No. LJ COMMERCIAL FERTILIZERS. 12i) 



the luutit expensive element to supply, costing, on the average, 

 four to live times as much per ponnd as the minerals. 



As a rule, too, soils that have been worked for a long 

 time show a greater deficiency in nitrogen than in the min- 

 erals, — probably due in part to the greater liability to 

 loss of nitrogen. In fact, all data we have point to the ne- 

 cessity of a liberal use of nitrogen if we are to obtain 

 maximum yields, and its rational use if we are to obtain 

 jjaying crops of this character. 



For these crops, therefore, we must adopt a method which 

 will encourage the largest use of soil supplies, as well as 

 to furnish the nitrogen in such amounts and forms as will 

 be utilized to the fullest extent, and applied at the time when 

 the plant is in the greatest need and absorbs it most com- 

 pletely. 



The profitable use of fertilizers for these crops depends 

 largely upon this point, viz., the utilization of the element, 

 nitrogen, both in the soil and in the materials applied. The 

 use of the soil nitrogen will, furthermore, depend upon the 

 use of minerals, for the liberal use of minerals will stimu- 

 late and encourage the plant to draw more heavily upon the 

 soil supply of this element. Following these suggestions, 

 and keeping in mind the fact that we are growing crops 

 of a high fertility value, a general formula which will furnish 

 a maximum supply of mineral constituents which are liable 

 to be useful for all crops in the rotation is used. We have 

 found that a formula made up of ground bone, 100 pounds, 

 acid phosphate, 100 pounds, muriate of potash, 50 pounds, 

 per acre will furnish enough of the mineral constituents, es- 

 pecially, to provide for such an increase in crop as will more 

 than pay for the fertilizers used and the expense involved, 

 and leave a residue available for other crops, as the kind 

 of materials used are such as to provide against such changes 

 as will result in fixed or insoluble com}X)unds, — the phos- 

 phoric acid being partly drawn from organic sources, and 

 thus gradually converted to available forms. 



The cost of this formula, if the materials are purchased 

 in their oric:inal form, would not be heavy (not to exceed 

 $4 per acre), and could be applied to each crop in the rota- 



