Exchange of greenhouse gases between soil and atmosphere: interactions of soil physical factors and biological processes

Abstract

Summary This review examines the interactions between soil physical factors and the biological processes responsible for the production and consumption in soils of greenhouse gases. The release of CO2 by aerobic respiration is a non‐linear function of temperature over a wide range of soil water contents, but becomes a function of water content as a soil dries out. Some of the reported variation in the temperature response may be attributable simply to measurement procedures. Lowering the water table in organic soils by drainage increases the release of soil carbon as CO2 in some but not all environments, and reduces the quantity of CH4 emitted to the atmosphere. Ebullition and diffusion through the aerenchyma of rice and plants in natural wetlands both contribute substantially to the emission of CH4; the proportion of the emissions taking place by each pathway varies seasonally. Aerated soils are a sink for atmospheric CH4, through microbial oxidation. The main control on oxidation rate is gas diffusivity, and the temperature response is small. Nitrous oxide is the third greenhouse gas produced in soils, together with NO, a precursor of tropospheric ozone (a short‐lived greenhouse gas). Emission of N2O increases markedly with increasing temperature, and this is attributed to increases in the anaerobic volume fraction, brought about by an increased respiratory sink for O2. Increases in water‐filled pore space also result in increased anaerobic volume; again, the outcome is an exponential increase in N2O emission. The review draws substantially on sources from beyond the normal range of soil science literature, and is intended to promote integration of ideas, not only between soil biology and soil physics, but also over a wider range of interacting disciplines.

Improving rice production sustainability by reducing water demand and greenhouse gas emissions with biodegradable films

“…As also observed in other studies353637, the N 2 O emissions were largely influenced by the soil temperature, WFPS, and mineral N concentrations. Thus, lower N 2 O emissions for the CP can be explained by the strongly reductive soil conditions, which hamper the microbial oxidation of NH 4 + to NO 3 − by nitrification.…”

“…Thus, the N 2 O emissions in the GCRPSs were stimulated by the high mineral N availability following urea application (see Supplementary Figs S2, S3, S4 and S5) and the optimal soil water content as well as increased soil temperature. All of these factors strongly stimulated soil microbial processes such as mineralization and coupled nitrification-denitrification, fueling N 2 O emissions3536. On the other land, Liu et al 25.…”

Field-Based Estimates of Global Warming Potential in Bioenergy Systems of Hawaii: Crop Choice and Deficit Irrigation

“…Deficit irrigation effects on WFPS were dependent on date (p = 0.002), but for the majority of the sample dates WFPS was lower under the deficit treatment. Although the water deficit was 50%, the WFPS was reduced by only 4% and the soil moisture remained within the range for microbial activity associated with the production and consumption of GHG [33]. …”

“…A negative flux (or increasing uptake) in upland agricultural systems generally indicates that methane oxidation from the atmosphere is taking place in these soils [33,34]. There have been very few site-specific or regional datasets collected on CH 4 flux in sugarcane and none on napiergrass.…”

Smith, K.A., Ball, T., Conen, F., Dobbie, K.E., Massheder, J. & Rey, A. 2003. Exchange of greenhouse gases between soil and atmosphere: interactions of soil physical factors and biological processes. European Journal of Soil Science, 54, 779–791.

“…The paper we and Jon Massheder wrote on physical factors affecting the exchange of these gases between the soil and atmosphere was published in 2003 (Smith et al, 2003). The paper we and Jon Massheder wrote on physical factors affecting the exchange of these gases between the soil and atmosphere was published in 2003 (Smith et al, 2003).…”