May, 1929] Potato Production Costs in New Hampshire 11 



TABLE VII. 

 Kind of Soil and Suitable Potato Area on Farms in Survey by Counties. 



Rotation 



Hardenbiirg'^' and Fox^^^ in New York found that yield low- 

 ered as the length of the rotation increased, but because of the 

 small differences in yield the decreases were not significant. Better 

 tillage practices, or a slight increase in seed or fertilizer, might well 

 account for the increases on the shorter rotations. In New Hamp- 

 shire the smaller amount of residual organic matter left by the long 

 rotations is largely replaced by regular applications of manure for 

 potatoes. It is true, however, that the more frequent tillage in the 

 shorter rotations tends to keep down insects and weeds which are 

 partly responsible for the increases in labor per bushel in the long- 

 er rotations. (See Table VIII.) From the standpoint of labor per 

 acre and per bushel the shorter rotations are desirable. 



There are insufficient data from the survey to prove the value 

 of a clover sod in increasing yield of potatoes. The evidence, how- 

 ever, does show that labor per acre and per bushel is consist- 

 ently less on the short rotations than on the longer rotations. 

 Shorter rotations proved more profitable even though cost per bush- 

 el remained practically constant. A saving in labor of 20 to 30 

 hours per acre in the shorter rotations is one of sufficient impor- 

 tance to consider in the potato organization. 



Date of Planting 



The short season in Coos County necessitates planting in the 

 spring as early as the season will allow to give the crop time to ma- 

 ture early enough in the fall to permit digging of the entire crop 

 without danger of frost injury. In the southern part of the state 

 early planting often brings the setting of the crop in hot August 



