ECONOMICS OF WEEDS 57 



season in corn and potato fields require hand pulling 

 because tillage then would injure the crops, and often 

 even hand pulling involves some loss through the disturb- 

 ance cf the roots. 



The most famous definition of a weed is that it is a plant 

 out of place. In soil devoted to a crop of a given kind, 

 the presence even of other crop plants is generally not 

 wanted. So under some circumstances our ordinary grains, 

 vegetables, and flowers may appear as weeds. In fact, in 

 the case of the flowers many weeds have originated as gar- 

 den escapes, and there is always danger that new ones may 

 be so introduced. 



THE STRUGGLE FOR LIFE 



It is well known that the most troublesome weeds are 

 those best equipped in the struggle for life. By being 

 able to grow quickly where other plants grow slowly, by 

 producing many seeds where other plants produce few 

 seeds, or by being able to do anything else that enables it 

 to get on in the world better than* its neighbors a plant 

 has an advantage that tends to make it a weed. There is 

 always an intense struggle for soil, moisture, air, and sun- 

 light, and the plants best fitted to take advantage of con- 

 ditions existing at a given time and place will win. It is 

 the farmer's business so to plan his operations that the 

 crops he sows will have the advantage of all weedy in- 

 truders. 



One of the chief advantages that most weeds have in 

 the struggle for life lies in the production of great num- 

 bers of seeds. This is well shown in the following esti- 

 mates by the Kansas Experiment Station of the number of 

 seeds ripened by one plant, made after careful studies of 

 each species : 



