96 THE POTATO .^Hl 



draw the moisture from the soil, that would make 

 irrigation advisable sooner. 



In the irrigated West the crop should be culti- 

 vated deeply, soon after planting making a loose, 

 deep seed bed. Cultivator shovels fourteen working 

 inches long and about four inches wide, two on 

 each side of the row, are valuable for this work. 

 If this deep cultivation just after planting turns 

 up the soil rough, a harrow may follow to fine the 

 surface in order to hold moisture. The second 

 cultivation can come when the plants begin to 

 show. The number of cultivations depends on the 

 condition of the soil, weeds, and number of irri- 

 gations or rains. Cultivation after the tubers 

 are set should not be so deep nor so near the hills, 

 because a potato torn off while in the forming 

 stage is lost. Tearing off feeder roots or rootlets 

 at this stage also reduces yields. 



Ditches between the rows for irrigation are made 

 with a double shovel plow attachment fastened to 

 one beam and a two-horse cultivator. The best 

 potatoes and the heaviest yields have been pro- 

 duced where deep ditching and heavy ridging have 

 been practised. Ridges must contain plenty of 

 dirt to protect the tubers from the sun and to pre- 

 vent greening, but growing in fairly loose, well- 

 aired soil into which the moisture comes up from 

 the bottom has proved best. The bulk of the . 

 roots of the plant go deeper, but the tubers have 

 the benefit of forming and developing in a favor- 

 able environment. 



Flat cultivation, stirring the surface only, so 

 as not to destroy the surface roots, is advocated 

 in potato growing in some sections of the rain belt. 

 There, all moisture is applied evenly over the sur- 

 face in the form of rain, and it is necessary that 



