86 A MANUAL OF FARM GRASSES 



Cotton Belt. .While best adapted to meadows, it can 

 be used for pasture but does not well withstand the 

 trampling of stock. Furthermore there has been some 

 trouble from the poisoning of stock as the plants under 

 certain conditions may produce hydrocyanic acid as do 

 sorghum and its allies. Johnson grass is closely related 

 to the sorghums, belonging to the same genus, hence 

 might be expected to produce the same poison. 



Notwithstanding the fact that Johnson grass gives 

 excellent results as a meadow grass, it becomes under 

 certain conditions an extremely pestiferous weed. This 

 is due to its aggressiveness. After once occupying a 

 field, it is eradicated with great difficulty. For this 

 reason, many farmers hesitate to plant it or allow it to 

 obtain a foothold upon their places. In another para- 

 graph will be. given directions for eradicating this grass 

 when a meadow is needed for other purposes. 



Eradication of Johnson Grass. — The eradication of 

 Johnson grass depends upon suppressing the growth of 

 the rootstocks.* Where cultural methods can be used 

 it is recommended that the infested field be turned into a 

 meadow or pasture and that the grass be kept closely 

 cropped, either by grazing animals upon it or by mowing 

 it for one or more seasons. If the plants are not allowed 

 to blossom the rootstock development is reduced and 

 what is produced remains near the surface. After the 

 sod has remained undisturbed for a year the soil is 

 plowed shallow, thus throwing up most of the rootstocks. 



* A full account of the experiments with Johnson grass and the 

 different methods tried in Texas for its eradication will be found in 

 Farmers' Bulletin 279 (U. S. Dept. Agr.). 



