ARID AGEICULTURE. 99 



tions of the furrow method are used to adapt it 

 to different conditions of soil, crop, or head of 

 water used. For grain drilled in rows eight 

 inches apart it is usual to make the furrows nar- 

 row and deep, four to five inches wide, three to 

 four inches deep, and twenty-four to thirty-two 

 inches apart. For alfalfa and other drilled hay 

 crops the practice is much the same ; the furrows 

 being perhaps a little larger. The head ditches 

 or laterals between which the furrows are run 

 should not be over 200 feet apart, as a general 

 rule. That is, the furrows should not be so long 

 that the water will not run through from end to 

 end in a reasonable time, say half an hour to an 

 hour. They should be long enough, so the water 

 will have time to "sub," or seep to the side and 

 dampen all the soil between the furrows. The 

 best length will depend on the soil, the slope, the 

 size of, and distance between the furrows. It 

 is determined by the individual farmer for his 

 own conditions without great difficulty. 



Root crops are almost always found to do 

 best under the furrow system. Potatoes, espe- 

 cially, show the bad effects of even a break be- 

 tween the furrows, and consequent flooding. In 

 this case the furrows are made quite large, the 

 rows being ridged, and one furrow between each 

 two rows. Sometimes, the best method for the 

 crop and the most economical of water, is to 

 irrigate only alternate furrows, as with sugar 



