92 AGRICULTURE 



rattlesnakes. Where the life-giving water has been distributed, 

 it is now fair with farmhouses, pleasant gardens,, and fertile 

 fields. 



Arid Soils. The irrigated land of the arid states is very valuable 

 for agricultural purposes. It is a light, sandy, or silty, loam, which 

 absorbs water freely, parts with it slowly by evaporation, yet yields 

 it regularly and freely to plants. Instead of changing, as most 

 soils do, at a depth of a few inches to a subsoil^of different character, 

 it is almost the same for twenty or thirty feet. The soils in humid 

 regions dry hard, with a surface crust; these arid soils dry loose, 

 forming a natural soil-mulch. 



The weather is a great and usually an uncertain factor in crop 

 production. In irrigated arid lands, this is not the case. The 

 farmer turns on the water when his crop needs it, and the plants 

 are sure to get the moisture they need, no more, no less. As there 

 is no danger of rain during harvest season, grain is often allowed 

 to ripen on the stalk; it is harvested by a combined steam harvester 

 and thresher, and carried from the fields in bags, ready for the 

 mill. 



EXERCISE 



i. Fill a shallow box with dry soil. Bore a hole on one side near the 

 center. Make a trench across the middle of the soil and pour water 



slowly in till it runs out at the 

 hole. Remove the soil next to the 

 ^- trench and see how moisture has 

 spread by capillary action. This 

 is the principle upon which irri- 

 gation is based. 



ILLUSTRATION OF EXPERIMENT i 1^-11 



2. Do you know of any land 



that usually or often suffers from lack of water? Do you think it 

 could be irrigated profitably? Give reasons for your opinion. 



