Apr. 9,191 y 
Water-Retaining Capacity of Soil 
37 
soil was added as above described and the same amount of water, 15 
pounds, added. All four were opened at the end of 126 days. The 
moisture conditions are shown in Table IV. The moisture content was 
much higher, over 6 per cent on the average, than in the cylinders having 
no layer of coarse material. Further, in those with the sand or gravel the 
moisture in the soil column was not uniformly distributed, being about 6 
per cent higher, just above the coarse layer, than near the surface. 
Neither the sand nor the gravel used in this experiment was as coarse as 
much of the material found naturally underlying arable soils. 
C.— With layers of six different soils variously arranged. —In 
this experiment we used soils selected to exhibit a wide range in hygro- 
scopicity while still confining the set to soils representing important 
Nebraska types. These were placed in seven metal cylinders, open at 
both ends, 18 inches long, and 6 inches in diameter. The cylinders had 
been placed in a trench, 2 feet deep, dug in the loess floor of the green¬ 
house. In the case of each the sharp edge of the lower end of the cylinder 
was driven into the bottom of the trench to a depth of 2 inches. Then 
each cylinder was filled, in 2-inch layers, with six different soils, the layers 
being arranged differently in each (Table V). Thus, direct capillary 
connection was established between the natural subsoil and the soil 
column. Each soil in an air-dry condition was filled into the cylinder as 
above described. After the whole of the layer had been tamped in a 
small square piece of J-inch mesh galvanized-wire screen was placed on 
the surface before beginning the addition of the next layer, so that the 
dividing surfaces between the different layers of soil might be more 
readily recognized on opening the cylinders. 
In the arrangement of the soils in Cylinders II to VII each soil appears 
once at the top, once at the bottom, and once in each intermediate 
position. In No. I the soils are arranged from top to bottom in the 
order of their hygroscopic coefficients, the soil with the lowest being at 
the top, while in No. VII the order is reversed. 
Table V .—Arrangement of soil layers in the different cylinders, showing the soils used , 
their hygroscopic coefficients , and their moisture equivalents a 
SOILS 
« The heavy lines indicate the position of the sand layers. 
