THE SOIL. 



31 



ANALYSES OF THREE SOILS AND SUB-SOILS AND THE WEIGHTS 

 OF COTTON PRODUCED FROM EACH. 



Soil No. 2, the poorest soil, produces the largest crop ; 

 the soil richest in plant food, No. 3, produces the smallest 

 yield of cotton. If the physical properties of these soils 

 are compared (see physical properties) it will be noticed 

 that soil No. 2 is more permeable and not nearly so 

 tenacious as the other soils. This table is sufficient to 

 show the unreliable nature of chemical analysis as regards 

 the fertility of the soil. 



It will be shown later, in dealing with the relation of the 

 plant to the soil, how an excess of any soluble substance 

 in the soil is harmful to the growth of the plant, and this 

 even although the salt be a valuable plant food. Hence 

 either a scarcity or excess of food results in a poor crop. 



