20 INTENSIVE FARMING 



turn. Fortunately for the grower this condition 

 seldom actually exists. 



Potato growing has come to be a high art 

 within recent years. Expert growers have 

 learned to select their seed by using the " tuber 

 unit " method in combination with the " prog- 

 eny row " to build up highly productive strains 

 of seed. 



The tuber unit method of potato improve- 

 ment is based on tubers weighing from six to 

 eight ounces, carefuly selected with regard to 

 type, size, and uniformity. As each potato is 

 planted it is cut into four pieces of as nearly 

 the same size as possible by splitting it length- 

 wise. Each piece is placed from twelve to four- 

 teen inches apart in the row. The next tuber 

 is treated in like manner, a vacant space being 

 left between the four pieces forming any par- 

 ticular tuber. This makes it possible to mark, 

 during the growing season, the groups which 

 are vigorous and free from disease. The most 

 productive of these can be selected at harvest 

 time so that, by two observations, the tubers 

 secured are healthy, vigorous, and productive. 

 The product of the four hills from any par- 

 ticular tuber can be thrown together and re- 

 tained for next season's planting. The product 

 of any tuber which is carried over and planted 



