PHOSPHATES IN MASSACHUSETTS AGRICULTURE. 145 



Asparagus — Com'parative Results, Phosphoric Acid and Potash, 1914. 

 (Yield and Increase per Plot. ^) 



Acid Phosphate. 



Amount applied per Plot 

 (Pounds). 



Yield. 



Pounds. 



Ounces. 



None, 

 15.00, 

 22.50, 

 30.00, 



404 

 420 

 436 

 436 



Increase. 



Pounds. 



Ounces. 



Muriate of Potash. 



None, 

 8.67, 

 13.00, 

 17.33, 



' Oae-twentieth of an acre. 



The objection may possibly be raised — as in the case of the soil test 

 work, in which some of the results cited for corn and other crops were 

 obtained — that the potash being used at a greater rate per acre than 

 the phosphoric acid, the comparison may be misleading. If, however, 

 phosphoric acid be the element present in minimo, certainly even a very 

 moderate apphcation should give a notable increase in crop; and further, 

 if it be the element in minimo and our application be too small, no amount 

 of potash could exercise much effect, for it cannot take the place of phos- 

 phoric acid. 



Yet further, in view of the facts that the ratio of phosphoric acid to 

 potash is 1 to 3 in the crop (spring shoots), while in our apphcations the 

 ratio between the two is 1 to 1.9, it can scarcely be urged that we are 

 using phosphoric acid in disproportionately small amounts. 



So]) Beans, Oats and Rye. ■ — Soil test experiments with soy beans have 

 given much larger increases in crop with potash than with phosphoric 

 acid. Similar experiments with oats and rye have shown a relatively 

 small superiority for the potash. Neither is the dominant element for 

 these crops. 



Cniciferce. — Absolutely the only crops which have ever responded 

 in our soil test work more largely to an application of phosphoric acid 

 than to one of potash are those belonging to CrKciferce, such as the cab- 



