Thirty-eight experiments on swedes and turnips, using factorial designs without replication, were carried out to measure the responses and two-factor interactions produced by applying nitrogen, phosphorus and potassium. The effect of F.Y.M. was measured at fourteen of the centres.

The yield of tops was substantially increased by nitrogen. Phosphorus produced a moderate response but potassium had practically no effect on top growth.

The yield of roots showed small to moderately large responses to nitrogen in most experiments. There was a considerable variation in the rate required to produce the largest response, depending on the previous cropping of the field.

Phosphorus increased the yield of roots in all but four of the experiments and this nutrient generally had a greater effect than either nitrogen or potassium.

The response to potassium was significant in only half of the experiments and its effect on yield was normally less than that of nitrogen.

The two-factor interactions were practically without exception small and far from significant, the highest values usually occurring on responsive soils. The means show no interaction between nitrogen and phosphorus, and small positive interactions between nitrogen and potassium and between phosphorus and potassium.

F.Y.M. produced higher yields at the majority of the centres but had very little effect at some. At suboptimal P2O5 levels F.Y.M. tends to increase the response to nitrogen, but with adequate phosphorus this manure reduced the most profitable nitrogen rate. The response to phosphorus was markedly reduced by placing F.Y.M. in the bottom of the ridges but the effect of ploughing-in this manure during autumn or early winter on the phosphorus response was very small. In all experiments F.Y.M. produced a substantial reduction in the response to potassium.

As a result of the inadequate phosphorus rates these experiments do not provide satisfactory estimates of the amounts of nutrients supplied by F.Y.M. but suggest that 15 tons per acre will supply at least 15 lb. N, 15 lb. P2O5 and 70 lb K2O to the first crop grown after application.

The mineral composition of the roots showed large variations between crops grown on different soils. The application of a nutrient generally produced a small increase in its percentage in the roots. The nutrient uptakes showed a much greater apparent recovery of both nitrogen and potassium than of phosphorus.

The most profitable nutrient dressings have been calculated from these experiments, and at current prices about 65 lb. N, 125 lb. P2O5 and 125 lb. K2O should be about the average optimal rates per acre in the absence of F.Y.M. In the presence of a normal dressing of the latter suitable optimal rates seem to be about 50 lb. N, 110 lb. P2O5 and 55 lb. K2O.

1. The rectal temperatures of shorn and unshorn Awassi sheep were measured at various hours of the day and during various seasons of the year in two different locations in Israel.

2. An increase in body temperature accompanied an increase in environmental temperature. A steeper temperature increase was noted in shorn sheep kept in the shade. When ambient temperatures were below 30° C. the body temperature of shorn sheep was lower than that of the unshorn sheep by an average of 0·16° C.

3. When ambient temperatures were above 30° C. the body temperature of shorn sheep was equal to or higher than that of unshorn ones.

4. Upon exposure to direct sunlight, the body temperature of shorn sheep exceeded that of unshorn animals. However, when the animals were transferred to the shade, or after sunset, the shorn sheep cooled at a faster rate. Their body temperature fell below that of the unshorn sheep during the cool hours of the day.

5. Wind velocity, both in the shade and in the sun, had a greater effect on shorn than on unshorn sheep.

6. A rise in the relative humidity of ambient temperatures above 25° C. caused body temperature to rise, particularly in unshorn animals. The body temperature of shorn sheep exceeded that of unshorn ones when the animals were maintained in a hot and dry environment.

7. While the body of the shorn sheep was entirely affected by the macroclimate, the unshorn sheep were greatly influenced by the microclimate existing in the fleece. Fleece temperatures always lagged behind and were rarely equal to environmental temperatures. Since it was postulated that heat tolerance of certain animals was related to their ability to exploit cool hours of the day, it is suggested that in certain ‘tolerance tests’ records should be taken not only during exposure to heat but also during cool hours of the day.

1. A comparison was made between the pulse rate of shorn and unshorn sheep maintained in the shade and direct sunlight during the various seasons of the year.

2. The variability of the pulse rate during the day generally agreed with the daily changes in body temperature and presumed level of metabolism. Fluctuations were greater in unshorn sheep.

3. Pulse rate was lower during summer (60–100 for unshorn and 63–100 for shorn sheep) than in winter (90–130 for unshorn and 90–115 for shorn sheep). It tended to increase with a rise in ambient temperature, especially during winter and spring. A lower pulse rate accompanied a rise in environmental temperature, during summer. The slowest pulse rate of 42 per minute was observed during summer in the hot dry area.

4. The pulse rate of both groups increased with a rise in rectal temperature, particularly at low ambient temperatures. At comparable rectal temperatures, a higher average pulse rate was observed in shorn sheep during winter and spring. With elevated summer temperatures, equal pulse rates were noted in both groups of equal rectal temperatures. Since the rectal temperatures of the shorn exceeded that of unshorn sheep, in high environmental temperatures, and in the sun, their pulse rate under these conditions was also higher.

5. The differences in pulse rate between the two groups appeared to reflect the combined effects of metabolic rate, body temperature and the vasomotor activity, all of which vary with season and environmental temperatures.

1. Respiration rate of shorn and unshorn sheep was compared; animals were maintained in the shade and in direct sunlight during various seasons of the year, and at different hours of the day. The average respiration rate, for all seasons when sheep were maintained in the shade, was 55 and 32 respirations per minute, for the unshorn and shorn sheep, respectively.

The diurnal trend of the respiration rate of shorn sheep resembled that of the ambient temperature. There was a delay in the lowering of respiration rate of the unshorn sheep during the evening hours.

2. The critical temperature for the increase in respiration of animals maintained in the shade was 22° C. and 26–30° C. for the unshorn and shorn sheep, respectively.

When the animals were exposed to the direct sunlight the critical ambient temperature for the increase in respiration rate was 15–18° C. and 18–22° C. for the unshorn and shorn sheep, respectively. The respiration rate of the shorn sheep exceeded that of the unshorn but decreased very steeply when the animals returned to the shade.

3. The effect of humidity was noted particularly with ambient temperatures exceeding 27° C. The respiration rate of the unshorn sheep increased and that of the shorn decreased with the rise in the relative humidity. In the sun there was a rise in the respiration rate of both groups with increase in humidity. The rise was steeper in the shorn animals.

4. The effect of the wind in reducing respiration rate was particularly noted on shorn sheep and at elevated ambient temperatures.

5. With equal rectal temperature, the respiration rate of shorn sheep was lower than that of the unshorn ones. Assumed critical rectal temperature for the rise in respiration rate was lower in the unshorn sheep.

6. The differences between the respiration responses of the unshorn and shorn sheep stemmed from the variation in their thermal balance. The latter resulted from the differences in the insulating characteristics of body surface and the differences between the macroclimate and the microclimate existing in the fleece.

1. A comparison was made between the skin temperature, humidity and temperature within and on the surface of the fleece of unshorn and shorn sheep. This study was conducted during various seasons of the year, at different environmental temperatures, while sheep were maintained in the shade or subjected to direct sunlight.

2. Accompanying the rise of ambient temperature (in the shade) from 10 to 43° C. there was an increase in skin temperature from 34 to 40° C. and from 28 to 40° C. of the unshorn and shorn sheep, respectively.

3. The relationship between the rise in skin temperature and that of ambient temperature was not linear, but showed a stepwise pattern in which the ‘breaks’ occurred at similar environmental temperatures for both groups, although skin temperatures of shorn sheep were lower than the unshorn.

4. The diurnal change in skin temperature of the shorn sheep was similar to that of the ambient temperature. The decrease in skin temperature of unshorn sheep sometimes lagged behind the fall in environmental temperature. The seasonal variations between summer and winter were more significant in shorn than in unshorn sheep.

5. Fleece surface temperatures measured at the same ambient temperatures ranged between 13 and

42° C. and 16·5–39·5° C. in the unshorn and shorn sheep, respectively. In the break points of the rise in skin temperature, there occurred a drop in temperature gradients between the skin and fleece surface. This probably indicates a rise in thermal conductivity of the fleece at these points.

6. The temperature gradient per unit of fleece thickness is inversely related to the depth of fleece and is greater the nearer to the skin.

7. With exposure to the sun, skin temperatures of both groups greatly increased and occasionally reached 47° C. Under these conditions the differences between shorn and unshorn groups were not consistent.

8. Fleece temperatures of unshorn sheep increased greatly upon exposure to the sun. The maximal temperatures were recorded midway between the fleece surface and skin. These temperatures generally reached 55° C. and sometimes even exceeded 60° C.

9. At ambient temperatures of 30–35° C. the vapour pressure close to the skin of unshorn sheep ranged between 35–40 mm. Hg. With shorn sheep, however, the vapour pressure close to the skin was similar to that of the environment. In Yotvata there was a rise in vapour pressure close to the skin when the ambient temperature increased to 40–43° C. This rise in humidity was paralleled by a rise of vapour pressure throughout the wool. It was not linear but rather showed a ‘step-wise’ pattern.

10. The vapour pressure in fleece and near the skin of sheep subjected to direct sunlight increased considerably (up to 80 mm. Hg). This rise showed a wave-like curve with various degrees of persistency. Appearance of fluid on the skin of Awassi sheep was observed on several occasions.

1. The contents of moisture, total nitrogen and intramuscular fat (and its iodine number), and the ultimate pH, were determined on longissimus dorsi (lumbar and thoracic regions), psoas major, rectus femoris, triceps (lat. head), superficial and deep digital flexor, sartorius and extensor carpi radialis muscles from ten pigs, of accurately known history, in each of three weight groups—pork, bacon and manufacturing (150, 200 and 250 lb. live weight, respectively).

2. In addition, the myoglobin content of longissimus dorsi (lumbar), psoas major, rectus femoris, triceps (lat. head) and extensor carpi radialis was also determined. In all five muscles there was an increase in pigment content with increase of body weight, but there was some suggestion that the myoglobin content of psoas major and triceps showed a proportionally greater increment between pork and bacon weights and rectus femoris and extensor carpi radialis between bacon and manufacturing weights.

3. In pigs of all three weight groups there were highly significant differences in fat-free moisture content between muscles and between animals. The mean, fat-free moisture content of longissimus dorsi (lumbar) (76·33%) is significantly less than that of longissimus dorsi (thoracic) (76·94%) and the mean value in the latter is significantly less than that in all the muscles except psoas major (77·28%). The mean fat-free moisture content of deep digital flexor (80·00%) is significantly higher than that in all the other muscles studied. There is evidence for a direct, but not linear, relationship between the contents of fat-free moisture and connective tissue (as calculated from hydroxyproline concentration).

4. Differences in ultimate pH between animals and between muscles were highly significant; but not those between the three weight groups, although there was a tendency for higher values in the muscles from bacon and manufacturing groups.

5. Both for the data overall, and within a given muscle, there was a direct proportionality between ultimate pH and fat-free moisture content. Except in the case of deep digital flexor correlation coefficients between these two parameters were significant. These correlations varied in significance for different muscles between the three weight groups.

6. Overall, the mean total nitrogen content (fat-free) of longissimus dorsi (lumbar) (3·77%) was significantly greater than that of longissimus dorsi (thoracic) (3·69%) and the latter greater than that of psoas major (3·58%). Such differences were also apparent within each weight group. The values were significantly greater than those for the six other muscles studied. The overall mean fat-free nitrogen content of deep digital flexor (3·17%) was very significantly less than that for all the other muscles. For the muscles of pork, bacon and manufacturing weights, overall nitrogen contents (fat-free) were 3·38, 3·44 and 3·55%, respectively. There was a significant inverse correlation between nitrogen (fat-free) and moisture (fat-free) (r = –0·88).

7. The ranking of muscles with respect to their contents of intramuscular fat was significantly different between weight groups. In contrast to the bovine, there was no significant difference overall between the intramuscular fat contents of longissimus dorsi in lumbar and thoracic regions; and these were both significantly higher than levels in psoas major, although the converse is true in the bovine.

8. Variation in the intramuscular fat content of the lumbar region of longissimus dorsi was strongly reflected by those in longissimus dorsi (thoracic), psoas major, rectus femoris, triceps and superficial digital flexor; but little with those in extensor carpi radialis and deep digital flexor; and not at all with that in sartorius.

9. There was no significant difference overall in the iodine number of intramuscular fat between weight groups. Iodine numbers in both thoracic and lumbar regions of longissimus dorsi were significantly lower than those in all the other muscles studied. The overall correlations between intramuscular fat and its iodine numbers were r = –0·70, – 0·71 and – 0·66 in pigs of pork, bacon and manufacturing weights: each of these was significant.

10. In discussing the results, it is suggested that those circumstances causing a high ultimate pH in muscle (e.g. fatigue) may concomitantly effect redistribution of body water and hence explain the observed proportionality between water content and ultimate pH. Significant differences in moisture content between muscles may be related to their relative proportion of connective tissue or to its nature. On the basis of much of the chemical data obtained, the muscles studied appear to fall into three groups—longissimus dorsi (lumbar and thoracic), deep digital flexor, and the rest, although such a conclusion does not accord with that suggested by anatomical dissection. Aspects of the relative maturity of the muscles are considered.

1200 chicks comprising 300 each of Light Sussex × indigenous, Rhode Island Red × indigenous, White Leghorn × indigenous and Black Australorp × indigenous cross-breeds were reared from day old to 24 weeks under good conditions of feeding and management and growth rates, food consumption and feed conversion measured weekly to assess any improvements brought about by cross-breeding the indigenous poultry of Uganda and compare the value of the four imported breeds for this purpose.

Growth rates of the indigenous birds were greatly improved by crossing with Light Sussex, Rhode Island Red and Black Australorp cockerels, the Light Sussex cross giving the best results, but the White Leghorn cross not greatly improving the growth rates of the indigenous birds.

Crossing with Light Sussex and Rhode Island Red cockerels gave birds with greatly improved feed conversion figures over the indigenous poultry, with the Light Sussex cross again being superior, and nearly as good as the imported breeds. Crossing with Black Australorp and White Leghorn cockerels did not produce birds with improved feed conversion rates over the indigenous poultry.

An investigation was carried out into the fertility, hatchability and chick mortality levels of the progeny of indigenous poultry of Uganda crossed with cockerels of four imported breeds, these being Light Sussex, Rhode Island Red, White Leghorn and Black Australorp.

Altogether 11,888 eggs were incubated and 1584 day-old chicks reared in the production of these data.

The percentage fertility of eggs from females of all four cross-breeds both when mated to cross-bred and pure-bred imported cockerels was significantly higher than that of eggs from the pure Rhode Island Red breed. Among the four cross-breeds, the Light Sussex × indigenous birds gave the highest fertility figures.

The percentage hatchability of eggs from females of all four cross-breeds when mated with cross-bred males was significantly higher than that of eggs from the Rhode Island Red breed and when mated with cockerels of imported breeds was higher, but not significantly so, than that of the Rhode Island Red. Among the four cross-breeds, the Black Australorp × indigenous birds produced eggs with the highest hatchability figures.

Chick mortality rates of the four cross-breeds from 0 to 20 weeks ranged from 15·7 to 20·0%, the causes of mortality being listed.

Albumen quality, shell thickness and incidence of blood and meat spots in eggs from the progeny of indigenous poultry of Uganda crossed with four imported breeds were compared with results from the pure imported Rhode Island Red breed and discussed relative to figures previously obtained from indigenous poultry. The measurements were taken for a 5-day period during the 12th month of age of the birds when maintained under a high environmental temperature in Uganda.

The albumen quality of all four cross-breeds, as measured by Haugh units, was significantly higher than that of the Rhode Island Red breed.

All four cross-breeds produced eggs with shells significantly thicker than the Rhode Island Red, only slightly below the generally accepted figure of 0·013 in.

The incidence of both blood and meat spots was lower in all four cross-breeds than in the Rhode Island Red, in the case of blood spots significantly lower in one cross-breed and in the case of meat spots significantly lower in three cross-breeds.

Data on egg production, egg weight, food consumption, broodiness, mortality and body weights of the progeny of indigenous poultry of Uganda crossed with Light Sussex, White Leghorn, Rhode Island Red and Black Australorp breeds were collected collected over the 25-week period from 161 to 336 days of age and compared with the performances of indigenous poultry.

In comparison with the indigenous birds, the cross-breeds had a 61% higher mean egg production rate, a 34% lower food consumption per pound of eggs produced, a 15% higher egg weight, a 30% reduction in mortality, a 23% increase in body weight and a decrease in broodiness.

All the cross-breeds were superior in productive respects to the indigenous birds and the White Leghorn and Light Sussex breeds appeared to be the best for use in the upgrading of indigenous stock for highest egg production results.

The effects of four five-course and six four-course rotations on some physical and chemical properties of a sandy loam overlying London Clay are reported.

Periods under ley increased the water stability of the air-dry soil aggregates, the resistance of moist soil aggregates to simulated raindrops, the rate of drainage under 60 cm. of water tension as measured in the laboratory, decreased the draw-bar pull during ploughing and the force required to crush air-dry aggregates. These effects increased with the number of years under grass.

After 2 years of arable cultivation the effect of a 3-year ley on water-stable aggregation was still apparent whereas the effect of a 2-year ley had largely disappeared, and those of a 1-year ley had completely disappeared.

A 2-year ley in a five-course ley-arable rotation was sufficient to maintain the total soil nitrogen at about 0·16%. With one year of ley in a four-course rotation a slow decline in nitrogen was found when the initial level was about 0·21%.

The rate of CO2 formation in soils of the arable break was proportional to the number of years they had been under ley; the longer the period the greater the volume of CO2 produced.

Evidence is presented that fertilizer nitrogen is used most efficiently by cereals growing in soil in good physical condition. This is usually best following a period under grass.

Self-diffusion coefficients (D) for Rb+ have been measured in a heteroionic Lower Greensand soil over a wide range of moisture contents at three different compactions. The moisture content is shown to have a considerable effect on the value of the self-diffusion coefficient, a rapid rise in the value of D taking place between 5 and 10% moisture content. It is shown that this effect is not simply due to the increased volume of water-filled pore space at higher moisture contents, and other possible factors which could influence the shape of the diffusion coefficient/moisture content curve are discussed. Diffusion coefficients for Rb+ in eight other soils at pF 2 are also reported, but no simple correlation with any of several soil properties measured could be found. A value of 1·0 × 10−7cm2/sec. would seem to be a reasonable generalization for the self-diffusion coefficient of Rb+ in moist calcium-dominated soils.

Laboratory indices of P availability were compared for six soils. Phosphorus soluble in sodium bicarbonate, ammonium fluoride and citric acid solutions, and in water was determined. Maximum P adsorption capacity was calculated from data by a batch method obtained from equations using the Langmuir isotherm. Adsorbed P values were derived from the same equations. Measurements of P adsorption obtained by leaching soil samples with a phosphate solution yielded asymptotic curves which also allowed the maximum adsorption capacity to be calculated. Results obtained by the two methods were very similar. Leaching of soil samples by water was the basis for calculating maximum P desorption values; these agreed well with the adsorbed P values obtained from the Langmuir isotherm.

Phosphorus uptake by plants, determined in a greenhouse experiment, was correlated with the various data and parameters obtained in the laboratory; there were no significant correlations with the P values from extraction methods, but there were good correlations with some of the parameters from the equilibration and leaching experiments.

The ‘built-up or deep’ litter system for housing poultry came into use in America during World War II, when labour and materials were restricted. It consists of recently used Utter, at least 6 in. in depth, containing micro-organisms which produce beneficial heating, synthesizing and sanitizing effects (Halbrook, Winter & Sutton, 1951; Kennard & Chamberlain, 1951). Four requirements have been laid down by Bott, Ferguson, Berkland & Winter (1952) for proper functioning of deep litter; they are:

(1) The depth of the litter must be greater than 6 in. to ensure the absorption of fresh dropping and for effective chemical and biological activities.

The L-threonine requirement of the weanling pig is 0·45% of the air-dry food. This level supports as good growth and economy of food conversion and promotes as good retention of nitrogen as higher amounts.

It is unlikely, when pigs are fed normal rations, that L-threonine will be the limiting essential amino acid.

A comparison in the period 120–180 lb. live weight between diets supplying 0·47 and 0·87% L-lysine, respectively, showed no benefit from feeding the higher amount. It seems uneconomic to feed animal-protein to supply lysine after 1201b. live weight. The requirement can be met at less cost from vegetable sources.

In conclusion, the author desires to express his indebtedness to Messrs V. Thurlbourn and R. D. Willis for taking charge of the experimental animals during the N-balance trial. Also to Mr E. A. Porter for his care of the pigs during the growth trial.

1. The effect of shelter from winter conditions was studied in terms of body-weight change of dry sheep individually fed a maintenance ration. In 2 years, one a mild and the other a hard winter, the exposed group lost weight relative to the sheltered group.

2. Within the treatments attempts were made to relate individual weight loss to a variety of fleece components. These results were not conclusive, but they suggest that such components as depth of wool and weight or volume of wool per unit area of skin have some effect in reducing weight loss under climatic stress conditions.

3. A method of measuring the insulation provided by the fleece in dry environmental conditions was developed. It was shown that exposure to moderate winds increased the heat flow by between three and five times. The results again suggested that significant differences in insulation could be found between sheep within a breed. It was not possible to demonstrate the overwhelming importance of any single fleece component.

The errors of 454 cereal experiments organized by the National Institute for Agricultural Botany between 1956 and 1960 are examined in relation to block size. All the experiments used long, narrow plots and were harvested by combine. The most important conclusion is that the gain in efficiency by using small blocks in cereal experiments is as great now as it was before combine-harvesting and long, narrow plots were introduced. An empirical rule is that the variance per plot is roughly proportional to n½, where n is the number of plots per block.

1. Records are presented of observations of the sexual behaviour of indigenous Uganda cattle and the fertility to artificial insemination.

2. The mean cycle length found was 20·9 days,s.d.1·38 days. Mean length of oestrus was 2 hr. 14 min.

3. Marked pro-oestrus and metoestrus periods occurred averaging 14 hr. and 11 hr. 7 min., respectively. The mean total length of time that cows remained attractive to the bulls was 26 hr. 21 min.

4. The number of services and attempts to serve by three bulls was recorded and frequent small grunts were noted to be an important expression of excitement by the bulls.

5. The highest percentage of animals conceived to artificial insemination when inseminated between 15 and 25 hr. after commencement of pro-oestrus.