1. These researches were undertaken in order to analyse and define with precision the causes of infertility in a heath soil at Wareham Forest, Dorset.

2. The presence of substances actively inimical to growth has been confirmed and the origin of the resulting toxicity established.

3. A new technique for biological analysis, the nutrient-agar-film method, makes it possible to estimate the relative degree of toxicity in any given sample, thus facilitating development of methods of laboratory control for elimination and redistribution of the factor or factors responsible.

4. It has been proved that the toxic substances are of biological origin and that they operate directly by inhibiting fungal growth. The resulting biological inertia is exemplified by almost complete cessation of cellulose decomposition. Following upon this inertia are indirect effects of a secondary character on growth of the higher plants, in the case of trees restricting root growth, impeding mycorrhiza formation, and curtailing supply of nutritive requirements.

5. Justification for the use of organic composts for relieving the observed infertility under field conditions has been provided by laboratory experiments proving that removal of toxicity and profound alteration of the organic substrate and soil bionomics follow addition of compost. Changes so induced are self-propagating and the effects on growth persistent.

6. The bearing of these results on fertility in other natural soils and in cultivated soils is discussed.

1. Some preliminary observations on the carbonic anhydrase activity of the hen's oviduct are reported.

2. It is suggested that the carbonic anhydrase activity of the uterine epithelium is higher than that of the remaining oviducal tissues, and that this activity may play a part in shell secretion.

1. Some recent developments of mineral balance studies on laying fowl are discussed and applied to the interpretation of the average results of twenty-six balance experiments with pullets.

2. Several of the experiments are re-examined in detail from the same standpoint.

3. A tentative hypothesis covering the relations between the calcium metabolism of shell formation and the calcium-phosphorus metabolism of bone is put forward on the basis of this reconsideration of available data. It is suggested that some degree of mobilization of skeletal calcium is a normal feature of shell formation in the fowl, the fraction of bone mineral material mobilized always having a higher Ca: P ratio than the skeleton as a whole, although the actual ratio may vary with the calcium in the diet and with the form in which the calcium is provided.

1. An account is given of the distribution of four separate boulder clays, which form the parent materials of the soils of eastern Kincardineshire.

2. The mineral composition of the fine sand fractions of the boulder clays is given.

3. The boulder clays, notwithstanding colour similarities, have been shown by mineralogical examination to be distinct.

4. The middle boulder clay, largely influenced by rocks of Old Red Sandstone age, is shown to have a higher proportion of ferromagnesian silicate minerals than soils from glacial drifts similarly derived elsewhere in Scotland.

By growing peas in water cultures with carefully regulated amounts of manganese, the effects of a deficiency of this element have been studied.

Complete absence of manganese produces a mottling of the younger leaves and death of the growing tip as previously reported. The plant does not reach the flowering stage.

Small amounts of manganese, insufficient for normal requirements, enable increased growth and seed formation. The seeds show marsh spot lesions, the severity of the lesions being greater at the lower manganese concentrations.

Normal growth and sound seed are produced when sufficient manganese is present in the nutrient solution.

Marsh spot results from a partial deficiency of manganese, the amount available to the plant being sufficient for its normal vegetative requirements but not for healthy seed production.

Experiments on evaporation from freely drained soils are described. Under isothermal conditions characteristic winter field behaviour is obtained, even when the air drying power is greater than its normal English midsummer value. Characteristic summer field behaviour is obtained when the rapid drying of a thin surface layer is achieved, either by using an extremely high air temperature under ‘isothermal’ conditions, or by raising the surface temperature by means of radiation—the normal method in nature. The effect of a high salt concentration in the soil water is shown to lead to greater evaporation losses and to a tendency for the salt to concentrate in the more salty patches.

It is suggested that mulching will only be beneficial during the isothermal part of the year, i.e. when soil surface and air temperature are approximately equal, and that it will have little effect on water conservation where the soil will be self mulched by the action of summer sunshine. The cause of this self-mulching action is briefly considered in the light of our limited knowledge of soil water dynamics; it appears to depend on the existence of a dual mechanism of water movement in soils—as liquid and as vapour—the rates of movement being very different functions of moisture content and moisture gradient.

1. The degree of dispersion on shaking of the heavy clay Gezira soil has been studied in relation to its initial moisture content when it is added to the water. A minimum dispersibility was found at about 7% initial moisture content. Such behaviour is different from that found with certain English soils by Puri & Keen.

2. Spontaneous dispersion was studied using the same soil, and by this method it was found that the dispersion decreases with increasing moisture content over a range of zero to 9% moisture.

3. This relation between dispersion and water content is discussed in relation to possible effects in the field of practice. Attention is drawn to possible seasonal and daily differences in the effect of rainfall.

Pot experiments were made with red clover and with soy beans to determine how far the number of nodules developed was a specific character of the strain of Rhizobium supplied.

The number of nodules per gram of root was found to reach a limit specific to each strain. This limiting equilibrium was attained regardless of the size of the root system or the age of plant at which the culture was first supplied, provided enough time were allowed for the limit to be reached.

When two different strains were applied to the root surroundings in succession, the final number of nodules was determined by the limit specific to the strain in contact with the roots while these were making most of their growth. In clover this was the second and in soy beans the first applied strain.

The digestibility coefficients of old barley straw fed with a basal ration of oats, bran and maize to two adult horses and of the same straw after treatment by Beckmann's method were ascertained. The coefficients of the nitrogen-free extractives and the crude fibre of the untreated straw were 33·23 and 38·24 respectively and of the treated straw 54·14 and 63·71. There was a reduction in the digestibility of the small quantity of protein and fat.

Taking into account the 14·5% of dry matter lost during treatment, the starch equivalent value of the treated material was somewhat higher than that of poor quality meadow hay.

The digestibility coefficients were considerably lower for an immature horse previously maintained entirely on fresh grass.

Failures of cereal crops are occasionally reported, the seed having been dressed with an organo-mercury seed disinfectant and the failures attributed to the dressing. It should be noted, however, that prior to the introduction of the organo-mercury seed dressings similar crop failures had often been recorded, and in many cases failure had been attributed to the dressing which had been applied, or alternatively, to the conditions under which the treated grain had been stored.

Reduced germination during storage is common to all agricultural and horticultural seeds, but although the interaction of the factors involved is complex it is generally recognized that for satisfactory germination to be maintained over the maximum period of storage the following conditions should be observed:

(1) The seed should be of relatively high initial germination.

(2) The moisture content of the seed should approximate to the average for that kind.

(3) Storage temperature and humidity should both be relatively low and not subject to wide fluctuation.

(4) Ventilation should be adequate.

It is now generally recognized that the pH of a silage is the best single criterion of its quality. In other words, it is regarded as the best single guide to the type of fermentation that has taken place in the mass in the silo and thus serves to indicate the degree of success achieved in the ensilage process, whatever the crop or its stage of growth. For instance, in the case of silages, made with or without molasses, where the pH is at or below 4·0, the silage would be deemed to be of ‘excellent’ quality, that at 4·0-4·5 would be designated ‘good’, that at 4·5–5·0 only ‘moderate’, and at or above the latter figure the silage would be classified as ‘bad’. To get a complete picture of the chemical changes that have taken place and to assess the feeding value of a silage is quite a different matter and is not the object of the present note.