256 SOILS 



checks may be irrigated at the same time, and the 

 water drawn off into the next lower checks sim- 

 ultaneously. Instead of cutting the bank there may 

 be ditches with head gates between all the checks. 

 Obviously the water stands deeper on the lower 

 side of a check than on the upper; the more the 

 slope the greater the difference. Thus if a field 

 slopes 8 inches in 300 feet, in order to give the soil 

 on the upper part of a check 300 feet wide 2 inches 

 of water, the water would have to stand 10 inches 

 high at the lower bank. Build the banks at least 

 3 inches higher than the water will stand on them. 



Wild Flooding. Another system of flooding 

 auite commonly practised in the West, is to cover 

 trie field with a thin stream of running water; this 

 is sometimes called "wild flooding." It is practi- 

 cable only when the slope is quite moderate and 

 uniform. Deep furrows are plowed down the 

 slope 50 to 125 feet apart or following an easy 



frade. A V-plow is used which throws the eartn 

 oth ways, making a ridge on either side that throws 

 the water outward. Water is diverted into these 

 furrows from the head ditch and each furrow is 

 dammed at a suitable distance merely by a piece of 

 canvas fastened to a 2 x 4, which is laid across the 

 furrow and the edge of the canvas held down with 

 soil. The water backs up in the furrows and over- 

 flows across the intervening spaces. When the 

 soil is sufficiently wet the canvas dams are moved 

 farther down the furrows. A wooden or metal 

 "tappoon" is used for this purpose in California 

 and Arizona, being thrust down into the soil so that 

 it obstructs the furrow. The furrows may be tem- 

 porary, when tilled crops are grown ; or permanent, 

 when sod and grain crops are grown. All the 

 water will not soak into the ground; some will 



