CULTIVATION. 217 



many of the seeds contained will be killed by the 

 heat of fermentation. 



By hoeing, or otherwise destroying growing weeds 

 before they mature their seeds ; and 



By keeping the soil in the best chemical condition. 



This last point is one of much importance. It 

 is well known that soils deficient in potash will 

 naturally produce one kind of plants, while soils 

 deficient in phosphoric acid will produce plants 

 of another species, etc. Many soils produce certain 

 weeds which would not grow on them spontaneously 

 if they were fitted for the growth of better plants. 

 It is also believed that those weeds, which naturally 

 grow on the most fertile soils, are the ones most 

 easil}^ destroyed. There are exceptions (of which 

 the Thistle is one), but this is given as a general rule. 



By careful attention to the foregoing points, 

 weeds may be kept from increasing, while those 

 already in the soil may be eradicated in various 

 ways, chiefly by mechanical means, such as hoeing, 

 plowing, etc. 



Prof. Mapes used to say, and experience often 

 shows, that six bushels of salt annually sown broad- 

 east over each acre of land, will destroy very manj 

 weeds, as well as grubs and worms. 



The common hoe is a very imperfect tool for the 

 purpose of removing weeds, as it prepares a better 

 Boil for, and replants in a position to grow, nearly as 

 many weeds as it destroys. 



The scuffle-hoe (or push-hoe) is much more effec- 

 tive, as, when worked by a man walking backward, 



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