Plants reduced nitrous oxide emissions from a northern great plains saline/sodic soil

Authors: CLAY, SHARON - South Dakota State University; NLEYA, THANDIWE - South Dakota State University; CLAY, DAVID - South Dakota State University; JOSHI, DEEPAK - South Dakota State University; BHATTARAI, DWARIKA - South Dakota State University; Marzano, Shin-Yi; PETLA, BHANU PRKASH - South Dakota State University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2024
Publication Date: 4/29/2024
Citation: Clay, S., Nleya, T., Clay, D., Joshi, D., Bhattarai, D., Marzano, S.L., Petla, B. 2024. Plants reduced nitrous oxide emissions from a northern great plains saline/sodic soil. Agronomy Journal. 116(3):1343-1356. https://doi.org/10.1002/agj2.21573.
DOI: https://doi.org/10.1002/agj2.21573

Interpretive Summary: Saline/sodic soils of the Northern Great Plains are often barren, dispersed, and support a limited number of ecosystem services. In this study, nitrogen cycle genes (nirS, nirK, and nosZ) controlling the nitrous dioxide (N2O) release during denitrification were quantified after vegetation was established in the saline/sodic soil. Established plants in a saline/sodic soil reduced the abundance of nirK, nirS genes and increased nosZ. In greenhouse study, barley, Florida broadleaf mustard, and Kernza wheatgrass reduced N2O emissions from the saline/sodic soil. Because N2O is nearly 300 times more potent than CO2 as a greenhouse gas, establishing plants in the degraded saline/sodic areas will help restore ecological function to these areas.

Technical Abstract: Fertilizer-derived N2O-N emissions from northeastern South Dakota barren saline/sodic soils (EC1:1 and %Na values of 6.23 dS/m and 33.87%, respectively) were over 57% greater than from productive soils (EC1:1 and %Na values of 0.56 dS/m and 1.4%, respectively). The nirS gene copy number in the saline soil was 42-fold greater than productive soil. In this study, nitrogen cycle genes (nirS, nirK, and nosZ) were examined after vegetation was established in the saline/sodic soil using qPCR techniques. Plants in the saline/sodic field soil reduced nirK (-80%) and nirS (-32%) copies, whereas nosZ copies increased 4-fold compared with numbers from barren areas. In a replicated 63-day greenhouse study, CO2-C and N2O-N emissions were quantified from productive soil and a saline/sodic soil taken from a barren area when planted with three different plant species [barley (Hordeum vulgare), Florida broadleaf mustard (Brassica juncea), and Kernza wheatgrass (Thinopyrum intermedium)] and compared with no-plant controls. Emissions were measured six times daily from day 1 (planting) to 22 days after planting (DAP) and from 42 to 63 DAP. Plant and microbial biomass and mineral uptake were measured. CO2-C emissions were greater from both soils when plants were present. N2O-N emissions from no-plant controls were 10 times greater from the saline/sodic soil compared to the productive soil. Plants in the saline/sodic soil reduced N2O-N emissions from 30 (Kernza wheatgrass) to 90% (barley). Plant establishment in saline/sodic soils is essential to stabilize soil and reduce N2O-N emissions.