30 



Richard H. Boerker 



The per cent, of hygroscopic water in the soils was the amount 

 of moisture the soils held at room temperature. The amount 

 of pore space in the soils was equivalent to the total amount of 

 water the soils would hold. This would also be the amount of 

 air in the soil when air dry. In determining the amount of pore 

 space the soil used was air dry, hence the amount of hygroscopic 

 water in the soil had to be added to the amount of pore space. 

 The amount of capillary water was the amount of water the soils 

 held against gravity. The same soils were used in all three 

 experiments and the samples consisted of about 150 grams each 

 except in the volume determinations in which 100 cubic centi- 

 meters of soil were used in each case. This table shows very 

 strikingly the Water and air relations in these soils. The great 

 amount of air in gravel when it is at its maximum capillary 

 water content is also shown approximately. 



The mechanical analyses of representative samples of these 

 soils which were kindly furnished by the department of agronomy 

 of the University of Nebraska are given below: 



Mechanical Analysis of Soils 



Separate 



Stones 



Coarse gravel 



Fine gravel 



Coarse sand 



Medium sand 



Fine sand 



Very fine sand .... 



Silt 



Clay 



Volatile matter. . . . 



Total 



Diameter, Mm. 



Sand 



ve! 



21.045 



29.418 



21.709 



25-708 



1.074 



-346 



0.700 



38.639 

 40.382 

 14-051 



4-245 

 1.062 

 0.770 



0.268 



0.583 



Besides these determinations soil samples were taken once a 

 month to determine how much moisture these soils held at the 

 end of a day in the cultures in the greenhouse. These results 

 bear out the findings in regard to capillary water held by the 

 soils shown in A preceding table. These moisture contents are 

 given below : 



