94 THE POTATO 



periment Station 3 to 5 inches deep gave the heavi 

 est jdelds, but 5 to 6 inches deep is recommended, as 

 tubers of better quality are produced.' While in a dry 

 season, on a rich clay loam soil, Green^ of Minnesota, 

 obtained better results from deep planting, the yields 

 being, per acre, planted on the surface, 216 bushels; 

 3 inches, 227 bushels ; 6 inches, 297 bushels ; 8 

 inches, 328 bushels, it was felt that the results would 

 have been different if the season had been wet. The 

 New Jersey Experiment Station' obtained similar re- 

 sults, but found a depth of 4 inches most profitable. 

 From the data submitted and other sources, 3 inches 

 to 4j^ inches seems to be the most profitable. depth. ^ 

 On soils which are heavy and bake, and under certain 

 climatic conditions, the seed should be planted fairly 

 deep, but not covered more than 2 inches or so, to aid 

 germination.* The soil can then be gradually worked 

 toward the potatoes until level culture is obtained. 

 This system is sometimes advocated for the second 

 crop in the South." 



Influence of Depth of Planting on the Depth 

 at Which Tubers Form. — This question is of im- 

 portance, because mechanical diggers must be used, 

 and it is essential to know the depth to which they 

 must work in order to dig all the crop. Zavitz," of 

 Ontario, as the result of three years' trial, found that 

 on an average potatoes from tubers planted 



' N. D. Report, 1901, p. 97. ^ Minn. Bui. :o, p. 74. 



» N. J. Bill. 120, p. 10, and Botanist's Report, 1S96, p. 31S. 



« Ga. Bui. 29, p. 304. Tex. Bui. 71, p. 7- * ^a. D. A. Report, 1902. p. 722. 



• Ga. Bui. 29, p. 305. ' Ont. Agr. Coll. Farms Report, 1S94, p. 9S. 



