Glomalin contribution to soil organic carbon under different pasture managements in a saline soil environment

• Published in: Archiv für Acker- und Pflanzenbau und Bodenkunde Vol. 68; no. 3; pp. 340 - 354
• Main Authors: Banegas, Natalia, Dos Santos, Daniel Andrés, Guerrero Molina, Fernanda, Albanesi, Ada, Pedraza, Raúl
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 23.02.2022; Taylor & Francis Ltd
• Subjects: Arbuscular mycorrhizas; Biomass; Carbon; carbon sinks; Chloris gayana; Continuity (mathematics); edaphic factors; Fertilization; glomalin; glomalin-carbon content; Grazing; Nitrogen; Nutrient cycles; Nutrients; Organic carbon; Pasture; Pasture management; pastures; perennial grasses; Saline soils; Soil environment; soil organic carbon; Soil profiles; Soil properties; Spores; total glomalin; total nitrogen; tropical perennial-grasses; vesicular arbuscular mycorrhizae
• ISSN: 0365-0340; 1476-3567; 1476-3567
• DOI: 10.1080/03650340.2020.1834536

The glomalin produced by arbuscular mycorrhizal fungi has beneficial effects on soils. We studied the vertical profile of glomalin-related soil protein (GRSP) in pasturelands grown under saline soils and exposed to different management practices. Treatments included haying and grazing of Chloris gayana subject to either N-fertilization or not. We measured mycorrhizal colonization, spores, root biomass, total GRSP, GRSP-carbon (GRSP-C), organic carbon (OC) and total nitrogen (TN). In the meanwhile, we also developed a mathematical procedure to fit continuous power functions to binned soil data. Power decay functions adjusted excellently well the measured data across the 1-meter soil profile. Meaningful increases of root biomass, OC, TN, GRSP and GRSP-C values were associated with grazing and fertilization. Particularly, GRSP-C averaged 1,134 kg C ha −1 at the beginning experiments and increased significantly up to 1,261 kg C ha −1 in grazed and fertilized pastures at the end of the study period. Carbon accounted for between 17% and 50% of GRSP, representing in turn 0.52-1.62% of SOC stock. So, a tropical perennial grass can contribute to the carbon stock in saline soils by promoting production of GRSP. This contribution increases when inputs and cycling of nutrients are enhanced (grazing and N-fertilization).