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Grassland management influences the response of soil respiration to drought

In a study published in the journal Agronomy in March 2019, scientists demonstrated that farm management practices can alter the relationship between soil respiration and soil water content.

Marcenat Experimental Farm © Christophe Maitre
Updated on 05/10/2019
Published on 05/06/2019

How can we improve carbon sequestration in soils?

Increasing soil carbon stocks in agricultural grasslands has a strong potential to mitigate climate change. However, large uncertainties around the drivers of soil respiration hinder our ability to identify management practices that enhance soil carbon sequestration.

In a context where more intense and prolonged droughts are predicted in many regions, it is critical to understand how different management practices will temper drought-induced carbon losses through soil respiration.

Grazing and soil respiration

In this study, the scientists compared the impact of changing soil volumetric water content during a drought on soil respiration in permanent grasslands managed either as grazed by dairy cows or as a mowing regime. Across treatments, root biomass explained 43% of the variability in soil respiration (p < 0.0001). Moreover, analysis of the isotopic composition of CO2 emitted from the soil, roots, and root-free soil suggested that the autotrophic component largely dominated soil respiration. Soil respiration was positively correlated with soil water content (p = 0.03) only for the grazed treatment.

Their results suggest that the effect of soil water content on soil respiration was attributable mainly to an effect on root and rhizosphere activity in the grazed treatment. We conclude that farm management practices can alter the relationship between soil respiration and soil water content.

Find out more

Grassland Management Influences the Response of Soil Respiration to Drought
Gabriel Y. K. Moinet, Andrew J. Midwood, John E. Hunt, Cornelia Rumpel, Peter Millard and Abad Chabbi
Agronomy, March 2019, Volume 9, Issue 3, 124

On the subject of

Autotrophic?

An autotrophic organism is an organism capable of generating its own organic matter from mineral elements.