1. In the comparatively humid climate, of the west of Scotland, the water content of oat grain, threshed soon after harvest, amounting, as a rule to between 16 and 18 %, fell, during storage, to between 12·0 and 14·5 %. Grain grown in the drier climate of the south of England and Wales contained on an average 12·2 % compared with 14·4 %. The weight of stored grain varied to a certain extent according to the hygrometric condition of the atmosphere. The maximum variation amounted to between 4 and 5 % of the initial weight of the grain.

In addition to the usual analytical data, it was found to be of great advantage, in connection with each sample of grain examined to keep a record of, date of threshing and date of analysis, proportion of whole grain, weed seeds, husk, etc., average weight of 1000 grains, height above sea-level, type of soil, length of growing period, rainfall, previous cropping and manuring, condition of the crop.

2. Between 11 and 12 % of the fatty substances in the oat kernel is present in the germ (embryo), the remainder is principally in the aleurone layer. The amount of extractable substances varied according to the solvent employed, ether and petroleum ether yielded the smallest and alcohol the largest extract. From 88 to 96 % of the total, was dissolved out by different solvents, in a five hour extraction. With repeated five hour extractions, ether still gave a small residue in the sixth extract. All the extracts contained finely divided solid matter in suspension, which could be made to separate out as a yellow residue and it amounted to between 0·25 and 6 % of the ether extract.

The extracts were found to be slightly higher from “air dry” meal and ordinary ether compared with “dry” meal and dry ether.

Free fatty acids were almost absent in the oil from freshly ground kernel, but afterwards they rapidly increased and in 24 days, calculated as oleic acid, they formed over 55 % of the extract. Drying the grain such as is done in the manufacture of oatmeal, had the effect of slowing down the rate of hydrolysis of the fat, but the amount of acid finally liberated was the same.

In view of the efforts which are being made to secure increased production of cheese throughout the country, it is of importance that greater consideration should be given to the problem of the profitable utilisation of the whey, which results as a by product of the cheese industry.

At the present time no exact records exist (except those given in British Breeds of Live Stock published by the Board of Agriculture and Fisheries and by McConnell in his Notebook of Agricultural Facts and Figures) which show the relative qualities of the various British breeds of cattle in respect of their ability to grow, fatten and increase in weight. Also there exists no estimate as to the actual average amount of food produced by the different breeds on slaughter and the average proportion of consumable meat and offal in the dead body.

1. Protein in wheat is the most important constituent, and therefore the chief constituent to breed for. No wheat variety possesses at once combined the desired characteristics of high protein, high yield, maximum flour production, and maximum bushel weight.

2. So far as climatic factors are concerned, a short, comparatively dry growing season, especially in the spring, in the case of winter wheat, favours the development of grain rich in gluten, and hence high in protein.

3. The most important ground factor in determining the starchprotein ratio is the water supply. The protein content has been found to vary from 11·63 per cent, under 22–24 inches of rainfall to 14·93 per cent, under 12–13 inches (Minnesota); and from 12·63 per cent, under 25 inches of irrigation to 13·62 per cent, under no irrigation (Utah).

With the development of irrigation projects in intermountain areas of the Rocky Mountain States has come an enormous increase in the amount of wheat produced annually with irrigation. The crop commands the attention and consideration of millers and grain men generally in intermountain sections and will continue to do so because there is in cultivation at present a small fraction only of the acreage that can be successfully farmed with irrigation. The general run of irrigated wheat regardless of the class to which the varieties may belong is plump and relatively heavy. It is unfortunately at the same time soft and starchy and because of its relatively low protein content is almost invariably sold on markets that do not stress strength in wheat flour.

Even an amateur in agricultural science will admit that nowadays the fertilising effect of a substance cannot be tested merely by adding the substance to the soil and inspecting the resulting crop. This is not an experiment, it may give rise to an observation, but not to a conclusion. The production of the crop is connected with the fertilising process as a post hoc, not as a propter hoc.

1. A method is described by which it is possible to estimate the numbers of active protozoa in a soil.

2. The total number of protozoa is first found by a dilution method. A fresh portion of the soil is then treated with 2 per cent. HCl (sp. gr. 1·15) overnight. By this means all active forms are killed. A second count by the dilution method gives the number of cystic protozoa in the soil. From these results the number of active forms can be ascertained.

Many authors, for example, Settegast, Pusch, Kašpárek, Kraemer and Rostafinski, have attempted to draw conclusions concerning age, quality and breed of cattle from the type of hair produced. Exact investigations of the length and other features of the hair are, however, rare in the literature. Bilek has recently made some investigations of this kind under the direction of Professor Kašpárek, and has estimated the relation between the medulla and the fibrous layer, and has shown that the cross section of the hair is sometimes circular and at other times elliptical in shape.

1. Craibstone soil—a glacial drift soil which has not undergone very profound weathering and is free from calcium carbonate—has a considerable absorptive power for ammonia from a solution of sulphate of ammonia.

2. It was found possible to make a mechanical analysis of a large quantity of this soil without the use of acid and alkali, and although the separation into fractions was by no means perfect, a very fair comparison was obtained of the absorptive capacities of the different fractions.

3. The absorptive power per unit weight of the fractions, as would be naturally expected, increases with the decrease in size of the particles, reaching a maximum in the case of “clay.”

4. “Fine silt” and “silt” have also a high absorptive power. This may be partly due to the presence of organic matter, but allowing for that, these fractions have a high power of absorption.

5. It was not the object of these experiments to draw any detailed conclusions as to the relation between surface and absorptive power, but it seems probable, from the results obtained, that the absorptive power is not determined by surface alone, and that the chemical composition of the fractions has an influence on the absorptive power.

Since the publication in 1914 of the results obtained by Daikuhara (2) in an investigation of certain acid soils of Japan, considerable prominence has been given in the literature of Soil Chemistry to the presence of iron and aluminium salts in the solution of sour soils.

In 1870 Lawes and Gilbert constructed the famous drain gauges at Rothamsted and commenced a series of measurements of the amount and nitrate content of water draining through uncropped and unmanured land. The essential feature of the experiment, and one wherein it differs from many others, is that the soil in the gauges is in its natural condition and has never been disturbed: the gauge was constructed by building a wall around a block of soil and then tunnelling underneath to allow of the construction of a chamber in which the collecting and measuring cylinders could be set up.

It is shown in the preceding pages that under certain cultural conditions the nodule organism from the roots of red clover, broad bean, lucerne and lupin exhibits a tendency towards granular disintegration of the cell with the formation of small non-motile coccoid bodies, about 0-4μ diameter.

In the cultures ordinarily in use these coccoid bodies are not formed extensively, but cultivation on soil extract media rapidly leads to their production, until finally they constitute the predominant type in the culture.

“Silt”, like most insoluble substances, when suspended in water is most easily flocculated by calcium salts when the suspension is neutral. The addition of alkali stabilizes the suspension and renders flocculation more difficult. Soil “clay,” however, behaves in an opposite manner and is precipitated from alkaline suspensions more readily than from neutral suspensions. In this behaviour clay resembles silicic acid and some other members of the so-called “emulsoid” colloids, and it is suggested that the clay particles are protected by such colloids and thus behave as an “emulsoid” and not as a “suspensoid.”

If this is true then the action of lime, which being alkaline nevertheless flocculates clay, is seen to be in accordance with the facts of colloid chemistry.

The view is advanced and some experimental support of it is described, that clay, as an “emulsoid,” protects the larger particles which by themselves are “suspensoid.” The soil aggregates are conceived as having large nuclei surrounded by particles which become smaller from the centre of the aggregate outwards, the clay ultimately imposing its “emulsoid” nature on the whole aggregate, and on the whole soil in normal cases. Fine silt soils are not flocculated by calcium hydroxide on account of the inefficiency of the relatively small amount of “emulsoid” clay to protect the large “suspensoid” surface exposed by the fine silt.

In any systematic account of the work done on the moisture in soil and its behaviour under varying conditions, it is necessary to keep constantly in mind that the underlying hypotheses have been profoundly modified in recent years. When physical methods were first applied to the examination of soils, the results were interpreted on the obvious hypothesis that the soil could be regarded as composed of mineral particles of varying shapes and sizes, over the surfaces of which the water was distributed in a thin film. The movements of the film water and its average thickness at any time, under the varying meteorological and soil influences, could be predicted more or Jess completely from known physical principles such as surface tension, etc. Similarly, the concentration of the plant nutrients in the soil moisture was considered mainly as a matter of solubility in, and diffusion within, this moisture. The foundation of the subject of soil physics was laid upon these lines in the early 19th century by Davy and Schübler.

It has been shown in Part II that a glacial drift soil in a comparatively unweathered condition has a considerable power of absorption for ammonia, although it has sometimes been held that it is the weathered material in soils that is responsible for the absorptive power. Glacial drift, as exemplified in the Craibstone soil, however, though its weathering is geologically recent compared with that of many English soils, has been subjected to age-long weathering since the glacial period, and in the process of soil formation a certain amount of weathering with the resultant decomposition has necessarily taken place. Craibstone soil has also been shown (Table II, Part II) to contain a fairly large percentage of organic matter and it might be contended that the absorptive power was chiefly due to either or both of these factors.

A Previous investigation by the writer (1) showed that cyanamide readily breaks down, yielding ammonia in normal clay and sandy soils. The evidence, however, threw no light upon the cause or nature of this change. This question was accordingly reserved for a later investigation. The concensus of the available evidence indicated that the production of ammonia from cyanamide in the soil is due to direct bacterial action. This view was held by Immendorff(2) and Kappen(3), who concluded that in poor soils of low bacterial activities cyanamide is not converted into ammonia but is chemically transformed into dicyanodiamide. Löhnis(4) at first accounted in a similar way for the formation of ammonia from cyanamide in the soil. He(5) assumed later, however, that cyanamide is normally decomposed by soil colloids into urea or possibly some other substances, and the latter are then converted into ammonia by the soil organisms. He adduced no direct evidence of the production of urea from cyanamide in the soil.

Ammonia can be recovered from soil with an efficiency of 98·5 to 99·5 per cent, in six hours in the apparatus described.

For most purposes it is sufficient to aerate the soil for three hours.

Highly dunged glasshouse soils undergo partial decomposition in the cold with magnesia. In such cases the soil should be aerated with magnesia and strong sodium chloride solution for a definite time, say three hours.

The complete recovery of added ammonia from a calcareous soil is difficult unless the soil is finely ground.

The use of straw as fodder is beset by the double difficulty that on the one hand its bulky character seriously limits the extent to which it can be consumed by the animal, whilst on the other hand its tough and fibrous nature entails such a heavy expenditure of energy to secure the high degree of comminution and further preparation essential for effective action of the digestive agents that only a comparatively small surplus of energy remains over to serve productive nutritional ends. Thus it was found by Kellner and Köhler in the case of oat straw that of the total energy contained in the straw only 35·8 per cent, was usefully digested, whilst only 12·9 per cent, could be applied after digestion to productive purposes. For wheat straw the corresponding proportions were 31·1 per cent, and 5·5 per cent, respectively. These may be contrasted with the proportions of 49 per cent, and 20·7 per cent, respectively found by the same observers for meadow hay; and the proportions of 74·9 per cent, and 45·9 per cent, respectively found by Armsby and Fries for maize meal.

In a previous communication attention was called to the possibilities of partial sterilisation under field conditions in the case of the summer fallow of Egyptian agriculture.

This fallow period or “sheraqi” is particularly characteristic of the basin system of agriculture during the interval between the harvest of the winter crop and the Nile flood, but it is also common under perennial. conditions of irrigation after the winter crops.