Weed Eradication by Spraying with 

 Solutions of Sulphate of Iron. 



THE IDEA of eradicating weeds by spraying fields with 

 solutions of chemicals originated in France and was 

 the result of observing that when grape vines were 

 sprayed with solution of sulphate of copper and the spray 

 accidently fell upon the common field mustard this plant was 

 killed. This observation was made by Bonnet.f 



M. Brandin demonstrated in field experiments the correct- 

 ness of Bonnet's observation. M. Mantin in Pas de Calais 

 made the claim that Sulphate of Iron gave better results than 

 the sulphate of copper. 



M. Duclos, Director of the Agricultural Station in Meaux, 

 investigated the subject and compared the action of copper 

 ' salts with Sulphate of Iron on field mustard, and found that a 

 l# per cent nitrate of copper worked the best, the mustard 

 being destroyed while the grain remained unaffected. He 

 showed that a 20 per cent solution of Sulphate of Iron com- 

 pletely eradicated wild mustard without injury to the grain, 

 and that with a 40 per cent solution the grain was but slightly 

 injured. 



Experimenting with sulphate of copper and sulphuric 

 acid in equal parts (2J^ per cent solution), he found the mix- 

 ture destroyed wild mustard and affected grain but slightly. 

 That a 5 per cent solution of sulphate of copper alone 

 destroyed wild mustard completely without injury to the 

 grain ; that a 10 per cent solution destroyed wild mustard 

 completely and injured grain but slightly ; that a 20 per cent 

 solution while destroying the mustard injured the grain badly. 



Finally M. Duclos recommends the following solutions, 

 namely: l% kgo. nitrate of copper to 1 hectolitre water (2% 

 lbs. to 22 galls.); or, 30 kgo. of Sulphate of Iron to 1 hecto- 

 litre water (66 lbs. to 22 galls.); or, 2^ kgo. sulphate of copper, 



f BONNET, L. — Le cuivre contre les ravenelles et les senes. Cornice agricole de Reims, 

 seance 12 Dec. 1896. Journal de Brabant-Hainaut,i8a7, p. 521. 



