384 INVESTIGATION BY CULTURE EXPERIMENTS 



POTATOES EVERY YEAR ON Hoos FIELD, ROTHAMSTED 



On another part of Hoos field potatoes were grown every year 

 for 26 years (1876-1901). There were several changes in the va- 

 rieties grown, so that but little importance, at most, should be 

 attached to the yields in successive periods as indicating decreas- 

 ing or increasing fertility, except in those cases where the change 

 is so regular and so marked as to leave no room for doubt. It is 

 especially to be kept in mind that the variety " White Beauty of 

 Hebron " was grown only during the last five years (1897-1901). 

 During the previous 21 years the varieties grown were " Rock " 

 for 4 years, "Champion " for n years, " Button's Abundance " 

 for 5 .years, and " Bruce " for one year, and, in this order, from 

 1876 to 1896. Thus, the two five-year periods from 1882 to 1891 

 should be comparable, but, of course, seasonal variation renders 

 even that possible comparison of doubtful value. 



The special object of the experiment was to ascertain the effect 

 upon the yield of potatoes of different fertilizing materials, as indi- 

 cated in Table 68, which shows the general plan, the treatment 

 applied, and the yields obtained each year. 



One of the points most clearly indicated by the data in Table 68 

 is that " White Beauty of Hebron," grown from 1897 to 1901, 

 was a very poor yielding variety. 



It may be said that 1879 was an exceedingly wet year at Rotham- 

 sted, the rainfall being 2.79, 3.48, 5.55, 4.24, and 6.56 inches for 

 the respective months April to August. 



In any consideration of these potato experiments, it should be 

 kept in mind that potatoes are a market-garden crop, and constitute 

 one form of intensive agriculture. An annual investment of $25 

 to $40 an acre for fertilizing materials is not beyond consideration 

 for a crop that may yield 300 bushels, that may be worth $150 

 an acre. 



In the last lines of Table 68 are given the average yields for the 

 first 6-year period and for the four successive 5-year periods, and, 

 finally, the average for the 26-year period, followed by the several 

 averages for the value of the increase and the cost of treatment. 



Since New York leads in the production of potatoes, the price 



