68 WILSON & TOOMLU FKKTILIZKR COMPANY 



nitrogen compounds in exchange for sugar and other 

 carbohydrates manufactured in the green leaves of their 

 hosts. The bacteria enter tender roots and multiply 

 rapidly. As the colony of bacteria grows the root cell 

 expands, forming a ^nodule." These nodules vary in 

 shape according to the host, but careful examination will 

 prevent anyone from confusing them with the distorted 

 roots caused by "root knot." 



Legumes The hosts of nitrogen-fixing bacteria which 

 are of profit to the grower are called "legumes," and 

 those which particularly interest us here in Florida are 

 the cowpea, velvet bean, and beggar weed. These all, but 

 particularly the first two, grow on new land, and by 

 their extensive root system do much toward bringing the 

 soil into good tilth. The stems and leaves have a high 

 nitrogen content, and enrich the soil by this as well as 

 by the addition of humus matter if the crops are mowed 

 and dried, and then disked into the land ; or if they are 

 kept for hay or used for grazing they make most valuable 

 stock food. Under suitable conditions the bacteria will 

 supply at least two-thirds of the nitrogen that is in the 

 tops of the plant and over half of that in the nodules on 

 the roots. In other words, they will take from the air 

 enough nitrogen to make the crop and to leave the soil 

 richer in this element than it was before the crop was 

 planted. 



Besides proper air and water content, secured by tilth 

 and drainage, there are three main factors in making a 

 crop of legumes profitable: 



