水保所知识产出(1956---)知识库

黄土区地形破碎，土地利用复杂多样，准确获取局域尺度上土壤有机碳变异因子
是准确估算黄土区土壤有机碳储量的基础。本研究以黄土丘陵沟壑区燕沟流域为平
台，以流域内3 种地形部位峁顶、峁坡、沟底和8 种土地利用类型农田、果园、人工
草地、天然草地、人工灌木林、天然灌木林、人工乔木林和天然乔木林为研究对象，
利用网格法采集表层0-20cm 土壤样本314 个、剖面0-100cm 土壤样本53 个，通过对
不同地形部位、不同土地利用方式和不同深度条件下SOC 分析，研究了流域SOC 空
间变异的影响因素。在此基础上，结合地形图、土地利用图、坡向图，利用ArcGIS9.2
图层运算功能按照多元线性回归方程进行叠加运算，生成流域土壤有机碳含量空间分
布图，基于GIS 研究地形和土地利用方式对小流域尺度表层和深层土壤有机碳空间分
布、储量的影响。
主要结果如下：
黄土丘陵沟壑区燕沟流域表层0-20cm 土壤有机碳密度为1.63 kg·m-2, 0-100cm 土
层有机碳密度为5.04 kg·m-2，土壤有机碳储量为217.6×103 MgC，深层（20-100cm）
土壤有机碳储量占总储量的67.5%。
地形和土地利用方式极显著（P<0.0001）影响小流域表层0-20cm 土壤有机碳含
量与分布，并且交互作用显著（P=0.0511）。地形影响下，土壤有机碳空间分布表现
为沟底>峁坡>峁顶，土壤有机碳含量沟底（8.0 g·kg-1）、峁坡（7.1 g·kg-1）分别是峁
顶（4.2 g·kg-1）的1.9、1.7 倍。土地利用方式影响下，土壤有机碳空间分布表现为天
然乔木>天然灌木>人工乔木>天然草地>人工灌木>人工草地>农田>果园。考虑地形和
土地利用交互作用条件下，沟底农田（6.9 g·kg-1）、果园（8.8 g·kg-1）、天然草地（9.3
g·kg-1）有机碳含量分别是峁顶的1.9、2.0、1.9 倍。峁坡林地（灌木林和乔木林）土
壤有机碳含量远远高于沟底，其中峁坡天然乔木林土壤有机碳含量（24.6 g·kg-1）是
沟底（16.4 g·kg-1）的1.5 倍（P<0.05）。
地形、土地利用方式、土层深度及其两者交互作用对流域剖面0-100cm SOC 空间分布有极显著影响（P<0.01）。深层10-100cm 与表层0-10cm 土壤有机碳在三种地
形上的分布不同。0-10cm 土壤有机碳峁坡（10.7 g·kg-1）>沟底（8.9 g·kg-1）>峁顶（4.4
g·kg-1）,而10-100cm 土壤有机碳沟底（5.6 g·kg-1）>峁坡（4.5 g·kg-1）>峁顶（3.2 g·kg-1）。
其中，10-40cm 峁坡SOC 与峁顶差异显著，但与沟底差异不显著；40-60cm 与峁顶和
沟底都有显著性差异；60-100cm 与峁顶差异不显著，但与沟底差异显著。不同深度
SOC 空间分布因土地利用方式存在显著差异。与农田相比，果园0-40cm 土层SOC
含量降低21%，40-80cm 土层二者差异不大，但80-100cm 土层SOC 含量提高13%；
人工灌木林、人工乔木林0-10cm 有机碳含量显著（P<0.05）高于农田，但10-40cm
却分别低于农田12%、6%；40-100cm 人工灌木林（2.6 g·kg-1）低于农田19%，人工
乔木林（3.4 g·kg-1）高于农田6%。在所有土地利用方式中，0-20cm 土层天然乔木林
有机碳含量最高，天然灌木林次之；20-100cm 天然灌木林各层含量均最高。其中
40-100cm 天然灌木林各层含量与其它利用方式均呈显著性差异（P<0.05），但天然乔
木林与其它土地利用方式差异较小。
空间格局图上，相比地形，0-40cm 有机碳含量受土地利用影响程度较大；
40-100cm 受地形影响的程度更大。在0-10cm 土层，峁顶、峁坡、沟底高值1斑块分
别占2%、16%、7%；中值斑块分别占50%、62%、70%；10-40cm 没有高值斑块；
中值斑块分别占10%、20%、25%；低值斑块分别占90%、80%、75%；40-100cm 均
为低值斑块，低值绿色斑块分别占13%、34%、8%；低值青色斑块分别占76%、63%、
78%。土地利用方式上，在0-10cm 土层，乔木林、灌木林、草地上高值斑块分别占
18%、47%、10%，川坝地、农田和果园没有高值斑块，中值斑块分别占80%、53%、
85%、73%、39%、23%。10-40cm 土层，乔木林、灌木林、草地、川坝地、农田和
果园中值斑块分别占21%、46%、22%、19%、5%、4%；40-100cm 除灌木林有1%
中值斑块外，其它土地利用方式均处于低值斑块区。低值绿色斑块分别占7%、51%、
11%、40%、2%、4%；低值青色斑块分别占75%、48%、76%、57%、69%、70%。
坡向上0-100cm 各层土壤有机碳含量半阴坡（北部、东北、东部）最高，半阳坡（西
部、西南、南部）含量较低。

Loess Plateau was with fragmented topographies , complex and diverse land uses , in
which the typical erosion characteristics of gully region and hilly region were shaped at
local scale. Soil organic carbon storage in Loess region was based on accurate factors on
spatial distribution of SOC in local scale. In this study, the spatial distribution of SOC at
different depths was studied at a typical watershed of Yanggou in hilly region of loess
Plateau, based on three topographies (tableland ,slopeland, gullyland) and eight landuses
(farmland, orchard, manmade and secondary grassland, manmade and secondary shrubland
and manmade and secondary woodland) , 314 soil surface (0-20cm) samples and 53 profile
(0-100cm) samples were collected to investigate effects of topographies and landuses on
spatial distribution of soil organic carbon in the watershed. The spatial distribution map of
soil organic carbon was generated by using the raster calculation function of ArcGIS9.2 to
overlap the longitude map , latitude map, slope map and coded topographic map, land use
map, aspect map according to multiple linear regression equation calculation, soil organic
carbon content in different topographies and land uses was statistical. The main results are
as follows:
The surface (0-20cm) SOC density was 1.63 kg3s-2 and 1m SOC density was 5.04
kg·m-2 at the watershed scale. Soil organic carbon reserves at 1 m soil layer was 217.6 ×
103 t , and 67.5% of SOC reserve was at subsoil (20-100cm).
Topographies and landuses significantly (P <0.0001) affects spatial distribution of
soil surface organic carbon in Yangou watershed, and their interaction significantly (P
=0.0511) impact on the spatial distribution of soil organic carbon .Under the influence of
topographies, the spatial distribution of soil surface organic carbon expressed as
gullyland > slopeland> tableland Trends, and the soil surface organic carbon contents of
gullyland (8.0 g·kg-1) and slopeland（7.1 g·kg-1）were as 1.9 ,1.7 times as tableland (4.2
g·kg-1) respectively.Under the influence of landuses, the spatial distribution of soil surface  organic carbon performanced for secondary woodland> secondary shrubland> manmade
woodland> secondary grassland> manmade shrubland> manmade grassland> farmland>
orchard. Under the influence of their interaction , soil surface organic carbon of farmland,
orchards and grassland were gradually concentrated on gullyland under the condition of
soil slope erosion. Forests (shrubland and woodland) were different from
farmland ,orchard and grassland , and reflected that soil surface organic carbon contents of
the slopeland were much higher than the gullyland . The soil organic carbon content of the
slopeland of secondary woodland (24.6 g·kg-1) which was 1.5 time of gullyland (16.4
g·kg-1)reached a significant level compared with gullyland.
Topographies , land uses ,depths and interaction of them significantly (p <0.01)
affects spatial distribution of soil organic carbon in subsurface in Yangou watershed. SOC
had different spatial distribution in topographies between subsurface (10-100) and surface
(0-10).In 0-10cm soil layer , the content of soil organic carbon of slopeland （10.7 g ·kg-1）
was the highest ,followed by gullyland（8.9 g·kg-1）, the content of SOC of tableland （4.4
g·kg-1）was the lowest. But the contents of SOC every layer in10-100cm expressed as
gullyland > slopeland> tableland Trends, the average contents of SOC were 5.6 g·kg-1 ，4.5
g·kg-1 and 3.2 g·kg-1 . land uses significantly (p <0.05) affects spatial distribution of
SOC in subsurface in Yangou watershed. Compared with farmland , the content of SOC of
orchard in 0-40 cm decreased by 21%, yet increased by 13% in 80-100cm. The content of
SOC of manmade shrubland (2.6 g·kg-1) was 19% lower than farmland , while that of
manmade woodland (3.4 g·kg-1) was 6% higher than farmland. The content of SOC of
secondary shrubland was higher than any other land uses in 20-100cm ,but it is
significantly （p <0.05）different form other land uses in 40-100cm , the average contents
was 5.3 g·kg-1 , which was 66% higher than farmland. The content of SOC of secondary
woodland was higher than any other land uses in 0-20cm, but it was less differences form
other land uses in 40-100cm. The storage of SOC of gullyland（5.04 kg·m-2）in subsurface
(20-100) was the highest , accounted for 71.4% in 1m profile , the relative storage of SOC
of slopeland and tableland accounted for 63.6% and 72.6 % respectively. The storages of
SOC of secondary shrubland in subsurface (20-100cm) were the highest , it was 6.0 kg·m-2 ,
accounted for 64.7% in 1m profile, while the relative storage of secondary woodland was
the lowest , only accounted for 49.7% . The storages of SOC of farmland and orchard both
accounted for more than 70% of 1m profile.
Land use has greater effect on organic carbon content of the upper soil layers
(0-40cm) than topography, which covered the influence of topography under soil erosion
laws, but topography has greater influence on the subsoil (40-100cm), so we can see the  clear significant difference between gullyland and tableland or slopleland.The topography
of tableland was dominated by middle value plaque (50%) and low value plaque (48%);
slopeland by middle value plaque (62%) ,followed by low value plaque (22%); slopeland
by middle value plaque (70%) ,followed by low value plaque (23%). Tableland ,slopeland
and gullyland were dominated by low value plaque in10-40cm, accounted for 90%, 80%
and 75% respectively. Also dominated by low value plaque in 40-100 cm and low value
green plaque of gullyland accounted for 34%, much higher than slopeland (8%) and
tableland (13%). For land use, It was significant effect of land use on spatial distribution in
0-40 soil layers ,but no significant in 40-100 cm.The high value plaque of woodland,
shrubland and grassland accounted for 18%, 47% and 10% respectively, while plain land,
farmland and orchard were no high value plaque and the middle value plague of them
accounted for 80%, 53%, 85%, 73%, 39% and 23% respectively. The middle value plaques
of woodland, shrubland , grassland, plain land, farmland and orchard in 10-40 cm
accounted for 21%, 46%, 22%, 19%, 5% and 4 % respectively. But in 40-100cm, the SOC
of all land uses were at low value plaque. For aspect, the SOC contents of the area of
semi-shady (East + northeast + North) were the highest, while the area of semi-sunny
(West + South West + South) the lowest .