1162 



EARLE V. HARDENBURG 



TABLE 5. RELATION OF ELEVATION TO YIELD ON 290 FKANKLIN AND CLINTON COUNTY 



FARMS IN 1913 



influence of this factor. With the amounts of seed and the value of manure 

 and fertilizer used approximately equal, the best yields were produced at 

 the higher mountain elevations. 



Since the increase in elevation for this 'region is accompanied by a con- 

 siderable variation in soil type, a part of the increase in yield at the higher 

 levels may be due to the latter factor. However, since Franklin County 

 has not been soil-surveyed, it is impossible here to measure accurately 

 the influence of the soil. Very little difference in soil type was evident 

 between the Dover fine sandy loam of the lower elevations and the 

 Caloma fine sandy loam of the higher elevations in Clinton County. 



CROP ROTATION 



The benefits of crop rotation to a heavy-feeding cultivated crop such as 

 potatoes have long been recognized. The crop survey as a means of com- 

 paring various rotations in a given region, however, has very limited possi- 

 bilities, for in the older farming regions the same general type of rotation 

 is followed thruout. Very few tests have thus far been made by the experi- 

 ment stations to determine the most suitable place in the rotation and the 

 best length of rotation for potatoes in a given region. Probably the most 

 valuable work has been done by Hartwell and Damon (1916) in their 

 twenty-years comparison of different rotations of corn, potatoes, rye, and 

 grass, at the Rhode Island Station. The principal feature of this work 

 lies in 'a comparison of four-, five-, and six-years rotations of potatoes, 

 jye and rowen, grass, corn, the grass being left down for from one to three 

 years. No stable manure was used, but complete commercial fertilizers 



