Soil carbon sequestration by three perennial legume pastures is greater in deeper soil layers than in the surface soil
Soil organic carbon (SOC) plays a vital role as both a sink for and source of atmospheric carbon. Revegetation of degraded arable land in China is expected to increase soil carbon sequestration, but the role of perennial legumes on soil carbon stocks in semiarid areas has not been quantified. In thi...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-01-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/527/2016/bg-13-527-2016.pdf |
| Summary: | Soil organic carbon (SOC) plays a vital role as both a sink for and source
of atmospheric carbon. Revegetation of degraded arable land in China is
expected to increase soil carbon sequestration, but the role of perennial
legumes on soil carbon stocks in semiarid areas has not been quantified. In
this study, we assessed the effect of alfalfa (<i>Medicago sativa</i> L.) and two locally adapted
forage legumes, bush clover (<i>Lespedeza davurica</i> S.) and milk vetch (<i>Astragalus adsurgens</i> Pall.) on the SOC
concentration and SOC stock accumulated annually over a 2 m soil profile.
The results showed that the concentration of SOC in the bare soil decreased
slightly over the 7 years, while 7 years of legume growth substantially
increased the concentration of SOC over the 0–2.0 m soil depth. Over the
7-year growth period the SOC stocks increased by 24.1, 19.9 and 14.6 Mg C ha<sup>−1</sup> under the alfalfa, bush
clover and milk vetch stands, respectively, and decreased by 4.2 Mg C ha<sup>−1</sup> in the bare soil. The sequestration of SOC in the 1–2 m depth of
the soil accounted for 79, 68 and 74 % of the SOC sequestered in the 2 m
deep soil profile under alfalfa, bush clover and milk vetch, respectively.
Conversion of arable land to perennial legume pasture resulted in a
significant increase in SOC, particularly at soil depths below 1 m. |
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| ISSN: | 1726-4170 1726-4189 |