I9I91 



ALWAY, McDOLE, a- TRUMBULL—SUBSOIL 



201 



ever to be found in prairie fields at Lincoln, showed dry subsoil 

 onl}- within the first 5 ft., below this depth the ratios lying between 

 extremes of 1.9 and 2.7, or in general between 2.0 and 2.4, the 

 moisture retaining capacity of the subsoil. On only one occasion, 

 and then only in the first foot, was the moisture content found 

 reduced as low as the hygroscopic coefficient, and there it is to be 

 attributed to the surface few inches of the foot section having been 

 dried by evaporation to a point much below this value, with the 

 result that the average for the whole foot section shows a low ratio. 

 In this connection it is of interest to know the ratios which 

 normally prevail in the deeper 'subsoil of the eastern prairies. In 

 April 191 1, a field situated on a gentle slope and 50 ft. or more above 

 ground water was sampled to a depth of 18 ft. (table XII). Below 

 the fifth foot ratios ranging only between 2.1 to 2.4 were found. 



TABLE XII 



Moisture conditions in prairie near Lincoln, April 13, 1911, showing 



NORMAL condition OF DEEPER SUBSOIL 



Thus as near the surface as the sixth foot, when conditions 

 were such as to develop the driest subsoil, the ratio was not much 

 below that found in the deep subsoil under normal conditions. 

 This failure of the natural vegetation of the prairies of eastern 

 Nebraska to exhaust the free water of the deeper subsoil is in sharp 

 contrast with the conditions found on the short-grass prairies of 

 the southwestern part of the state, as previously described. That 

 this moist condition is due to a difference in the conduct of the 

 native plants and not to any peculiar properties of the humid 

 subsoil is evident from the fact that in the alfalfa fields adjacent 

 to the prairies kept under observation the ratios were quite com- 

 monly found reduced as low as i . 2 to i .4 to a depth of 15 or 20 ft., 



