94 



Development and Activities of Roots of Crop Plants. 



Field Experiments, 1920. 



During the spring and summer of 1920, experiments were conducted to 

 determine more precisely the water-absorbing power of crop-plants at various 

 soil-levels. Barley was employed and the crop was grown under field con- 

 ditions adjoining the crop-plats already described on the lowland area at 

 Belmont. 



FiQ. 40. — Diagram of containers and development of barley, 1920. Positions of wax seals, 

 6 inches apart, indicated by cross-lines. 



Containers of large size and especially designed for ease of root examina- 

 tions were used. The larger ones, in which the crops were grown for long 

 periods or to maturity, were cylindrical in shape, 1.5 feet in diameter, and 3.5 

 feet deep. They consisted of heavy galvanized sheet-iron rolled into a 

 cylinder, with an overlap on the edge of 5 inches, fitted into a one-piece cir- 

 cular bottom with an upright edge of 0.5 inch, and held in place by three 



