MOVEMENTS OF SALTS IN SOILS. 



69 



CAPILLARY CONCENTRATION OF SALTS UNDER FIELD CONDITIONS. 



Field studies relating to this subject were made by the writer 

 and Mr. J. O. Belz during the season of 1901*, which demon- 

 strated that, under the conditions of furrow irrigation, on both 

 a medium clay loam and on a light, sandy soil very notable 

 movements of nitrates occur through downward, lateral and up- 

 ward capillarity ; and it appears from those studies that the in- 

 fluence of the lateral capillary sweeping of salts was great enough 

 to be reflected in the yield of potatoes across a distance of more 

 than 6 feet or in the third row away from the last irrigated fur- 

 row. 



As an illustration of the magnitude and rapidity of the 

 movement of nitrates in field soils, resulting from capillary 

 action, after irrigation by the furrow method, and to show what 

 must often take place after heavy rains where ridge and furrow 

 cultivation is practiced, as is so generally done in many parts 

 of the South, the following observations are cited : 



IN A COARSE SANDY SOIL. 



A field of potatoes, on coarse sandy land, at Stevens Point, 

 Wis., with rows 3 feet apart and hilled, was examined for 

 nitrates under and between the rows just before it was to be 

 irrigated. The same rows were again examined for nitrates at 

 different intervals after the water had been applied. Four 

 series of observations were made upon this sandy soil and the 

 results are given in the next table : 



Concentration of nitrates by lateral capillary movement in xandy 



soil. 



* United States Department of Agriculture, Office of Experiment Stations, 

 Bulletin. No. 119, p. 345. 



