226 



WEEDS 



Results of spraying with iron sulfate Continued 



With the exception of the application to the poison ivy, the iron 

 sulfate was applied as a 20 per cent solution, using it at the rate of 

 100 to 150 pounds per acre. 



At the South Dakota Station the following weeds were entirely killed 

 by the use of iron sulfate : 



Wild mustard (Brassica arvensis) ; ragweed (Ambrosia artemiswfolia) ; 

 king-head or greater ragweed (Ambrosia trifida) ; bindweed (Convol- 

 vulus Sepium) ; marsh elder (Iva xanthifolia) ; milkweed (Asclepias 

 sp.) ; pepper-grass (Lepidium Virginicum) ; pigweed (Amarantus sp.) ; 

 sweet clover (Melilotus alba and M. officinalis). Those that were 

 more or less badly injured : Russian thistle (Salsola Kali) ; sunflower 

 (Helianthus sp.) ; dandelion; dock (Rumex crispus) ; thistle (Carduus) 

 sp.) ; white clover (Trifolium repens) ; red clover (Trifolium pratense) ; 

 alfalfa (Medicago saliva). The following were but slightly injured: 

 plantain (Plantago major) ; sheep sorrel (Oxalis violacea) ; prairie 

 rose; lamb's quarters (Chenopodium album). Grasses in general, 

 including the grains (wheat, oats, corn, barley, and speltz were sprayed 

 in our experiments) were none of them seriously injured. 



According to the Ohio Station, salt has thus far proved the best spray 

 tested for Canada thistle, poison ivy, yarrow, and horse-nettle. In the 



