Application of routine Mehlich‐3 and EC ratio tests for salinity and sodicity management in Delmarva coastal croplands

Abstract The Delmarva Peninsula in the Eastern United States faces growing threats from saltwater intrusion, necessitating accurate and timely salinity diagnostics to reduce crop productivity losses. The globally recognized saturated paste (SP) extraction method, which yields critical measures, including electrical conductivity (EC e ), is labor‐intensive, costly, and generally unavailable in routine Eastern U.S. laboratories, creating logistical barriers for effective management. The objective of this study was to establish the utility of converting routine Mehlich‐3–extractable sodium (M3‐Na) results directly into standard SP equivalents and to present additional region‐specific conversion relationships to improve the accessibility of salinity and sodicity risk assessments. We analyzed 291 soil samples collected from 13 salt‐affected Delmarva agricultural fields (2020–2023) using standard SP methods, rapid EC measurements (EC 1:2 , EC 1:5 ), and M3 and ammonium acetate extractions. Strong linear correlations were observed between M3‐Na and the rapid EC methods; EC 1:2 proved to be an efficient proxy for EC e . These reliable, region‐specific conversion models (e.g., EC e = 2.11 × EC 1:2 and EC e = 1.13 × M3‐Na without intercept) enable laboratories to efficiently report critical EC e values and perform timely screening for salinity and the associated sodicity risk using existing M3 data, effectively eliminating financial and logistical barriers for managing salt‐affected soils in the Mid‐Atlantic.