The Texture of the Soil. 



471 



in the sample. As it contains less organic matter, it therefore 

 has less nitrogen than the good soil (Sample II.). Probably be- 

 cause of this less percentage of organic matter, this lumpy soil 

 also contains less moisture than the other. As a matter of fact, 

 however, these differences which the chemist found in the organic 

 matter, nitrogen and moisture, are not sufficient to account for 

 the very great differences in the productivity of the two soils. 

 The chemical examination would have thrown more light upon 

 the value of these soils if a determination had been made of the 

 amount of potash and phosphoric acid which is soluble; but even 

 then, the chemist could not have told, from analysis alone, how 



138.— Sample I. 



Sample H. 



valuable this land might be for any particular crop. Analysis 

 does not show how agreeable or comfortable the land may be to 

 the plants. There is sufficient potash in the rock (Sample III.)? 

 and even enough phosphoric acid, to grow a crop of beans; and 

 yet, even if I add the nitrogen and water and make the mineral 

 plant food soluble, I cannot hope to grow a crop on the walls of 

 m,y house. In brief, a chemical analysis of soil is only one of 

 several means of deterinining the value ofland^ and in the general 

 run of cases it is of very secondary value. 



How can the texture of lands be improved? In general, by 

 three means — by judicious plowing and tillage, by the incor- 

 poration of humus, and by the use of underdrains. The value of 



