CEREALS UNDER IRRIGATION 421 



scribed (430). After plowing and harrowing, the land is 

 gone over once each way with a rectangular plank or 

 float. This implement leaves the surface smooth, so 

 that the smaller irregularities in slope are easily noticed, 

 which are then leveled with a regular land grader. The 

 grader cuts off the little elevations and dumps the mate- 

 rial into depressions. 



The flooding method of irrigation involves least prepa- 

 ration of the land, and is therefore preferred by the new 

 settler, but it requires more labor in applying the water. 

 A supply ditch is run down the slope of the land, and 

 from this, field ditches are run across the slope with just 

 enough grade to carry the water, which flows over the 

 lower bank of each ditch and down the slope to the next 

 ditch. A man with a shovel must direct the water. 



447. The border method of irrigation is a modification 

 of the flooding method, which requires more preparation 

 of the land before irrigating, but less labor in applying 

 the water. It is a process of flooding between levees or 

 borders. A head ditch runs across the greatest slope at 

 the upper end of the field, and from this, parallel borders 

 are run down the slope at intervals of 40 to 60 feet, divid- 

 ing the field into lands. Each land is level between the 

 borders, so water will flow down this slope in a sheet 

 extending from border to border. After turning water 

 into a border, no further attention is needed until that 

 part of the field is sufficiently watered, when the water is 

 shut off. This method is used considerably in the South- 

 west, and is recommended in southern Idaho. The greater 

 the slope the less practicable is the border method, as 

 the field may have to be too small in order to be level. 



448. Flooding in checks is provided for by running 

 levees in both directions across the field, dividing it into a 



