44 A TEXT-BOOK OF GRASSES 



in spite of its good qualities, it is looked upon as a per- 

 nicious weed. It is not wise to introduce this species on 

 land that is free from it. A meadow should be a part of a 

 rotation, and Johnson-grass does not readily give up its 

 place to the following crop. When a permanent meadow 

 is desired, this grass, if its weedy habit be not taken into 

 consideration, is probably the best for the purpose in 

 those parts of the South, such as the black soil of central 

 Texas, where it reaches its highest development. It is 

 less satisfactory as a pasture-grass since, not well with- 

 standing grazing, the yield decreases after two or three 

 years. If a farm is already infested with Johnson-grass 

 it is well to take advantage of its useful qualities as a 

 meadow-grass. As this species tends to become sod-bound 

 in a few years owing to the rapid multiplication of root- 

 stocks, the field should be plowed every two or three years. 

 50. Eradication of Johnson-grass. — Johnson-grass can 

 be eradicated, but the process requires more care than in 

 the case of most weeds. Plowing in the fall with a turn- 

 ing plow, harrowing out and removing the rootstocks, 

 sowing the field to early- maturing grain, oats or rye, 

 cut for hay in the spring, and following with a cultivated 

 crop, will keep the grass in subjection. In the region where 

 Johnson-grass reaches its greatest development, alfalfa 

 also thrives. Hence an excellent method to utilize an 

 infested field is to sow alfalfa. This is done in the fall 

 after the field has been plowed and harrowed to remove 

 the rootstocks. The alfalfa soon smothers out most of 

 the Johnson-grass, and the hay is not injured by the pres- 

 ence of such of the latter as may remain. Johnson-grass 

 shares with sorghum the tendency to poison stock through 

 the production, under certain conditions, of hydrocyanic 

 acid. (See Farmers' Bulletin No. 279.) 



