SOIL SESSION. 143, 



products. The selection of crops with special reference to their adaptation 

 to certain types cf soil; to cUniatological and to market conditions; to 

 the development of drough:, diseas.^ and insec -resisting- strains; and 

 the selection and care of seed are all important lines of proce:!ure tend- 

 ing to increase yield; but back of an 1 b-forj thess and all else is the 

 soil itself, which must be carried to and maintained at the hig'v. st pro- 

 ductive capacity before, either singly or in combination, the oth.r lin^s 

 of effort can yield their highest returns. It a hir Iv strai 1 of w ea , 

 fo/ example, will increase the yi-ld on a 13-bushel soil to 16 bushels 

 per acre, on the same soil brought into a 26-bushel condition, the hardy 

 strain of wheat ought here to increase the yield beyond three bushels 

 per acre, making it 32 or more instead of 29 bushels. Where the yield 

 of wheat on a given field has shrunk from 40 to 15 bushels per acre; 

 where that of oats has shrunk from 70 to 20 bushels and that of corn 

 from 80 to 25 bushels per acre, there is no reason to hope that the in- 

 troduction of new varieties or the use of more vigorous seed wdll force 

 the yield up to the old standards. The main help must be sought through 

 the restoration of the old physical, chemical and biological conditions 

 of the soil itself which will put the productive capacity inherent in the 

 soil back where it was when the yields w^ere high. 



Having said this much, in a general way, regarding the great im- 

 portance of more attention being given to the soil itself, I desire to 

 bring to your consideration, as briefly but forcibly as I may, a few- 

 fundamental facts and principles which lie at the foundation and must 

 direct all lines of effort aiming to secure higher yields from our fields 

 through a better, more economical and more rational management of the 

 soil. 



There is nothing which can do so much, in a business way, for any 

 line of industry as a clear, full un lerstanding of the great facts and 

 principles, which, if intelligently adhered to and applied, lead with cer- 

 tainty to the d. sired results. In illustration of what is here referred to 

 let me call your att ntion for a moment to the manner in which the 

 world's supply of nitrogen is maintained in the soil today and has been 

 through unnumbered ages. For many years it has been known that 

 green plants draw their main supply of carbon directly from the air 

 in the form of carbon d.'ox!de or carbonic acid gas. But it is only 

 within the memory of the youngest in this audience that the real source 

 of that v^ry important element, nitrogen, has been made known to the 

 agricultural world. The most careful observers and the most thoughtful 

 practical men among the farmers of all countries and throughout all 

 history had associat d an observ d increase of crop following the grow- 

 ing of different members of the clover family upon more or less exhausted 



