260 ALFALFA FARMING IN AMERICA. 
sweet potato, an exceedingly troublesome pest in 
corn fields in the Middle States, is exterminated al- 
most completely when the land is put into alfalfa. 
So of many other troublesome things that might be 
mentioned. 
Weeds that Kill Alfalfa—There are weeds, how- 
ever, that get the best of the alfalfa. Quack or 
couch grass is one of these. This grass fills the soil 
with a dense mat of roots, each one a burrowing, 
creeping underground stem armed with a sharp 
point. Wherever it gets a good foothold it is usual- 
ly too much for the alfalfa and I am unable to out- 
line any good and easy system of destroying it. 
When it first appears upon the farm it should be 
fought and exterminated before it gets much foot- 
hold. It is possible that alfalfa could be sown in the 
fall and so stimulated with phosphorus that it would 
start very vigorously in spring and thus get ahead 
of the grass and smother it out. It is well worth 
experiment at any event. And it may be that by vig- 
orous use of the disk harrow, followed with the 
spring tooth harrow the roots could be so disturbed 
that they would give it up, and the alfalfa yet re- 
main practically unhurt. 
Kentucky blue grass is another grass that is too 
much for alfalfa. It creeps in and thickens up till 
after a time the alfalfa is seriously weakened. It is 
hardly worth while to fight so good a thing as blue 
grass though it can be torn out with a spring-tooth 
harrow. Blue grass does not usually come in before 
three or four years, and by that time it is well to 
