CONCLUSION 303 



phoric acid and the salts of potash. There 

 is no quarrel over the practice. 



One point, however, stands out clearly, and 

 that is that the use of minerals as fertilizers, 

 whatever may be their effect, is little under- 

 stood by either side of the controversy, and a 

 great deal of money is being wasted by their 

 indiscriminate use. The fact that in a long 

 series of tests ninety-six soils out of every one 

 hundred responded better to organic manures 

 and lime than to phosphoric acid and potash, 

 while only four soils out of every one hundred 

 favored the minerals, should indicate to the 

 farmer that the evidence at the present time 

 is overwhelmingly in favor of the organic 

 manures. 



Hopkins, the most advanced of the ad- 

 herents to the theory of Liebig, says the farmer 

 need add only phosphoric acid if he practice 

 the accepted system of farming. The organic 

 manures and the microflora and fauna of the 

 soil, properly controlled, provide nitrogen; 

 and potash, except in rare instances, such as 

 some reclaimed swamp soils, is not wanting. 

 Yet, if the farmer seek among the records, he 

 finds plenty of data which seems to indicate 

 potash, as, for instance, in coloring fruit. 



