xl Department of Soil Technology 



and percolate through the soil, and the percolate was collected, measured, 

 and analyzed. Crops were grown each year in some of the tanks, and 

 others were kept bare of vegetation all the time. 



The average annual rainfall for the five years was 31.14 inches, of which 

 24.40 inches, or 78.35 per cent, percolated through the unplanted soil 

 and i6.g6 inches, or 54.46 per cent, through the cropped soil. Thus about 

 one-fourth of the rainfall was utilized by the plants. The average evapo- 

 transpiration ratio for the cropped soil was i : 580, the crops being maize, 

 oats, timothy, clover, and mixed grasses. The average minimum 

 transpiration ratio for the same crops was 1:290. The minimum tran- 

 spiration ratio was least for maize and greatest for the grasses, while oats 

 were intermediate. 



Although the crops were large, amounting in the case of maize to over 

 one hundred bushels of grain to the acre, there was never a deficiency 

 of moisture in the soil, which illustrates the great water-holding capacity 

 of a well-drained soil. 



The data on the nitrogen removed in crops and by drainage water 

 appear to support the idea that certain kinds of higher plants have a 

 depressing influence on the production of nitrates in soil. 



Cropping the soil resulted in a conservation of calcium as compared 

 with leaving the soil bare, as shown by the fact that the drainage water 

 from the unplanted soil contained 180 pounds more calcium per acre 

 than did the crops and drainage water combined from the planted soil. 

 The greater removal of calcium from the unplanted soil was due in part 

 to the larger quantity of nitric acid in the drainage of this soil, and in part 

 to a greater removal as bicarbonate. 



Concerning the question as to the effect of applications of calcium 

 on the liberation of soil potassium, the data indicate that in this soil 

 there was no such substitution. On the other hand, applications of 

 potassium sulfate markedly increased the removal of calcium and to a 

 less extent that of magnesium. 



The removal of sulfirr in the drainage water was from three to six 

 times as great as in the crops. There was as much earned off by the 

 drainage water from the unplanted soil as by both drainage water and 

 crops from the planted soil. The application of lime was accompanied 

 by an increase in the quantity of sulfur in the drainage water. Of. the 

 sulfur added annually to the soil in the form of potassium sulfate, more 

 than one-half was removed in the drainage. 



Investigation under the Hatch fund. — There is one project under the 

 Hatch fund, the designation of which is " The composition and properties 

 of certain soil types and the effect of some plants when grown on them." 



An experiment in fertilizing a six-years rotation of crops has reached 



