THE POTATO 97 



moisture be carefully conserved for fear of drought 

 at some time during the growing season. The 

 available plant food is also more largely in the 

 first few inches of surface soil than in the more 

 loose desert soils that have had the action of the 

 elements for ages without the packing and leaching 

 heavy rainfall. 



It is important to run the irrigation water low 

 in the furrow to keep from solidifying the soil and 

 soaking the tubers. The root system seems to go 

 deeper and adapt itself to the conditions as long as 

 the irrigation water is supplied evenly and the soil 

 is rich. Each of these conditions is under control 

 where the water is abundant and the soil fertile. 



Irrigation is followed by cultivation, and by 

 irrigation again as soon as necessary. This is 

 determined by examination of the soil and the 

 color of the leaves of the plants. If the soil about 

 the roots is so dry it will not remain moulded with 

 the imprint of the hand when a small handful is 

 compressed, it is too dry and needs water. This 

 cannot be taken too literally, but some judgment 

 must be used even in making as simple a test as 

 this. One novice, making this test, found that the 

 mould he formed stood all right, but on being 

 touched crumbled away. Literally, as he under- 

 stood the rule, the test showed sufficient moisture. 

 Actually, the ground was getting dry and. needed 

 irrigation. 



When potatoes require water they indicate it 

 by the dark green, almost black, color of the leaves. 

 When watered too heavily they get too light 

 green, almost yellow. The characteristic healthy 

 medium green of a potato plant in good condition 

 and doing well must be seen to be appreciated, 

 but these things are easily learned. 



