Restoring Ecological Function to South Dakota Saline/Sodic Soils Using Perennial Grass Mixtures

Revegetation of saline/sodic soils is extremely challenging. Over 10 million saline/sodic hectares are intertwined with highly productive soils in the Northern Great Plains with 3.4 million hectares in South Dakota. Chemical amendments and tile drainage have not improved conditions for row crop production. Establishing salt-tolerant perennial plants provides soil cover and remediates degraded barren areas. Two mixes of perennial salt-tolerant grasses [slender wheatgrass + beardless wildrye (Mix 1); or slender wheatgrass + creeping meadow foxtail + western wheatgrass + AC Saltlander green wheatgrass (Mix 2)] were dormant planted in two years (2018 and 2019) along a soil catena having high (EC1:1 = 0.39 dS m–l; 72 mg kg–1 Na+); moderate (EC1:1 = 1.64 dS m–l; 343 mg kg–1 Na+); and low (EC1:1 = 3.87 dS m–l;1680 mg kg–1 Na+) productivity zones. Vegetative biomass was measured after grass seeding (2018 and 2019) and during subsequent growth (2020 and 2021) and compared areas seeded to maize and a nonplanted area. Biomass varied with year and productivity zone. Except for 2018 (the first year after the first fall seeding), grasses generally had greater biomass in the moderate and low productivity zones than maize (Zea mays L.). Sodium content in 2020 and 2021 grass biomass was 10 times greater in vegetation collected in the low than the high and moderate productive zones (0.25% vs 0.02%, respectively). However, if good quality water is available, this forage is suitable for livestock feed. By 2021, grass biomass was similar for both mixes in all productivity zones and grasses spread into nonplanted areas