Soil Amendments to Reclaim Salt-Affected Natural Gas Well Pads: Gypsum, Sulfur, and Langbeinite with Compost.

Energy development in arid regions frequently requires disturbance of naturally salt-laden soils, which can introduce subsurface salts and clays to topsoil during reclamation. Excess salts can cause phytotoxicity, osmotic stress, and inhibit C and N mineralization; excess Na degrades soil structure by dispersing clays, causing poor water infiltration and conductivity in the soil. The objective of this study is to evaluate the use of gypsum, elemental sulfur, and langbeinite as chemical soil amendments to reclaim one sodic and one saline-sodic natural gas well pad, under the field conditions of low rainfall, no supplemental water, and logistical and economical restraints associated with arid region reclamation. Another objective of this study is to evaluate the capacity of municipal solid waste (MSW) compost to improve the dissolution and overall success of these chemical amendments by applying each chemical amendment alone and with compost. Eight treatments were applied as follows: gypsum, gypsum + compost, sulfur, sulfur + compost, langbeinite, langbeinite + compost, compost alone, and a control. Treatments were replicated four times for a total of 32, 7- by 7-m plots on each site of the two sites. All amendments were incorporated to a depth of 15 cm. Samples were taken in summer 2012 for pre-treatment, and in summer 2013 and 2014 for post-treatment, at 0-5 and 5-15cm. Soil was analyzed for texture, dry bulk density, dry and water-stable aggregate distributions, Ca, Mg, K, and Na concentrations, electrical conductivity (EC), pH, carbonates, organic C, total N, root biomass, and final CO₂ respiration.  Results of this two year study will compare the success of these chemical amendments under arid field conditions, their success with and without compost, and their impacts on chemical, biological, and physical soil properties. Final results will be compiled after summer 2014 sample collection and analysis.