The discrepancies between nursery plots and field plots, found by previous workers when investigating yield problems with wheat, are discussed. The reason for these differences is given, and the true optimum plant density identified.

It is shown that the intensity of competition for water and soil nutriments influences the optimum plant density, and that a high intensity of competition is associated with a low optimum plant density. A summary of literature is given, and the varying values for the optimum seed rates in different parts of the world interpreted in the light of water and soil nutriment supplies.

It has been shown that a diet supplying, in addition to barley meal, weatings and 2% of lucerne meal, 5% of fish meal up to 90 lb. live weight, 2% from 90 to 150 lb. and no protein-rich food from 150 lb. to slaughter at about 200 lb. live weight, will give almost as good results, from the standpoints of mean daily live-weight increase and efficiency of food conversion over the whole period as one that provides 10% of fish meal from weaning to 150 lb. and 5% of a protein-rich food such as ex. soya bean meal from 150 to 200 lb. live weight. The small differences noted in the present trial were not statistically significant. It is true that the reduction of the fish meal supply to 5% or less retards to a significant extent the rate of growth up to 90 lb. live weight, but this initial setback, according to the results of this and the writers' previous investigations, tends to be wiped out during the later stages of feeding.

Further, a diet supplying, in addition to cereal, weatings and a small proportion of lucerne meal, as little as 2% of fish meal up to 90 lb. live weight and no protein-rich food at all thereafter has been shown to give results that are not seriously inferior, particularly when viewed against the background of wartime conditions, to those obtained on the standard diet. In this treatment, the protein required for growth beyond 90 lb. live weight was supplied by a diet of barley meal and weatings reinforced by 2% of lucerne meal.

An account is given of artificial insemination of 733 grade cows in Kenya from January 1936 to August 1939. 76·8% of the cows inseminated calved, with an average of 1·88 inseminations per conception. The different doses and dilution of sperm used gave very similar results, as did two inseminations, compared with one insemination, in a single heat period.

Experiments on evaporation from freely drained soils are described. Under isothermal conditions characteristic winter field behaviour is obtained, even when the air drying power is greater than its normal English midsummer value. Characteristic summer field behaviour is obtained when the rapid drying of a thin surface layer is achieved, either by using an extremely high air temperature under ‘isothermal’ conditions, or by raising the surface temperature by means of radiation—the normal method in nature. The effect of a high salt concentration in the soil water is shown to lead to greater evaporation losses and to a tendency for the salt to concentrate in the more salty patches.

It is suggested that mulching will only be beneficial during the isothermal part of the year, i.e. when soil surface and air temperature are approximately equal, and that it will have little effect on water conservation where the soil will be self mulched by the action of summer sunshine. The cause of this self-mulching action is briefly considered in the light of our limited knowledge of soil water dynamics; it appears to depend on the existence of a dual mechanism of water movement in soils—as liquid and as vapour—the rates of movement being very different functions of moisture content and moisture gradient.

1. In metabolism experiments undertaken to study the channels of elimination of copper under varying conditions, the rabbit was chosen as experimental animal for convenience of manipulation. This choice, although not defeating the main objects of the work, accidentally added valuable informationon the little-known habit of “physiological faecal refection”in this animal.

2. On a normal diet of bran and oats, containing the usual traces of copper, the rabbit is in copper equilibrium, excreting as much in faeces and urine as is taken in the food. Urinary elimination is of the order of 0·07–0·38 mg. per litre, but this is very subsidiary to faecal elimination of about 2·5 mg. per 100 g. of dry matter, which may account for even more than 96 % of the total food copper.

3. Increase of food copper is not reflected by material increase of urinary output, the higher quantities appearing almost entirely in the faeces. Of 50 mg. of copper or nearly 200 times the normal food intake, as the dissolved sulphate dried on to the food, only 0·1 mg. appeared in the urine, the remainder being slowly excreted in the faeces over the unexpectedly long period of 4 or 5 weeks.

1. The degree of dispersion on shaking of the heavy clay Gezira soil has been studied in relation to its initial moisture content when it is added to the water. A minimum dispersibility was found at about 7% initial moisture content. Such behaviour is different from that found with certain English soils by Puri & Keen.

2. Spontaneous dispersion was studied using the same soil, and by this method it was found that the dispersion decreases with increasing moisture content over a range of zero to 9% moisture.

3. This relation between dispersion and water content is discussed in relation to possible effects in the field of practice. Attention is drawn to possible seasonal and daily differences in the effect of rainfall.

The results obtained from artificial insemination of high grade Merino sheep in Kenya are given and discussed in relation to the season of the year, time of insemination during oestrus, the number of inseminations in each oestrous period and the degree of dilution of sperm.

1. A study of the length of the rachilla in barley shows that it is a varietal character, although strongly affected by environmental factors.

2. Rachilla length as a varietal character is affected by the density of the ear and the type of hairs or bristles borne on the rachilla.

3. In six-row barleys the length of the rachilla of the lateral spikelet is greater than that of the corresponding median spikelet.

4. In the absence of any of the complicating factors mentioned above, rachilla length is inherited as a straightforward quantitative character with an intermediate F1 and no signs of segregation in the F2. The number of major factors when the extremes of length are hybridized appears to be in the neighbourhood of four.

5. Hybridization of “Archer” and “Chevallier” type parents has given “dominance” of length and a possible heterotic effect. Long rachilla in these crosses appears to be linked with the “Chevallier” rachilla type.

Calcification on 1% of controlled cod-liver oil was less satisfactory than on 1% of genuine cod-liver oil as judged by radiography at 5 weeks old. Growth rates were not significantly different.

⅔ of 1% of the genuine cod-liver oil promoted calcification as satisfactorily as (and significantly better on one diet than) 1% of controlled oil. The mean tarso-metatarsal distances on ⅔ of 1% of controlled oil were too wide for the calcification to be regarded as normal. It has thus been shown that satisfactory growth is no criteria of adequate calcification and bone structure.

From the age of 6—16 weeks, ⅔ of 1% of controlled cod-liver oil mixture was not adequate, as demonstrated by radiographic examination, for optimal calcification; but using the criteria of naked eye examination and weight, no significant difference would have been found between genuine cod-liver oil and the controlled mixture. These birds showing subnormal calcification could not be expected to stand up well to the strain of laying, which puts heavy demands upon the calcium metabolism.

Pot experiments were made with red clover and with soy beans to determine how far the number of nodules developed was a specific character of the strain of Rhizobium supplied.

The number of nodules per gram of root was found to reach a limit specific to each strain. This limiting equilibrium was attained regardless of the size of the root system or the age of plant at which the culture was first supplied, provided enough time were allowed for the limit to be reached.

When two different strains were applied to the root surroundings in succession, the final number of nodules was determined by the limit specific to the strain in contact with the roots while these were making most of their growth. In clover this was the second and in soy beans the first applied strain.

The total nitrogen and carotene have been determined in sixty-three samples of white clover, cocksfoot, rye-grass and timothy taken at different times during the growing season from various localities.

Except for rye-grass, there was more carotene in the leaves and stems than in the heads or flowers. A late dressing of ammonium sulphate increased the carotene content of rye-grass by 55 and 17% in the leaves and heads respectively. The effects of lime and slag on the carotene content of cocksfoot and rye-grass were much less marked and there were no obvious effects due to environment.

The predominant factor in determining both nitrogen and carotene, which were very closely related, was stage of growth. Grazing effected important increases in both constituents.

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

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

The digestibility coefficients were considerably lower for an immature horse previously maintained entirely on fresh grass.

Failures of cereal crops are occasionally reported, the seed having been dressed with an organo-mercury seed disinfectant and the failures attributed to the dressing. It should be noted, however, that prior to the introduction of the organo-mercury seed dressings similar crop failures had often been recorded, and in many cases failure had been attributed to the dressing which had been applied, or alternatively, to the conditions under which the treated grain had been stored.

Reduced germination during storage is common to all agricultural and horticultural seeds, but although the interaction of the factors involved is complex it is generally recognized that for satisfactory germination to be maintained over the maximum period of storage the following conditions should be observed:

(1) The seed should be of relatively high initial germination.

(2) The moisture content of the seed should approximate to the average for that kind.

(3) Storage temperature and humidity should both be relatively low and not subject to wide fluctuation.

(4) Ventilation should be adequate.

It is now generally recognized that the pH of a silage is the best single criterion of its quality. In other words, it is regarded as the best single guide to the type of fermentation that has taken place in the mass in the silo and thus serves to indicate the degree of success achieved in the ensilage process, whatever the crop or its stage of growth. For instance, in the case of silages, made with or without molasses, where the pH is at or below 4·0, the silage would be deemed to be of ‘excellent’ quality, that at 4·0-4·5 would be designated ‘good’, that at 4·5–5·0 only ‘moderate’, and at or above the latter figure the silage would be classified as ‘bad’. To get a complete picture of the chemical changes that have taken place and to assess the feeding value of a silage is quite a different matter and is not the object of the present note.