EXTERMINATION OF WEEDS 97 



and benefited the grass it also killed the clover, the rea- 

 son for this destruction being due to the power of the 

 salt to draw the moisture from the plant. It was found 

 that dry salt killed greater quantities of grass than when 

 wet. 



Prof. L. R. Jones and A. W. Edson in some experi- 

 ments made in 1900, concluded that common salt was 

 less efficacious for miscellaneous weed killing than arse- 

 nate of sodium, carbolic acid or sulphuric acid> but is the 

 best chemical for the destruction of orange hawkweed. 



We found that dry salt in concentrated form will kill 

 quack grass when applied at the rate of about 600 barrels 

 per acre, but close to the edges of the patch, quack grass, 

 treated thus, sprouted out as before. A much smaller 

 quantity than this might be used, but even in considerably 

 less amounts the salt renders the soil unfit for the growth 

 of agricultural crops, and cannot, therefore, be recom- 

 mended as a weed exterminator, especially for quack 

 grass. Professor Bolley has found salt effective against 

 kinghead and mustard at the rate of one-third barrel of 

 salt to 52 gallons of water. 



Carbolic Acid. This well-known germicide has also 

 been us;ed to kill weeds. Jones found it to be very quick 

 in action, but observed that it does not penetrate into the 

 soil deeply enough to kill all the root, hence the treated 

 plants invariably recovered. 



An experiment was made with carbolic acid on quack 

 grass, using the acid at the rate t>f 2% barrels to the 

 acre, two applications being made, one on October loth, 

 and a second on October 26th. The growth of the quack 

 grass had been very rank and vigorous and while it was 

 temporarily checked by the carbolic acid, the roots were 

 not destroyed. Therefore, we cannot recommend the 

 use of carbolic acid for treating quack grass. Other 

 weeds, especially annuals, were affected in a similar 

 manner, but did not recover as the perennial weeds did. 



