106 Practical Farming 



cropping and annual dependence upon commercial fer- 

 tilizers. But from whatever cause, it is found that this 

 acidity is fatal to the growth of the soil bacteria that 

 carry on the process of transforming organic nitrogen 

 into nitrates. In the one case, while there is an abund- 

 ance of the organic matter for their use, the acidity of the 

 soil is detrimental to their growth. In the other case, 

 they have simply been starved out by the lack of their 

 food. The acidity in the soil is also fatal to the bacteria 

 that live on the roots of clover and other legumes and 

 enable them to acquire the free nitrogen from the air. In 

 either case, then, lime is the remedy by which the alka- 

 linity of the soil is restored. 



Lime promotes the nitrification of organic matter in 

 the soil, not only through its effect in sweetening the soil 

 and making conditions more favorable to the nitrifying 

 bacteria, but also in another way. It is directly helpful 

 to the bacteria; for these microscopic plants, having no 

 green leaves, are not able, Hke plants with green leaves, 

 to get carbon from the air; but they have the power that 

 no green plant has, to get the carbon needed from a 

 chemical combination. They get carbon from the car- 

 bonate of Hme in the soil, and in this way their growth 

 and activity is greatly increased. It is found, therefore, 

 that lime has an important bearing on the formation of 

 nitrates in the soil, for the use of crops with green leaves 

 which take nitrogen from the soil only in the form of a 

 nitrate of lime or potash or whatever base may be 

 present in the soil. The bacteria on the legumes get 

 what they need directly from their host plants, and 

 though they are parasitic to this extent they return more 



