1. Calcium and phosphorus balance experiments with pullets during which the plasma alkali reserve of the birds was followed are described. Evidence is produced in support of the view that the onset of reproductive activity in the pullet is accompanied by an increase in plasma alkali reserve, as well as of calcium retention, provided the ration contains adequate calcium carbonate.

2. These high levels of plasma alkali reserve tend to decrease with the beginning of laying, but apparently the plasma alkali reserve of laying birds tends in general to remain higher than that of the non-laying bird or of cocks.

3. The possible bearing of these observations on bone mineral composition and Ca/P retention ratios is discussed.

4. It is shown that on a cereal ration moderately low in calcium, where the apparent digestibility, of phytic acid phosphorus is of the order of 40–70%, it was not possible to correlate apparent digestibility with the calcium metabolism of shell formation. When the same ration was supplemented with 5% calcium carbonate, so that the apparent digestibility was of the order of 9–25%, then it was possible under circumstances of intense laying to detect a slight increase of apparent digestibility in association with laying.

Evidence is adduced to show that sowing the fertilizer in restricted zones or bands gives higher yields of swedes, sugar beet and mangolds than broadcasting and harrowing in fertilizers.

Sowing fertilizer in bands at one or both sides of the seed is the most satisfactory method of application. The bands should be about l½ in. from the seed and an inch or so below it. Placing the bands much further away than 1½ in. gives inferior results.

Sowing fertilizer in bands at both sides of the seed involves risk of bad sowing, as, on bad seed beds, clods may jam between the fertilizer coulters even if they are staggered. Sowing fertilizer in a single band at the side of the seed obviates this difficulty and sometimes gives higher yields. It is recommended that for swedes, mangolds and sugar beet, complete fertilizers should be sown in one band about 1 in. below and distant laterally about 1½ in. from the seed.

On soils very deficient in one or more nutrients, sowing fertilizer in a band below, but not in contact with the seed, gives very good results, but on most soils it is likely to lead to a poor stand of plant and low yields.

Sowing fertilizers in the drills in contact with the seed gives good results on soils acutely deficient in one or more nutrients, but it can only be recommended for specific fertilizers in restricted areas (e.g. super-phosphate can be used in this way for swedes on some soils in Wiltshire and Dorset) since it involves serious risk of impaired germination.

Any conclusions drawn from the foregoing results will of course apply only to the necessarily limited range of soils in one county. This range is limited geologically and the Aberdeenshire soils belong largely to the class of light to medium acid soils of low base status. The results for these soils indicate that:

(a) The occurrence of grass sickness is not confined to soils of any particular geological origin.

(b) The range of textural conditions in the soils examined is a wide one covering loams, sands and peaty types with a few moderately heavy soils. There does not appear to be any relationship between soil texture and the incidence of grass sickness.

(c) The soils examined all fall into the class of acid soils and in only a very few—about 5 to 10%—could the addition of lime be considered unnecessary from the general agricultural point of view. As against this there are no striking abnormalities in the ratios of exchangeable or readily soluble cations in the soils, which might serve as a clue to the occurrence of grass sickness. Although little is known of the actual magnesium, manganese and strontium requirements of hay and pasture plants, the range of values covered in the soils examined is sufficiently wide to make it very unlikely that there is any relationship between the incidence of grass sickness and the magnesium, manganese or strontium contents of the soil. In view of the relatively widespread acidity in the soils examined, the possibility of a relationship between the occurrence of grass sickness and soil acidity has to be borne in mind. It would be of value to find out if grass sickness occurs to an appreciable extent on limestone soils, or on soils which have been systematically limed and which have pK values in the neighbourhood of 7.

(d) The majority of the soils are, from the general agricultural point of view, somewhat low in readily soluble or available potash and phosphate, but against this about 30% of the soils have satisfactory phosphate contents and about 20% of the ordinary surface soils and 46% of the top 2 in. samples, in which occur the bulk of the plant roots, have satisfactory potash contents. It does not appear likely therefore that the occurrence of grass sickness is to be related directly to the phosphate and potash contents of the soil. As far as reserves of the common plant foods are concerned there is likewise no abnormality which could account for the disease.

The haemoglobin values for the blood of clinically normal cows and ewes over England and Wales are very similar, with a mean value around 11·5 g. per 100 ml. Although the extreme range is wide, about 8–17 g., the distribution of values is such that the common normal range may be taken as 9·5–13·5 g. per 100 ml. There is no striking difference in age groups.

Metabolic disorders such as ‘milk fever’ and ‘grass tetany’ in cows and ‘pregnancy toxaemia’ in ewes have no specific effect on haemoglobin level. Chronic hypoglycaemic ketosis of the dairy cow leads to progressive anaemia in which levels down to 6 g. per 100 ml. were found. Border or Northumbrian ‘pining’ of sheep is accompanied by an even more pronounced progressive anaemia, values as low as 3·2 g. per 100 ml. being encountered.

It is a pleasure to acknowledge the technical assistance of Mr F. J. Salt and the direction and interest of Dr H. H. Green in the main programme from which the protocols were drawn.

1. The results of a six-year cultivation rotation experiment are given. The rotation used was wheat-mangolds-barley and the seed-beds for these were prepared either by ploughing, using a rotary cultivator or a tractor-drawn grubber.

2. The yields of these crops were barely influenced by the depth of ploughing, a 4 in. depth giving throughout the six years just about the same yield as an 8 in. depth. The mangold crop was possibly a little larger on the deeper ploughed plots.

3. The mean yields of the seed-beds prepared with the tractor drawn grubber or cultivator followed by harrows etc. were lower than the ploughed seed-beds for all the crops, and this was particularly so on those seed-beds prepared by only one grubbing down to 4 in. depth.

4. The mean yields on the seed-beds prepared by the rototiller were lower than on the ploughed seed-beds for wheat and mangolds. If the seed-bed was prepared by rototillage to a depth of 8 in. by going over the land twice, the yield of barley was the same as on the ploughed seed-beds, but was definitely less on the seed-bed rototilled only once to 4 in.

5. Seed-beds prepared by the rototiller or grubber have only a small residual effect on the crop yields in the following year.

6. It is concluded that the primary function of ploughing is weed control, and that it is only advisable to omit ploughing either if the land is already fairly clean or if the crop will be hoed very early on in its development.

7. For wheat and mangolds differences in weed infestation of the seed-bed were probably of greater importance than differences in tilth in so far as the crop yield was concerned. The reverse may have been true for barley.

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.

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.

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.