FORAGE CROPS 



97 



Department of Agriculture at Washington has already conducted 

 a number of successful experiments along this line. The intro- 

 duction of these bacteria into the soil or plant is usually styled 

 inoculation. 



Methods of Inoculation. In general there are three ways of 

 inoculating the soil: 



1. By growing the same plant until the bacteria formerly present 

 in the soil adapt themselves to the host. 



2. By adding artificial cultures of the proper form of bacteria. 

 The Department of Agriculture at Washington is now distributing 

 liquid cultures in small hermet- 

 ically sealed tubes to farmers, 



with full instructions for increas- 

 ing and applying the bacteria. 



3. The third method is the 

 direct application of soil from a 

 field rich in nitrogen-bearing 

 bacteria at the rate of one hun- 

 dred pounds or more to the 

 acre. 



A few days before planting, 

 the fresh bacteria-laden earth 

 should be scattered over the 

 field and immediately harrowed 

 into the soil. Another method 

 is to flood the field, when pos- 

 sible, with water strongly in- 

 oculated with the bacteria. 



The Clovers. This group of 

 plants comprises a large number 

 of species, variously estimated 

 from one hundred and fifty to 

 three hundred; but the varieties 

 most generally known are: crimson clover (annual); red clover 

 (biennial); Alsike or Swedish clover (triennial); white clover 

 (perennial) . 



Clovers are profitable crops for forage purposes and at the same 

 time are valuable as soil improvers, because they enrich the soil 



PRAC. AGRICUL. 7 



Tubercles on clover roots. 



