| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
a Dep. of Agronomy and Range Science, One Shields Avenue, Univ. of California, Davis, CA 95616
b Natural Resource Ecology Lab., Colorado State Univ., Fort Collins, CO 80523
c S. Degryze, Dep. of Land Management, Faculty of Agricultural and Applied Biological Sciences, K.U. Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
d Dep. of Biology, Bradley Univ., 1501 West Bradley Avenue, Peoria, IL 61625
e Eastern Cereal & Oilseed Research Center, Agriculture Canada, Central Experimental Farm, Ottawa, ON, Canada K1A 0C6
* Corresponding author (jwsix{at}ucdavis.edu)
Forested ecosystems have been identified as potential C sinks. However, the accuracy of measurement and understanding of the underlying mechanisms for soil organic C (SOC) storage in forested ecosystems needs to be improved. The objective of this study was to use aggregate and soil organic matter (SOM) fractionation techniques to identify SOC pools that preferentially stabilize SOC in the long term and elucidate SOC sequestration mechanisms in forested soils. At two sites (Wildlife area, Ohio and Kemptville, Ontario) representing two different soils (Hapludalf and Hapludoll), we sampled soils under agriculture, afforestation, and forest and separated them into aggregates. Different size classes of intra-aggregate particulate organic matter (iPOM) fractions were isolated by density flotation, dispersion, and sieving. At both sites, aggregation and whole SOC content were greater in the forested than in the agricultural ecosystems. The greater aggregation in forested ecosystems resulted in greater iPOM C concentrations, especially the iPOM C fractions associated with microaggregates (53–250 µm) and microaggregates occluded within macroaggregates (mM) (250–2000 µm). The sum of C in these fractions (microaggregate protected C) was 468 ± 29, 696 ± 171, 673 ± 70 g C m-2 in the agricultural, afforested, and forested soils at Kemptville, respectively. The difference in the microaggregate protected C between the agricultural and the afforested soils accounted, on average, for 20% of the difference in whole SOC stocks between the soils. We conclude, SOC is stabilized for a relatively longer term within microaggregates formed in afforested and forest systems. Therefore, we suggest a new fractionation scheme to isolate this microaggregate associated SOC for assessing the impact of land use, land management, and climate change on C storage.
Abbreviations: fPOM, fine particulate organic matter • iPOM, intra-aggregate particulate organic matter • LF, light fraction • mM, microaggregates within macroaggregates • imMPOM, intra-microaggregate particulate organic matter • MWD, mean weight diameter • POM, particulate organic matter • SOC, soil organic C • SOM, soil organic matter
This article has been cited by other articles:
|
|
 |
|
  H. Chung, J. H. Grove, and J. Six Indications for Soil Carbon Saturation in a Temperate Agroecosystem Soil Sci. Soc. Am. J., June 18, 2008; 72(4): 1132 - 1139. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Rasmussen, M. S. Torn, and R. J. Southard Mineral Assemblage and Aggregates Control Carbon Dynamics in a California Conifer Forest Soil Sci. Soc. Am. J., September 29, 2005; 69(6): 1711 - 1721. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. A. Paul, S. J. Morris, J. Six, K. Paustian, and E. G. Gregorich Interpretation of Soil Carbon and Nitrogen Dynamics in Agricultural and Afforested Soils Soil Sci. Soc. Am. J., September 1, 2003; 67(5): 1620 - 1628. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Journal of Natural Resources and Life Sciences Education |
Vadose Zone Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
