Gypsum, langbeinite, sulfur, and compost for reclamation of drastically disturbed calcareous saline–sodic soils

Abstract

Soil disturbance during arid region energy development often redistributes subsurface salts, including sodium (Na), to the surface. Elevated Na degrades soil structure and inhibits germination and establishment of native plants important for ecosystem functions. Strategies for rapid reclamation of thin surface horizons are needed. Study objectives were to evaluate chemical amendments and compost for remediation of saline–sodic soils on a well pad that had electrical conductivity (EC) of 8.7 dS m⁻¹ and exchangeable sodium percentage of 38.6% following reclamation practices in south-central Wyoming. Eight treatments applied in October 2012 included gypsum, langbeinite, and elemental sulfur (S) with and without compost, plus compost alone, and an untreated control. Plots were sampled four times over 1 year at depths of 0–3, 3–8, and 8–15 cm. Samples were analyzed for exchangeable plus solution concentrations of Na, calcium (Ca), magnesium (Mg), and potassium (K). Results indicate that Na was leached from surface soils in all the treatments and the untreated control. Langbeinite most effectively enhanced movement of Na and caused initial increases in salinity that abated within 1 year. Gypsum enhanced movement of Na to lesser degree, and movement under S and compost was equivalent to untreated controls. Added compost did not affect activity of langbeinite, gypsum, or S. Langbeinite effectively reduced sodicity, but high cost and initial increases in soil salinity warrant additional investigation of appropriate application rates and alternative management practices, such as delaying planting until high-salinity abates.