364 THE CEREALS IN AMERICA 



or dike thrown up around them. On at least one side of each 

 field there must run a canal or sub-canal. These fields vary in 

 shape and size according to the topography of the land and the 

 ability to bring water to it. Usually the fields range in size 

 from ten to forty acres. These fields are now subdivided into 

 smaller areas, in order to get the water over the whole area with 

 some uniformity. It is at this point that the system followed in 

 the South Atlantic States differs radically from that of the South 

 Central States. In the former the fields are subdivided by 

 ditches placed parallel, usually about fifty feet apart, through 

 which the water is conveyed to and from the land. In the 

 South Central States the fields are divided into sub-fields or 

 cuts, this being done by throwing up field or cut levees along 

 the contour lines twelve to eighteen inches high. To flood the. 

 field, water is turned into the highest cut and conveyed from 

 there to the next highest cut, and so on until the field has all 

 been flooded. A drainage ditch at the long part of the field 

 removes the water. The main features of the two systems ar<5 

 shown in the illustrations on pages 362 and 363. 



It is important that each of the smallest units of land be as 

 level as possible, so that the water can be kept at as uniform 

 depth as may be over the whole area, since uniformity of depth 

 of water is a prime factor in the growth and maturity of the 

 crop. To obtain the best result, there should not be a variation 

 of more than six inches in the depth of water. 



51 T. Water Supply. — In the South Atlantic States the lands 

 chiefly used for rice culture are the deltas near tidewater. Land 

 is selected so that it may be flooded from the river at high tide 

 and drained at low tide ; and is sufficiently remote from the 

 sea to be free from salt water. Rice may be grown in slightly 

 brackish water, but salt water is disastrous. Usually the land 

 is not less than fifteen nor more than thirty miles from the 

 sea. A tide of four feet is sufficient and less is sometimes used. 

 Where properly located, water in this region is ample. Along 



