ORGANIC MATTER 



because nitrogen is unstable in character and has 

 escaped from all agricultural land in vast amounts 

 during past ages. 



Profitable farming is based upon the great fact 

 that we have one class of plants which can use 

 bacteria to work over the nitrogen of the air into 

 a form available for their use, and the store of 

 nitrogen thus gained can be added to the soil's 

 supply for future crops. These plants, known as 

 legumes, embrace the clovers, alfalfa, the vetches, 

 peas, beans, and many others of less value. They 

 not only provide the organic matter so much 

 needed by all thin soils, but at the same time they 

 are the means of adding to the soil large amounts 

 of the one element of plant-food that is most 

 costly, most unstable, and most deficient in poor 

 soils. Their ability to secure nitrogen for their 

 own growth in poor land also is a prime considera- 

 tion in their selection for soil improvement, assur- 

 ing a supply of organic matter where otherwise 

 partial failure would occur. 



Storing Nitrogen. Man needs protection from 

 his own greed, and nature's checks are his salva- 

 tion. An illustration is afforded in the case of 

 legumes grown for the maintenance of soil fer- 

 tility. The clovers and some other legumes are 



[39] 



