In the account of “Pining” in sheep given by McGowan(1) there are so many points of similarity, both in the symptoms and in the general environmental conditions under which the disease is developed, with the disease known in New Zealand as “Bush-sickness,” as to suggest that these two diseases may be of a similar nature.

The pigeon pea (Cajanus indicus or C. cajan) grown extensively in India, Africa, and other tropical and semitropical countries has attained considerable prominence as a stock food in Hawaii, where it is being grown as an important field and pasture crop in some sections. Its culture and utilisation in Hawaii have been exhaustively treated in a bulletin of the Hawaii Agricultural Experiment Station written by F. G. Krauss(1).

A regular optimum spacing among plants is the theoretical ideal. Regularity is difficult to secure and the ever varying optimum is not determinable. But earlier investigations have shown that field crops of corn are marked by extremely high fluctuation in population density along the rows of plants; and further, that in this fluctuation lies an important limitation to potential yield. Wider knowledge of this limitation is being sought. The experiments have clearly confirmed plant density fluctuation as a characteristic of field crops (of wheat). Measures of this fluctuation and analyses of its nature and causes are the subject of the paper.

In relation to plant development and yield, fluctuations in density or spacing from point to point along the row, are the most important features associated with drill action. These have been measured by counts, both of seeds and of plants, on unit lengths of row. Such “census” counts are described in detail for four normal fields. Plant counts were made periodically. In general a unit length of one foot of row was adopted. For analytical purposes the refinement of a per-inch count proved necessary.

Fluctuation in seeds deposited per foot may be illustrated by the data from one of the fields. The mean was 18·0 and the standard deviation was 7·2. In aggregate the field could be regarded as consisting of five equal portions (quintiles of the per-foot distribution) for which:

Number of seeds per foot = 5·0–12·2; 12·2–15·0; 15·0–18·0; 18·0–22·3.

Equivalent seeds rates (bushels per acre) = 1·42; 2·00; 2·35; 3·11; 3·70.

The distribution per inch, determined by a specially devised method, is illustrated for two fields in Diagram I. Four equal aggregates (quintiles of per-foot distribution) from one and the same acre had the widely different seedings displayed in Diagrams II and III.

1. The interaction of physical conditions of the soil and the establishment of plant together with its subsequent growth and yield have been studied for wheat and swedes on a variable piece of land, maintained as a uniformity trial.

2. Ploughing draught was taken as a criterion of the physical condition of the soil and various simple measurements on the crop were made from time to time during growth.

3. The establishment of wheat showed substantial negative correlations with ploughing draught but the correlations between ploughing draught and the performance of the plant diminished as growth progressed. This was shown to be the result of the overwhelming importance of the spacing factor operating beneficially on plots where the plant was abnormally poor. The effect of this factor is traced step by step.

4. Swedes differing from wheat in almost every detail of cultivation and growth, cycle showed no correlation between soil conditions and germination or between the various growth stages and physical soil conditions. The highest significant correlation was between the number of roots per plot after singling and ploughing draught and an explanation of this is given.

5. There was a significant but only moderate correlation between the yields of the two crops.

1. Considerable differences were found in the specific conductivities of different soils at any one time of the year, and considerable differences in any one soil at different times of the year, the specific conductivities being highest in March and lowest in June and July. Hence it is only possible to compare different soils when samples of these soils are taken at the same time of the year.

2. A relation has been found between the specific conductivities of the soil extracts and the mean weights of lint per plant per row in the case of 2 strains of Ishan cotton. Other data are presented showing that the specific conductivity of a 1 to 5 soil extract is an index of the fertility of the soil.

3. It has been found that the specific conductivity of a soil decreases under continuous cultivation. There is evidence that the rate of solution also decreases under the same condition.

Three years of subsidised sugar-beet growing in England has made clear the chief agricultural features of the crop. Many of our soils suit it well; the climate is favourable; it fits satisfactorily into some of our typical rotations. With the 1928 crop will come into operation the first of the subsidy reductions. The consequential change in standard price per ton of beet—46s. instead of 54s. as in 1925–7—has aroused anxious interest in the likelihood that the crop will outlive the subsidy. What price the factories will be able to offer on termination of the subsidy is not yet known. It will, of course, be decided by world-prices of sugar. Values between 30s. and 35s. per ton have been tentatively suggested. It has been claimed, further, that any price which covers cost of production will make the crop an asset to English agriculture because of the benefit to following crops. Whatever the strength of this claim farmers are and will continue to be anxiously concerned about net monetary return per acre. Now this return is governed by three factors—cost of growing, yield per acre, and price per ton. Costs of growing are not likely to alter substantially. Price per ton is considerably influenced by sugar content. The factories have devoted much effort to routine sampling and testing of deliveries but have not convinced farmers that their ascertainments are reliable. It may well be doubted whether any workable factory testing can be devised to ensure accuracy to 1 per cent, of sugar content.

It has been urged by Bouyoucos (l) and by Haines (2) that soil granulation is caused by the action of water on lumps of partially dried soil, and it is usually accepted that alternate dryings and wettings are largely responsible for the production of tilth. The work described in this article was undertaken to determine whether measurements of the time required for the complete disintegration by water of lumps of dry soil might furnish a reliable method of soil comparison in accordance with these ideas.

On the arid, sparse, phosphorus deficient pasture of the Vryburg district of the Cape Province, grading up of scrub cattle, by combining the introduction of pure bred bulls with the feeding of bone meal to the cows, is attended with great success so far as shown by the first crossing. Remarkable differences in favour of the mineral supplement are shown, in respect to reduced mortality incidence, increased fertility of cows, and superior development of calves.

Age, it will be remembered, is here measured in lactations, but little error is involved if the true age in years, at the commencement of the lactation, is taken as two more than the number of the lactation—e.g. a cow, on the average, calves her third calf when she is roughly 5 years old.

In an earlier communication on this subject(1), the writers arrived at the conclusion that the main reason for the comparative failure of attempts to grow maize as a silage crop in this country was due in large measure to the general use of the late maturing variety, American Horse Tooth. It was predicted that success would probably depend on discovering a variety of maize which is able to reach the desirable stage of maturity under English conditions before being cut for the silo. Preliminary trials had indicated that the necessary qualities might be found in certain varieties like Saltzer's North Dakota, Longfellow, Compton's Early and White Cap, all of which mature at least a month before American Horse Tooth.

The study of the relation of plant-growth to environmental factors has led to much research directed to the elaboration of General Formulae expressing the quantitative response of the experimental plant or crop to the quantity of the nutrients with which it is supplied. For variations of a single nutrient only many different mathematical expressions will serve to describe the facts to the accuracy with which these are usually ascertained by experiment; the practical value of such formulae is, however, much impaired if the parameters or constants which they involve change their value from experiment to experiment. If, on the contrary, we can obtain formulae of a general character which represents satisfactorily not only the response to variation of a single factor, but the response to simultaneous variation of two or more different factors, then we have reason to believe that the parameters of such formulae will not depend upon the casual or non-essential conditions of the experiment, but will be capable of direct interpretation as physical quantities. We have shown that the Resistance Formula does fit the data of several two-factor experiments and the agreement of the three values of an determined from the three potato crops as well as the agreement of the difference in the values of k on a dunged and undunged plot with the potash expected to be available from the ten tons of dung shows that this expectation is so far justified. The parameters of the Resistance Formula are capable of a direct and definite physical interpretation; for each nutrient there are two constants; one represents the importance of the nutrient considered to the crop concerned, and may be expected to vary from crop to crop and from variety to variety, and so to afford a direct comparison between varieties of their manurial needs, while the second represents the amount of nutrient available in the unmanured soil.

Determination of the phosphorus partition in blood is described, combining dry combustion with the ceruleo-molybdate procedure of Deniges. Advantages in speed and convenience are claimed over the conventional Briggs methods.

Certain heavy ferruginous soils do not respond to the usual preliminary treatment with hydrogen peroxide for mechanical analysis by the pipette method.

A method of preliminary treatment is described, involving the use of ammoniacal hydrogen peroxide and repeated gentle rubbing with a rubber pestle which appears to give a satisfactory dispersion with such soils.

The results are not affected by mechanical shaking, which may therefore be omitted.

Although the experiment described in this paper was undertaken in the first instance to obtain information on local conditions, the results are of general interest as an experiment in the effects of cultivation on the yield and returns of the sugar beet crop. The objects of the experiment were:

(a) To make a comparison of the effect on yield of growing the crop on the ridge with growing on the flat.

(b) To obtain data on the effect of spacing on the yield.

(c) To endeavour to give a financial expression to the results.

1. The relative proportions of exchangeable bases in nine soils from the east of Scotland area and the changes effected by dilute chloride solutions have been examined.

2. The changes due to N/50 solutions are large, and magnesium is displaced to a greater extent by calcium than by potassium.

3. The changes due to N/500 solutions are very small, comparable to what might be expected in manurial practice, and not greater than field sampling error.

4. The content of exchangeable bases and their relative proportions, therefore, seem to be fairly permanent for any soil under normal conditions, but vary considerably from soil to soil, and should prove useful as an additional characteristic of soil type as distinguished in the field.

Data are recorded concerning the phosphorus partition of the blood of cattle grazing over phosphorus deficient pasture of the Union of South Africa. The outstanding characteristic is low inorganic phosphorus, with a correlated reduction in total phosphorus.

When a small ration of bone meal is given to the cattle, comparatively normal figures are shown. Heifers approaching two years in age, supplied with bone meal from weaning onwards, show a normal inorganic P fraction of 5 mg. per 100 c.c. of blood. Control heifers without bone meal show 2·3 mg., or less than half. Control cows may drop to 1 mg., or even lower. Calves of control mothers are normal so long as milk supply is adequate, but may show reduced inorganic P if aphosphorosis of the mother is acute. In general, low inorganic P in the blood is associated, with poor condition of the animal. Rapid colorimetric determination of inorganic P in the blood of the grazing animal, easily obtained from the jugular vein, provides a simple means of detecting phosphorus deficiency in the pasture.

Although long-continued phosphorus deficiency leads to the clinically recognisable disease “Styfsiekte,” especially in lactating animals, the less pronounced deficiency, manifested as malnutrition and stunting of growth, without direct mortality, is detected by blood analysis with equal certainty.

In the paper “Minimum Mineral Requirements in Cattle,” by Theiler, Green and du Toit (1927), analytical data concerning the mineral constituents of the blood of a calf, born of a cow suffering from aphosphorosis, were recorded, but left over for later consideration.

1. Cultures of B. radicicola derived from eight different host plants have been studied and a description is given of the morphology and reproductive processes of the organisms.

2. The growth forms described include rods, coccoids, branched forms, gonidangia, gonidia and dwarfed growth, and microcysts.

3. The different cell types represent normal stages in the development of the organisms.

4. The reproductive processes described are fission, budding, liberation of gonidia, formation of regenerative bodies, and germination.

5. The formation of symplasm and the regeneration of cells is discussed.

1. Digestibility trials with oats, carried out with White Leghorn cockerels, indicate that certain varieties of oats are more suitable as sources of food nutrients for poultry than others.

2. In the trials carried out, Grey Winter oats proved more suitable than Black Bountiful or Scotch Potato oats for poultry feeding.

3. The suitability of varieties of oats for poultry feeding appears to be linked with the fibre content, and thin husked varieties appear to be most suitable for this purpose.

4. Oats do not appear to be very palatable to poultry.

In the course of investigations into the cause of an obscure pathological condition of the tea bush, it became necessary to make pH determinations of certain soils. Electrometric apparatus and a suitable centrifuge for clearing the solutions were not available. Considerable difficulty was experienced in making the determinations with accuracy by indicator methods owing to two causes. First, the turbidity of the soil solutions made comparison with standard buffer solutions somewhat difficult; secondly, the colours developed in the soil and buffer solutions with some indicators were different in hue, as distinct from shade or tint. This rendered exact matching quite impossible. The latter difficulties also arose when the drop ratio method was used instead of standard buffer solutions. The errors resulting from these causes were believed to be unduly large, and it was felt that greater accuracy would be attained if these difficulties could be overcome.