Studies in the Nutrition of Vegetables

A progressive reduction in the amount of nitrogen applied as sodium nitrate to sand-cultures of lettuce (var. May King) resulted in a progressive reduction in size and weight, a progressive development of anthocyan pigment, and finally a tendency to etiolation of the remaining green portions of the leaves with sometimes formation of a golden-yellow colour in the oldest leaves. An adequate supply of nitrogen tended to give earliness of maturity as shown by ‘hearting’, and to favour the growth of tops rather than of roots. I thank my assistants, Messrs. T. W. McKean and J. F. Leonard, for their great help during the course of this experiment.