SOIL. 89 



soil is the ultimate employer of all industry the source 

 of all wealth and the universal banker." Hill. 



250. A sample of soil having a surface area of one 

 square foot and a depth of 12 inches, was dug from a 

 clover field .and weighed. The upper 6 inches weighed 

 60.1 pounds; the lower, 61.4 pounds. These two layers 

 were then dried and weighed, and the following weights 

 were obtained : for the first, 51.1 pounds ; for the second, 

 52.7 pounds. The moisture was what per cent of the dried 

 weight in each layer? 



251. What was the per cent of moisture in the 12- 

 inch section of soil ? 



252. What is the weight of an acre of the upper 6 

 inches of this soil after being dried? 



Process : Multiply number of square feet in an acre by 51.1 



253. What is the weight of the water contained in an 

 acre of the upper 6 inches of soil ? Of the lower 6 inches ? 



254. The water in the upper 6-inch layer would have 

 what depth if extracted and spread evenly over the same 

 area? 



Process : 



1. Divide the weight of water per square foot of surface area 

 by 62.5 (weight of 1 cubic foot of water). This will give the 

 depth in feet. 9 -f- 62.5 = 0.14 feet. 



2. Multiply quotient by 12 (inches in a foot) to obtain the 

 depth in inches. 0.14 X 12 = 1.7 inches. 



Note. This is equivalent to dividing by 5.2, since 

 62.5 -4- 12 = 5.2 



255; How many inches depth of water in the second 

 6 inches of soil ? 



256. Assuming no loss by evaporation or drainage, to 

 how many inches of rainfall does the water in the 12-inch 

 depth of soil correspond ? 



