WEEDS OP THE FIELD 



261 



depth most favorable for quick and early growth. Certain 

 plants, like buckwheat, that grow up quickly, smothering the 

 weeds, are often used to clean a weedy field. Potatoes, on 

 the contrary, being slow to appear above ground, are certain 

 to be beaten in the occupation of the soil by many weeds. 

 So they are often tilled just before they appear above the 

 ground. The weed seedlings are easily killed when little. 

 Tillage breaks their mooring in the soil. The weeds are thus 



FIG. 100. Sun prints of weeds, showing the extent to which they shade 

 the ground, i , paint-brush ; 2, moth-mullein; 3, evening primrose; 

 4, creeping spurge; 5, door- weed or goose-grass. 



given a second setback, while the stout potato shoots come 

 along uninjured. The farmer ought to be something of a 

 naturalist, for his success in handling plants must needs be 

 based on observations of their habits, their powers, and their 

 requirements. 



The farmer might save himself much labor of exterminating 

 weeds in his fields, if he was more careful not to encourage 

 their growth outside the fields. He provides too many 

 reserves for them in roadside and barnyard and fence-row. 

 Enormous crops of weed seeds are matured in such places. 

 It is not enough to keep the fields clean. The fence-row 

 may be a source of reinfestation. A clean field may 



