A STUDY OF FACTORS INFLUENCING THE YIELD* OF POTATOES 1173 



Depth of plowing ' 



It might be expected that a crop such as the potato, which develops 

 underground and is subject to varying conditions of soil moisture and 

 soil texture, would be influenced by the factor of depth of plowing. How- 

 ever, no actual experiments with this problem have come to the writer's 

 attention. Dickens (1914) states that shallow plowing has given the best 

 results on loamy soil at the Kansas station. Stone (1905) states that 

 at the Cornell station, deep plowing on the Dunkirk gravelly soil gave the 

 best results. Generally speaking, shallow plowing has been recommended 

 for heavy soils and deep plowing for light soils. 



The possibility of drawing definite conclusions from a study of a factor 

 depending so much on the grower's estimate and on only one year's results, 

 is necessarily limited. This is one of the factors that for its ultimate solu- 

 tion must depend upon carefully controlled experiments on a given soil 

 type in each region concerned. From the following discussion of the regions 

 herein considered, it would appear that depth of plowing is an important 

 factor only on soils of either extreme of texture deep planting increasing 

 the area for tuber development in heavy soils, and providing for planting 

 at the moisture-table depth in light soils. 



Depth of plowing on Long Island 



Altho the soils of Long Island are noticeably lighter than those of any 

 other potato region in the State, a marked correlation of depth of plowing 

 with yield is evident in table 17. An increase in the depth of plowing was 

 accompanied by the use of more seed and fertilizer per acre and a greater 



TABLE 17. RELATION OF DEPTH OP PLOWING TO YIELD ON 328 LONG ISLAND FARMS IN 1912 



