COMMERCIAL FERTILIZEES FOR 

 POTATOES. Ill* 



W. H. Jordan. 



SUMMARY. 



(1) Experiments in potato growing conducted for four years 

 on four Long Island farms with fertilizers varying in quantity 

 from 500 lbs. to 2,000 lbs. per acre show that on the average the 

 largest profit was realized from the use of 1,000 lbs. 



(2) The so-called Long Island formula, 4, 8 and 10, proved to 

 be superior to a potato formula, 7, 4 and 10. 



(3) Experiments with varying quantities of potash gave results 

 which do not justify the use of such large quantities of this in- 

 gredient as are now being applied in potato growing by many 

 Long Island farmers whose conditions are similar to those under 

 which these tests were made. 



(4) It is clearly evident that a large supply of available plant 

 food does not necessarily insure a satisfactory crop. Other con- 

 ditions which largely pertain to culture, such as texture, humus 

 and water supply, exercise a controlling influence, and when these 

 conditions are unfavorable their effect is not overcome by heavy 

 applications of fertilizer. 



INTRODUCTION. 



Experiments in the use of commercial fertilizers in growing 

 potatoes were begun on Long Island in 1895. Tlie results pre- 

 viously reached have been reported in four bulletins, Nos. 93, 



•Reprint of Bulletin No. 187. 



