Wheat Growth in Soils Treated by Ex Situ Thermal Desorption

Successful remediation of oil‐contaminated agricultural land may include the goal of returning the land to prespill levels of agricultural productivity. This productivity may be measured by crop yield, quality, and safety, all of which are influenced by soil characteristics. This research was conducted to determine if these metrics are affected in hard red spring wheat ( Triticum aestivum L. cultivar Barlow) when grown in soils treated by ex situ thermal desorption (TD) compared with wheat grown in native topsoil (TS). Additionally, TD soils were mixed with TS at various ratios to assess the effectiveness of soil mixing as a procedure for enhancing productivity. In two greenhouse studies, TD soils alone produced similar amounts of grain and biomass as TS, although grain protein in TD soils was 22% (±7%) lower. After mixing TS into TD soils, the mean biomass and grain yield were reduced by up to 60%, but grain protein increased. These trends are likely the result of nutrient availability determined by soil organic matter and nutrient cycling performed by soil microorganisms. Thermal desorption soil had 84% (±2%) lower soil organic carbon than TS, and cumulative respiration was greatly reduced (66 ± 2%). From a food safety perspective, grain from TD soils did not show increased uptake of polycyclic aromatic hydrocarbons. Overall, this research suggests that TD soils are capable of producing safe, high‐quality grain yields. Core Ideas Wheat was grown in crude oil‐contaminated soil remediated using thermal desorption. Remediated soil matched topsoil in grain yield, but grain protein was decreased. Mixing topsoil with remediated soil decreased yield but increased grain protein. Grain from remediated soil contained no more petroleum hydrocarbons than topsoil. Mixing topsoil with remediated soil decreased the C:N ratio and increased respiration.