Lysimeter Experiments 



61 



caused a liberation of calcium and of magnesium, the potash of this 

 fertilizer was practically all absorbed by the soil. The rapid leaching 

 of a potash fertilizer from a clay loam soil is not a danger. 



REMOVAL OF SODIUM 



Of the four bases studied, sodium was, with the exception of magnesium, 

 removed in the least quantity in the crops produced, and, with the 

 exception of calcium, in the greatest quantity in the drainage water. 

 The average amounts of sodium (Na) removed annually from the soil 

 by drainage water during the five-years period, and by crops during the 

 first four years of the period, are given in table 49: 



TABLE 49. Sodium in Drainage Water and in Crops 

 (Pounds per acre, annual average) 



Very little sodium is removed in the crops as compared with that leached 

 out by the drainage water. There was not a great difference between 

 the planted and the unplanted soils so far as the total removal is concerned. 



Effect of plant growth on removal of sodium 



Sodium is like calcium and magnesium, and differs from potassium, in 

 that it is removed in greater quantity from the unplanted soil than from 

 the planted soil. Since it is not essential to plant growth its loss is not 

 so serious as is that of the other three bases; but the lack of it tends to 



6i 



