CHAPTEE XIII. 

 WHERE WINTER WHEAT IS THE MONEY CROP. 



A study of the manurial requirements of the wheat crop, at more than 

 one Station, have shown that potash applied alone to the crop, has, on a 

 typical wheat soil, hardly any appreciable effect. At the Virginia Station it 

 was found that nitrogen gave some increase of yield, but not enough to pay 

 the cost of the application. That potash and nitrogen applied together gave 

 no better results than when applied separately. Their combination was in- 

 ferior to the results obtained from a separate application of phosphoric acid. 

 Phosphoric acid doubled (or more than doubled) the yield of straw and 

 grain every year, and gave profitable returns. In combination with either 

 potash or nitrogen it was unmistakably effective. It gave better results in 

 combination with nitrogen than with potash. These experiments were made 

 on a fertile limestone-valley soil. The Delaware Station found that the 

 combination of phosphoric acid and potash was most effective on their soil. 

 Many years ago the farmers in the upper counties of Maryland and Delaware, 

 on the Peninsula, found that on their soil they got as good returns in the 

 wheat crop, from the simple application of acid phosphate, as from the use 

 of a complete fertilizer, when they used a short three year rotation. For 

 many years, in the finest wheat growing section of Maryland and Delaware, 

 hardly any fertilizer except acid phosphate, has been used by the best wheat 

 farmers. The Delaware Station has tried to show them that a small addition 

 of potash would be an advantage on their soil. But few have been induced 

 to change their practice. An old and intelligent farmer of Queen Anne 

 county, Maryland, recently wrote to me that he had used no other fertilizer 

 than simple acid phosphate, for twenty or more years, and that with his rota- 



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