ISWC OpenIR  > 水保所知识产出(1956---)
张 金
Thesis Advisor许明祥
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword深层土壤 有机碳储量 有机碳来源 稳定碳同位素 黄土丘陵区

13 C 同位素示踪法,研究不同土地利用类型及年
(1)黄土丘陵区不同植被类型下 SOC 储量在剖面上分布均表现为:0~
100 cm 内随土壤深度增加而显著降低,变化范围为 5.10~12.85 t∙hm -2 ;而在
100~400 cm 则稳定于 5.12~6.13 t∙hm -2 之间,不同层次间仅存在轻微波动。
碳变化趋势不明显,但储量很高,约占 0~400 cm 剖面土壤有机碳的 60%。
其中 80~100 cm 土层的土壤有机碳储量与深层 100~200 cm 和 200~400 cm 的
土壤有机碳储量呈显著线性相关,是 0~100 cm 5 个土层中与深层土壤有机
(3)人工刺槐林、柠条林和自然撂荒地表层(0~20 cm)土壤有机碳储
100~400 cm 土 壤 有 机 碳 平 均 累 积 速 率 分 别 为 0.14 t∙hm -2 ∙a -1 和 0.19
t∙hm -2 ∙a -1 。在估算黄土丘陵区植被恢复的土壤固碳效应时,应考虑深层土壤
13 C 值随着深度的增加而增高,而坡耕地δ
13 C 值的变化趋势并不明显。人工刺槐林表层土壤有
机碳来源于林地凋落物和根系的比例为 69.6%,深层 1~3m 内土壤有机碳
来源于林地凋落物和根系的比例远远小于表层,约分布在 7.0~17.0%的范

Other Abstract

Vegetation restoration based mainly on conversion of cropland to forest and
grassland was an important ecological construction project in loess hilly region,
which not only changed the land use and topsoil carbon sequestration status in
the region, but also affected the deep layer soil carbon storage as well as
ecosystem carbon cycle. At present only a few research were carried out on deep
soil organic carbon. The accumulation process and sequestration mechanism is
unclear, which may lead to bias estimates of soil carbon storage. To meet the
requirement of soil organic carbon research and assessment of the benefits of
soil carbon sequestration on the Loess Plateau, through field investigation and
sampling, using
13 C isotopes method, this paper was designed to explore deep
soil organic carbon storage, its distribution in profile, accumulation dynamics
and its response to LUCC under different land use types and land use years. The
sources of deep soil organic carbon were also discriminated. The results could
provide scientific basis for estimating regional soil carbon storage and
certification of carbon sequestration in the Loess Plateau. The main conclusions
were as follows:
(1) The distribution of soil organic carbon storage in soil profile under
different vegetation types in the loess hilly region was: the storage decreased
significantly as the depth increased and ranged from 5.10 to 12.85 t∙hm -2 in the
0–100 cm layer; but the storage just varied from 5.12 to 6.13 t∙hm -2 , and there
were only slight fluctuations among different soil layers.
(2) In 0-100 cm soil profile, the organic carbon storage decreased
significantly with the increase of soil depth. However, in deep soil, the organic
carbon storage had a slight fluctuation. The total organic carbon storage in
100-400 cm soil profile was considerably high, accounting for approximately  60% of that in 0-400 cm soil profile. The organic carbon storage in 80-100 cm
soil layer had a significant linear correlation with that in 100-200 cm and
200-400 cm soil layers, and among the organic carbon storages in the five layers
in 0-100 cm soil profile, the organic carbon storage in 80-100 cm soil layer had
the strongest correlation with that in 100-400 cm soil profile, being able to be
used to estimate the soil organic carbon storage in deep soil in this region.
(3) The organic carbon storage in 0-20 cm soil layers in the three types of
revegetation lands was significantly higher than that in slope croplands, but the
organic carbon storage in deep soil had no significant difference among the land
use types. The organic carbon storage in deep soil increased with the increasing
years of revegetation. In R. pseudoacacia woodlands and C. korshinskii shrub
lands, the average increasing rate of the organic carbon storage in 100-400 cm
soil layer was 0.14 and 0.19 t∙hm -2 ∙a -1 , respectively, which was comparable to
that in the 0-100 cm soil layer. It was suggested that in the estimation of the soil
carbon sequestration effect of revegetation in the hilly Loess Plateau region, the
organic carbon accumulation in deep soil should be taken into consideration.
Otherwise, the effect of revegetation on soil carbon sequestration could be
significantly underestimated.
(4)  The δ 13 C value of soil organic carbon increased as the depth increased
in the soil profile of R. pseudoacacia woodlands, whereas in slope croplands,
theδ 13 C value had a slight fluctuation. The proportion of organic carbon that
come from the plant residues of R. pseudoacacia woodlands in 0-20 cm was
69.6%, which was much higher than the proportion that between 7.0~17.0% in
100-300 cm soil layer.
KEY WORDS: Deep soil; SOC storage; SOC sources; stable C isotope; hilly
Loess Plateau

Document Type学位论文
Recommended Citation
GB/T 7714
张 金. 黄土丘陵区深层土壤有机碳的储量及来源[D]. 北京. 中国科学院研究生院,2013.
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