Phytoremediation and high rainfall combine to improve soil and plant health in a North America northern great plains saline sodic soil

A field study, conducted between 2017 and 2021, investigated the effect of phytoremediation on soil and plant health in a landscape containing productive, transition, and saline/sodic soils. Four phytoremediation treatments [none, corn, (Zea mays) and 2 perennial grass mixes] were examined. Perennial grasses were dormant seeded in winter 2017 and 2018 and corn was grown in 2018, 2019, and 2020. Soil samples (0- to 15-cm) were collected on 24 July 2018, 23 July 2019, 24 July 2020, and 15 April 2021. Across soil zones, corn production was 5,990, 3,900, and 6,150 kg ha-1 in 2018, 2019, and 2020, respectively, whereas in the perennial grass treatments yields were 1,220, 9,065, and 7,375 kg ha-1 in 2018, 2019, and 2020, respectively. High rainfall occurred between 2018 through summer 2019 and the depth to ground water, EC1:1, and Na decreased in all treatments, with phytoremediation reducing the Na/EC1:1 ratio. Drier conditions started in fall 2019 through spring 2021: 1) with the depth to groundwater increasing, 2) EC1:1 decreased in the productive soil and increased in the saline/sodic soil; and 3) the risk of soil dispersion (Na/EC1:1 ratio) increased in the productive and transition soils and was static or decreased in the saline/sodic soil. Phytoremediation when combined with high natural rainfall reduced soil EC1;1 and Na in all soils, however as the soil dried in the saline/sodic area EC1:1 increased. These findings suggest that northern Great Plains saline/sodic soils are interdispersed in fields containing very productive soil. These saline/sodic soils can have high nitrous oxide emissions (N(2)O) and can be rapidly eroded. We believe that planting perennial plants and not applying N fertilizer to these soils can reduced the impact of agriculture on the environment and provide habitat for wildlife.