Plant diurnal cycle drives the variation in soil respiration in a C-4-dominated tropical managed grassland exposed to high CO2 and warming

Author(s)

Dias de Oliveira, Eduardo Augusto ^[1] ; Manchon, Fernanda Tomita ^[2] ; Ricketts, Michael P. ^[1] ; Bianconi, Matheus ^[3] ; Martinez, Carlos Alberto ^[2] ; Gonzalez-Meler, Miquel A. ^[1]

Affiliation

^[1] Univ Illinois, Dept Biol Sci, Ecol & Evolut, Chicago, IL 60680 - USA

^[2] Univ Sao Paulo, Dept Biol Sci, Ribeirao Preto, SP - Brazil

^[3] Univ Sheffield, Dept Anim & Plant Sci, Sheffield, S Yorkshire - England

• Document type: Journal article
• Source: PLANT AND SOIL; v. 456, n. 1-2, p. 391-404, NOV 2020.
• Web of Science Citations: 0

Abstract

Aims To identify factors driving soil respiration (R-soil) in a tropical C-4-dominated perennial managed grassland ecosystem exposed to elevated carbon (C) dioxide concentration ({[}CO2]) and temperature. Methods The perennial grassPanicum maximumwas grown at 600 mu mol CO2 mol(-1)and + 2 degrees C above ambient temperatures for one full growing cycle (from grazing to regrowth for about similar to 30-45 days) using a free-air CO2 and infrared warming system. Plant growth and CO(2)fluxes were measured during the growing cycle. Results Both high {[}CO2] and warming increased canopy photosynthesis but warming alone increased biomass by 53% and R-soil by 26%. There was a strong diel effect on R-soil, which was 16% greater at noon than at 18:00 h. R-soil had low sensitivity to soil temperature (Q(10) similar to 1) regardless of the CO2 treatment. Conclusions In this tropical managed pasture, diel variation in photosynthesis strongly affected R-soil, suggesting that R-soil may be more limited by substrate availability than abiotic factors such as temperature. Predicted changes in climate for the region will likely affect the C dynamics of C-4-dominated tropical pastures. Although, the short-term experiment may limit the extrapolations of our findings, the highly controlled settings of the experiment highlighted the role of canopy photosynthesis on R-soil respiration in tropical C-4-pastures. (AU)

• FAPESP's process: 08/58075-8 - Miniface climate-change impact experiment to analyze the effects of elevated CO2 and warming on photosynthesis, gene expression, biochemistry, growth, nutrient dynamics and yield of two contrasting tropical forage species
• Grantee: Carlos Alberto Martinez y Huaman
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 14/00317-7 - Flux of carbon and greenhouse gases in a pasture ecosystem constituted by Panicum maximum Jacq. and Stylosanthes capitata Voegel cultivated under elevated CO2 and warming in a FACE/T-FACE system
• Grantee: Eduardo Augusto Dias de Oliveira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral