AMONG SCHOOL GARDENS 



moisture. In such a soil, the nitrates are apt to 

 be lacking; they are so soluble they wash away. 

 Plants must have nitrogen, and their root fibers 

 will accept it only in the form of nitrates in solu- 

 tion. One whole class of plants, however, the 

 leguminosae, of which the pea and bean and the 

 clover are typical are an exception, for they 

 possess the unique characteristic of bearing on 

 their rootlets nodules in which dwell colonies of 

 bacteria that have the power to take free nitrogen 

 from the air and convert it into nitrates. It is 

 well to remember that white beans and sand peas 

 will grow in the poorest of soils, and that crimson 

 clover is a good cover crop.* Therefore, if you 

 have almost to construct a good soil, plant beans, 

 and later turn them in.f Buckwheat is a good 

 crop for poor soils. Crops with tap roots help 

 to keep the soil open. 



The prime object is to make a soil that shall be 

 fertile, fme and friable, — in one word ''mellow," — 

 and further to so control and utilize the natural 

 water supply in the earth that the chemical com- 

 pounds in the soil shall be held in suspension 

 in the water films. This is absolutely essential 

 where an artificial water supply, by hydrant or 

 irrigation, is not possible. In aiming for a fine 



♦The reason for a cover crop is three-fold: to keep soils from 

 washing away (as down hillsides); to keep their soluble foods from 

 leaching out; and to add enrichment when used as green fertilizers. 



t In localities adapted to them cow-peas are excellent for this 

 purpose. 



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