136 SOILS 



when heat is applied to the soil: the nitrogen content 

 remains unchanged. On the other hand, the same soil 

 shows an increase in nitrogen if untreated by chemicals, 

 heat or other influences that endanger or destroy the 

 floral life therein contained. 



While safe enough evidence shows that soils do have 

 the power of fixing nitrogen, it is to a very limited de- 

 gree, only ; it is too little, in fact, to base upon it a ration- 

 al system of farming. 



Early experiments suggested the advisability of culti- 

 vating these friendly bacteria (whose work it is to cap- 

 ture atmospheric nitrogen) and so treat them that they 

 might work more effectively, at least to send them into 

 soils where they had not gone previously, thus giving 

 them unusual work to do in all soils, in all sections. 

 Some European investigators went so far as to prepare 

 a culture that should be able to do the work. 



A better way was found, however. It is this : Get the 

 right conditions in the soil that permit a favorable de- 

 velopment of these bacterial germs rather than inoculate 

 the soil, since the germs are usually present in the soil 

 and inactive only because their environments are against 

 them. To make them active, give to the soil every influ- 

 ence that shall stimulate the bacteria to vigorous activity, 

 that shall make them healthy and robust, even eager to 

 secure the nitrogen of the air and to fix it in the free soils 

 of the fields. Soil culture, thorough tillage, and soil ma- 

 nipulation, therefore, are to be preferred, in fact, these 

 are indispensable, if the helpful cooperation of these soil 

 workers is to be had. 



More is needed: let legumes help. But this help is all 

 too little. The farmer must have assistance more abun- 

 dantly and more laden with good results. This may be 

 obtained by cooperation with the legumes. They act 



