bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of ammonia and nitrate in soil
Authors: Bremner J. M. , Shaw K.
Published: March 2009

1. Methods for the determination of ammonia and nitrate in soil are described. The ammonia and nitrate are extracted at pH 1·0–1·5 with a mixture of potassium sulphate and sulphuric acid, and the ammonia is determined by distillation with magnesium oxide at 25° C. in a modified Conway microdiffusion unit. Ammonia plus nitrate is determined on a separate sample of the same extract by reduction of the nitrate to ammonia with titanous hydroxide and subsequent distillation with magnesium oxide, both the reduction and distillation being carried out in a modified microdiffusion unit at 25° C.

2. The methods are applicable to coloured extracts and are not affected by substances found to interfere with other methods of determining ammonia and nitrate.

3. It is suggested that the methods may also prove useful for the determination of ammonia and nitrate in plant materials.
A comparison between the mode of sction of organic matter and synthetic polymers in stabilizing soil crumbs
Authors: Emerson W. W.
Published: March 2009

Synthetic soil crumbs stabilized by the addition of small quantities of a polymer, and natural soil crumbs from old grassland, have been extracted with neutral sodium pyrophosphate and alkali and the strengths of the crumbs compared before and after extraction, using the sodium saturation technique. Three polymers were used: polyvinyl alcohol (a non-ionic polymer), sodium alginate, and a vinyl acetate-maleic anhydride co-polymer (Vama), the latter both carboxylated polymers. Pyrophosphate was able to displace the carboxylated polymers from the synthetic crumbs, but not the stabilizing fraction of the organic matter from the grassland crumbs. 0·5N-NaOH produced a much greater reduction on the strength of the alginate treated crumbs compared with Vama crumbs, which is attributed to the weaker hydrogen bonds formed by the former. Prolonged leaching with alkali removed a considerable part of the stabilizing organic matter in the grassland crumbs. Neither method of extraction affected the stability of the polyvinyl alcohol crumbs.

It is concluded that the grassland crumbs are stabilized by the formation of inter-lamellar complexes with the clay in the crumbs, and probably that the substance forming the complexes is a polymer and contains amino-groups.

Evidence is also given that phosphate ions and the carboxylated polymers are attached in the same manner to the edges of the clay crystals.
The digestibility of the carbohydrate complex by birds of different ages
Authors: Bolton W.
Published: March 2009

1. The digestibility of the carbohydrates in compounded poultry diets has been estimated, using both conventional and individual methods for certain components.

2. In the conventional analysis, crude fibre was apparently digested to the extent of 5%; this has been shown to be due to the comparison of different complexes in the food and the droppings.

3. Sugar and starch were digested by birds of all ages, and cellulose and lignin were indigestible. The digestibility of pentosan increased with increased age of the bird.

4. By deleting crude fibre and adopting available carbohydrate for the partition of the carbohydrate complex in foods, the nutritive ratio of a compound diet can be estimated from analytical data, and the amount of extra protein necessary when a diet is supplemented by fat can be calculated.
Energy values in pig nutrition:3. The digestible and metabolizable energy content of barley, wheat, maize, oats and rye
Authors: Wiseman J. , Cole D. J. A. , Lewis D.
Published: March 2009

The digestible energy (DE) and metabolizable energy (ME) content of eight samples of barley, eight of wheat, four of maize and two each of oats and rye were determined using growing gilts. The DE content of barley ranged from 15·35 to 15·89 MJ/kg D.M., from 15·15 to 16·42 MJ/kg D.M. for wheat and from 16·05 to 16·47 MJ/kg D.M. for maize. DE values for the two oat samples were 12·48 and 12·74 MJ/kg D.M. and 15–04 and 15–47 MJ/kg D.M. for the two rye samples. There was a significant correlation between DE and ME:

ME (MJ/kg D.M.) = 0·050 + 0·965 DE: r = 0·99; P < 0·001.

The ratio ME/DE was significantly influenced by crude-protein content:

ME/DE = 100–0·254 CP%: r = –0·77; P < 0·001.

ME values were also corrected to zero nitrogen retention (MEno) and to 30% nitrogen retention (MEN30). The effect of such corrections was expressed as MEN0/ME and MEN30/ME. Values thus obtained were 0·98 and 1·00 respectively for the pooled values for all cereals.

The data indicated that there was unlikely to be significant variation in the DE content of samples of the same cereal species, selected from commercial sources within the U.K. when evaluated under standardized experimental conditions.
A study of mole drainage with simplified cultivation for autumn-sown crops on a clay soil
Authors: Cannell R. Q. , Goss M. J. , Harris G. L. , Jarvis M. G. , Douglas J. T. , Howse K. R. , Grice S. Le
Published: March 2009

A replicated, long-term field drainage experiment on a clay soil was started in 1978 to investigate the effects of mole drainage on land that had been direct-drilled or ploughed. We here describe the background and the need for this work, details of the experiment and summarize the results for the first 2 years. The main factors causing point-to-point variability in the soil at the experimental site and their relative contributions were assessed. Variations in inherent soil properties were small, except for depth to calcareous clay. Site hydrology was also generally uniform, especially soil water content, and was little affected by the presence of subsoil drainage schemes dating from the 19th century. There were some variations in micro-relief. The drained and undrained plots were hydrologically separated. Equipment was installed to measure separately surface runoff, lateral flow at the bottom of the cultivated layer (the interflow) and deep drainage from the mole and pipe system (in the drained plots only). The design and performance of that equipment is described. In both years much of the undrained soil became saturated in winter, but a residual cultivation pan limited the effect of the mole drains in 1978–9. In 1979–80, after disrupting the pan, the water table in the moledrained plots was about 25 cm deeper than in the undrained plots, root growth was greater and yield of winter wheat 11% heavier. About 90% of water and nutrients draining from the drained plots were carried in the mole and pipe system. The results on water balance, nutrient losses, crop growth and yield are fully reported in companion papers (Harris et al. 1984; Ellis et al. 1984).
Phosphorus economy in potato cultivation by soaking mother seed tubers in a solution of urea and phosphate
Authors: Sharma R. C. , Sahota T. S. , Sharma U. C. , Sharma A. K.
Published: March 2009

Investigations were carried out during 1976–80 on the alkaline alluvial soils of Daurala and Jullundur and on the acid hill soils of Simla and Shillong to study the effect of soaking non-dormant mother seed tubers in a solution of single superphosphate alone and in combination with urea, KCl, gum acacia and agromin (micro-nutrient mixture) on the tuber yield and P economy of the subsequent potato crop. On the alluvial soils, soaking increased the yield of daughter tubers but only on P-deficient soil. Increasing the period of soaking above 6 h and the concentration of superphosphate above 1·5% in the solution tended to reduce the emergence and tuber yield. On the acid hill soils soaking tubers for 4 h in a solution of 0·5% urea + 1·5% single superphosphate + 0·2% Dithane M-45 increased the yield of daughter tubers. Inclusion of KCl, agromin or gum acacia in the soaking solution had little effect. The increase in yield due to soaking was produced by an increase in number and size of daughter tubers and was equivalent to about 22 kg P/ha applied to soil.
Effect of airdrying, γ-irradiation and chloroform fumigation of soil on extractability of trace elements
Authors: Sparling G. P. , Berrow M. L.
Published: March 2009

In many instances soils are routinely air-dried and sieved prior to chemical analysis to permit ease of handling and decrease variability. Such drying, however, can increase the extractability of some elements, for example, the amount of P extracted by 0'5 m-NaHCO3 (Brookes, Powlson & Jenkinson, 1982). Much of the increased P is derived from soil micro-organisms killed by the soil drying (Brookes et al.1982). Similarly, much of the flush of C and N mineralization that occurs after rewetting of dried soils can be derived from killed soil micro-organisms (Jenkinson & Powlson 1976; Marumoto et al.1977; Marumoto, Anderson & Domsch, 1982).
Comparison of equations for predicting voluntary intake by dairy cows
Authors: Neal Heather D. St. C. , Thomas C. , Cobby J. M.
Published: March 2009

Rations for dairy cows are often formulated using predictions of voluntary feed intake calculated from regression equations. The accuracy of the predictions of dry-matter intake by seven equations is investigated. Comparisons are made when live weight is taken to be the observed weekly mean (MLW), the observed live weight after calving (CLW) or an estimated breed weight accompanied by a notional pattern of live-weight change (BLW). Data recorded on a British Friesian dairy herd at the Grassland Research Institute fed mostly silage ad libitum and various supplements are used. The mean square prediction error (MSPE) is calculated for each week and summarized over the whole experimental period.

The least MSPE's are 2·1, 2·8 and 2·4 (kg D.M.)2 for comparisons using MLW, CLW and BLW respectively. The Ministry of Agriculture, Fisheries and Food (1975) equation involving only live weight and milk yield performs well and would be useful when only the limited measurements of live weight and milk yield are available, but the more complex equations of Vadiveloo & Holmes (1979) and of Lewis (1981) give consistently the best predictions. The importance of using the original definitions of the variables when applying a predictive equation is illustrated. Even so, the large errors found in the predictions of intake points to the need for further research.
Effect of boron on the protein and amino acid composition of wheat grain
Authors: Iqtidar A. , Rehman S. F.
Published: March 2009

Field experiments were conducted for 2 years in Peshawar, North West Frontier Province of Pakistan, to study the effect of three levels of boron (1, 2 and 3 kg/ha) on the amino acid composition of wheat protein. The soil was clay loam, alluvial in nature, with a pH value of 7·8, and hot-water-soluble boron content of 0·58 mg/kg.

Positive linear and negative quadratic effects of boron were observed on the protein and ash contents of wheat grain. Most of the essential amino acids were linearly increased with increasing supply of boron. There was a negative linear relationship of boron with all non-essential amino acids, except histidine and tyrosine.

Lysine was the most deficient amino acid in wheat protein. Chemical score based on this amino acid was positively affected by boron. There was also an improvement in the amino acid profile due to boron.
Manganese equilibrium in submerged sodic soils as influenced by application of gypsum and green manuring
Authors: Sadan U. S. , Bajwa M. S.
Published: March 2009

A pot experiment studied the effect of gypsum and green manuring on equilibrium soil solution pH, pE, Mn concentration and Mn equilibrium in three sodic soils. Submergence decreased soil solution pH and increased Mn concentration in all the soils. Addition of gypsum with green manure further decreased soil solution pH and increased Mn concentration. Maximum Mn concentration in all the treatments was observed at 4 weeks of submergence in Kaheru soil and at 6 weeks of submergence in Jagjitpur and Langrian soil followed by a decline up to 12 weeks. In spite of wide variations in pH, pE and Mn concentration in soil solutions, the solubility of Mn after peak values appeared to be mainly controlled by the MnC03-Mn2+ system irrespective of the treatments, and the Mn2O3-Mn3O4 system appeared to operate after 2 weeks of submergence in the control and gypsum-treated soils.
Investigations on yield in cereals. VII. A Study of development and yield of wheat based upon varietal comparison
Authors: Engledow F. L. , Ramiah K.
Published: March 2009

In England, the corn-growing situation, after a span of precarious years, has now become critical. Even if prices rise substantially and fairly soon, what may be described as essentially the “English cereal yield problem” will remain.
The vascular supply of the skin of Ayrshire calves and embryos
Authors: Goodall A. Myfanwy , Yang S. H.
Published: March 2009

1. A method of perfusing the skin of the flanks and the backs of Ayrshire calves and embryos with indian ink is described.

2. The distribution of blood vessels in the perfused skins has been studied.

3. Three plexuses of blood vessels have been observed in the skins. The first lies below the corium; the second is at a level between that of the ‘sweat glands’ and the sebaceous glands; and the third extends from beneath the epidermis to above the second plexus and is a deep network of many fine blood vessels.

4. The presence of venae comites in the skin is discussed.

5. The ‘sweat glands’ appear to have a very poor blood supply, while the hair follicles and papillae are richly supplied.

6. Both the ‘sweat glands’ and the hair follicles are supplied with blood from the second plexus.

7. The vessels of the third plexus appear to enmesh the individual hair follicles at different levels.

8. Blood vessels supplying the skin in the back and flanks of the animals originate from the intercostal arteries and so pass through the heat generating intercostal muscles.
Growth analysis of the domestic fowl II. Effect of plane of nutrition on carcass composition
Authors: Wilson P. N.
Published: March 2009

1. Two sample cockerels from each plane of nutrition treatment were killed and dissected at 0, 4, 10, 15 and 24 weeks of age. Details of the dissection technique are given.

2. All organs and tissues were weighed both wet and oven-dried. The total dry-matter content of the birds increased from 21% at hatching to 32% at 24 weeks.

3. The chief age changes in the proportions of the major joints of the bird consist of a marked increase in relative mass of wing, and a lesser increase in the leg joints. The early maturing head and neck joints decrease in relative mass by approximately onehalf. There are no treatment differences in the gross proportions of the birds calculated on the basis of weights of the major joints.

4. The advantages and disadvantages of the various methods of presenting quantitative growth analysis data are discussed. Reasons are given for employing several different methods in this work.

5. The amount of fat in the carcasses analysed varies considerably between individual birds. There are no consistent age or treatment effects on the fat contents of the cockerels. The interpretation of McMeekan's dissection analysis data is discussed, and reasons are advanced for conducting future experiments of similar nature on the basis of a fatfree carcass. It is argued that adipose deposits should not be considered in the same category as body organs and tissues.
Studies on soil phosphorus. I. A method for the partial fractionation of soil phosphorus
Authors: Williams Colin H.
Published: March 2009

Ghani's method for the partial fractionation of soil phosphorus has been simplified. From results obtained with soils and representative phosphatic minerals it has been shown that successive single extractions with 2·5% acetic acid-l% 8-hydroxyquinoline and 0·1 N-sodium hydroxide gives a good fractionation of the phosphate compounds present.

The relative effects of cupferron and 8-hydroxyquinoline as reagents for blocking the adsorption of phosphate were also investigated. Cupferron precipitated aluminium more completely than did 8-hydroxyquinoline at the pH used for the extraction. However, because of its instability and also because of indications that it may attack organic forms of phosphorus cupferron was considered to be of less value than 8-hydroxyquinoline in the fractionation of soil phosphorus.

The recovery of phosphate added to soil, the reaction of which had been varied by the use of sulphur or calcium carbonate, was almost complete at all reactions used (pH 4·5–8·2) for amounts of phosphate up to the equivalent of 500 parts of PO4 per million parts of soil. The distribution of this added phosphate between the acid and alkali soluble fraction showed that in acid soils the phosphate tended to be fixed mainly by adsorption or as a basic ferric and aluminium phosphates, while at an alkaline reaction most of the fixation was due to precipitation by calcium.
Some effects of season of the year and herd management upon the dairy shorthorn cow I. The effects of seasonal changes in climate, feeding and management upon the milk yields of four herds
Authors: Burt A. W. A.
Published: March 2009

Milk records and records of farm and herd management collected over a 2-year period have been used to study the effects of seasonal changes in climate, feeding and management in each of four Dairy Shorthorn herds.

Differences in climatic conditions and management between the four farms appeared to be reflected in mean lactation yields, herd D having a slightly higher, and herd C a considerably lower average than the other two herds.

In each herd, mean yields in each week were corrected for the effects of potential productivity and mean stage of lactation of the cows to give a weekly value designated the yield index. Variations in this quantity were used as a measure of the effects of seasonal changes in climate, feeding and management upon milk yields.
The chemical composition of oats I. The oil and free fatty acid content of oats and groats
Authors: Hutchinson J. B. , Martin H. F.
Published: March 2009

The petroleum-ether extractable oil content of native oats (dry-weight basis) ranges 3·0–8·5%, and is chiefly dependent upon variety and kernel content (which is itself a varietal characteristic). That of the kernel, which comprises 64–81% of the grain by weight, is 4–11% with a spread of about 2·5% within the variety. The kernel contains in addition about 2·5% of more complex insoluble fatty material which is released on acid hydrolysis. The husk, on the other hand, contains only a few tenths of one per cent of petroleum-ether soluble oil together with about 1% of more complex material that can be released by acid hydrolysis.

Certain environments favour higher levels of oil content within all varieties whereas others favour lower levels; Scottish samples tend to be slightly higher in oil content than English samples of the same variety.

The free fatty acid content of the oil in the kernel ranges 3–10% for sound, viable grain; the value for any sample is more dependent on environment during cultivation, harvest and storage than on the variety. After the grain is milled or pulverized the free fatty acid content rises to much higher levels within a few days.
The effect of environmental temperature and humidity on the respiration rate of Ayrshire calves
Authors: Beakley W. R. , Findlay J. D.
Published: March 2009

1. The respiration rates of three 4-month old Ayrshire bull calves were measured in individual 6 hr. daily exposures to 15, 20, 25, 30, 35 and 40° C. dry bulb temperatures at 17 mg./l. absolute humidity and at 7 mg./l. saturation deficit at temperatures of 30, 35 and 40° C. in a planned sequence of environmental temperature. The schedule of experiments on each animal lasted 45 days consisting of five replications of these nine environmental conditions. Throughout the experimental programme the respiration rates of these three animals and of three control animals were measured in a holding room just before the experimental animal of each pair was transferred to the hot room.

2. The frequency of respiration of all the calves increased with increasing environmental temperature and humidity.
The effect of environmental temperature and humidity on the frequency of the heart beat of Ayrshire calves
Authors: Beakley W. R. , Findlay J. D.
Published: March 2009

1. The heart rates of 4-month-old Ayrshire bull calves were measured in individual 6 hr. daily exposures to 15, 20, 25, 30, 35 and 40° C. dry bulb temperatures at 17 mg./l. absolute humidity and at 7 mg./l. saturation deficit at temperatures 30–40° C. The schedule of experiments on each animal lasted 45 days and consisted of five replications of these nine environmental conditions. Throughout the experimental schedule the heart rates of three paired control animals were measured in a temperature-controlled holding room.

2. The heart rates of all experimental animals increased with increasing environmental temperatures above 20° C. and with increasing humidity above 30° C.
A theoretical model for the decline in the protein content in plants during growth
Authors: Greenwood D. J. , Barnes A.
Published: March 2009

The protein contents of plants decline with increasing size and age even when the plants are adequately supplied with nitrogen. The quantitative nature of this decline needs to be defined for use in models for nitrogen response and to improve diagnostic criteria for detecting nitrogen deficiency. For this reason we have considered the use of photosynthate for the synthesis of the organic constituents within a plant and for maintenance purposes. It has led us to deduce that

In (P/P0) = (δβ/a) In (F/F0) – βMG(T–T0),

which in the special case of exponential growth approximates to

In (P/P0) = (δβ/a) In (F/F0),

where P is the critical protein content at time T, F is the total weight of nitrogen-free organic matter at time T, P0 and F0 are the corresponding weights at some initial time T0; δ is a coefficient related to the relative rates of production of protein and the nitrogenfree constituents of plants. β and α. are energy coefficients for the conversion of glucose into protein and nitrogen-free organic matter and MGis the maintenance respiration rate in g of glucose/g of protein/day.

The values for β and α depend on the chemical composition of the crops but for forage crops appear to be about 0·62 and 0·76 respectively over a wide range of temperatures. MG is temperature dependent and experimental evidence suggests that it is about 20 mg of glucose/g of protein/day at 15 °C. Less information is available about δ although when there are ample supplies of nitrogen it is probably near unity.
Measurement and prediction of the changes in protein contents of field crops during growth
Authors: Greenwood D. J. , Barnes A. , Cleaver T. J.
Published: March 2009

A theoretical model for the influence of plant size and age on plant protein content was tested against the results of 13 field experiments on vegetable crops grown with high rates of application of N, P and K fertilizers.

For each crop the protein contents of individual plants of similar age (but of different sizes) harvested at regular intervals during growth were found to bear a linear ln-ln relationship to their contents of nitrogen-free organic matter. The slopes of the lines of best fit were almost the same at each harvest date. The intercepts were similar irrespective of harvest date when growth was exponential but showed an approximately linear decline with length of growing period when it was not. These features are in agreement with the theory.

Maintenance respiration rates were deduced by interpreting the data in terms of the theoretical model. The values determined in this way were between 8 and 21 mg of glucose/g of protein/day for the above ground parts of the plant compared with values of between 8 and 87 mg that have been obtained by entirely different methods.

It is concluded that during the exponential phase of growth the critical protein and, thus, nitrogen contents depend primarily on plant size and on the chemical composition of the nitrogen-free organic matter, but that when growth is not exponential plant age and maintenance respiration are also of importance. The models should facilitate the determination of the critical nitrogen contents for crops grown under different conditions.
Conception Rate in ewes: effect of method of breeding and number of inseminations
Authors: Smith P. A. , Boland M. P. , Gordon I.
Published: March 2009

With the development of effective methods of oestrus synchronization (Gordon, 1975), it is now possible to breed ewes at most times of the year. Encouraging conception rates have been reported following insemination (Colas & Brice, 1970; Colas et al. 1973; Gordon, 1975). A major disadvantage with the technique is the need to inseminate ewes twice at 10–14 h intervals. Because of the anatomy of the ovine cervix, it is not possible to deposit semen in the uterus as in the bovine. The present experiment was designed to compare a single or double insemination with natural service. Two types of inseminating gun were employed in an effort to deposit semen deep in the cervical folds.
A survey of beef production in west wales, 1943–8 Part II. Variations within the region and the ecology of beef production
Authors: Phillips R.
Published: March 2009

1. Differences in cattle population (4 June returns) and in average body size of fat cattle (data from the collecting centres) have been illustrated for the three counties (Cardiganshire, Carmarthenshire and Pembrokeshire) constituting this region. They indicate the superiority of Pembrokeshire.

2. The six westerly collecting areas of Pembrokeshire produce the heaviest cattle of better grading. It has a higher proportion of steers to heifers than the rest of the region.

3. The statistical analysis of the data has made it possible to partition the region into four main groups of centres, which show significant differences in the size of the fat cattle.

4. The superiority of group 1 has been demonstrated in relation to (a) the seasonally of deliveries, (b) the percentage grading and (c) in the average live weights.

5. These differences are examined in greater detail by comparisons of the deliveries to the Pembroke and to the Llandilo centres. These show that Pembroke is superior in average live weights, percentage grading and in the proportion of steers to heifers.

6. The ungraded cattle are also examined, and the results indicate the same trends within the region as for the graded cattle.

7. The possible explanation of the variations or the ecology of beef production has been discussed in the light of Ashton's (1930) suggestions that variations in body size between cattle of different breeds is mainly due to the calcium and phosphorus content of the soil.

8. The conclusion is drawn that differences of climate dominate the whole picture, because of the effect of rainfall on leaching and soil erosion, as well as on the quality of the harvested fodders, the effect of temperature on the length of the growing season and of the beneficial influence of sunshine on the quality of both grass and hay.
Photosynthetic rates and the effects of applied gibberellin in some dwarf, semi-dwarf and tall wheat varieties (Triticum aestivum )
Authors: Gale M. D. , Edrich Jennifer , Lupton F. G. H.
Published: March 2009

Photosynthetic rates of flag blades were measured in eight wheat varieties. The differing rates observed were not correlated with winter or spring habit, plant height or gibberellin sensitivity. The rates were correlated inversely with the flag blade area in these varieties.

Applied gibberellin increased photosynthetic rate and the maximum increase was 17% in the variety with the lowest control rate. However, the varieties did not differ significantly in their response to the hormone.
In vivo and in vitro ethanolic fermentation of milk replacers by the naturally occurring yeast Torulopsis glabrata
Authors: White R. W.
Published: March 2009

An investigation was undertaken to determine whether commercial milk replacers provide fermentable substrates for the yeast Torulopsis glabrata and thus produce ethanol in the stomachs of new born lambs and calves. Samples of stomach contents from calves in two small rearing units and a small number of farm bred calves, all being fed commercial milk replacers, were also examined. Ethanol was produced from certain replacers in all cases, and its association with Torulopsis glabrata was confirmed.
Isolation of anatomically defined cell walls from fodder kale, and their contributions to determining the in vitro cellulase digestibility of the whole plant
Authors: McCluskey J. G. , Allison M. J. , Duncan H. J. , Jarvis M. C.
Published: March 2009

Vascular and non-vascular cell walls were isolated separately from leaves, upper stems and lower stems of 12 kale (Brassica oleracea L.) cultivars, by a sieving technique. The digestible organic matter in the dry matter (DOMD) of the cell walls and of the whole plants was determined by pepsin-cellulase digestion. The measured whole-plant DOMD correlated closely with the DOMD predicted by adding together the amounts of non-digested material derived from all the plant's component cell-wall fractions. Differences in DOMD between cultivars were determined primarily by the amount of vascular cell walls in the stems, particularly the lower stems; that is, by the stem anatomy. The vascular cell walls of the upper stems had a wider range of DOMD values and a higher mean DOMD than the vascular cell walls of the lower stems. Thus cell-wall composition made some contribution to determining the whole-plant DOMD, although it contributed less than the anatomy of the stem.
The growth and activity of winter wheat roots in the field: root growth of high-yielding crops in relation to shoot growth
Authors: Barraclough P. B.
Published: March 2009

Root growth is considered in relation to shoot growth for high-yielding crops of winter wheat grown on three soil types in 1980 and 1981. From the time that nitrogen was applied to anthesis, shoot growth was rapid and effectively linear in relation to thermal time, whereas root growth entered a rapid linear phase after about 500–600 °C days, well before the application of nitrogen. Between double ridges and anthesis, shoots accumulated dry matter 10 times faster than roots on average. The relationship between root and shoot growth was different in the two years, which was probably due to reduced assimilate production in 1981 as a result of the dull, cloudy weather. At anthesis, average root: plant ratios for 1980 and 1981 were 0·132 and 0·093 respectively but no significant differences were caused by sowing dates or sites, despite the presence of a plough-pan on one of the soils.

Root:plant ratios declined from about 0·4 in winter and early spring to about 0·1 by anthesis. There was considerable variability in root:plant ratios for different crops during winter and early spring, caused in part by differences in soil-N availability and timing of application of fertilizer nitrogen.
The calcium requirements of poultry with particular reference to their needs for maintenance
Authors: Tyler Cyril , Willcox James Stuart
Published: March 2009

1. The question of the maintenance requirement of calcium for poultry is discussed.

2. On the basis of curves relating intake of calcium to calcium in the droppings, a maintenance value for laying and non-laying birds is estimated.

3. It is suggested that in the case of both laying and non-laying birds the maintenance requirement of calcium is about 0·10 g. and that the endogenous calcium value is about 0·05 g.
War-time rations for pigs: Report of experiments with mangolds and biscuit waste, fodder yeast, urea and dried skim milk
Authors: Braude R. , Foot A. S.
Published: March 2009

1. An individual feeding experiment using forty-eight pigs and a group feeding experiment using twenty-nine pigs have been carried out with the object of testing the so-called Lehmann system of pig feeding, where the amount of meal allowed for the fattening pig is restricted to a basal ration of 2½ lb. each and farm bulky foods or food wastes fed ad lib. used as supplementary foods.

2. Using a mixture of 6 parts mangold and 1 part biscuit waste as a supplementary food, live-weight gains only slightly less than with all-meal feeding have been obtained and a great saving in meal consumption effected. Under more favourable conditions as much as 1¾ lb. of meal has been saved for each 1 lb. live-weight gain.
The nutrition of the bacon pig: V. The minimum level of protein intake consistent with quick growth and satisfactory carcass quality
Authors: Woodman H. E. , Evans R. E.
Published: March 2009

The present investigation is the sequel to an earlier pig-feeding trial in which a diet supplying only half the standard amounts of protein supplement, in the form of a mixture of feeding blood meal, dried separated milk and ex. soya bean meal, was found to give as good results from the standpoints of rate of growth, efficiency of food conversion and carcass leanness and quality, as a diet that contained the full standard allowances.

It was considered desirable to repeat this initial exploratory experiment, making use this time of a totally different form of protein supplement, since the question of the biological efficiency of the protein supply might conceivably be of critical importance at the lower levels of protein feeding. In the present trial, therefore, the mixture of the three protein foods was replaced by a single protein food, namely, white fish meal. The standard-protein treatment C supplied 12% of white fish meal up to 90 lb. live-weight, 10% from 90 to 150 lb., whilst from 150 lb. to slaughter at about 200 lb. live-weight, the white fish meal was omitted from the diet, its place being taken by 5% of ex. soya bean meal. The corresponding allowances of protein food in the low-protein treatment B were 5, 4 and 3% respectively. The low-protein treatment A, which was introduced as a link between the previous and the present trials, contained the protein supplement composed of feeding blood meal, dried separated milk and ex. soya bean meal and supplied the same amount of digestible protein as was contained in the low-protein treatment B.
The determination of the size distribution of soil clods and crumbs
Authors: Russell E. W. , Tamhane R. V.
Published: March 2009

1. It is possible to determine the size distribution of clods in the field by simple sieving of the soil without any pre-treatment provided the soil is not too wet. There is a personal factor involved in the sieving, but with care and training this will not affect comparisons of results obtained by that person. If the soil is too wet the individual clods smaller than 3 mm. stick together on the 3 mm. sieve. This sticking together is first apparent on the 3 mm. sieve but may become appreciable on the ¼ in. (6 mm.) sieve. No certain way was found for overcoming this difficulty.

2. There appears to be no best method for determining the size distribution of the soil crumbs, i.e. of the water-stable aggregates in the soil. The method and the technique must be chosen so as to give the maximum amount of useful information. If an appreciable proportion of the crumbs are larger than ½ mm., a water-sieving method is practically essential.

3. The method of wetting to be used can only be chosen from a consideration of what information is wanted. If possible it would be desirable for general purposes to use a very slow or a vacuum wetting technique and a very rapid wetting technique such as wetting the soil by immersion in water.

4. The decision whether air-dry or field-moist soil should be used depends entirely on the information needed. For general purposes the use of air-dry soil is recommended.
Hormonal augmentation of fertility in sheep: I. Induction of ovulation, superovulation and heat in sheep
Authors: Hammond J. , Hammond J. , Parkes A. S.
Published: March 2009

1. Gonadotrophic extracts of horse-pituitary gland, of pregnant mare serum and of urine of pregnant women, as well as oestrogenic substances, will induce ovulation in anoestrous sheep. The number of ova shed is apparently independent of the dosage given and lies within the normal range.

2. The oestrogens probably act by evoking ovulation-producing activity on the part of the animal's own pituitary gland, and it is likely that the gonadotrophins also initiate the same chain of events by causing oestrogen secretion by the ovary.

3. Oestrogens induce heat in the anoestrous sheep, but horse-pituitary extract and P.M.S. evoked sexual receptivity only in animals having a regressing corpus luteum. In the absence of a corpus luteum, ovulation occurs without heat, while the presence of an active corpus luteum usually suppresses both ovulation and heat.

4. Administration of horse pituitary a few days before the corpus luteum is due to regress results in superovulation at the succeeding heat, as many as twelve simultaneous ovulations having been obtained under these conditions.
Factors affecting the stability and estimation of carotene in artificially dried grass and hays
Authors: Kon S. K. , Thompson S. Y.
Published: March 2009

1. The influence of storage in the light and in the dark at ordinary temperature and in a heated room at 70–80° F. on the carotene content of finely ground artificially dried grass stored in paper sacks and jute sacks was studied. There was an initial drop in carotene content from 61·1 to 46·5 mg./100 g., i.e. 23·9%, in the first month, and a total loss of 31·4% during 6 months' storage (August to February). No difference could be detected either between treatments or types of containers.

2. There was a marked loss of carotene during 13 months' storage of baled artificially dried grass and of hays, amounting to 30–40% of the original value.

3. Two methods of estimating carotene were compared. The method of Ferguson & Bishop (1936) gave higher results than the method of Peterson, Hughes & Freéman (1937). The difference is probably due to incomplete extraction in the latter method.

4. Chromatographic analyses of “carotene” fractions from the above grasses showed the presence of coloured impurities amounting to 20·5–33·8% of the total recovered pigments.

5. As these impurities are biologically inactive, chromatographic analysis or the use of special solvents are probably necessary for the accurate determination of carotene in forage.
Preliminary experiments on the estimation of traces of heteroauxin in soils
Authors: Parker-Rhodes A. F.
Published: March 2009

A method is described by which small quantities of indolyl acetic acid can be detected and measured quantitatively, depending on the effect of this substance on osmotic pressure of root hair cells of wheat seedlings. Full details are given of the procedure adopted and the precautions which it was found necessary to take, and suggestions are put forward as to how the method might be rendered more accurate if necessary. Possible sources of e"rror are also discussed.

An experiment is described in which this method is used to determine what effect is produced by different manurial treatments on the content of indolyl acetic acid in the soil. It was found that farmyard manure tended to increase the quantity present.
Lattice squares
Authors: Yates F.
Published: March 2009

A new method of analysing the results of experiments arranged in lattice (quasi-Latin) square designs is described. By this method the information contained in the inter-row and inter-column comparisons is recovered. The procedure followed is to estimate the actual accuracy of the inter-row and inter-column comparisons relative to intra-row and column comparisons, and assign weights proportional to these relative accuracies.

The methods of computation by which this procedure can be carried out expeditiously are described in detail, and are illustrated by two experiments carried out at Rothamsted and Woburn. The gains in accuracy obtained in these two experiments (as compared with ordinary randomized blocks) were approximately 30% and 60% respectively, allowing for losses of information due to inaccuracies of weighting.
The teart pastures of Somerset: II. Relation between soil and teartness
Authors: Lewis A. H.
Published: March 2009

1. Teart soils contain molybdenum in amounts varying from about 0·002 to 0·010% in the surface horizon and are neutral or alkaline in reaction and often calcareous. The contents of molybdenum increase down the soil profile. Teart soils are developed from Lower Liassic materials, but all soils formed from the Lower Lias are not teart. Those which are acid in reaction in the surface horizons are not teart even if their molybdenum content is high. Others which contain little molybdenum are also not teart; such soils cover a large area in Glamorgan.

2. Molybdenum appears to be concentrated in the (uppermost) argillaceous component of the Lower Lias. The limestone contains little molybdenum. The soils of Somerset are largely derived from the upper, argillaceous component while those of Glamorgan are largely derived from the lower, limestone component. This may explain why the soils of Somerset contain much more molybdenum than those of Glamorgan.

3. Somerset soils formed from Keuper, Middle Lias, Upper Lias and Cretaceous material generally contain little molybdenum and are not teart.

4. How a knowledge of the relation between soil and teartness can be turned to practical advantage is briefly discussed.
Milk-fed calves:4. The effect of herbage allowance and milk intake upon herbage intake and performance of grazing calves
Authors: Baker R. D. , Barker J. M.
Published: March 2009

The effect of herbage allowance and milk intake upon herbage intake and performance was investigated using 48 Hereford × Friesian calves purchased at 10–12 days of age and reared on reconstituted milk substitute. Groups of 24 calves were fed low (L) or high (H) daily quantities of milk normally associated with 240-day lactation yields of 1000 or 2000 kg. Six calves on each milk treatment were allocated to four daily herbage allowances during the grazing season. These were 20, 40, 60 or 80 g/kg herbage dry matter/kg live weight.

There was no effect of herbage allowance before day 95; thereafter both herbage intake and live-weight gain of the L20 and H20 groups were depressed. The effect was greatest for the L calves. Additional milk consumption reduced herbage intake at all herbage allowances. Milk intake influenced the extent to which calves were buffered from the effects of a low herbage allowance.
The estimation of the nutritive value of feeds as energy sources for ruminants and the derivation of feeding systems
Authors: Blaxter K. L. , Boyne A. W.
Published: March 2009

The results of 80 calorimetric experiments with sheep and cattle, mostly conducted in Scotland, were analysed using a generalization of the Mitscherlich equation R = B(l–exp(–pG))–l, where R is daily energy retention and G daily gross energy intake, both scaled by dividing by the fasting metabolism. The relations between gross energy and metabolizable energy were also examined. Methods of fitting the Mitscherlich equation and the errors associated with it are presented.

It is shown that the gross energy of the organic matter of feed can be estimated from proximate principles with an error of ±2·3% (coefficient of variation) and that provided different classes of feed are distinguished, the metabolizable energy of organic matter can be estimated from gross energy and crude fibre content with an error of ±6·9%. Parameters of the primary equation made with cattle agreed with those made with sheep and there was no evidence of non-proportionality of responses on substitution of feeds in mixtures.

The efficiency of utilization of gross energy for maintenance and for body gain of energy was related to the metabolizability of gross energy and, in addition, to fibre or to protein content. Prediction equations are presented which describe these relationships.

It is shown that the primary equation can be manipulated to express a number of biological concepts and that its two parameters B and p can be simply derived from estimates of the two efficiency terms for maintenance and production.

The results are discussed in relation to the design of feeding systems for ruminant animals and to the derivation of optima in their feeding.
The respiration rate and loss of dry matter from stored bran
Authors: Snow Douglas , Wright Norman C.
Published: March 2009

1. Experiments were made on the respiration of bran at different moisture levels using a continuous absorption apparatus in which the humidity of the air-stream was adjusted to be at equilibrium with the respiring bran. The rate of respiration was accelerated with increasing moisture content and was very rapid deterioration due to the high respiration rate and microbiological damage.

2. Experiments were made on the storage of bran at known moisture contents in closed tins in the laboratory and also in sacks kept under farm conditions. The total nitrogen content of the bran stored in the tins appeared to increase during storage. From similar increases in total phosphorus, it is clear that the increase in total nitrogen was caused by a loss of dry matter from the stored feeding stuff, a fact which was further demonstrated by the loss in dry weight of the sacks of bran with attributed to two causes: (1) the respiration of the plant cells still active in the bran itself, and (2) the respiration of developing micro-organisms. It is evident from these experiments that fresh bran, free from insect infestation and stored at a moisture content of less than 13%, will have a very low respiration rate and will, therefore, not be liable to heating. Bran of 15–19% moisture content respires at a much faster rate and the time for which such material can be stored with freedom from heating or other types of deterioration will be limited.
Lactation in heifers induced by oestrogen implants
Authors: Day F. T. , Hammond J.
Published: March 2009

Average lactation curves have been prepared from selected animals in a group of heifers treated for 60 or 100 days with stilboestrol or hexoestrol tablet implants. A treatment period of 100 days appears to give poorer results than one of 60 days. The optimum duration, on the average, is probably about 75 days, but seems to depend upon the way lactation develops—which bears no obvious relationship to the amount of oestrogen absorbed.

A rise in yield follows tablet removal whether this is done while the yield is still rising or after it has begun to decline. Yield in an induced lactation may fall very far short of the animal's inherent capacity, but comparison between induced lactations and those at subsequent calvings shows that it may very nearly approach what would be a normal yield.

A heifer which was treated twice did rather less well in her second induced lactation.

Breeding histories of a number of implanted heifers are outlined. They were all animals which had failed previously to get in calf. 5–10% (without further treatment) did not return to an ovulatory cycle. About 70% of anatomically normal heifers got in calf, the service rate being about 2·6. A rather high incidence of abortions may be a feature of a recovery period from treatment, but may have been due to selection of animals with such a tendency.