No. 6. DEPARTMENT OF AGRICULTURE. 677 



the soil besides the applieatiuu we inaki' in the way of plant food. 

 It seems to me there must be something going on besides the chemi- 

 cals that produce the changes in the soil. 1 would like to have 

 some scientitic answer to it. I don't see how the application of 

 two or three hundred pounds of plant food, to an acre, would have 

 much plant food in itself, but at the same time the results are often 

 very remarkable for a small application. 



The SECRETARY : It is very likely that Dr. Funk is able to 

 answer the question and we would be glad to hear from him. 



DR. FUNK: Ail commercial fertilizers contain, in addition to 

 the actual plant food, large proportions of other ingredients, such 

 as lime, magnesia and other mineral elements which, although not 

 actual fertilizers in themselves, yet they indirectly act as such by 

 going through chemical changes in the soil, forming new chemical 

 compounds and liberating other elements which, in turn, act upon 

 the soil, disintegrating and breaking it up, setting free, nitrogen, 

 phosphoric acid and potash, which exists in large quantities in 

 all moderately- fertile soils, of which analyses shows that the first 

 eight inches contains 17,500 pounds of potash, 9,000 ptounds of phos- 

 phoric acid and from 4,000 to 8,000 pounds of nitrogen. Now by 

 adding even a comparatively small portion of immediately available 

 fertilizer w^hich feeds the plant in its early and feeble stage until 

 it has established sufficient root system to reach out and gather 

 in the essential elements for its growth, that is being contantly set 

 free by the chemical action of such ingredients contained in the 

 fertilizer and, by other elements working in the great laboratory of 

 nature, such as air, moisture, heat and cold. The acids and gases — 

 even by the roots of the plants themselves, which form an acid at 

 their terminal end, acts upon the small particles in the soil, corrod- 

 ing, breaking up and liberating such food as it needs. If a crop 

 of tw^o hundred bushels of potatoes take from the soil about 110 

 pounds of nitrogen, 55 pounds of phosphoric acid and 192 pounds 

 of potash, and when we apply 500 pounds of fertilizer analyzing 

 5, 6, 12, we have 25 pounds of nitrogen, 30 pounds of phosphoric 

 acid and 60 pounds of potash; the balance required must be taken 

 from the soil. If the season is very favorable, with suflicient rain- 

 fall, and it is given plenty of cutivation this may be accomplished, 

 but at a fearful loss of soil fertility and, ordinarily, nature rebels, 

 and because she does so the farmer who has applied this |8 worth 

 of fertility in comparison with |25 worth of stable manure, if he 

 does not get as good results, condemns the commercial fertilizer, 

 whereas, had he applied equal money value, the commercial fertilizer 

 would have outvielded the stable manure. 



