56 



is tied a piece of muslin or fine wire gauze. From a graduated 

 glass pour water slowly upon each sample until the water begins to 

 drain from the bottom of the tube. In this way it can be shown 

 which soil has the greater power of holding moisture. Both samples 

 should then be set away to dry. By weighing the samples each day 

 it can be determined which soil has the greater power of retaining 

 moisture. This experiment can be conducted not only with sand 

 and humus, but with clay, loam, gravel and all other kinds of soil. 



Experiinfient No. 7. — A finely pulverized soil will hold more 

 film-moisture than a cloddy soil. To illustrate the importance of 

 texture as related to moisture, soil should be secured which is cloddy 

 or lumpy. One tube should be filled as heretofore described (Exp. 

 No. 6) with the lumpy soil, and the other tube with the fine soil 

 which results from pulverizing the lumps, equal weights of soil 

 being used in each case. From a graduated glass pour water upon 

 each sample until the drainage begins from the bottom. Notice 

 which soil possesses greater power of absorbing moisture. Put the 

 samples away to dry, and by carefully weighing each day it can be 

 determined which soil dries out most readily. 



The prudent farmer will take measures to prevent the escape of 

 this moisture into the air. All the film- moisture (on the soil parti- 

 cles) needs to be carefully conserved or saved, for the plants will 

 need very large amounts of moisture before they mature, and they 

 can draw their supply only from this film-moisture. We can again 

 apply the lesson learned in the woods. The soil is there always 

 moist ; the leaves form a cover or blanket which prevents the evapo- 

 ration of moisture. Underneath an old plank or board the soil will 

 be found moist. If w^e can break the connection between the soil 

 and the air we can check the escape of moisture. A layer of straw 

 over the soil will serve to prevent the loss of moisture. But a whole 

 field cannot be thus covered. It has been found that by keeping 

 the surface soil loose, say about three inches of the top soil, it can 

 be made to act as a blanket or covering for the soil underneath. 

 "While this top layer may become as dry as dust, yet it prevents the 

 escape by evaporation of moisture from below. It is a matter of 

 common observation that if tracks are made across a freshly culci- 



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