214 THE WASTE AND CONSERVATION OF PLANT FOOD. 



iiKTeasiiiii'. or at least not lossoiiiiii:-, in fertility. This bcinu true, the 

 liistory of Ameriean ajiriculture to within a few years must be the his- 

 tory of bad fanning", for everywhere we have seen fertile lields losing 

 their fertility and farms once ]>rodnetive abandoned. No ditVerenee 

 how great the store may be, if it be continually drawn upon and never 

 replenished the day will sometime come when it will be exhausted. 

 This day has come to a larg'e portion of the agri<'ultural lands of tliis 

 eountry. and to-day there is an awakening everywhere in regard to the 

 best methods of checking the waste and of restoring what has been 

 lost. 



I desire for a brief period, on this occasion, to call the attention of 

 the chemists of this country to some of the methods by which plant 

 food is removed from the tields and some of the direct and indirect ways 

 in which it is and nuiy be returned. On a former occasion ' I have dis- 

 cussed the extent to which plant food is removed from the soil directly 

 in the crops and the dangers which arise to an agricnltural community 

 which continnally exi>orts its agricultnral i)roducts. On that occasion 

 1 pointed out the amount of potash, phosphoric acid, and nitrogen per 

 acre annnally removed by the crops of the United States, and showed 

 that the only safe agricultnral i)roducts to send out of a country were 

 sugar, oil, and cotton. It is true that with native, unexhausted soils a 

 country may acquire great wealth by agricultural exports, but tlu' his- 

 tory of the world Shows that a country which ilepends fen- its wealth 

 and its commerce on agricultural exportation is in the eml reduced to 

 l)aupei'ism. ^V single exam])le nuiy serve to accentuate this rennirk; I 

 refer to the island (>f Cyprus, which two thousand years ago was the 

 granary of many cities bordering on the ]\Ieiliterranean Sea. Supply- 

 ing hundreds t)f thousands of people with corn, it gradually became 

 impoverished, and to-day its soils are perhaps the poorest of any known. 



The waste to which I desire to call your attention today is not that 

 which nornmlly takes place in the production of a crop, but that which 

 is incidental to the cultivation of the soil and to a certain extent 

 unavoidable. My purpose is to develop, if it be possible, the relations 

 of agricultural chemistry to this waste, with the purpose of pointing out 

 a course by which it can be returned and in what way we may at least 

 reduce to a mininnnn the unavoidable removal of valuable i)lant food. 

 You have all, perhaps, surmised the character of this waste; 1 refer to 

 the denudation of fields by water and to the removal of soluble plant 

 food by the percolation of water through the soil. 



The losses due to the denudation of tields are i)urely of a mechanical 

 character. The natural forest, or the natural covering of grass over an 

 area of soil, prevents to a large extent the denudation due to heavy 

 downpours of rain. The removal of the forest and the destruction of 

 the grass by cultivation leave the soil in a condition in which it is 



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'Vice-presidential address before the American Association for the Advancement 

 of Science, Buffalo, 1886. 



