Soil Chemical Treatment Impact On Na Leaching In Northern Great Plains Sodium Effected Soils.

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.   Sixteen, undisturbed 15 cm diameter soil columns that were 30 cm long were collected from White Lake, SD (43° 40' 40" N and 98° 45' 50" W) in the fall of 2012.  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 3 to 20.  The amount of Na leached following the surface application of equivalent amounts of gypsum, calcium chloride, and sulfuric acid was determined.  The ratio between the total Na leached and Na contained in the saturated paste was 4.1, 5.1, 4.7, and 3.4 for gypsum, calcium chloride, sulfuric acid and control treatment respectively. 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.