258 GRASSES AND HOW TO GROW THEM. 



breathing thus would doubtless involve great labor, but it 

 should prove effective. It has been claimed that pastur- 

 ing will eradicate it, but the claim is not well supported 

 by facts. Close and constant pasturing will greatly de- 

 crease it, but some of the plants remain ready to in- 

 crease and take possession should the land be again cul- 

 tivated. It is also claimed that swine will eradicate 

 it if allowed to dig up its roots for the purpose of feed- 

 ing on them. To accomplish this, however, may require 

 several seasons, and though successful is only applica- 

 ble to limited areas. 



But it is easily possible to adopt measures that will 

 prevent it from gaining a foothold on a farm on which 

 it has not yet appeared, and from spreading on one 

 where it may be growing. 



The chief agencies in spreading it are the following: 



1. Carrying portions of the root to new centers of dis- 

 tribution by means of the plow, harrow, cultivator or 

 other implements of tillage. 2. Sowing the seeds along 

 with those of gi-ain amid which Johnson grass may have 

 matured. 3. Seeds scattering from plants that may 

 have grown up and matured in a crop of grain or in 

 corn or cotton after these have been laid by. 4. In the 

 droppings of cattle that may have eaten the seed. The 

 last named is one of the most common mediums by which 

 the seed is carried. 



The nreventive measures are : 1. Exercise such care 

 in tilling land where the grass already exists in certain 

 places as will prevent carrying the roots to new centres. 



2. Exercise even greater care in the purchase of seed 

 grain or in cleaning the same. 3. Prevent seed from 



