1. A reliable identification of grain samples of related wheat varieties of different grain values is of economic importance.

2. The distensometer test distinguishes with a high degree of reliability between Tuscan and Cross 7 grain, whereas eye inspection, baking and fermentation tests cannot be relied upon for differentiation between the two varieties.

3. A testing service for the use of farmers, grain merchants and millers would involve no technical difficulties.

The task of wheat growing in New Zealand is limited to providing for the needs of a population of 1½ million. Owing to the long distance from other wheat-growing countries it is considered essential for the Dominion to remain independent in its supply of wheat and flour. A sliding scale duty fixes the price of wheat at a level sufficiently remunerative to the grower to insure the production of approximately the required amount. Since 1927, when this duty was introduced, the area under wheat has varied between 236,000 and 302,000 acres, and the annual production between 6½ and 11 million bushels. The requirements for flour milling, seed and stock food being slightly less than 9 million bushels, shortages due to unfavourable seasons are covered by the carry-over from the previous season, and/or by importation. It is only in seasons of excessive yields that export of wheat becomes necessary. Under the compulsory pooling system in force since 1932·3, losses due to the difference between local and export prices are distributed amongst all the wheat growers in the Dominion.

The study of the effect of rainfall on the yields of wheat from the continuous experiments on Broadbalk, Rothamsted, gave clear evidence of a close relation between the response in yield to rainfall and the manurial treatment of the soil. In later investigations of a similar nature on barley at Rothamsted and on wheat and barley at Woburn, however, the evidence did not point to a significant effect of rainfall on yields, and on this account little can be said with confidence from these investigations. The present note shows that the relation between seasonal variations in yield and manurial treatment is just as clear at Woburn as on Broadbalk, the difference between the two centres being that similar studies on rainfall effects have had more definite and successful results on Broadbalk. At Woburn, indeed, little progress has been made towards elucidating the particular weather factors whose quantitative influence is important.

The variations in sticky point of homionic soils as determined by kneading with electrolytic solutions have been examined. In the case of sodium soils, a well-marked maximum has been found in the sticky-point/electrolytic concentration curve; and the form of the curve shows parallelism with the extent of flocculation produced by varying electrolytic concentrations.

The crude-fibre determination is misleading, because the fraction obtained does not bear any definite relationship to the structural constituents of the material. The cellulose is partially attacked, and lignin extensively removed. Considerable variation is found in the lignin content of crude-fibre fractions. Highly lignified materials do not necessarily yield a crude fibre high in lignin.

Since the presence of lignin exercises a direct effect on the digestibility of the material, any empirical method should include all the lignin, and alkaline treatment must be avoided. Acid hydrolysis may be a possible alternative method, if a correction for protein be made in the case of materials high in nitrogen, and a determination of the lignin content made.

Fat colour is of importance in beef produced for English markets because of discrimination against deep yellow fat. The factors at present known to affect colour are genetic(1,4) and those relating to food supply(2,3), but not much is yet known of the various circumstances or natural conditions under which the colour will vary in shade. It was the purpose of this investigation to determine some of these. Rabbits were selected for the preliminary experiments, as, although it is questionable whether the colouring matter in the fat is quite the same as in cattle (3, 5), it is very probably affected by the same conditions. Experiments could be done quicker and cheaper in rabbits than in cattle on which the results could be tested after the pioneer work in the rabbit was completed.

The estimation of the experimental yields of cereal crops by sampling methods is considered in the light of results of eighteen experiments which were harvested by these methods at Rothamsted and its associated centres. The harvesting results of the Crop-Weather series of experiments are also included.

A preliminary discussion of the interpretation of the analysis of variance as applied to sampling results is given, and an expression is found for the loss of information arising out of sampling. The results of the discussion are applicable to all types of sampling carried out on replicated experiments.

The sampling and experimental errors of all the experiments have been calculated. The variation between sampling units in the same subplot (usually between l/100th and l/200th acre) was found to be such as would arise if each metre length of row had a standard deviation (about the plot mean) of the order of 25–30 per cent. of the mean yield.

In this paper are brought together a number of data concerning the ratio of the amount of leaf to stem in the lucerne crop, at different stages of growth, and the separate composition of the leafy and stemmy fractions.

It is shown that the proportion of leaf falls off as the crop advances in maturity, and that the rate of decrease of leafiness is greater before budding than during the period from the beginning of budding to early flower. The changes in the leaf-stem ratio largely account for the fall in protein content, the rise in fibre content and the running-off in digestibility and feeding value that take place as the crop passes through the successive stages of growth up to flowering.

1. The details of the Dennstedt dry-combustion method for determining carbon in soils were described, and some simplifications suggested.

2. The Bangor modified Kjeldahl method for carbon and nitrogen in soils requires carefully standardised heating. Errors may arise from contamination of sandy soils by material abraded during grinding in iron or porcelain mills.

3. For many heavy soils the addition of water before the Kjeldahl digestion is convenient but not essential. For heavy alkaline soils with little organic matter it is advisable to grind the soil very finely and to add water.

1. Attention is drawn to the remarkable dissimilarity between the cacao and the grapefruit tree in their nutrient requirements, indicating that grapefruit is calcicolous in physiological habit. This conclusion is mainly based on a consideration of the results of chemical analysis of representative leaf material produced by trees grown on soil of known chemical and physical characteristics, under the same climatic conditions in Trinidad.

2. The nutrient relationships that obtain between the cacao and the grapefruit tree respectively and the soil in which they are growing have been gauged by means of chemical analysis of representative leaf material.

3. For this purpose, leaf material was obtained from trees growing on the differently manured plots of two large-scale field experiments in Trinidad.

An outline is given of an investigation that has dealt with disinfectant dusts containing mercury, and it is shown that the majority of the inorganic mercury salts are of little value in this respect. Some organic mercury salts have been tested and the result of laboratory and field work suggests that there is a close relationship between composition and fungicidal power. In the series R-Hg-X, where R is a hydrocarbon and X an acidic radicle, the fungicidal power appears to decrease with the increase of the molecule of R. A study is made of the significance of X in the methyl series and the results as they apply to disease control are recorded on a series of graphs.

The specificity of some of the compounds is noted and a brief mention is made of the treatment of seeds other than cereals.

It is suggested that there is no evidence for stimulation in the sense of tonic effect but that instances of better germination, growth and crop yields are due not only to the control of seed-borne organisms but to the preservation of the food reserves in the seed from the attack of soil organisms or mould organisms adherent to the seed.