FORMS OF SOIL WATER 



5 1 



growth of roots but was left unanswered at the 

 time (see page 14). The question was this: Of 

 what value is it to the farmer to know that roots 

 enter the soil to a depth of three to six feet? We 

 know that roots will not grow without air. We 

 also know that if the soil is full of free water 

 there is no air in it, and, therefore, roots of most 

 plants will not grow in it. It is, therefore, of interest 

 to the farmer to see that free water does not come 

 within at least three or four feet of the surface of the 

 soil so that the roots of his crops may have plenty of 

 well ventilated soil in which to develop. If there 

 is a tendency for free water to fill the soil a large 

 part of the time, the farmer can get rid of it by 

 draining the land. We get here a lesson for the 

 grower of house plants also. It is that we must 

 be careful that the soil in the pots or boxes in which 

 our plants are growing is always supplied with film 

 water and not wet and soggy with free water. 

 Water should not be left standing long in the sau- 

 cer under the pot of a growing plant. It is best to 

 water the pot from the top and let the surplus water 

 drain into the saucer and then empty it out. 



Which soils have the greatest capacity for film 

 water ? 



Experiment. Place in a tumbler or bottle one- 

 half pound of pebbles about the size of a pea or 

 bean ; pour a few drops of water on them and shake 

 them ; continue adding water and shaking them till 

 every pebble is covered with a film of water; let 

 any surplus water drain off. Then weigh again ; 



