Corn and Soybean Yield Response to Salinity Influenced by Soil Texture

Soil salinization is a global issue affecting 831 million ha of arable land and resulting in approximately US$27.3 billion in crop losses annually. The purpose of our research was to determine the effects of natural gradients in soil salinity on field-grown corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] in silty clay loam and sandy loam soils in southeastern North Dakota. Both corn and soybean yield were hand-harvested at the ends of the 2014 and 2015 growing seasons and related to the electrical conductivity (ECe) of the root zone using the modified discount response function (MDRF). Neither corn nor soybean yields demonstrated significant declines when grown in finer-textured soil. Contrarily, when corn and soybean were grown in sandy loam soils, significant declines occurred. Calculated values at which 50% yield reductions occurred (EC50) in sandy loam soil resulted in salinity tolerance indices (STI) of 9.68 for corn and 7.04 for soybean. The lack of yield declines for both crops in silty clay loam soil may indicate a reduced effect of salinity stress in finer textures. Additionally, the composition of ions in the soil solution may also play a role in crop response to salinity.