HOWARD AND HOWARD 35 
When the subsoil is gradually waterlogged from below after the seed is 
sown, still greater changes in the root system are obtained. Gradual water- 
logging from below after sowing is obtained by growing the crop in lysimeters, 
the drainage openings of which can be closed at will. In 1918, a series of such 
experiments was carried out and at the end the growth and root-development 
obtained under drained and waterlogged conditions was compared. The 
results are shown in Fig. 2. 
Fic. 2, The effect of waterlogging after sowing on the root- 
development of Java indigo. 
