72 



RELATIONS OF SOIL TO WATER 



TABLE X 



WATER IN NATURALLY SATURATED SOILS 



The Eroadbalk soils afford a good illustration of the influence 

 of manures on the water capacity of a soil. These soils had 

 grown wheat continuously for twenty-five years ; they were 

 sampled in January 1869 after long continued rain. The 

 figures show the quantities of water held in the first six inches 

 of soil. The soil which had been continuously unmanured 

 holds the least water. The soil which had grown large crops 

 of wheat with artificial manures holds distinctly more water : 

 here the soil contains more humus, the residue of the roots 

 and stubble of the larger wheat crop. The soil which had 

 received 14 tons of farmyard manure annually for twenty-six 

 years far exceeds all the others in the amount of water which 

 it contains, owing to the large accumulations of humic matter 

 within it. The accumulation of humus, and the increased 

 water-holding power associated with it, is however practically 

 limited to the first nine inches from the surface. 



Illustrations of the amount of water held by a field soil in 

 a natural state of consolidation, and in its wettest condition, 

 are furnished both by the Hotharnsted and Wisconsin ex 1 



