IMPROVEMENT DUE TO 



(e) The preparation of soil for them, as well as the growth of 

 cover crops, will tend to check the growth of weeds. 



Improvement Due to Green Manuring. 1. Probably the chief 

 benefit following the use of green manure is the addition of humus. 

 This is often the most satisfactory way of adding humus to the 

 soil, particularly on farms where there are only a few animals. 

 During the decay of the green crop a number of changes take 

 place which are in themselves directly beneficial. 



2. During the growth of the green manure crop its roots gather 



FIG. 75. Plowing under a green manure crop of rye, which was sown the fall before. (Pro- 

 ductive Farm Crops.) 



plant food which might otherwise be wasted, or not be available 

 for use of other crops. This accumulation of plant food in roots, 

 stems and leaves becomes quickly available after the crop begins 

 to decay, and helps the crop which is to follow. The growth of 

 such green manure crops at off-seasons, when the main crops are 

 not occupying the soil, conserves much plant food which would 

 otherwise be lost by leaching or in some other way. Such losses 

 cannot be prevented by any other practical method. The rapidity 

 with which plant food is liberated from the green manure crop 

 after decay begins will depend upon the temperature of the soil 



