346 



BUI^LETIN 82 



arable cultivation and hoeing was necessary to hold back the Johnson 

 grass. By late fall of that year, however, only seedling Johnson grass 

 brought in by late summer irrigating w^ater, was in evidence. In 

 January and February, 1917, the land was plowed and a good deal of 

 leveling done. This necessitated frequent irrigations, and the soil was 

 at all times moist until after it had been planted to cotton in the mid- 

 dle of March. Very little Johnson grass emerged, however, and what 

 did appear was easily controlled by means of the cultivator and by 

 hoes. 



Fig. 9. — Wheat on Field G, May, 1916; no Johnson grass in sight. 

 FII^LD G ; SUMMER FALLOW. WINTER GR.\IN 



This 20-acre field was partially mowed and burned over in the fall 

 of 1915. In March of the following year it was plowed dry. The 

 Johnson grass soon came up again in abundance. The growth was 

 kept in check by means of a weeder until August when the field was 

 replowed. A three-inch rain early in September gave new life to the 

 almost exhausted plants and for a time the weed was nearly out of 

 control. In the middle of December the field was irrigated and sown 

 to wheat. A very heavy stand and luxuriant growth of wheat held 

 the Johnson grass in check until June, 1917, when the grain was 

 harvested. The ground being very dry, the growth of weeds fol- 

 lowing the removal of the wheat w^as not rapid but by September 



