64 PRODUCTIVE FARMING 



EXERCISE. To Show Capillarity in Soils. Tie cloth 

 over the large ends of lamp chimneys and fill with different 

 kinds of dry soils, as shown in Fig. 35. Set them in a dish 

 of water. The water will rise in the soils by capillarity. 

 Does it rise higher in the finer soils such as clay and loam? 

 Moisture rises quickly but not so high in coarse land. 



Increasing Soil Moisture. Since humus holds so much 

 capillary water, the farmer has one sure way to increase the 

 water-holding power of any soil. The addition of green 

 manure and barn manure will cause humus to form in the 

 soil. Large quantities of humus will hold more moisture in 



FIG. 35. Water rises higher by capillarity through fine soils 

 than in coarse soil. 



the capillary form and thus encourage the growth of larger 

 crops. Deep plowing will increase the depth of the water 

 reservoir. Harrowing and cultivating will help, because 

 the more a soil is stirred the less water it will lose by evapo- 

 ration. Furthermore, rains sink into a loose surface better 

 than into a hard compact one. Underdrainage of soils will 

 increase this power to hold capillary moisture, because the 

 volume of soil above the free water level is made greater. 



How to Save Soil Moisture. Spaces between soil grains 

 serve as very crooked small tubes to conduct the lower soil 

 water toward the surface. Harrowing and cultivating the 



