Next Article in Journal
Comparison of Heat Transfer and Soil Impacts of Air Curtain Burner Burning and Slash Pile Burning
Next Article in Special Issue
The Potential of Juniperus thurifera to Sequester Carbon in Semi-Arid Forest Soil in Spain
Previous Article in Journal
How Climate Change Will Affect Forest Composition and Forest Operations in Baden-Württemberg—A GIS-Based Case Study Approach
Previous Article in Special Issue
Carbon Stocks across a Fifty Year Chronosequence of Rubber Plantations in Tropical China
Article Menu
Issue 8 (August) cover image

Export Article

Open AccessFeature PaperArticle

The Impact of Water Content on Sources of Heterotrophic Soil Respiration

Department of Forest Resources & Environmental Conservation, Virginia Tech, Blacksburg, VA 24061, USA
Author to whom correspondence should be addressed.
Forests 2017, 8(8), 299;
Received: 13 June 2017 / Revised: 7 August 2017 / Accepted: 11 August 2017 / Published: 16 August 2017
(This article belongs to the Collection Forests Carbon Fluxes and Sequestration)
PDF [2284 KB, uploaded 17 August 2017]


Heterotrophic respiration (RH) is a major flux of CO2 from forest ecosystems and represents a large source of uncertainty in estimating net ecosystem productivity (NEP) using regional soil respiration (RS) models. RH from leaf litter (RHL) may contribute greatly to annual RH estimates, but its contribution may be misrepresented due to the logistical and technical challenges associated with chamber-based field measurements of RHL. The purpose of this study was to evaluate the sensitivity of sources of RH (mineral soil-derived heterotrophic respiration [RHM] and leaf litter-derived heterotrophic respiration [RHL]) of a loblolly pine plantation (Pinus taeda L.) to varying soil and litter water content over the course of a dry down event. Additionally, we investigated whether fertilization influenced RHL and RHM to understand how forest nutrient management may impact forest soil carbon (C) dynamics. RHL was measured under dry conditions and at field capacity to evaluate water content controls on RHL, determine the duration of increased CO2 release following wetting, and evaluate the potential contribution to total RH. We also measured RHM inside collars that excluded plant roots and litter inputs, from field capacity until near-zero RHM rates were attained. We found that RHL was more sensitive to water content than RHM, and increased linearly with increasing litter water content (R2 = 0.89). The contribution of RHL to RH was greatest immediately following the wetting event, and decreased rapidly to near-zero rates between 3 and 10 days. RHM also had a strong relationship with soil water content (R2 = 0.62), but took between 200 and 233 days to attain near-zero RHM rates. Fertilization had no effect on RHM (p = 0.657), but significantly suppressed RHL rates after the wetting event (p < 0.009). These results demonstrate that there is great temporal variability in both CO2 released and the water content of differing sources of RH, and forest fertilization may largely impact forest floor C stocks. This variability may not be captured reliably using conventional weekly to monthly chamber-based field sampling efforts and could lead to over- or underestimation of RH. In the context of climate change, changes in the frequency and intensity of wetting and drying events will likely alter RHL and its contribution to RS. Separate consideration of RH sources and controls, along with increased field sampling frequency using chamber-based methodology under a broader range of specific environmental conditions, are likely needed to reduce variability in RH estimates and improve the accuracy of forest NEP predictions. View Full-Text
Keywords: carbon cycle; fertilization; soil CO2 efflux; leaf litter; loblolly pine plantations carbon cycle; fertilization; soil CO2 efflux; leaf litter; loblolly pine plantations

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

McElligott, K.M.; Seiler, J.R.; Strahm, B.D. The Impact of Water Content on Sources of Heterotrophic Soil Respiration. Forests 2017, 8, 299.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Forests EISSN 1999-4907 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top