Evaluating Soil Amendment Options to Reconcile South Dakota Degraded Saline / Sodic Soils.

Saline and sodic soil problems are reducing arable land use in the Northern Great Plains (NGP) of the United States at an increasing rate.  In many watersheds, a rising water table linked to increased rainfall have contributed to the transport of salts contained in subsoil sediments to surface soils.  Increasing NGP acres affected by saline and sodic soils are attributed to policy changes (reduced CRP acres, higher agland taxes), changes in climate (warmer spring temperatures), decreased crop prices, land-use changes, and changes in producers’ perception that their ‘under-utilized’ land will produce high crop yields if the water issues are addressed with agriculture drain tile installation.   The traditional approach to remediate a saline/sodic soil in the arid, irrigated regions of the Southwestern United States is to: 1) apply water with a low electrical conductivity (EC), 2) add a soil amendment that will release calcium in the soil for exchange with sodium; for example, gypsum and 3) allow for adequate drainage, which is most commonly done by installing agriculture tile drainage.  The results of a three year study using soil amendments to remediate saline/sodic soils will be presented.  Soil amendments of calcium chloride, gypsum, or elemental sulfur were applied to saline sodic soils in fall 2012 or spring 2013.  Select soil amendments slightly reduced the soil sodium absorption ratio (SAR).  SAR values decreased on average about 2 points; from SAR = 15 to 13 at some locations.  While slight decreases in SAR values were observed with certain location and amendment combinations, the traditional approach to remediate saline/sodic soils in the NGP did not provide adequate reclamation of the land over the three year study period.  Environmental factors that prevent rapid reclamation of these land parcels will be presented and potential alternative management approaches will be discussed.