SOIL. 80 



soil is the ultimate employer of all industry — the source 

 of all wealth and the universal hanker." — 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 

 ()0.1 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. 

 •32.7 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 G 

 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 H inches of soil ? Of the lower 6 inches ? 



254. The water in the upper G-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 63.5 (weight of 1 cubic foot of water). This will give the 

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



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

 depth in inches. O.U X 12 = 1-7 Inches. 



Xote.— This is equivalent to dividing by 5.2, since 



62.5 ^ 12 = 5.2 



255. How many inches depth of water in the second 

 G 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? 



