LIMING OF SOIL 109 



green manure and by the action of certain chemical fertilizers. 

 Few farm crops thrive in sour soils. The action of lime is there- 

 fore beneficial to all such crops. 



For clover, alfalfa and most other members of the legume 

 family, lime seems to act as a direct plant food, supplying a 

 material actually used in the growth of the plant (Fig. 78). 



When lime is applied after the plowing under of green manures 

 or other vegetable matter, decay takes place much more rapidly. 



The presence of lime in the soil makes conditions more favor- 

 able for the rapid development and growth of bacteria. This is 

 particularly true of those forms of bacteria which aid legumes in 

 acquiring nitrogen from the air. It is doubtless also helpful to 

 other kinds of soil organisms. 



FIG. 78. Liming the soil improves the growth of leguminous crops. The large yield was 

 from the limed plot. The other was unlimed. (U. S. D. A.) 



Its general action upon sand, clay and organic matter helps 

 in the liberation of plant food in all soils. This may in some cases 

 be more rapid than the growing crop can use the food thus liberated. 

 If some form of lime is applied, the action of which is not too rapid, 

 the growing crop may use the liberated food without appreciable 

 loss. 



The combined use of green manure, or other vegetable matter, 

 with the application of lime, causes the most favorable action in 

 soils for the production of large crops. Much activity is set up 

 within the soil, making the conditions most favorable. By the 

 use of lime the soil will produce much larger crops of alfalfa, clover 

 and other legumes. These in turn have their beneficial effects 

 upon the soil, and make it possible for the owner to carry the soil 

 improvement to the utmost limit. It is often found that the 



