resistance and plant growth is demonstrated.
Physiological studies of competition in Zea mays L: I. Vegetative growth and ear development in maize
Authors: Eddowes Maurice 
Published: March 2009

SUMMARYPreliminary field studies were carried out to obtain an understanding of the progress of dry-matter accumulation in maize and its end-point at harvest. Dry-matter accumulation and its partition between morphological parts was affected, at various stages of growth, by competition. For maximum total yield per unit area of land, early and rapid development of leaf area was needed to exploit the relatively high net assimilation rate early in the season. This leaf area should persist as long as possibleto maximize leaf area duration. A high total plant yield, and high yield of the important ear component, by the individual plant, was obtained at a plant population of about 40000 per acre. The photosynthetic area of the ear made no significant contribution to cob weight.
Seasonal production of Andropogon gayanus
Authors: Haggar R. J. , Ahmed M. B. 
Published: March 2009

SummaryThe crude protein content and in vitro dry-matter digestibility (I.V.D.) of leaves and stems of Andropogon gayanus, grouped into four different age categories, were measured at weekly intervals during the secondhalf of the 1968 wet season. The crude protein content of all categories of leaf and stem rose to a maximumat ear emergence; significant reductions occurred thereafter, especiallyin the younger categories of leaf and stem. At any point in time the younger leaves and stems contained significantly more crude protein than the older leaves and stems.Although the mean crude protein content of each stem category was significantly lower than the corresponding leaf category, the young, elongating stems had a significantly higher crude protein content than the older, mature leaves at the time of ear emergence.The mean I.V.D. of all leaf and stem categories was highest at the start of the recording period. At ear emergence the I.V.D. of the young elongating stems was at least as high as the mature leaves. After ear emergence the I.V.D. of the stems fell more rapidly than the leaves.The results support the principle of cutting at ear emergence to achieve maximum yields of digestible nutrients.
Effects of high levels of fertilizer on yield of potatoes grown for ware
Authors: Rodger J. B. A. , Robertson G. M. 
Published: March 2009

SUMMARYNine experiments in the East of Scotland were completed in the years 1966, 1967 and 1968 to test the response of potatoes grown for ware to five levels of a 15½–15½–21 fertilizer applied at rates of 0, 4, 8, 12, 16 and 20 cwt per acre.1. Mean yield of ware tubers increased up to the highest fertilizer level.2. Mean yield of small tubers increased only up to the 8 cwt per acre level and then declined.3. Dry matter content of ware tubers decreased with increasing levels of fertilizer.4. Increasing fertilizer levels lowered soil pH. At one site this was associated with a significant reduction of common scab on the tubers.
Results from experiments measuring the residues of nitrogen fertilizer given for sugar beet, and of ploughed-in sugar beet tops, on the yield of following barley
Authors: Widdowson F. V. 
Published: March 2009

SummaryFive sugar beet experiments were made from 1964 to 1968 to measure yields of roots, of sugar and of tops from dressings of 0, 63, 126 or 188 kg N/ha. In 1964 and 1965 the sugar-beet tops were ploughed-in on all plots, but afterwards on only half of the total number of plots. Barley followed the sugar beet and was given 0, 41, 83 or 126 kg N/ha, in all combinations with the dressings of N to the sugar beet; grain was weighed and analysed for % N.The maximum yield of sugar (8·24 t/ha) was with 126 kg N/ha. The yield of barley was increased greatly by giving it 83 kg N/ha, but not with more. When the barley was not given N, the residues of 126 kg N/ha for sugar beet increased grain yields by 0·17 t/ha, where the tops were carted away, and by 0·77 t/ha, where the tops were ploughed-in, but when the barley was given 83 kg N/ha, the residues increased yield negligibly (by 0·07 t/ha). Together the two sources of residue were equivalent to giving about 30 kg N/ha to the barley. Percentage N to the grain was consistently increased by both kinds of residue, but the grain never recovered more than 10 kg N/ha from them. So, sugar-beet tops had little residual value for barley, but offer a largely unused source of animal feed, rich in N.
Miscible displacement of reactive solutes in saline-sodic soils under varying flow conditions
Authors: Dahiya I. S. , Abrol I. P. , Hajrasuliha S. 
Published: March 2009

SummaryThe paper reports a laboratory study on miscible displacement of reactive solutes during leaching a highly saline-sodic soil rich in soluble sodium carbonate with solutions of calcium chloride. The effect of varying flow velocities, initial soil moisture content and concentration of calcium in the leaching water on the extent of carbonate precipitation and replacement of sodium by calcium from the exchange positions was studied in soil columns. The results showed that precipitation of soluble carbonates in the soil increased with increasing flow velocity, initial soil moisture content and concentration of calcium in the leaching solution. The results further showed that the calcium exchange capacity of the soil was reduced significantly and nearly proportionally with decrease in the degree of water saturation as a consequence of decreased water application rate and initial soil moisture content. In view of the results obtained, a simple model to describe calcium-sodium exchange under unsaturated flow conditions in saline-sodic soils under consideration has been proposed. Possible implications of the results in actual field situations is discussed.
Copper in diets for growing pigs
Authors: Braude R. , Hosking Zena D. 
Published: March 2009

SUMMARYTwenty-eight centres participated in two co-ordinated trials to obtain further evidence on responses of growing pigs (20–86 kg) to different levels of copper sulphate (CuSO4. 5H2O) supplementation, and on effect of lowering the amount of copper in the ‘finishing’ diet. The levels of copper supplied were 141, 232 and 276 mg Cu/kg diet in the ‘starting’ diet in trial 1 and 125, 200 and 250 in the ‘starting’ diets continuing or reducing to 125 mg Cu/kg diet in the ‘finishing’ diets in trial 2. The results varied to such an extent that no definite conclusion could be drawn, but there was a tendency to support rather than dispute the accumulated evidence in world literature that the most effective levels of copper supplementation are from 200 to 250 mg/kg diet throughout the growing period.
The effects of nitrogen upon three stiff-strawed winter wheat varieties
Authors: Widdowson F. V. 
Published: March 2009

Eleven winter wheat experiments were carried out from 1955–57, to compare the effects of nitrogen on three stiff-strawed varieties of winter wheat, Heine 7, Hybrid 46 and Minister. In 1955 the experiments tested ‘Nitro-Chalk’ top-dressings at rates supplying 0·45, 0·90 and 1·35 cwt. N/acre. In addition, drilled dressings supplying 0·15 cwt. N/acre were supplemented with either 0·30 or 0·75 cwt. N/acre as a top-dressing.In the 1956 and 1957 experiments ‘Nitro-Chalk’ top-dressings were applied at 0·60 and 1·20 cwt. N/acre. In addition, divided dressings were compared by supplementing 0·15 cwt. N/acre by combine-drill with 0·45 cwt. N top-dressing.Significant increases in yield were obtained from the first increment of nitrogen in twenty-three of the thirty-three available comparisons. There were significant additional gains from the second increment of nitrogen in only seven of the same comparisons. Responses to nitrogen varied considerably between seasons. Large and consistent responses were obtained at all centres in 1955 and dressings supplying 0·9 cwt. N/acre were well worthwhile. In 1956 responses were generally smaller and dressings in excess of 0·6 cwt. N/acre could only be justified at two centres. Mean responses in 1957 were lower than those obtained in either of the previous season and 0·6 cwt. N/acre was sufficient for maximum yields at three of the four centres.There was little advantage in dividing dressings of nitrogen between autumn and spring in any of the experiments and none of the differences reached significance. On average, higher yields were obtained by retaining the whole of the nitrogen until the spring, than by applying part of the dressing in autumn by combine-drill.Comparisons between the varieties show that Hybrid 46 was the only variety which was able to take consistent advantage of the heaviest rates of manuring. In each year Hybrid 46 produced the highest percentage increase in yield and Minister the lowest. In addition Hybrid 46 contained the highest percentage of nitrogen in the grain when averaged over each level of manuring. The percentage recovery of nitrogen was calculated for each year and each variety. Comparisons of this data show that Hybrid 46 converted more of the fertilizer nitrogen into grain or crude protein than either of the other two varieties. The experiments provide evidence that there are considerable variations in the efficiency with which present-day winter wheat varieties can utilize nitrogen, and that varieties with both high fertilizer efficiency and high unmanured yields are likely to increase the level of crop production.
The use of progesterone and serum gonadotrophin (P.M.S.) in the control of fertility in sheep. I. The hormonal augmentation of fertility in the ewe during the breeding season
Authors: Gordon I. 
Published: March 2009

1. Over four breeding seasons (1952–6) field trials, involving a total of 2504 treated and control ewes of nine breeds (Romney, Clun, Suffolk, Cheviot, Lincoln, Welsh Mountain, Ryeland, Southdown and Hampshire) were conducted in an attempt to increase flock fertility by injections of p.m.s. hormone. The hormone employed was in three forms of preparation: purified, freeze-dried and whole serum. Dosage levels from 250 to 1000 i.u. were injected subcutaneously.2. There is no evidence that the treatment affected the ability of the ewe to conceive.3. A significant increase in fertility was induced by treatment. The extent of the increase apparently depended on the dosage level and form of p.m.s. employed, and was found to be affected by the normal fertility status of the sheep undergoing treatment. At any given dosage level of p.m.s. the increases induced by treatment were greatest where flock fertility was very low.4. When used at comparable dosage levels, whole serum tended to be more effective in inducing superfertility than freeze-dried or purified serum. Freezedried serum tended to be more effective than purified serum.5. 1047 injected sheep that conceived to service at the treatment oestrus produced 1898 lambs (1·81 lambs per ewe); 997 control ewes that conceived at the same time produced 1506 (1·51 lambs per ewe).
Maternal influences on litter size in pigs
Authors: King J. W. B. , Young G. B. 
Published: March 2009

The effects of inbreeding of the sow and plane of nutrition after mating on litter size at 28 days were investigated.Outbred Large White sows were mated at first heat after weaning to inbred boars, and inbred sows to outbred boars, so that both groups of sows carried the same type of embryo. The sows were then placed at random on either high or low planes of nutrition until slaughter 28 days later, when their corpora lutea and number of embryos were counted.Litter size was significantly higher in outbred than in inbred sows by 2·52 ± 0·93 pigs. This resulted from 2·89 ± 0·94 more ova shed and 0·37 ± 0·93 more embryos dying. The general conclusion is that inbreeding of the sow reduces early litter size mainly by depressing ovulation rate.The different planes of nutrition produced negligible differences in within-litter mortality and, therefore, on litter size, but resulted in a marked difference in conception rate. All animals on the high plane were pregnant, whereas on the low plane 25% were empty, this difference being highly significant.Age of the sow, but not her weight, was found to be significantly correlated with number of corpora lutea (r = 0·39). The latter had a correlation with litter size of 0·55 and with mortality of 0·45. The correlation between litter size and mortality was −0·50.Parity increased and inbreeding reduced the length of the uterus which was not, however, significantly correlated with litter size.
Factors affecting birth weight of Holstein-Friesian calves in Western Nigeria
Authors: Adeneye J. A. , Bamiduro T. A. , Adenbanjo Adetowun K. , Akinyemi A. A. 
Published: March 2009

SUMMARYThe birth weight of Friesian and Holstein calves in Western Nigeria was generally lower than that recorded in other tropical countries. This was attributed to a low plane of nutrition during pregnancy and a consequent reduction in length of gestation of the dams. On average, pure-bred Friesian, pure-bred Holstein and Holstein x Friesian calves weighed 29·1, 30·8 and 30·7 kg respectively at birth. Male and female Friesian, Holstein and cross-bred calves averagely weighed 29·9 and 28·2 kg, 29·9 and 31·7 kg, and 32·6 and 28·8 kg respectively. Both the sex differences and breed x sex interaction were not significant.Positive correlation coefficients of 0·45, 0·38 and 0·26 found between calf birth weight and gestation length for the Friesians (P < 0·05), Holsteins (P < 0·01) and their crosses (P > 0·05) respectively suggest that gestation length had a significant effect on Friesian and Holstein calf birth weight. In many cases, parturition occurred 8–16 days earlier than expected.Calves born during the rainy season (April–September) were approximately 10% heavier at birth than those born during the dry season (October–March). The heaviest calves were born during the second half (July–September) of the rainy season. The breed x sex x season of calving interaction was significant for the Holstein breed (P < 0·05). Holstein male calves born during the rainy season were significantly (P <; 0·05) heavier than those born during the dry season. Friesian dams with three or more parities and Holstein dams that were 3 years old and above produced calves that were significantly (P < 0·01) heavier at birth than calves of younger dams.
The growth and carcass characteristics of crosses of Hereford and Friesian with Angoni, Barotse and Boran cattle in Zambia
Authors: Thorpe W. , Cruickshank D. K. R. , Thompson R. 
Published: March 2009

SUMMARYSeven hundred and fifty purebred Angoni, Barotse and Boran cattle and their crosses sired by Friesian and Hereford bulls were compared for live-weight and carcass characters in Zambia. The cattle were born between September and December in three consecutive years and were reared on unimproved veld. In the first year all females and a random half of the males received supplementary feed in winter and the males were slaughtered at 2·5 years of age. The remaining males received the same total amount of winter supplementary feed prior to slaughter at 3·0 years of age. The males born in the second year were pen fed for a period prior to slaughter at 3·0 years of age. Males born in the third year were slaughtered at 3·5 years of age and received no supplementary feed.Genotype differences were important at all live weights and there were year of birth x genotype interactions at the 0·5, 1·0 and 1·5 year weights and a genotype × feed treatment interaction at the 2×0 year weight. Boran purebreds were heavier than the Angoni and Barotse purebreds; at 3·0 years the differences were +42·3 kg ( + 12·9%) and + 25·2 kg (+ 7·7 %) respectively. Cross-breds had heavier live weights than their corresponding purebreds with Boran crosses consistently heavier than the Angoni and Barotse crosses. The Friesian and Hereford sired Boran cross-breds were + 51·0 kg (+13·5 %) and + 43·0 kg (+ 11·6 %) heavier respectively than the purebred Borans at 3·0 years of age.There were large differences between the genotypes for all carcass characters with Borans having heavier carcasses than the Angonis and Barotses by + 20·3 kg (+ 10·6 %) and + 19·1 kg ( + 10·0%) respectively. The average carcass weight advantages of Friesian and Hereford crosses with the Angoni, Barotse and Boran breeds over the corresponding purebreds were + 40·3 kg ( + 19·0%), + 33·6 kg ( + 16·2%) and + 31·0 kg ( + 14·0%) respectively. There were few important carcass differences between the corresponding Friesian and Hereford crosses.The mortality rate during the experiment was 8·2% with only small differences between genotypes.The interactions found in the experiment indicated that breed comparisons should be conducted over a number of years and at various management levels. For growth and carcass production under the conditions of the experiment the use of exotic crossbreds is clearly advantageous.
Lysine and nitrogen measurement by infra-red reflectance analysis as an aid to barley breeding
Authors: Gill A. A. , Starr Carol , Smith D. B. 
Published: March 2009

SUMMARYThe feasibility of measuring lysine and protein nitrogen in barley using an infra-red reflectance analyser was examined. This is a very rapid technique, requiring no manipulative skills, and measuring several components simultaneously using milled grains. The results show that this instrument is sensitive to changes in lysine and protein nitrogen and can be calibrated to measure these components to a high degree of accuracy. It is shown that the gross morphological and biochemical abnormalities of high lysine mutants do not affect these measurements, indicating that this method is suitable for the rapid screening of material from breeding programmes designed to improve the lysine content of barley proteins.
Artificial cooling of buffaloes (Bubalus bubalis) in a hot environment, and plasma oxytocin concentration
Authors: Sharma A. K. , Gangwar P. C. , Srivastava R. K. , Dhingra D. P. 
Published: March 2009

SUMMARYNine normal lactating Murrah buffaloes from the Punjab Agricultural University Dairy herd were used to assess the effect of showers and evaporative cooling on plasma oxytocin concentration, let-down time, milking time and milk yield in buffaloes. The animals were showered four times daily between 10.30 and 16.30 h or provided with evaporative cooling from 07.00 to 21.00 h. In the hot and dry period the oxytocin concentration in buffaloes given a shower was significantly greater than that of the buffaloes of the control group. In the hot and humid period there was a similar trend.It is concluded from these studies, that cooling may increase the effective milk ejection reflex because the milk-ejection response to a given blood oxytocin concentration is different when the animal is heat stressed from when it is cooled.
Competition and the superparasitism of Spodoptera littoralis (Boisd.) larvae by Microplitis rufiventris Kok.
Authors: Hegazi E. M. , Shabaan M. A. 
Published: March 2009

SummaryAn experiment to compare the effect of diverse ratios of 0–6 h old Microplitis rufiventris Kok. progeny within Spodoptera littoralis (Boisd.) larvae is described and the results discusssed. Five to 21% of parasite progeny was eliminated during the egg stage. Surplus parasite larvae were eliminated mainly by physical attack, physiological suppression and perhaps by encapsulation. Parasite larvae which escaped competition during their first instar were subjected to physiological suppression. Some of the super-numerary parasite larvae other than the winners survived competition mechanisms and developed in the host haemocoele. Nevertheless, most of these parasites suffered from moulting failure and emergence problems at the end of their endoparasitic development. The development of the winning parasite was retarded by 1–2 days during its egg-larval stage while the duration of its pupal stage was about the same as parasites from singly parasitized hosts.
Triple test cross analysis in first backcross populations of four wheat crosses
Authors: Singh S. , Singh R. B. 
Published: March 2009

SUMMARYThe triple test cross analysis (Kearsey & Jinks, 1968; Jinks & Perkins, 1970) was used to detect and estimate the additive, dominance and epistatic components of genetic variation for four metric traits, namely, final plant height, number of spikelets per spike, 100-kernel weight and yield per plant, in the first backcross populations of four wheat crosses (Norteno 67 α Moti, Sonalika α Moti, Kalyan Sona α Sonalika and Kalyan Sona × NP 876). Epistasis was a more important component of variation for final plant height and yield per plant than for number of spikelets per spike and 100-kernel weight. On the other hand, the additive component was highly significant for all four characters in all eight backcrosses.
Calcium and phosphorus balances with laying birds
Authors: Tyler Cyril , Willcox James Stuart 
Published: March 2009

1. A series of balance experiments to compare calcium carbonate, calcium sulphate and calcium gluconate as sources of calcium for laying hens is described.2. Not one of the three supplements showed all-round superiority, but calcium sulphate was the worst.3. The main results indicate that:(a) Calcium sulphate and gluconate cause scouring but carbonate does not.(b) The best retention of calcium occurs with gluconate and the worst with sulphate.(c) Calcium carbonate gives the best shells and calcium sulphate the worst.4. The experiments also throw fresh light on some more general aspects of calcium and phosphorus metabolism.5. On the basis of these general results and a review of the literature of blood calcium and phosphorus in laying hens a theory dealing with certain aspects of egg-shell formation is presented.
Observations on the value of whale-meat meal as a constituent of chick diets, with a note on the influence of added protein on the efficiency of utilization of the gross energy of a ration
Authors: Halnan E. T. 
Published: March 2009

1. A method of assessing the biological values of proteins by the slaughter method, using day-old chicks as experimental material, is outlined.2. Whale-meat meal, when added to a cereal basal ration, is shown to possess a high biological value for chicks.3. The method of preparation of animal proteins is shown to affect their nutritive value, whale meat dried at a low temperature giving better results than that dried at a high temperature.4. The nature and amount of a protein added to a cereal ration materially affects the efficiency of utilization of the gross energy of the ration. Arising therefrom, support is given to the system of expressing the nutritive value of feeding stuffs, and the nutritive requirements of animals, in terms of digestible protein and digestible nutrients or metabolizable energy.5. Outbreaks of feather picking in the whale-meat meal groups occurred, whereas none occurred in the basal group. A possible explanation for these outbreaks is given in the text.6. The presence of gizzard erosion was noted in all individuals in the whale-meat meal groups, whereas none occurred in the basal group.