Soil CO2 evolution and root respiration in 11 year-old Loblolly Pine (Pinus taeda) Plantations as Affected by Moisture and Nutrient Availability
We measured soil CO2 evolution rates with (Sff) and without (Sms) the forest floor litter and root respiration monthly in 11-year-old loblolly pine (Pinus taeda L.) plantations during the fourth year of fertilization and irrigation treatments. Values of Sff ranged from less than 1 µmol·m-2·s-1 during the winter to greater than 5 µmol·m-2·s-1 in late spring. Average Sff was significantly greater in unfertilized relative to the fertilized stands; however, there was no difference in average Sms among treatments. Soil temperature and the mass of the forest floor (litter) explained most of the difference in Sms among treatments. Soil temperature and volumetric water content accounted for 70% of the seasonal variation in Sff. Annual carbon efflux from the soil averaged 14.1 Mg per year for all treatments. Most of the evolved carbon was derived from root respiration (50-73%). Net ecosystem productivity was -1.1 and 6.9 Mg C·ha-1 per year for the unfertilized and fertilized stands, respectively. At age 11, the unfertilized stands were functioning as a net carbon source, while fertilized stands were a strong carbon sink. It was concluded that fertilization could decrease the time for a young pine plantation to change from a carbon source to a carbon sink.
Requesting Print Publications
Publication requests are subject to availability. Fiscal responsibility limits the hardcopies of publications we produce and distribute. Electronic versions of publications may be downloaded, distributed and printed.
Please make any requests at firstname.lastname@example.org.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
- Our online publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact the SRS webmaster if you notice any errors which make this publication unusable.
- To view this article, download the latest version of Adobe Acrobat Reader.