SECTION XXXI. WEEDS 



A WEED is simply a plant growing where it is not wanted. 

 Hence a kind of plant that is useful in some fields may be 

 a weed in other fields because it interferes with the growth 

 of some crop. Among the plants that are sometimes 

 weeds and at other times useful are Johnson grass, crab 

 grass, and beggarweed. 



How weeds injure the farmer. Weeds are injurious 

 because (i) they use plant-food and fertilizer needed by 

 the more valuable crop plants; (2) they rob the culti- 

 vated plants of water by taking up the moisture of the 

 soil for their own use; (3) they greatly increase the ex- 

 pense of cultivating the crops. Weeds are robber plants 

 and must not be allowed to become large and strong, for 

 then the crop will be ruined. Poor farmers cultivate their 

 crops only as much as weeds compel them to, but good 

 farmers cultivate the ground when there are no weeds, so 

 as to keep the lower layers of the soil moist 



Study the habits of weeds. To get rid of weeds in the 

 easiest and cheapest way, study their habits. First make 

 sure whether they are annuals. If they are annuals, such 

 as crab grass, foxtail, ragweeds, and bitterweed, all that 

 has to be done is to keep them from maturing seed. If 

 they are biennials, like sweet clover, no seeds should be 

 allowed to form for two years. If they are perennials, 

 ' like Johnson grass, nut grass, thistles, and dock, the forma- 



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