A STUDY, BY THE CROP SURVEy METHOD, 'OF; FACTORS 

 INFLUENCING THE YIELD OF POTATOES 1 " 



EARLE V. HARDENBURG 



Almost from the date of their establishment, practically all state and 

 federal experiment stations in this country, as well as many foreign 

 stations, have tested, by diverse methods, the relative influences of factors 

 affecting the yield of potatoes. A review of the abundant literature of 

 the subject shows that a majority of these tests concern the influence of 

 seed and fertilizers on yield. This fact, further substantiated by the 

 results of the study herein reported, indicates that, with the exception of 

 climate and soil, seed and fertilizers are the most vital factors affect- 

 ing yield. Because of the widely differing environmental conditions under 

 which the tests have been conducted, it is possible in only a limited degree 

 to draw definite conclusions from a summary of the results. Furthermore, 

 a large part of the literature fails to supply much detailed information 

 as to the methods used in the experiments, and gives little if any considera- 

 tion to factors affecting yield other than the one principally concerned 

 in the respective tests. This means that most of the evidence available 

 to date is of only limited application. 



A comparison of the conclusions reached and the recommendations 

 made by experiment stations, with those warranted by actual practice as 

 found on farms in a potato-growing region, is therefore of considerable 

 value. Such a comparison is, to some extent, made possible by the 

 use of the survey method of collecting and studying data on the influ- 

 ences affecting the yield of potatoes. The survey method has accordingly 

 been applied to the study of such factors in several potato sections of 

 New York, and the results are herein compared with those obtained 

 experimentally. As an additional check on the conclusions drawn, 

 the biometrical method as applied by Rietz and Smith (1910) 2 has 

 also been used in studying those factors which, according to the sur- 

 vey method, appear to affect the yield to the greatest extent. The survey 

 method of studying crop production, wholly aside from the agricultural 

 methods involved, has proved to be a most valuable means of determining 

 the actual practice thruout the State, and has aided in correcting many 

 false ideas of long standing concerning cultural methods used with this 

 crop. 



The collection of data was begun in the summer of 1913 and continued 

 thru the summer of 1914. In 1913, 330 records of the 1912 potato crop 

 were taken from as many potato farms on Long Island, and 360 records 



1 Also presented to the Faculty of the Graduate School of Cornell University, February, 1919, as a major 

 thesis in partial fulfillment of the requirements for the degree of doctor of philosophy. 

 ' 2 Dates in parenthesis refer to Bibliography, page 1274. 



1143 



