New York Agricultural Experiment Station. 



609 



Relation of Yield of Potatoes to the Amount of Fertilizer 



Applied. 



The figures given below show the average results from all the 

 experiments, and also from the two experiments, that, because 

 of the freedom of the vines and tubers from disease, and other 

 favorable conditions, proceeded in the most satisfactory manner. 



Table IV.— Increase of Yield from Different Quantities of Fertilizers. 



Amount of 

 fertilizer 

 per acre. 



Pounds. 



500 



1,000 



1,500 



2,000 



Average of All 

 expbrimknts. 



Increase 



large 



tubers. 



Bushels. 

 27.5 

 48.1 

 .55.9 

 55.6 



Total 

 increase. 



Bushels. 

 28.2 

 46.9 

 52.5 

 53 



Average op 

 Fleet and Hallock. 



Increase 



large 



tubers. 



Bushels. 

 34.1 

 69.1 

 77.5 



78.7 



Total 

 increase. 



Bushels. 

 31.6 

 62.3 

 65.1 

 71.3 



These figures show very plainly that an addition of fertilizers 

 above 1,000 lbs. per acre produced a very small increase of crop. 



The first 500 lbs. caused a marked increase of yield, as also did 

 the second. Moreover, the rate of production was proportionate 

 to the quantity of fertilizer used up to 1,000 lbs. per acre. The 

 crop from 1,500 lbs. of fertilizer was somewhat larger than from 

 1,000 lbs., but not enough so to warrant the extra expenditure, 

 as will be seen later. The production of merchantable tubers 

 with 2,000 lbs. of fertilizer was practically the same as with 

 1,500 lbs. 



Relative Yield from the Potato Formula and the Long 



Island Formula. 



The " potato " formula is supposed to supply the important 



elements of plant food in the proportions and amounts needed by 



the entire plant for a profitably large crop. The Long Island 



formula is the 4-8-10 fertilizer so largely in use by Long Island 



farmers. 



39 



