392 THE POTATO 



the contest would be lost, so far as a yield crop was 

 concerned, if the winner did all the work by 

 hand on a single acre, we decided to use horses 

 and machinery in all our operations. 



"In order to break the crust which had formed 

 over the field during the winter we used a double- 

 action disk harrow, which always leaves the surface 

 level, being a marked improvement over the ordi- 

 nary disk-harrow. This was followed with a drag 

 harrow and was harrowed several times at inter- 

 vals of one week. By the time we were ready to 

 plow nearly all the alfalfa was dead. All this disk- 

 ing and harrowing had thoroughly mixed the 

 manure with the soil, and had created a dust 

 mulch over the field. Being afraid of scab, we had 

 only applied twelve loads of manure per acre. 

 This was put on in the spring while we were killing 

 the alfalfa. Being so thoroughly mixed with the 

 soil and plowed under so deep, we had no scab, and 

 could have applied more and still have been safe 

 so far as scab was concerned. Before plowing we 

 corrugated and irrigated. We did this for several 

 reasons: First, to help get a better stand; second, 

 to carry the crop as long as possible without any 

 further irrigation, as we have found that the longer 

 the plants can grow and develop without needing 

 any further irrigation the better the results; third, 

 to cause the manure to rot and get in a shape that 

 the plants could use; fourth, to supply enough 

 moisture so that the soil would pack (not bake) 

 after it was plowed. It is always better to irri- 

 gate before plowing, as the plowing replaces the 

 air that the water has driven out. 



"As soon as the ground was dry enough it was 

 plowed from ten to twelve inches deep. As the 

 surface soil had been worked many times before 



