PHOSPHATES IN MASSACHUSETTS AGRICULTURE. 153 



Phosphate Field, 1899-1914- Increase over No-Phosphate Plots in Per Cent. 



Natural 



Mineral 



Phosphates. 



Corn, three years: — 



Grain 



Stover, 



Hay, two years: — 



Hay 



Rowen, .... 

 Total, 



Onions, two years: — 



Sound, ..... 

 ScalUons, .... 



Cabbage, two years (total). 



Oat hay, one year, . 



Hungarian hay, one year, 



Ensilage corn, one year, . 



Soy beans, one year: — 



Beans 



Straw 



Potatoes, one year: — 

 Marketable, 

 Total 



Oats and alfalfa hay, one year. 



Alfalfa hay, one year. 



-1.48 

 5.83 



5.28 



—11.34 



3.08 



-17.75 

 12.86 



116.01 

 4.22 

 4.30 



—4.42 



2.54 

 10.43 



—4.00 

 —2.97 



2.00 

 11.49 



1. The tabulation of averages shows that, with one exception, the per- 

 centage increases in crops of all kinds produced by the natural mineral 

 phosphates are far smaller than those produced by the other classes of 

 phosphates. The single exception is Hungarian hay grown as a second 

 crop in 1900 without a second application of fertilizers. This exception, 

 therefore, has no special significance in its bearing upon the relative 

 efficiency of the classes of phosphates under consideration. 



2. It will be noted that in a number of cases the averages for the slag 

 and bone meals are higher than for the dissolved phosphates. It should be 

 pointed out that in two respects the materials in the former class differ 

 from those in the latter: (1) the slag meal furnishes some free lime and a 

 considerable excess of lime in neutral combinations; (2) the bone meals 

 supply some nitrogen in organic combinations. 



It has been pointed out ^ that an attempt to equahze the organic nitro- 

 gen of the bone meals was made by the addition of hoof meal to the plots 

 receiving other phosphates. It is generally held that the availability of 

 the organic nitrogen in bone meals and in hoof meal is substantially equal, 

 but in some experiments this has not seemed to be the case. No doubt 

 the availabiUty in both is much affected by fineness of grinding. 



I See p. 149. 



