Chemical Amendments for Sodium Leaching in Saline-Sodic Soil.

In the northern Great Plains, the drainage of saline/sodic soils (Natrustolls, Natraquolls, and associated Argiustolls) can result in soil dispersion.  The objective of this study was to determine the impact of soil chemical treatment on sodium leaching.  Undisturbed 15 cm x 30 cm soil columns were collected from White Lake, Redfield and Pierpont, SD. In soil collected adjacent to each column, the EC (electrical conductivity) and Na content of saturated paste using a water extract was determined.  Soils in the columns had SAR (sodium adsorption ratio) values ranging from 1 to 22.  The amount of Na leached following the surface application of equivalent amounts of gypsum, calcium chloride, and sulfuric acid will be determined.  Leached Na was influenced by surface treatment and the initial Na content in the column. Analysis of covariance suggests that sulfuric acid was more effective in promoting Na loss than gypsum in the White Lake column study. All 3 sites combined analysis will provide insight on Na leaching mechanism under different soil properties with different treatment options.