An investigation has been made into the effect of time of application of nitrogen as sodium nitrate to the turnip. Experiments were arranged on a statistical basis, and were carried out in sand culture. The life of the turnip up to harvest was arbitrarily divided into three equal light periods, and the fourteen possible combinations of high and low nitrogen applied in these periods constituted the treatments. The absolute amount of growth was largely determined by the level of nitrogen, but the relative proportion of growth was independent of this level. Tops developed earlier than roots, and the effect of difference in nitrogen level was more marked with the roots than the tops. For a high yield of roots it seems desirable to apply nitrogen, early, but for a high yield of tops it would be preferable to apply the nitrogen as post-seedling dressings. The chief effect of level of nitrogen on moisture content was confined to the period in which the harvest took place. A comparison of top/ root ratios also showed that high nitrogen in the early stages of growth stimulated root development.

We thank Mr J. F. N. Leonard for his help during this experiment.