1. A detailed mineralogical analysis was carried out on soils, specially selected by members of the Soil Survey.

2. The heavy liquid separation showed a higher percentage of ferromagnesian minerals in soils from the Northern than the Southern Drift area.

3. The minerals identified in the soils may be referred to fairly local origins, but no close relationship with subjacent rock has been established.

4. The mineral assemblage was characteristically fresh and angular.

5. Hypersthene, sphalerite and hornblende are characteristic of the Southern Drift, while barkevikite is more pronounced in the Northern Drift.

6. Comparisons are made with results obtained by investigators in other areas.

A survey of the fertilizer value of certain highly concentrated N and NP materials, particularly salts of urea and of guanidine, which might be used as fertilizers, has been made. The evidence in the literature indicates that whilst guanidine carbonate and nitrate, especially the latter, may under certain conditions be toxic to the growth of certainc plants, under other conditions these guanidine salts have considerable fertilizer value which is, however, less than that of ammonium sulphate. Urea nitrate appears to have about the same value as guanidine nitrate. No reference to experiments with guanidine or urea phosphates could be found. Pot culture experiments were conducted with barley and mustard in acid and neutral soils to study the effects of ammonium, urea and guanidine salts, including their nitrates and phosphates, and of two extremely concentrated materials, phospham (PN2H) and phosphorus nitride (P3N5). The rate of nitrification of ammonium, urea and guanidine nitrogen were also studied in the laboratory.

A sand-culture experiment with inoculated lucerne was made to test the effect of increasing doses of sodium nitrate upon the yield and nitrogen content of tops and roots, and upon the number and development of nodules. The pots were divided into six series receiving from 0 to 10 gm. of sodium nitrate per pot containing 12 kg. of sand.

There was no correlation between yield or nitrogen content of the lucerne, and the dose of nitrate.

The number of nodules, though unaffected by 1 gm. of sodium nitrate, was progressively decreased by the stronger doses.

The length of nodules was reduced about 30 per cent, by 1 gm. of sodium nitrate, and decreased progressively with stronger doses.

Nodules were found to show a definite relationship between their overall length and the volume of contained bacterial tissue. Using this relation, the mean volumes of bacterial tissue per nodule and per pot for each series were calculated. The reduction effected by nitrate was far greater when measured in this way, owing to the small contribution of bacterial tissue derived from nodules less than 1·5 mm. in length.

1. Phosphorus in hydrochloric acid extracts of soil may be conveniently determined by digestion with sulphuric and nitric acids.

2. By boiling soil with hydrochloric acid (B.P. 110° C.) for 48 hours under reflux an end-point of extraction is reached.

3. Digestion of soil with sulphuric and nitric acids gives results in agreement with results by 48 hours” hydrochloric acid extraction.

4. It is suggested that the phosphorus thus extracted represents a definite category of soil phosphorus, which may be taken as the total phosphorus present in the soil.

5. Details of the suggested method are given.

An experiment has been carried out with dairy cows to measure the value of artificially dried grass, silage made with added molasses and A.I.V. fodder (silage made with mineral acid in quantity sufficient to bring the pH of the mass to between 3·0 and 4·0) in the diet, on the yield and quality of the milk. A preliminary period of 3 weeks when all cows were on the control diet was followed by an experimental period of 17 weeks. There were four treatments: a control ration consisting of hay, roots and concentrates; one in which artificially dried grass replaced part of the concentrates; a third in which molassed silage was fed; and a fourth including A.I.V. fodder. There were originally five blocks of four cows each, the four treatments being randomised in each block, each block of cows standing together in the cowshed to eliminate any possible effect of position. One block went dry after 8 weeks, but the remaining four blocks completed the experiment.

The need for physical measurements of soil structure to assist in studies of the relation between cultivation implements and plant growth is pressing.

The nature and measurement of soil compactness and consolidation are briefly discussed. Measurements of soil resistance give an indication of consolidation rather than of compactness.

An instrument used for the measurement of soil resistance is described, with some notes upon its performance.

A brief outline is given of studies on soil structure in relation to gyrotilling. It is shown that the soil-resistance apparatus described gives results similar to those obtained by the use of the drawbar dynamometer in ploughing. A relation between soil resistance and plant growth is demonstrated.

It is shown that the theory of diffusion of water through soil accomplishes three things:

(a) It accounts qualitatively for the water movement from wet to dry soil observed by the American workers quoted.

(b) It fits the best experiments numerically.

(c) It is at present alone in doing this.

An experiment was carried out with two groups of ten cows each, made up of two Guernseys, two Ayrshires, two Friesians and four Shorthorns.

The experiment was of the change-over type, the experimental period of 20 weeks being subdivided into four periods of 5 weeks, each cow alternating between the two treatments.

In two of the periods a normal winter ration of roots, hay and concentrates was fed. In the other two periods artificially dried grass replaced a proportion of the concentrates, an average of 8 lb. being fed per head daily. The two types of ration provided equal amounts of starch equivalent and protein equivalent, but the carotene intake was greater in the “dried grass ration”.

A statistical analysis of the difference in milk yields due to the contrast “Dried grass” v. “Control” revealed no signs of any effect, and if any actual effect does exist, it is quite negligible for the 5-week periods of this experiment.

In continuation of earlier work (2) on the destruction of annual weeds in cereal crops some thirty-four replicated experiments have been carried out during 1934 and 1935 in widely different localities. Besides sulphuric acid, nitric acid, ammonium and sodium hydrogen sulphates and ammonium thiocyanate were tested, while the effect of a wetting agent was also studied.

In every experiment the solution was applied by means of a knapsack sprayer at the rate of 100 gallons per acre. In general at the time of spraying the weeds were in the seedling stage, and the cereal crop not more than 6 in. high. Counts of the weed density were made in order to estimate the degree of control, while in the majority of the trials the yield of the cereal was determined.

Sulphuric acid at a concentration of 9·2 per cent. (1 gm. H2SO4 per 100 c.c.) gave a 90 per cent. control of Brassica arvensis (average of nine experiments) and when a 13·8 per cent, strength was used it gave a 95 per cent, control of Raphanus raphanistrum (average of eight experiments). Nitric acid at equivalent concentrations was slightly but significantly more effective in three out of nine trials for the eradication of these two species. Ammonium hydrogen sulphate (21·6 per cent.), sodium hydrogen sulphate (23·6 per cent.) or ammonium thiocyanate (3–10 per cent.) did not, on the whole, compare favourably with sulphuric acid. Decreasing the concentrations of sulphuric acid by a third resulted in a less effective destruction of Brassica arvensis or Raphanus raphanistrum. This loss of efficiency at the lower concentrations was not corrected by the addition of a wetting agent (Agral 1 at 0·1 per cent.); similar results were obtained for nitric acid.

The present practice of basing payment for bacon pigs not merely on carcass weight, but also on carcass quality as expressed in the factory grading results, has led necessarily to an enlargement of outook on the part of the investigator in the domain of swine nutrition. The interest of the experimenter in the past has tended to be restricted to such questions as the influence of nutritional factors on the rate of live-weight increase and the efficiency of food conversion, the problem of how feeding may influence carcass quality and conformation not having received the attention its importance merited.

While the questions of the rate of growth and the efficiency, in terms of meal consumption, with which such growth is achieved are still matters of primary economic importance, it is realized that much more attention must be devoted than heretofore to the study of carcass quality and conformation in relation to feeding. In present circumstances, a nutritional investigation can scarcely be considered complete unless a substantial part of the research is carried out in the bacon factory following the slaughter of the experimental animals.

That extreme environmental temperatures have a marked influence on metabolism is a well-established fact. The early investigators, Kellner, Atwater, Armsby and others, studied the energy income and output of farm animals in relation to various conditions of the environment, and from these studies the principles of basal metabolism, critical temperature, and physical and chemical regulation of body temperature have evolved.

The paper records the results of an investigation into the composition, digestibility and nutritive value of marrow stem kale (both unthinned and singled-out) and thousand head kale. A number of the main findings are recorded below.

The average dry-matter content of unthinned marrow stem kale during September and October was 13·3 per cent. During the following January it had reached a slightly higher level, namely, 14·2 per cent. Singling out of the marrow stem kale appeared to exercise little effect on the dry-matter content of the crop. Thousand head kale, with an average dry-matter content of 15·8 per cent., is significantly richer in dry matter than the marrow stem kale, although this advantage was offset by the lower yield, in terms of green matter, given per acre by the thousand head kale.

The effect of applying a nitrogenous fertiliser to wheat at seven different times and three rates, was studied in pot culture. It was found that the later the time of application the smaller was the increase in the yield of total dry matter and of straw. The increase in the yield of grain, on the other hand, was constant for the first six times of application, the last of which was made on May 25, but a later application made after ear emergence produced no increase.

Analysis of the grain yield showed that early application produced its effect by increasing the number of ears per plant. Later applications caused a smaller increase in ear number, but also increased the number of grains per ear and 1000-corn weight. There was no evidence of a critical time for tiller formation such as has been postulated by Doughty and Engledow.

The increase in total nitrogen uptake was equal for all times of application, but the ratio of nitrogen in grain to nitrogen in straw and chaff was greater, the later the time of application.

The writer wishes to thank Messrs A. M. S. Clarke, G. T. Detlefsen and S. A. W. French for much help with the experimental work, and Mr R. G. Warren for making the nitrogen determinations.

(a) A comparison was made between the catalytic efficiency of selenium and of copper sulphate in the Kjeldahl method as applied to the analysis of grass. The same value for total nitrogen was eventually obtained by both methods, but with selenium it was reached some 90 min. earlier than with copper sulphate.

(b) The clearing of the digested matter was no criterion for deciding whether all the nitrogen in grass had been converted to ammonium sulphate, maximum values not being obtained with selenium until between 2 and 3 hours afterwards.

(c) The catalysts were compared for three samples of soil with digestion periods ranging from when the digested material first cleared to 32 hours afterwards. The selenium figures showed an increase for the first 3 hours, and then remained constant up to the 32-hour period. The copper sulphate figures, however, showed a steady increase for the first 24 hours, after which they became constant at the same values as those reached earlier by the selenium figures.

In recent years a number of workers have investigated the influence of nitrogenous fertilizers on the growth of pastures. In some cases they have claimed that such fertilizers lengthen the grazing season by producing grass earlier than normal in the spring, but no research has been carried out on the factors controlling this spring growth. Watson et al. (15) in a study of the influence of nitrogenous fertilizers on the seasons’ yield of rotationally grazed pasture at Jealott's Hill, showed that in 1 year ammonium sulphate applied at the rate of 23·2 lb. nitrogen per acre in March enabled the treated plots to be grazed some 14 days earlier than the control. Richardson(13) found that 44·8 lb. nitrogen per acre gave marked increases in yield. Woodman & Underwood(16), however, claimed that ammonium sulphate (14·5 lb. nitrogen per acre) produced no strikingly higher yields.

A general account is given of four experiments in which the action on the soil of the Fowler “Gyrotiller” has been compared with that of the traditional cultivation implements. The gyrotiller has produced well-marked changes in the soil on both heavy and light land. These changes have been demonstrated and recorded by tests of the compactness, the resistance, the degree of comminution and the permeability of the soil.

On the heavy land, the initial effect has been to produce a very loose and open soil. This has gradually settled down until, after the end of the first winter, no difference in compactness was demonstrable by means of the revolver test. But the resistance of the soil, measured by a special recorder and by plough drawbar tests, has remained demonstrably lower on the gyrotilled plots than on the controls for a considerable time after this, and a method of soil fixation has shown that small cavities persisted for more than a year. In one experiment, differences in resistance have been shown to exist up to 19 months after gyrotilling.

1. An account is given of Marsh Spot in the seeds of the green pea (Pisum sativum L.); its economic importance and its effect on the plant, including the germination of the seed, are discussed.

2. Hypotheses advanced by seedsmen and growers to account for the presence of Marsh Spot are discussed.

3. The soils of 165 fields upon which green peas were grown under contract for seed in east Kent during 1933 and 1934, were surveyed in detail and are classified under the American system. A brief description of each is given.

4. The occurrence of Marsh Spot is correlated with the presence of a water table in the soil. A high percentage of Marsh Spot was encountered only in crops grown on fields with a water table within 52 in. of the surface. Thus, in the presence of a water table, the intensity of Marsh Spot reached a maximum of 100 per cent. of the seeds of a sample affected, whereas in the absence of a water table the maximum was only 3 per cent.

The results show clearly a more rapid and greater uptake of ammonium than of nitrate nitrogen by perennial rye grass grown in a sand-bentonite medium of pH 7·61. The extent to which the extra uptake with added ammonia was reflected in increased yields was dependent upon the age of the grass.

Except in the very early stages the percentage nitrogen content of the herbage was higher where nitrate nitrogen was applied than where ammonium nitrogen was applied. This indicates that any nitrate absorbed by the plant was less, efficient in increasing yields than was ammonium nitrogen.

The percentage P205 content of the grass was higher where the nitrogen was applied in the ammoniacal form than where it was applied as nitrate, and it appears that this greater P205 uptake with ammonium nitrogen resulted in increased growth.

Experiments were carried out in four successive years to compare the plough and the cultivator as implements for preparing a seed bed for wheat after potatoes: in the last two years direct drilling was introduced as a third treatment. Very diverse conditions were experienced, and an attempt has been made to formulate practical recommendations.

1. Several authors have previously reported that the sulphuric acid treatment of the cotton seed resulted in: (a) earlier germination, (b) higher percentage of seeds germinating, (c) higher yield of seed cotton per acre, and (d) better and more uniform planting (this paper is not concerned with the disinfecting effect of this process).

2. A series of experiments, both in the laboratory and under field conditions have been carried out to determine whether the above statements are in agreement with actual experimental data.

3. In so far as the rate of germination is concerned, it was found that: (a) untreated seeds often show a smaller percentage of germination than seeds treated with sulphuric acid for various time-intervals, particularly when tested in the laboratory; (b) cotton seed treated with the reagent for from 5 min. to 2 hr. or even 5 hr. in some cases, does not show any decrease in its germinative value as determined by laboratory tests. In field trials seeds treated for 5 or 12 hr. practically do not germinate at all, whereas the 2 hr. treatment often shows a small decline in germination; (c) an enormous difference in the rate of germination has been revealed between the laboratory determinations on the one hand and the field determinations on the other.