The investigation shows that when water-logged soils were treated with nitrogenous manures and fertilizers like oil cake, water hyacinth, ammonium sulphate and sodium nitrate, a large volume of nitrogen evolved as gas. This loss began 7–12 days after application of different treatments and was quicker from inorganic fertilizers than from organic manures. Besides loss as gas, a large amount of nitrogen was also lost in the drainage. The results suggest that if fertilizers like ammonium sulphate and sodium nitrate are applied to rice-fields by top dressing during the active vegetative growth of the crop, the loss nitrogen as gas will probably be greatly minimized.

1. A study has been made of the cause of urine burn in pasture.

2. It has been shown that urine burn could occur under dry soil conditions due to the osmotic pressure effects of the urine.

3. All seeds present in the urine-affected soil are killed.

4. An inhibitor of root growth, to which clover roots are especially sensitive, is present in the urine of cows and sheep.

5. This inhibitor, which is not heteroauxin, is acid in character and is destroyed in soil in a few days.

6. It is suggested that the inhibitor is an inhibitor-auxin complex, of which the auxin portion might be heteroauxin. The possibility that the inhibitor is an auxin precursor is discussed.

7. It is contended that the reduction of clover growth relative to grass growth in a urine patch is not simply the result of shading due to increased grass growth.

8. The root inhibitor, the temporarily high pH, the presence of free ammonia, and the high concentration of ammonium ions may be important factors in the reduction of clover growth.

1. Examination of the composition of hay grown in the east of Scotland during the 4-year period 1948–51 has confirmed earlier work indicating the low protein content of this material. In addition, the digestibility of the protein was found to be low, particularly in the case of the seeds-hays, most of which contained insufficient digestible protein to balance the starch equivalent in meeting the maintenance requirements of cattle.

2. In nutritive value the seeds -hays were markedly inferior to samples from England and Wales examined by other workers, but very similar to mature ryegrass hay grown in Northern Ireland. The meadow hays examined were of similar starch equivalent but somewhat richer in protein, and this was associated with a higher digestibility of the protein; in consequence the ratio between digestible protein and starch equivalent was more nearly balanced for the maintenance feeding of cattle.

3. Applications of sodium nitrate or ‘Nitrochalk’ about 10–20 days before mowing produced very variable responses in the unusually dry season of 1949, but in other years significant increases in protein content were almost invariably obtained. Low protein seeds-hays of the type commonly found in the Lothians were more responsive to this fertilizer treatment than timothy meadow hay, and while increases in protein content of 20–30% were commonly obtained, when relatively heavy dressings of fertilizer (3 cwt. or more per acre) were used, increases in the region of 50% were sometimes recorded. In most years treatment about 10 days before mowing was fully effective in improving the protein content of the hay. Earlier treatment may be preferable in a very dry season, but in more normal years this may increase the yield of the hay and so diminish the effect on protein percentage.

1. The amounts of amino sugar-N present in acid hydrolysates of six soils with nitrogen contents ranging from 0·17 to 2·82% have been estimated by colorimetric and alkaline decomposition methods.

2. Recovery of amino sugar-N after hydrolysis of chitin or glucosamine was found to be unaffected by the presence of soil during hydrolysis.

3. Substances known to interfere with the methods of amino sugar analysis employed were not detectable in the soil hydrolysates.

4. From the amounts of amino sugar-N liberated by acid hydrolysis it is deduced that 5·10% of the total-nitrogen of the soils examined was in the form of amino sugars.

5. The decomposition of amino sugars in soil has been studied by comparing the rates of decomposition of chitin, glucosamine, casein and yeast nucleic acid when incubated with soil under conditions found to produce rapid nitrification of ammonium sulphate.

6. Glucosamine and chitin are readily decomposed by soil micro-organisms but not so rapidly as casein or yeast nucleic acid.

A total of fifty buffaloes, thirty-five Shorthorn and Shorthorn grades and twenty-nine Egyptian (Baladi) cows of different ages were used to study the thermal reaction mechanism by exposing the animals to direct solar radiation followed by shade. The thickness of the skin was also measured in all animals as it is one of the main factors in heat regulation. The results were as follows:

1. There were species and breed differences in the thermal reactions. Buffaloes were more hyperthermic when exposed to direct solar radiation than either Shorthorn or Egyptian cattle. The Shorthorns were more affected by ambient heat than Egyptian cattle.

2. The skin thickness of the buffalo was double that of the cattle. In all animals the thickness of the skin increased with age.

3. It is suggested that the adaptability of farm animals to tropical and subtropical zones is better assessed under shade and under normal husbandry conditions than by exposing them to direct sunlight.

1. Thirty-one buffalo-cows of different ages were tested for the symptoms and duration of oestrus, and the incidence of post-partum oestrus and conception. Clinical examinations of the vagina were also carried out.

2. The symptoms of heat were less intense than in cattle and there was no homosexual activity.

3. Pro-oestrus occurred in 43% of the cases with an average duration of 21.20 hr. whilst metoestrus occurred in 67% of the cases with an average duration of 19.20 hr. The average duration of oestrus was 28.47 hr.

4. The onset and cessation of oestrus were either abrupt or gradual. The phenomenon ‘split oestrus’ was observed intervening normal cycles. This was not characteristic of the individuals.

5. The average interval to post-partum oestrus was 43.80 days. The average number of silent heats per individual was 0.86. Conception took place after an average of 1.71 services whilst the breeding efficiency was 93% in the calving buffaloes.

6. Normal clinical changes in the vagina (temperature; nature and amount of secretion; picture of smear) were not reliable indicators of oestrus.

7. Further problems concerning reproduction in the buffalo are suggested.

Between 1946 and 1950 multifactorial field experiments were carried out to determine the potentialities and effectiveness of chlorinated phenoxyacetic acids for the selective control of weeds in linseed (oil flax). The initial experiments of 1946 demonstrated that treatment with sodium 2-methyl-4-chlorophenoxyacetate led to considerable increases in the yield of seed through a reduction of the weed population and the consequent decrease in weed competition.

The subsequent experiments were undertaken on relatively weed-free crops so that the direct effects on the crop of compound, formulation, and stage of growth at the time of application could be investigated along with differences in varietal response. Amongst the observations made were time of flowering, straw length, the yield of seed, capsule production, seeds per capsule and the weight, oil content, protein content and germination capacity of the seed.

At similar dosages sodium methylchlorophenoxyacetate is less phytotoxic than sodium 2, 4-dichlorophenoxyacetate while the parent acid and particularly the ethyl ester of the dichloro - compound are much more injurious. With sodium methylchlorophenoxyacetate the tolerance is greatest between the post-cotyledon stage and a height of 20–25 cm.; within this range of plant development dosages up to 3·5 lb./acre have no adverse effects on the yield of seed. Treatment within 2–3 weeks of flowering delays flowering and reduces the seed weight. When dichloro-compounds are employed there are additional effects, such as the formation of abortive capsules or a reduction in the number of seeds per capsule. Under some conditions the oil content and the germination capacity of the seed is depressed but the protein content is increased.

1. An analysis has been made of the production records of over 1400 heifers got by A.I. bulls at five non-Board centres. The A.I. heifers, when compared with other heifers in the same herd in the same year, showed no significant increase in yield but a significant increase in fat content.

2. The difference in yield between A.I. and contemporary non A.I. heifers was not significantly different in herds at all levels of production. This would suggest that only a small proportion of the differences in yield between the herds in the sample was genetic in origin. In fat percentage, there was some evidence, though not very conclusive, that rather more of the inter-herd variation was genetic.

3. Significant differences were found between the progeny groups by different sires in both milk yield and fat content. The standard deviation of the variation due to the breeding value of the sire was 37 gal. and 0·13% fat respectively.

4. Methods of interpreting progeny tests made under A.I. conditions are discussed theoretically. It is concluded that the comparison with heifer contemporaries in the same herd is most satisfactory for milk yield and the simple average is best for fat content.

5. The relevance of these results to the genetic structure of breeds is discussed. They are in good agreement with the conclusions from pedigree analysis that the genetic differences between the dominant group of herds and the mass of commercial cattle in each breed is not great.

In order to form a basis for any improvements of cattle and pasture management in East Africa it was decided to observe the grazing habits of the local cattle. A review of the literature shows that animals' habits can be influenced by temperature, but no record could be found to indicate the effect on the animals of elevation and an equable climate.

A summary is given of the results obtained during 720 cow-watching hours. Comparing these results with those obtained by other workers it is clear that Bos indicus cattle on a high-level plateau under tropical conditions have distinct and unique habits. On the average, during days with 12 hr. daylight 7·7 hr. were spent in grazing, 93% of this time being during daylight; 5·2 hr. were spent in ruminating, only 23% of this being during the hours of daylight.

Detailed investigations on identification and classification of lucerne varieties and strains were conducted at Cambridge for four years, 1949–52, on lucerne sown in row plots and on twelve typical varieties planted out in replicated trials as single spaced plants, using 200 plants of each variety. A number of physiological and morphological characters were examined and the resulting data was analysed statistically.

The characteristics used for classification are those which showed considerable variation between varieties, but at the same time these differences were maintained consistently from year to year. They proved to be unaffected by a different way of growing the plants or by small differences in soil fertility or season. The results are shown in Tables 1–17, and three basic classifications with distinguishing features of types and varieties are given. The correlations established between various characters on twelve varieties are given under the heading ‘Correlations’ at the end of the results.

(a) The first classification into early, mid-season, late and extra-late types, based on the time of flowering, spring and autumn growth, gives a fair indication to the growers regarding earliness and productivity of various varieties.

(b) The behaviour of certain varieties from South America, and in particular Saladina, an Argentine variety, which is vigorous and productive under native country conditions but has lost this ability under Cambridge conditions, indicates plainly that classification based on these three characters can be applied only to the country under whose conditions it was established. Therefore any variety especially obtained from a country of extremely different environmental conditions and management system should be checked in these respects even if a description is given.

A short account is given of 7 years' breeding for high and low brooder-house viability in a White Wyandotte flock, in which mortality, to 8 weeks of age in most years, varied from almost 50% in the early years to 10% in the last year (1947). When separate sections of the flock were established, the lowviability section showed consistently greater rearing losses than the high-viability section.

Brooder house viability appeared to have a relatively low additive heritability, when estimated from such of the records as were suitable, the pooled estimate from differences amongst sires' progenies being only about 0·07. There was definite evidence that mortality was affected by the common maternal origin of full sibs, the heritability estimated from differences amongst full-sib progenies of dams mated to the same sire being significantly higher than that estimated from differences amongst the half-sib progenies of the sires.

1. Certain characteristics of bull semen have been examined at four artificial insemination centres in England. One hundred and twenty-one samples of semen, comprising 168 ejaculates from seventysix bulls of seven breeds, were examined. The semen from 119 tested samples was subsequently used to inseminate 4604 cows.

The following semen characteristics were studied: volume of ejaculate; concentration of spermatozoa; incidence of dead spermatozoa; incidence of morphologically abnormal spermatozoa; initial fructose concentration; resistance of spermatozoa to temporature shock; methylene-blue reduction; O2 uptake; fructose utilization; visual evaluation of motility; impedance change frequency; and fertilizing capacity (conception rate).

A clinical examination was made of the reproductive organs of each bull.

2. Variations in the concentration of living spermatozoa and in the incidence of dead spermatozoa were found to account for most of the variations in the metabolic activity of semon: they also largely explained differences in physical activity as assessed by visual estimation of motility or by impedance change frequency.

3. Although the rates of methylene-blue reduction, O2 uptake and fructolysis showed a close correlation with the numbers of living spermatozoa present, O2 uptake and fructolysis per living cell decreased with increasing cell concentration.

4. Variations in metabolic activity showed no correlation with variations in the morphological characteristics of the spermatozoa, except in the case of spermatozoa with bent tails. These forms occurred in some samples as a result of staining treatment, but their incidence was positively correlated with the O2 uptake and fructolysis per living cell.

5. There was evidence that highly active spermatozoa are more resistant to temperature shock than less active spermatozoa.