LOSSES or MOISTURE AND PLANT FOOD BY PERCOLATION. 47 



TABLE NO. 20. 

 Potash in Milligrams Per Part from Untreated Soils and Soils Which Received Potash. 



We must take into consideration the fact that these soils were un- 

 cropped and uncultivated, and that all the water which fell on the soil 

 either evaporated or went through. Growing crops would, of course, 

 use the potash in solution, and decrease the percolation of water, as they 

 evaporate it also. Hence the loss of potash due to the fertilizer would 

 be less on a cropped soil. "We should judge from, these results that 

 there is little loss of potash of fertilizer, due to percolation, when the 

 potash is applied to a soil on which crops are growing. Even on the 

 light sandy soil, the Norfolk sand, there should be only small loss, if any. 



Table No. 21 shows the loss of potash in pounds per acre, from the 

 uncultivated, unfertilized, uncropped soils, to which no fertilizer had 

 been applied. The loss varies from 9.7 to 66.6 pounds per acre. These 

 losses would, of course, be much less when crops are grown on the soil. 



TABLE NO. 21. 

 Average Loss Per Year in Pounds Per Acre. 



Let us assume that a bushel of corn requires one pound of potash. 

 Then the quantity of potash lost by percolation would produce the quan- 

 titv of corn given in the following table. We also give the average 

 active potash content of these soils, and the corn possibility as based on 



