C)54 Rural School Leaflet. 



II 



Capillarity of the Soil 



O. S. Morgan 



When you plant seeds, either in the window garden, the outdoor 

 garden, or the field, you firm or pack the soil about the seeds. Almost 

 all seed-planters have some provision for firming the soil about the 

 seeds. Why? 



First Lesson 



Purpose. — To determine the effect upon the germination of seeds of 

 firming the soil about them. 



Materials. — Two tin cans, seeds, and soil. 



Method. — Number the cans i and 2. Put prepared soil in both cans. 

 In number i leave the soil as loose as possible, and cover the seeds 

 planted in it with loose soil. In number 2 tap the can lightly as you 

 are filling it, then plant the seeds at the same depth as in number i, 

 but lightly firm the soil over the seeds in number 2. Observe which 

 seeds germinate first. 



Second Lesson 



Purpose. — To determine the effect of firming soil upon the movement 

 of soil water. 



Material. — Two tin cans, a pie-tin, soil, and water. 



Method. — Make holes in the bottoms of the tin cans. Number and 

 fill with soil as in experiment one, taking care, however, to, get equal 

 amounts of soil in both cans. Firm the surface soil in number 2 so that 

 it is smooth and level; sprinkle dry soil or dust over the surface of both 

 soils. Set the cans of soil in the pie-tin. Fill the tin with water to the 

 depth of a quarter of an inch. Observe in which can the water from 

 below first dampens the surface soil. 



Discussion 



In both of these experiments you have been observing a phenomenon 

 called capillarity. Capillarity in this case is the passage of water 

 through the minute spaces between soil particles. When the particles 

 of soil are far apart, and there are many large air spaces, the water 

 cannot pass readily by means of capillarity. 



In the first experiment the seeds in firmed soil were so closely sur- 

 rounded by moist soil that capillarity was set up between the seeds and 

 the soil. Thus favorable moisture conditions were established for seed 

 germination. In the second experiment the water from the pie-tin 



