234 ECONOMIC PLANTS 



the cut surface will become somewhat dried, and when 

 planted the seed will not be so apt to rot. 



Cultivation should closely follow planting. It should 

 follow each heavy rainfall as soon as possible, so that 

 the weeds may not get a start. Potatoes are culti- 

 vated from three to five times, according to the season 

 and the rainfall, until the vines so fill the spaces be- 

 tween the rows that it is no longer practicable to go 

 through them with the cultivator or team. If the 

 potato field is not kept free from weeds and a good sur- 

 face mulch is not maintained, no great yield of the crop 

 need be expected, 



In regions where irrigation is necessary, water is 

 turned on whenever conditions seem to require it, 

 whether to sprout the seed or to supply moisture neces- 

 sary for steadily continued growth. After the use of 

 water has been begun, the soil should never be allowed 

 to become parched and dry to the end of the growing 

 season. Experience has shown that a field of potatoes 

 having once been stimulated by the artificial application 

 of water must be watered frequently to avoid a set- 

 back in growth, for a check in the growth of either 

 a plant or a tuber after once irrigated is more injurious 

 than if the plant had lacked sufficient moisture con- 

 tinuously. 



When the tops of the potato vines are dead, the crop 

 is ready to harvest. In these days of farm machinery 

 field potatoes, when grown on a commercial scale, are 

 seldom dug by hand, because of the great expense of 

 hand labor. One man with two good teams can easily 

 dig six acres a day with a potato digger and with less 

 injury to the tubers than results from ordinary hand 

 digging. The soil should not be wet when potatoes are 



