A STUDY OF FACTORS INFLUENCING THE YIELD OF POTATOES 1237 



The influence of the planting system on yield and on the amount of seed 

 used is strikingly shown, for these three regions, in table 68. As is indicated 

 in this table, in all three regions the drill system of planting gave an average 



TABLE 68. RELATION OF PLANTING SYSTEM TO YIELD IN THREE OF THE REGIONS SURVEYED 



yield varying from 7.9 to 23.8 bushels per acre higher than that from plant- 

 ing in checkrows. It is shown further triat invariably about 3 bushels 

 more of seed per acre was required to plant by the drill system. The 

 yield was sufficiently higher from this method, however, to more than 

 pay for the extra seed necessary. 



On the basis of yield alone, these results favor the drill system of planting 

 for all the regions surveyed. However, it is possible that there are seasons 

 in which weed control is largely dependent on the possibility of cross 

 cultivation. The choice at such times becomes one of producing a medium 

 yield by checkrow planting with a minimum of labor, or a much smaller 

 yield by drill planting. 



DEPTH OF PLANTING 



Depth of planting is a factor which, tho given some experimental atten- 

 tion by various stations for many years, has received little consideration 

 from the potato grower. The depth at which the seed piece is usually 

 placed depends principally on the soil type and the method of planting. 

 Just as plowing and tillage are normally more shallow in heavy than in 

 light soil, so potatoes are normally planted less deeply in heavy than in light 

 soil. However, the depth at which the potato root system is allowed to 

 develop depends not alone on the depth of planting, but also on the system 

 of tillage employed. This is a factor too often neglected in the study of 

 the influence of depth of planting on yield. For example, the seed may 

 be planted shallow and the crop given ridge culture, or the seed may be 

 planted deeper and the crop receive level culture. With either method 



