THE WASTE AND COKSERVATION OF PLANT FOOD.i 



By Harvey W. Wiley. 



One of the greatest of tbe practical problems presented for solution 

 by agricultural chemistry is the conservation of plant food. With an 

 abundance of plant food and a favoring climate, it is difficult to place a 

 limit to the power of the earth for supporting life. We have read much 

 in political economy of the limit of subsistence, and one bold philoso- 

 pher has based a theory of the limitation of the number of human 

 beings upon the earth on the insufficiency of the earth to support a 

 greater number. Happily, however, the Malthusian philosophy was 

 promulgated before the days of that great agricultural renaissance 

 which has been brought about chietly through the efforts of experimen- 

 tal agricultural chemistry. I am not so blinded by the a(;hievements 

 of agricultural chemistry as to deny to many other branches of science 

 an important and, in many cases, necessary influence in this develop- 

 ment of agricultural science; but I think every candid man will admit 

 that in this development chemistry has always taken the front rank 

 and led the way. This is preeminently true of the investigations into 

 the nature and extent of the plant food available on the surface of the 

 earth. 



In this country, owing to the great stores of wealth which the past 

 had accunuilated in the soil, it is only within recent years that the 

 question of the supply of plant food has assumed any practical impor- 

 tance. As long as there were virgin fields at the disposal of the agri- 

 cultural rapist, the conservation and restoration of exhausted fields 

 were of little consequence. The result has been that the wealth of 

 hundreds or i)erhaps thousands of years slowly stored in the soil has 

 been jooured forth in a century, not only for the enrichment of this 

 country but for the benefit of all countries. Unfortunately, or fortu- 

 nately, these stores are now practically explored and there is little left 

 in this land of virgin fertility to tempt the farmer to new conquests. 

 Not only have these stores of plant food been utilized but, much to the 

 discredit of the American farmer, they have been wasted. The mark 

 of good agriculture is to see fields yielding annually good returns and 



'Retiring address of the president of the American Chemical Society, Baltimore 

 meeting, December 27, 1893. From the Journal of the American Chemical Society, 

 Vol. XVI, No. 1, January, 1894. 



213 



