FIELD EXPERIMENTS. 4I 



this burden of buying seed oats, purchase ordinary feed oats, 

 which as a rule are loaded with mustard seed. Thus the 

 farmer who buys cheap seed oats encounters weed seeds in 

 both harvesting his crop and in seeding his land. 



Extensive studies have been made of this plant and methods 

 of control in France and in Germany, particularly under the 

 auspices of the Germ.an Agricultural Society by Gustav Schultz. 



Using this work of Schultz as a basis in the years 1905 to 

 1908 inclusive the Maine Agricultural Experiment Station 

 carried on extensive experiments in an endeavor to kill wild 

 mustard in sown grain crops by spraying with iron sulphate and 

 copper sulphate. It was found that it was perfectly possible by 

 spraying with iron sulphate to rid the field of wild mustard at a 

 moderate cost. 



Experiments on wild radish were not so successful. Both 

 French and German experimentors, however, claim to have 

 killed wild radish by a 20 per cent solution of iron sulphate. 

 In their published results, however, they use the common names 

 and rarely distinguish between the wild radish and the wild 

 mustard in their field experiments. 



In 1912 further trials were made by this Station upon wild 

 radish and wild turnip. It was found possible to completely 

 exterminate wild turnip by spraying with sulphate of iron even 

 after the plants had obtained their sixth leaf. With wild radish 

 the plant was controlled by spraying when it had only shown 

 its fourth leaf. The results of these experiments indicate that 

 it is perfectly possible to handle, without injury to the grain 

 crop, wild mustard, wild radish and wild turnip wherever they 

 infest grain fields. While a single spraying may not kill every 

 plant it will so reduce the number that by a sm.all amount of 

 work in hand pulling it will be easily possible to free a grain 

 field absolutely from these pests. 



One of the experiments in 1912 was carried on on a farm 

 where in 191 1 practically 25 per cent of the threshed yield was 

 mustard seed. In this particular instance it was chiefly the 

 wild turnip. In an experiment on this farm where the wild 

 turnip was slow in starting so that the oats were well above it, 

 a single spraying applied when the wild turnip plants were in 

 the sixth leaf resulted in killing most of them, and where two 

 sprayings were applied, (the second three days later, at which 



