New York Agricultural Experiment Station. 597 



There are at least three important factors which should be 

 'considered in an attempt to buy and use commercial fertilizers 

 with profit. 



(1) The quantity of fertilizer to be applied should receive care- 

 ful consideration. Where a rapid rotation of crops is followed, 

 with severe cropping, this amount should not exceed that which 

 is necessary to secure the maximum profitable increase of the 

 immediate crop. The largest possible crop is not necessarily the 

 most profitable and a great excess of unused available plant 

 food, especially of nitrogen, at the end of the growing season 

 does not conduce to economy. 



(2) The fertilizer should be purchased, so far as possible, with 

 reference to both soil deficiencies and the needs of the crop. As 

 a rule the soil is the controlling factor. 



(3) The fertilizer applied should be one that will promote the 

 highest quality in the crop to be grown. 



With our present knowledge it is easier to state these princi- 

 ples than to point out their application to specific cases, and 

 much of the experimental work now being conducted in the field 

 of plant nutrition is directed towards answering the questions 

 which relate to these fundamental considerations. 



The farmers of Long Island are especially interested in all that 

 pertains to commercial fertilizers. In no part of New York are 

 these manures more largely purchased in proportion to the acre- 

 age of tilled land, and in but few localities do the conditions so 

 fully justify the very large money expenditure which this in- 

 volves. In the first place these farmers are in close proximity 

 to one of the world's largest markets, requiring an enormous 

 supply of market-garden and forcing-house products. Land so 

 situated must be worked intensively, which requires a liberal 

 and continuous use of manures. In the second place, much of 

 the soil in this locality does not possess great original fertility. 

 Its natural supply of available plant food is small, even with the 

 best of culture. Long Island farmers are obliged, therefore, to 

 go to the markets for a large part of the plant food which they 

 need in such generous quantities. An outlay of $800 to |1,000 



