Page 5 - การกักเก็บคาร์บอนในดินตัวแทนหลักภาคตะวันออกเฉียงเหนือ

ห้องสมุดกรมพัฒนาที่ดิน
iii

ABSTRACT

Soil carbon plays an important role in maintaining the soil system that resists
degradation. Carbon sequestration, the process by which atmosphere carbon dioxide is
taken up by plants through photosynthesis and stored as carbon in biomass and soils,

can help reverse soil fertility loss, limit greenhouse gases (GHG) concentrations in the
atmosphere, and reduce impact of climate change on agricultural ecosystems. Soil in
Northeast of Thailand has low organic carbon which resulted from deforestation,
biomass burning, tillage operation and soil erosion. Therefore, understanding on current

status of soil organic carbon is should be considered that lead to the strategy on
efficiency of long-term increasing in soil carbon. The objectives of this study were to 1)
investigate on distribution of soil organic carbon in the surface soil, 2) determine current
soil carbon stock and storage location, and 3) changes in soil organic carbon under

different land-uses and organic residues application. The 20 benchmark soils in Northeast
of Thailand were selected in this study.
The result of soil organic carbon distribution at 0 - 25 cm depth in Northeast
Thailand found that organic carbon content had ranged from 0.01 - 2.0%, which the

most of areas had low soil organic carbon (<0.5%). Considering on organic carbon stock
of 20 benchmarks soils throughout 100 cm depth, organic carbon stock had ranged from
-1
-1
3.2 to 13.7 tC rai , which highest in Kantharawichai series (13.7 tC rai ) followed by That
-1
Phanom series (12.5 tC rai ). The lowest organic carbon stock was found in Ban Phai
series (3.2 tC rai ). According to carbon stock at each depth, we found the most of soil
-1
organic carbon was stored in soil at 0 - 30 cm depth (45 - 77%TOC). In addition, we also
found organic carbon stock was correlated to soil particle especially in clay particle (r= 0.417

to 0.763). The result found that soil organic carbon stock at 0 - 30 cm depth, was negatively
correlated with bulk density (r= -0.350 to -0.371) but positively correlated with cation exchange
capacity (r= 0.747 to 0.803).
Organic carbon storage location at surface soil (0 - 30 cm) in three selected soil
series, found that the most of soil organic carbon content (62 - 63%TOC) in Sung Noen

and Chatturat series were stored in small macro-aggregate (0.25 - 2 mm). While the Ban
Phai series, the 75 percentages of organic carbon was stored in micro-aggregate. We
found high significantly linear relationship between organic carbon in soil aggregate and

2
2
quantities of aggregate size in Ban Phai series (R = 0.859**) Sung Noen series (R = 0.768**)
and Chatturat series (R = 0.731**), reflecting that organic carbon play important role on
2
soil aggregation.
In addition, organic carbon content in three soil series (180 cm) under different

land uses, showed that the highest organic carbon content was found at surface soil