114 The Principles of Fruit-growing 



2. It improves the chemical condition of the soil: 



Catches and holds some of the leaching nitrates; 



Adds humus; 



Renders plant-foods available; 



Appropriates nitrogen, if it is leguminous. 



As a rule, crops grown for cover alone should be sown 

 not earlier than midsummer. The most thorough tillage 

 can then be given early in the season, and the benefits of 

 the cover may be secured for early autumn, winter and 

 spring. It is usually advisable to grow a crop that answers 



Fig. 23. Plowing under a cover-crop in spring, 



for both cover and green manure, although it is possible 

 to make the soil too nitrogenous for some fruits by the 

 extravagant use of the legumes. It will also be observed, 

 from the above enumeration of the benefits arising from 

 cover-crops, that crops killed by the winter may still be 



