ARID AGRICULTURE. 101 



This is simply a modified flooding method 

 by which the water is retained at some depth on 

 the land, as long as the irrigator thinks best, 

 instead of being spread out by hand labor while 

 running, as in flooding. This is accomplished 

 by means of small dikes or levees thrown up, 

 either in rectangular, or square form, or along 

 contour lines. The square system jmakes the 

 fields take on somewhat the appearance of a 

 gigantic checker-board, whence the name given 

 this method. The check system is best suited to 

 land having very little slope. On practically 

 level ground the banks may be placed far apart. 

 In parts of Arizona and ISTew Mexico on such 

 land they may be as much as a half mile apart, 

 thus inclosing a quarter section in a single 

 "check. 7 ' But in general the "checks" or 

 squares are very much smaller, often containing 

 less than a quarter acre. The higher and 

 stronger the retaining banks are made, the 

 greater the area that can be enclosed in a check. 

 For crops that must be worked with horses and 

 machinery, it is not practical, as a rule, to make 

 the banks over one and one-half to two and one- 

 half feet high, as there is liable to be damage to 

 farm machinery in crossing higher banks. If 

 the side slopes of the banks are made slight, too 

 much area is taken from the land that could oth- 

 erwise be cropped. This system entails a large 

 first cost and is also subject to the following dis- 



