72 AGRICULTURE. 



total weight. Usually, however, there is not very much food 

 just ready for the plants to take up. If there are weeds growing 

 with the crops there will be less food for the latter. Some of 

 the weeds are heavy feeders. 



3rd. Many weeds have broad, spreading leaves which cover 

 over the tender young plants of our crops, and by shutting off 

 the sunlight smother them out. This may be seen best in a 

 pasture or on a lawn (dandelions and plantains for example). 



4th. Weeds draw moisture from the soil through the roots 

 and give it off through the leaves; weeds help to dry up the soil. 



5th. Weeds are feeding and breeding grounds for insects and 

 they assist in the spread of many crop diseases. 



6th. Frequently weeds are poisonous to stock, they taint the 

 milk, or they destroy wool. 



yth. Weeds offend the eye and degrade the taste for farming. 



Because of these facts every weed should be considered an 

 intruder, a thief, and a murderer of other crops, and every 

 farmer should try to keep his soil as clean as possible. To 

 succeed it will be necessary to know as far as possible the 

 nature and the mode of growth of the weeds. 



NATURE OF WEEDS. Wild mustard, lamb's quarters, shep- 

 herd's purse, and wild oats form seed the first season ; the 

 plants then die and the seeds are ready to sprout the next 

 season. Such weeds are annuals. They generally have fibrous 

 roots and produce a large number of seeds. The seeds in 

 many cases are oily and are covered with hard coatings ; they 

 are able to sprout after lying in the ground a long time, even for 

 many years. Thus the seeds may be plowed under deep and 

 the next year the field may appear clean. After a couple of 

 years they are brought up by plowing and cultivation, and once 

 more the field will appear weedy and dirty. If the weeds are 

 cut off before the seeds form they will be destroyed, for they 

 cannot survive or reproduce unless seeds are formed. 



