The method used in this paper to reduce sunshine data is that developed by Fisher(1). It consists, briefly, in fitting to the distribution for each year, a curve

where T0, T1T2, etc., are orthogonal polynomial functions of zero, first, second, etc., order in time. The constants s0, s1, s2, … etc., are found by least squares, and are correlated with similar rainfall constants (r0, r1, r2 etc.) and with the crop.

The regression of the wheat yield on rainfall has already been found (1), so a method has been devised, whereby those results can be used in order to find the partial regression of wheat yield on the sunshine sequence, eliminating all rainfall effect.

The addition of aluminium salts to culture solutions and to soils will bring about certain changes; these may be summed up as follows:

1. A change in the hydrogen ion concentration, which will vary in amount with the original buffer properties of the solution or the soil.

2. A change in the buffer properties of the solution or the soil; the hydrogen in concentration of a culture solution containing an aluminium salt will tend to remain more constant than that of a normal culture solution during the period of growth of the plant, when both start at the same pH value.

3. Precipitation of soluble phosphate as aluminium phosphate except in solutions or soils more acid than pH 3·5 to 4·0; this might lead to phosphate starvation in water cultures but would have little or no effect in a soil, where the particles would remain accessible to the plant roots.

Although the infertility of the subsoil in humid, semi-arid and arid regions has received much attention from investigators in Europe and America, in South Africa, as far as the writer is aware, no such work has been done.

1. A thermophilic organism which destroys cellulose at 65° C. has been isolated in pure culture.

2. The organism is motile, gram negative, forms spores in the swollen end, stains well with carbol fuchsin, poorly with methylene blue.

3. After growth on media without cellulose the organism is unable to ferment cellulose.

4. The range of fermentation is from 43° C. to 65° C. The organism lives at 38° C. and 72° C. but does not ferment at these temperatures.

5. The spores are very resistant to heat and withstand 115° C. for 35 minutes.

6. Heating the spores to 100° C. for 5 to 10 minutes causes an increased rate of germination.

7. Carbohydrates fermented: cellulose, starch, raffinose, sucrose, maltose, lactose, mannose, galactose, fructose, glucose, xylose and arabinose.

8. Organic nitrogen is necessary for the fermentation, and peptone is the best source.

9. The products from cellulose are: acetic acid, small amounts of butyric acid, ethyl alcohol, carbon dioxide and hydrogen. The amount of cellulose destroyed in a 1 to 5 per cent, suspension varies from 70 to 95 per cent. Of the cellulose destroyed, 50 to 55 per cent, is regained as acetic acid, 5 to 25 per cent. as ethyl alcohol and the rest as small amounts of butyric acid, carbon dioxide, hydrogen, and pigment. The pigment is a fatty substance soluble in ether.

Data from 26 flocks, involving a total of 5014 pure-bred Southdown ewes, were available for analysis and discussion. For ewes of all ages the proportion giving birth to twins is closely associated with the total yield of lambs, and while barrenness and abortion may to a certain extent be due to the same causes, it is those factors which cause abortion which also affect the yield by reducing the number of single births, rather than the number of multiple births.

The low fertility of shearling ewes is due to barrenness through reduced or delayed ovulation.

The writer wishes to express his thanks to the breeders who supplied the records of their flocks and particularly to the Honorary Secretary of the Southdown Sheep Society for his help in the collection of these records.

In human society, density of population is marked by striking variations. With these are associated geographic, social, and economic differences. Among the plant populations of our fields occur gradations of spacing or density which, by broad analogy, suggest problems akin to those arising from density differences in human populations. It is necessary to do no more than walk the length of one of the drill rows in a field of young corn to appreciate the general situation. The facts are patent some five weeks after sowing when the emergence of the seedlings is almost completed. Side by side with a foot length of drill in which are thirty plants may be another foot with only three. Complete gaps of 2 feet or more are to be found in places: in others the plants are almost too numerous to count. In every field of corn, even at this early stage, the density or closeness of the plants in the drills is extremely irregular. As the season advances various influences induce irregular reductions in the number of plants. Vermin and disease take sporadic toll. Competition between plant and plant with death or effective disablement of the weaker has some effect. Its intensity at any point is mainly determined by the density or closeness of the plants. By May, for winter corn, a static condition has generally been reached. Plants living then are likely to contribute grain and straw to the harvest. Among these survivors are great differences in spacing. This may be readily appreciated by uplifting and counting the roots in sample 1-foot lengths of drill on a stubble field.

1. The adaptation of plants to resist frost appears to depend on seasonal changes which give the protoplasm stability. A study has been made of the changes occurring in winter wheat plants, of varieties differing widely in winter hardiness, during the fall and winter months.

2. By analysing the press-juice as well as the entire tissues at progressive dates, it has been possible to study the distribution of the more important constituents between the physiologically active cell fluids and the relatively inert supporting framework.

3. One of the most important changes in the quantitative relations of the various plant constituents is the reduction in moisture content. This takes place to a greater degree in hardy varieties. The resulting concentration of colloids and sugars in the cell fluids increases the resistance to freezing.

1. Evidence is produced to show that the free water in a soil is 21.

2. Wilsdon's modification of the Briggs-Shantz equation is discussed, viz., M = xH + 21, in which x = the vesicular coefficient. From this equation the vesicular coefficient of any soil can be found from the values of M and H.

3. The values thus obtained agree for clay soils with those found by Hardy's method from the moisture at the point of maximum plasticity.

4. The vesicular coefficient of a soil is greater than that of its subsoil.

5. The total bound water = (M – 21), and the vesicular water = M – (21 + H). The vesicular water expressed as a percentage of the plastic soil is equal to the cubical shrinkage coefficient.

An account has been given of an investigation which was designed to test the efficacy of the process of ensilage in the stack for preserving hay crops which are in danger of spoiling in consequence of adverse weather conditions.

The character of the ensiled crops and the weather conditions at the time of ensiling, together with the process of building the stack, have been described in detail.

The results of continuous temperature readings in the stack have been given in graphical form. The significance of the two distinct temperature maxima which characterized the temperature curve has been discussed, and the importance of this method of investigation in regard to the elucidation of the processes which go on during ensilage has been emphasized.

The chemical character of the “sweet” silage samples obtained from experimental bags buried in different parts of the stack has been investigated. The losses of dry matter resulting from fermentation and drainage have been determined and the changes affecting the individual constituents of the crop have been followed quantitatively. The results so obtained have been compared with similar figures referring to the process of ensilage in the tower and the clamp.

It has been shown that the loss of dry matter in the “sweet” silage layers of the stack compares satisfactorily in magnitude with the losses accompanying the preservation of crops in the tower silo and is appreciably smaller than that associated with the production of “sour” silage in the clamp.

(1) The addition of basic slag to moist base-unsaturated soils, under laboratory conditions, causes an increase in their content of exchangeable calcium, degree of saturation, pH, and the amount of calcium soluble in an aqueous solution of carbon dioxide.

(2) Slag seems to be almost as effective as calcium carbonate or lime in increasing the exchangeable calcium and the degree of saturation of soils, but its action on pH is not so marked.

(3) The effect of dressings of slag on the lime status of soils from experimental plots is still evident after eight years.

(4) The exchangeable calcium of samples of soil taken from the same fields after an interval of six years shows a considerable fall due to leaching.

(5) It is suggested that the addition of low grade basic slag to unsaturated soils may tend to maintain or improve their lime status and will, to some extent, compensate for the loss of calcium due to drainage and crops.

An investigation has been described in which an attempt has been made to measure the losses of dry matter in a number of regularly spaced layers of silage contained in a tower silo, the immediate object being to determine the average loss of nutrient matter in the entire mass of material. The work was continued over the period of two silage seasons. The more important findings are summarised below:

1. It is usually asserted by writers on ensilage that the attainment of such high temperatures as are necessary for the production of “sweet” silage necessarily involves an excessive loss of the dry matter of the crop as a consequence of the oxidation of carbohydrate. This statement has been shown to be erroneous both on theoretical grounds and on the grounds of actual measurements of the losses of dry matter entailed in the production of “sweet” silage. The amount of destruction of carbohydrate bears no significant relation to the temperature attained during preservation, and the factors of (a) juice drainage, (b) bacterial decomposition of carbohydrate, (c) partial spoiling by undesirable bacterial activity, as with “sour” silage, are of much greater significance in causing unduly large losses of carbohydrate.

2. The results obtained in this investigation with crops containing from 26·5 to 33·9 per cent. of dry matter show that “acid brown” silage can be made in the tower silo with an average loss of dry matter equal to 5–6 per cent. of that contained in the green crop. It is further concluded that “sweet” silage, if made under good conditions, can also be produced in the tower silo with an average dry matter loss of the same order. With “green fruity” silage, the average loss under proper conditions of ensilage in tower silos is of the order of 8–9 per cent. The evidence affords strong disproof of the statement that the ensilage of green crops cannot be accomplished without large losses of nutrient matter.

In the Journal of Agricultural Science for October 1921, Dr J. W. Capstick described a calorimeter large enough to take a full-grown pig or a small bullock. This apparatus was in regular use up to the end of 1923 and proved, on the whole, quite satisfactory.

1. A measure of the errors involved in the weighing of dairy cows for experimental work is presented.

2. Methods of avoiding a considerable part of these errors are suggested.

1. Sampling of single roots of swedes by means of cores is subject to errors of various kinds, of which one, due to the asymmetrical growth of the root in a north-south direction, has previously been overlooked. Cores should be taken horizontally in a north-south direction.

2. In the case of plants left standing in the field there is a marked decrease in dry matter content during winter and spring; this is presumably due to movement of food-material from the root into the developing flowering shoot. A detailed study of the metabolism of the swede during the winter is urgently needed, if only for the practical purpose of determining the “metabolic turning-point,” which is the ideal time at which to determine potential dry matter content.

3. The fresh weight of a core is a function of the weight of the whole root (except in Tankard swedes).

4. There is a well-marked negative correlation (autumn – ·66, spring – ·51) between dry matter content and fresh weight of core, and hence between dry matter content and size of root.

5. For one pair of strains of common parentage clear evidence of the inheritance of dry matter content has been obtained. In other instances the figures are inconclusive.

The flooding with sea-water of land around the Humber in 1921 spoilt a considerable area of arable land.

The effects of the flooding, which consisted chiefly in an entire destruction of the tilth of the soil, are described, and compared with the recorded effects of similar floods in Holland and in Essex.

The results of an examination of the exchangeable bases in the flooded soil are considered in the light of modern work on the relation between the nature of the exchangeable bases in the soil and its physical condition. It is shown that the observed effects can be explained by replacement of a considerable proportion of the exchangeable calcium of the soil by sodium.

Dutch experience on the reclamation of flooded soils is discussed. It is shown that in the first few years after flooding the land should be cultivated as little as possible.

The use of lime or gypsum for the treatment of flooded soils, in order to hasten the restitution of calcium to the clay in place of sodium, is discussed. From an examination of the soil from plots which had been treated with these materials it is shown that although both produced in some degree the desired effect chemically, the action did not proceed far enough in 12 months to produce a noticeable improvement in the tilth.

It may be possible under favourable conditions to grow certain arable crops on flooded land, among which crucifers appear to be specially suitable.

However, the most satisfactory and promising means of hastening the recovery of tilth and fertility by flooded land appears to be the establishment of a ley of lucerne, clover, or “seeds” which can be left down for several years.

An account has been given of an investigation into the seasonal changes in the productivity, botanical and chemical composition, and nutritive value of pasture grass, the work constituting the initial stage of a comprehensive study of the nutritive properties of different types of pasture. The pasture on which the work was carried out was situated on a light sandy soil of low water-retaining capacity; the pasturage was of medium quality.

Grazing was imitated by the daily use of a motor-mowing machine, the system of cutting being such as to ensure the whole plot being cut over once per week. The season was divided into ten periods, each period corresponding with the duration of a digestion trial carried out on two wether sheep. The main feature of the weather conditions during the season was the extremely low rainfall during the period from early June to mid-July.

The pasture plot results were compared with corresponding results obtained from contiguous plots which were allowed to grow for hay, and from which, after removal of hay, several successive aftermath cuts were taken. The main findings of the investigation are summarised below:

Seasonal changes in the botanical composition of the herbage. Although precise and systematic botanical analyses of the herbage of the pasture were not carried out, yet careful surveys made at an early and a late date in the season, together with general observations made during the whole course of the experiment, enabled interesting conclusions to be drawn in respect of the seasonal activity and persistency of the different species of grasses in the sward. During the spring season, Bromus mollis, Lolium perenne, Poa annua and Poa trivialis accounted for almost 80 per cent, of the herbage.

A Unique correlation has recently been obtained from some experimental data at Rothamsted. In the autumn of 1924 a set of 47 unmanured plots were laid out in Sawyer's Field, and were sown with wheat to test the uniformity of the fertility of the soil. The plots were each ·098 acre. The produce of grain and straw from each was recorded, and an examination of the figures showed that the straw yield recorded for plot 1 A was much lower than one would have expected under normal circumstances. A careful enquiry into the matter revealed that by an oversight a weighing of straw had been removed from the scales before the weight had been entered in the record. As it was impossible to verify the exact value of the missing entry, the yields from this plot were omitted from all statistical reductions of the data, leaving 46 plots upon which to base an estimate of the various statistics.

The soil was found to be very variable in fertility, the average yield of total grain per plot being 149·57 lb., with a standard error of 6·39 lb. and the average yield of total straw per plot was 194·35 lb., with a standard error of 7·55 lb.

The grain and straw yields of the 46 plots are shown in the accompanying diagram. The very close association between the total weight of grain and total weight of straw is evident. The amount of the relationship was measured by correlating the 46 pairs of values.

The figures analysed in the subsequent pages were obtained (by the kind permission and help of Prof. S. Pennington) during the five years, May 1920 to May 1925, from the College Farm dairy cows at University College, Reading, and before proceeding, a few notes on the herd and its management are desirable.

The herd is small (14–18 animals), and was established in 1908 by purchasing non-pedigree Dairy Shorthorn heifers which have since been “graded up” by the use of Pedigree Dairy Shorthorn bulls. The cows are typical Dairy Shorthorns, of a fairly large size, and the degree of fatness normally maintained might be described as good thriving condition, and probably better condition than average dairy cows.

The exploitation of the herbage by means of the herbivora is a most ancient process. It seems at first sight that special nutritional problems are not involved, since flocks and herds are kept under conditions approximating very closely to the original environment of their species. In comparatively recent years, however, masses of herbivora have been in some cases either confined so that their range is greatly limited from that of their widely-grazing forbears, or transferred bodily to grasslands previously uninhabited by them, or transformed by the skill of breeders into creatures with a much higher output, and in consequence, a much higher intake. These novel factors have produced problems of their own which are not yet solved, though they have been, with some success, tackled by the practical man largely by empirical methods.

For the purposes of this article the “food capacity” is taken to be the amount of total dry matter consumed when the animal is offered as much as it cares to eat. This has been estimated from the results of a variety of experiments collected by the author for the purpose.

The evidence quoted shows that the food capacity of steers is subject to a nearly uniform acceleration of 40 lb. per month per month from birth up to the age of 12 or 14 months, after which it remains approximately constant. It cannot therefore bear any simple relation to the live weight of the animal.

In the case of steers the average constant rate of consumption was about 18 lb. of total dry matter, per head, per day, throughout the period from 1 to 4 years of age; in the case of milk cows it is probably about twice as great, viz. from 30 to 40 lb.

The food capacity of steers has been much exaggerated by various scientific writers. In Kellner's tables it seems to be implied that the capacity varies as the live weight and that it may be as much as 64 lb. per head per day, i.e. 3½ times as much as was found in the experiments under review.