132 LAND DRAINAGE AND IRRIGATION 



under irrigation than under rainfall. It follows, -therefore, that 

 the farmer's profits must be less with irrigation than without, 

 unless the yields are larger or the prices he receives for his produce 

 are higher. The prosperity of some of the irrigated sections of 

 the West has been more largely due to increases in the value of 

 land than to the profits in growing crops. This may also be said 

 of many sections in humid regions. 



According to some investigations made on irrigated farms in 

 Utah and in an irrigated section in Montana, the average farmer's 

 labor income^ on these farms seems to compare favorably with the 

 average labor income received by farmers of other states. 



Irrigatioii an Art of Antiquity. — When we learn of the advance- 

 ments that have already been made in reclaiming arid lands in 

 the United States, and of the almost magic transformations 

 resulting from irrigation, we cannot but wo^ader at it all, and com- 

 ment on the wonderful age in which we are living. Yet, when we 

 consider the remains of canals and certain other ruins of ancient 

 lands, including what is now Southwest United States — ruins 

 which give us but a glimpse of the elaborate systems of irrigation 

 operated by ancient and prehistoric peoples — ^we reflect the same 

 sentiment expressed nearly three thousand years ago by that 

 wise oriental king — "There is no new thing under the sun." The 

 art of irrigation has thus come down to us as a prehistoric heritage 

 to be improved by succeeding generations. 



Demonstrational Exercises. — Material Needed. — 2 large baking-powder 

 cans; 2 cubic feet of sandy soil; a thermometer; 3 three-inch clay tile; 2 10 X 

 12 X 10-inch wooden boxes. 



To Demonstrate That a Warm, Spring Rain Warms a Well-drained Soil 

 Quickly, While a Saturated Soil Remains Cold. — Procedure. — ^Fill 2 large 

 baking-powder cans within one-quarter inch of the top with a sandy soil. 

 One can should be water tight and the other should have the bottom perforated. 

 Saturate and flood the one soil with cold water. Bring the other soil to the 

 same temperature by passing cold water through it. Determine the tempera- 

 ture of the two soils. Now pour on each soil at least one-half a pint of warm 

 water. (The warm water will pass through the drained soil but will run off 

 the other.) Take temperature readings again and record results. 



Questions, — (a) Explain why warm spring rains do not warm saturated soils. 



(6) Why do warm rains warm cold well-drained soils most effectively? 



(c) Name other benefits of good underdrainage. 



^ 6 In comparing the profitableness of different systems of farm management 

 or in determining the profits in farming, the farmer's "labor'' or ''managerial 

 income" is the most convenient and accurate basis. Labor or managerial 

 income means profits above total costs — ^total costs including interest on money 

 invested and unpaid family labor. 



