Soil and plant response to unused potassium silicate drilling fluid application

Abstract

Drilling fluid, also referred to as drilling mud, is a major waste from oil and gas drilling. Land application is a novel approach to potassium silicate drilling fluid (PSDF) waste recycling, addressing its disposal requirements while potentially improving soil quality for land reclamation. Inorganic nitrogen (N) and phosphorus (P) fertilizer (0, 34N: 45Pkgha−1) was added with PSDF (0, 30, 45, 60m3ha−1) as eight PSDF amendments. PSDF amendments were incorporated or sprayed on four reclamation soils (sand, loam, clay loam 1 and 2). Response to PSDF application was assessed in the greenhouse with two plant species (Hordeum vulgare L. (barley) and Agropyron trachycaulum (Link) Malte (slender wheat grass).PSDF amendments had no detrimental effects on soil quality (macronutrients, pH, salinity, sodicity) and plant growth except in clay loam 2 soil. In loam soil, barley height and biomass were greater with PSDF at 45m3ha−1 with fertilizer relative to soil without PSDF. In sand soil with PSDF at the highest rate without fertilizer, wheat grass height was 1.08 times and biomass was 1.76 times greater than the control. High electrical conductivity in clay loam 2 soil, and decreased density, height and biomass of wheat grass at highest PSDF application rates or with PSDF incorporation, suggest a threshold beyond which conditions are compromised for PSDF application. Increasing PSDF application rate increased soil potassium availability by 1.6–4.1 times relative to no PSDF. This initial research demonstrates that PSDF may be an appropriate soil amendment for agricultural crops and native plant species on land reclamation sites with consideration of substrates properties, plant species tolerances and inorganic fertilizer.