SOO THE SOILS AND CBOPS OF THE FARM. 



apt to be introduced in this way. Every farmer should 

 avoid as much as possible getting grass and clover or 

 even other seeds from a distance, or from unknovirn 

 sources. Your neighbors' seeds may contain weed 

 seeds, but they are not so apt to contain those that are 

 not already on your farm. 



The importance of a few seeds is not realized unless 

 their prolificacy is fully understood. The number is 

 usually under-estimated. Lazenby found in a sample 

 of seed wheat, nine thousand seeds of chess per 

 bushel. If a bushel of wheat contains one pound of 

 chess, it would contain as many seeds of chess as of 

 wheat. 



Adaptability. — The adaptability of plants in their 

 struggle for existence often prevents their extermina- 

 tion. A fox-tail plant (Setaria) has been known to 

 ripen seed at two inches in height (one to two feet is 

 a common height) by being surrounded by other 

 plants. 



A chess plant, standing alone, may easily produce 

 four thousand seeds. When sown like small grain, it 

 will hardly produce one hundred fold. When subdued 

 by the generally stronger growing wheat probably 

 much less will be produced. 



When prairie lands were broken up, far away from 

 any other cultivated area, the striking horse weed 

 (Erigeron canadense) often sprang up in profusion. 

 This weed had not been seen there previously. The 

 only explanation that can be given is that the plants 

 were growing there, but were so kept in check by the 

 other vegetation as to be passed unnoticed, just as 

 would be the fox-tail above mentioned. 



Many weeds seed when they are very small. Pur- 



