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Response of Deep Soil Carbon Pools to Forest Management in a Highly Productive Andisol
Author(s) -
Dietzen Christiana A.,
Marques Eduardo R.G.,
James Jason N.,
Bernardi Rodolpho H.A.,
Holub Scott M.,
Harrison Robert B.
Publication year - 2017
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2016.09.0305
Subject(s) - environmental science , soil carbon , soil water , vegetation (pathology) , carbon sequestration , ecosystem , carbon cycle , carbon sink , hydrology (agriculture) , agronomy , carbon dioxide , soil science , geology , ecology , biology , medicine , geotechnical engineering , pathology
Core Ideas Deep soils are rarely included in studies of management effects on soil carbon. The majority of soil carbon at this site was stored in subsurface (>30 cm) horizons. Forest management did not significantly affect total carbon pools to a depth of 3 m. Control of competing vegetation increased carbon storage deep in the soil profile. Soil contains more C than the atmosphere and plant biomass combined. Consequently, it is the most important long‐term sink for C within terrestrial ecosystems. An understanding of the potential to induce C sequestration in soils through management is crucial in light of increasing anthropogenic CO 2 emissions. Nevertheless, soil has historically been under‐represented in C cycling research, especially regarding subsurface (>30 cm) layers and processes. Research on the effects of forest management practices on deep soil C has been lacking. To test the effects of biomass removal and vegetation control treatments on deep soil C, soils were sampled to a depth of 3 m at the Fall River Long‐term Soil Productivity Site in western Washington State. Treatments were installed 15 yr previously in a complete randomized block design. No difference was found in total soil C among treatments, but there was significantly less (a = 0.10) C stored at the deepest interval measured (250–300 cm) in the plots with vegetation control (8.6 Mg C ha ‐1 ) than in those without (16.3 Mg C ha ‐1 ). These results suggest the stability of soil C pools at Fall River and indicate that more intensive management practices may not deplete C pools at this site, but imply that these deep soil pools may be more sensitive to change than shallow pools. Here, 58.2% of the soil C pool is located below 30 cm, which demonstrates that shallow sampling significantly underestimates soil C pools and highlights the importance of understanding processes that control deep soil C.