CHAPTER XXVI. 



WEEDS. 



Soil culture is an active warfare against weeds. This 

 warfare occupies a great portion of the time of every 

 tiller of the soil. A million of weeds may grow on an 

 acre of land during a single season. 



Definition. — In ordinary usage any homely plant 

 is called a weed. The ox-eye daisy is universally con- 

 ceded to be a comely flower; the tomato a homely 

 plant. Emerson once said in his quaint way that a 

 weed was a plant, the virtue of which had not yet been 

 discovered. The roots of burdocks have medicinal 

 properties. Parsnips, mustard and hemp are examples 

 of cultivated plants which are pernicious weeds under 

 some circumstances. 



Perhaps the statement that a weed is a plant out of 

 place is the most satisfactory definition of the term as 

 we ordinarily use it. The plant is not out of place in 

 nature, but out of place so far as man is concerned; in 

 the way, as it were. 



How Injurious^. — Weeds are injurious in several 

 ways. 



1. They consume plant food. Every piece of land 

 has a limited quantity of available plant food. If part is 

 consumed by the growth of weeds, the amount of food 

 is thereby restricted for the cultivated crop. 



It has been found that a ton of air dry pig- weed, 

 Amaranttis retrofexus^ would contain as much phos- 

 phoric acid, twice as much nitrogen, and nearly five 

 times as much potash as a ton of ordinary manure. A 



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