ROTATION OF CROPS 2/5 



weeds were permitted to grow and no cultivation was 

 given, gave a yield of but seventeen bushels of shelled 

 corn per acre. Why this difference? The old explanation 

 is: weeds must be kept away else they will get 

 water and plant food that should go to the cultivated 

 crop. 



And now we are told that weeds crowd the root terri- 

 tory of the cultivated plant, and that they produce a toxic 

 effect in the soil, both being especially distasteful or hate- 

 ful to the more refined and delicate and tender crop. Be 

 the cause of enmity between cultivated crops and weeds 

 what it may, every bit of evidence points against any 

 favor being shown weeds. The whole trend of effort is 

 toward the banishment of weeds. 



Do plant roots throw off wastes? A new theory has 

 been advanced within the last two or three years, one 

 that claims that all plants excrete waste products through 

 their roots. According to it, no plant should be grown 

 on a soil for any great length of time, else the plant 

 excretions will accumulate in the soil faster than the soil 

 can rid itself of them. Time is needed for making away 

 with the excretions of the old plant or crop. When this 

 is done, the soil is made more sanitary and more congenial 

 to the new crop. 



In this connection, then, a manure or fertilizer or other 

 material that helps the soil is used, not because it supplies 

 plant food, but because it assists in renovating the soil of 

 waste products and in securing a more sanitary condition 

 of the soil. Hence, fertilizers and manures become soil 

 helpers by renovating and removing the excreta of the 

 previously grown crop. 



Now, it does not make much difference in just what 

 direction you must go for the true explanation of poor 

 soils; but whether you take one or the other, you find 



