SOIL MOISTURE AND PREPARATION OF SOIL. 73 



(g) Allow them to stand until the surface of the soil 

 in can No. i is dry. Weigh again, and compare with (^). 



(//) Carefully dig down into the soil of each can, and 

 measure the distance from the surface to a layer of 

 moist soil. Compare these distances In which can 

 would the conditions be better adapted to surface-feeding 

 plants? In which to deep-feeding plants? How does 

 the water escape ? Out of which can has it escaped 

 most slowly? Most rapidly? Why? In which can the 

 air most freely enter the soil ? In outdoor soils of these 

 three conditions, which would now allow the water to 

 pass into it least freely ? Which of these soils represent 

 a rolled soil? Which a loosely tilled soil ? How would 

 a rain affect each of these soils ? Why is it necessary to 

 till the soil about growing plants as soon as possible 

 after a rain ? What is the condition of soil in the field 

 in early spring? How 

 does early spring plow- 

 ing affect the evapora- 

 tion of soil moisture ? 



(/) Compare these 

 mulches, and record 

 your own conclusions 

 upon the teachings of 

 this experiment. 



Tillage for surface- 

 feeding roots may be 

 deep when the plants 

 are quite young, but 

 when they have made 

 considerable growth plowing must necessarily 

 be shallow to avoid destroying the roots (Fig. 

 26), which sometimes reach from row to row. 



Cultivation should not be repeated until the 



FIG. 26. TO SHOW THE EFFECT OF 



DEEP AND SHALLOW PLOWING. 



