550 Brenchley and Jackson . — Root Development of Barley and 
for another month. Superphosphate applied alone tended to hasten the 
rise to a maximum, but in this case the fall did not begin to occur 
immediately. The roots and shoots of the nitrate plants closely followed 
grm. 
Fig. 3. Wheat, plants grown in pots. Dry weights of shoots, upper curves ; dry weights 
of roots, lower curves. (Mean of two plants in each case.) 
those of the unmanured in weight throughout almost the whole period of 
growth, indicating that, under the experimental conditions at least, nitrate 
by itself, exercised very little beneficial action on the growth of wheat. At 
harvest time the shoots of the nitrate plants were, however, heavier than 
the unmanured, probably because the effect of nitrate is to lengthen the 
period of growth, so that while the rate of growth began to slacken off 
in the unmanured plants about six weeks before harvest, in the nitrate plants 
growth continued steadily to the end. 
