ISWC OpenIR  > 水保所知识产出(1956---)
侵蚀条件下土壤呼吸变化特征 及其影响因素
郭慧敏
Subtype硕士
Thesis Advisor郭胜利
2014-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword土壤侵蚀 模拟溅蚀 土壤呼吸 土壤有机碳 退耕还草
Abstract

土壤呼吸是陆地生态系统碳循环的重要生态过程,侵蚀影响陆地生态系统碳收支与
平衡。但侵蚀条件下土壤呼吸的变化特征及其影响因素尚不清楚。本文在分析侵蚀土壤
呼吸特征的基础上,模拟研究了溅蚀对土壤呼吸的影响,探讨了溅蚀影响土壤呼吸变化
的因素,并通过选取退耕还草条件下的苜蓿与农田对比,了解水土流失治理对土壤有机
碳蓄积量的影响。
以长武站为依托,基于相似植被和管理条件,于(2011 ~ 2013 年)系统监测塬面和
坡地土壤呼吸速率、土壤温度、土壤水分的变化,分析非侵蚀和侵蚀条件下土壤呼吸的
季节和年际变化差异及其影响因素;在中科院水保所人工降雨大厅,在固定降雨强度条
件下,通过遮网覆盖模拟溅蚀(非遮网)与非溅蚀(遮网),测定土壤呼吸速率、土壤
团聚体颗粒变化,研究溅蚀对土壤有机碳矿化分解的影响及其影响因素;基于建立于
1984 年的长期定位试验,于 2011 年 3 月至 2012 年 12 月,利用 Li-8100 系统(Li-COR,
Lincoln, NE, USA)监测了退耕还草(苜蓿)处理和农田(冬小麦)土壤呼吸季节变化
以及土壤表层(0 ~ 5 cm)温度和含水量,研究了土地利用变化下土壤呼吸变化特征及
其与土壤温度、水分以及有机碳特性之间的关系。
主要获得以下结果:
与塬面相比 , 坡地条件下土壤呼吸降低但温度敏感性提高
塬面果园与坡地果园土壤呼吸存在差异性。塬面果园平均土壤呼吸速率为 2.11
μmol•m -2 s -1 ,高出坡地果园(1.60 μmol•m -2 s -1 )32%,且通常在 4 月份之后,二者土壤呼
吸差距开始增大,至 10 月份,差距逐渐减小,其中,2013 年二者土壤呼吸速率差异最
大,达 40%。塬面果园平均累积呼吸量为 570.6 g CO 2 ·m -2 ,高出坡地果园(443.4 g
CO 2 · m -2 )29%。其中,2013 年二者累积呼吸量差异最大,为 50%,2012 年差异最小,
为 16%。
影响土壤呼吸的土壤温度、土壤水分等也存在差异:塬面果园平均土壤水分含量较
高,为 17%,高出坡地(14%)20%;3 年观测期间的平均土壤温度,坡地较高,为 15.7 ℃,
高于塬面(15.0 ℃)5%,其中 2011 年与 2013 年,坡地果园平均土壤温度高于塬面果
园,2012 年,塬面果园平均土壤温度与坡地果园接近(塬面 15.8 ℃、坡地 14.5℃)。
土壤呼吸与温度呈明显指数关系,而土壤水分对土壤呼吸的影响较为复杂。尽管塬
面果园土壤呼吸高于坡地果园,但 3 年观测期间,坡地果园温度敏感系数 Q 10 高于塬面
果园,坡地果园平均 Q 10 为 1.79,高出塬面果园(1.67)7%。
溅蚀影响土壤呼吸速率 , 降低土壤碳蓄存能力
相同降雨强度(90 mm/h)下,溅蚀与非溅蚀土壤呼吸速率存在差异,并且二者呼
吸差异的大小与降雨历时存在一定关系:溅蚀条件下的土壤呼吸速率高于非溅蚀条件,
10 分钟降雨历时下的呼吸差异高于 5 分钟降雨历时。5 分钟降雨历时下,两种处理的土
壤呼吸速率在 0.75 ~ 1.65 μmol·m -2 s -1 之间,裸露处理平均土壤呼吸速率为 1.25
μmol·m -2 s -1 ,盖网处理平均土壤呼吸速率为 1.20 μmol·m -2 s -1 ,前者高出后者 4%。土壤呼
吸测定初期,两种处理呼吸差异较小,最低仅为 1%,后期逐渐增大,差异最大值出现
在试验开始的第六天(9 月 5 号上午),高出比例为 14%。
10 分钟降雨历时下,两种处理的土壤呼吸速率在 0.97 ~ 1.61 μmol·m -2 s -1 之间,所有
10 组数据均显示裸露处理土壤呼吸速率高于盖网处理。裸露处理平均土壤呼吸速率为
1.42 μmol·m -2 s -1 ,盖网处理平均土壤呼吸速率为 1.21 μmol·m -2 s -1 ,前者高出后者 17%。
10 分钟降雨历时下,两种处理的土壤呼吸差异明显高于 5 分钟降雨,测定初期,差异最
高达 28%,随着测定时间的延长,呼吸差异最小值为仅 6%。
溅蚀条件下 , 土壤团聚体破碎影响有机碳矿化分解
溅蚀过程中,雨滴打击会对表层土壤团聚体颗粒产生一定影响,并且主要影响到粒
径 0.01 mm 以下的土壤团聚体。裸露处理土壤中该粒径团聚体颗粒含量高于盖网处理的
土壤。降雨前,0.01 mm 以下土壤团聚体含量为 32.5%,在雨滴打击作用下,团聚体分
散,0.01 mm 以下土壤颗粒均较降雨前有所增多: 5 分钟降雨历时下,盖网处理 0.01 mm
以下颗粒含量增至 36.3%,裸露处理增至 37.5%,分别较雨前提高了 12%和 14%;10 分
钟降雨条件下,0.01 mm 以下土壤团聚体含量,盖网处理为 35.5%,裸露处理为 36.2%,
分别较雨前提高 9%和 11%。同时,对比盖网与裸露两种处理,可以得出:裸露土壤直
接接受雨滴打击,0.01 mm 以下土壤颗粒较降雨前的增长量略高于盖网处理,5 分钟降雨条件下,裸露处理较盖网处理高出 3%,10 分钟降雨下,裸露处理较盖网处理高出 2%。
溅蚀对表层土壤矿化速率产生影响,降雨历时也是影响 CO 2 释放量的一个因素:5
分钟降雨条件下,盖网处理的平均土壤 CO 2 释放量为 29.58 ml/kg,裸露处理较之有所提
高,为 39.01 ml/kg,比前者高出 32%;10 分钟降雨条件下,盖网处理土壤 CO 2 释放量
为 39.80 ml/kg,裸露处理为 42.31 ml/kg,比前者提高 6%;降雨历时的延长,增加了降
雨后表层土壤 CO 2 释放量:盖网处理下,10 分钟降雨的土壤 CO 2 释放量高出 5 分钟降
雨 35%,裸露处理下,10 分钟降雨的土壤 CO 2 释放量高出 5 分钟降雨 9%。
退耕 30  年来 , 草地苜蓿土壤呼吸较农田小麦增强 ,Q 10 提高 , 水土流失治理提高了
影响土壤呼吸的生物因素 (SOC 、 微生物生物量碳 ) 含量
自 1984 年麦地转化为苜蓿地,土壤呼吸速率苜蓿地(3.55 μmol•m -2 s -1 )达小麦地(1.36
μmol•m -2 s -1 )的 2.61 倍,累积呼吸量苜蓿地(981 g•m -2 )达小麦(357 g•m -2 )的 2.75 倍。土
壤呼吸温度敏感系数(Q 10 )苜蓿地较小麦地 2011 年提高 24.5%,2012 年提高 2.4%。苜
蓿地 SOC 含量(10.5 g•kg -1 )较小麦地(6.5 g•kg -1 )提高 61.5%,微生物量碳(204 mg•kg -1 )
较小麦地(152 mg•kg -1 )提高 34%,0 ~ 5 cm 土壤水分含量同期高于小麦地,但二者土
壤温度差异不显著。土壤水分、SOC、微生物量碳等是造成二者呼吸差异的因素,水土
流失治理提高了土壤有机碳蓄积量。
关键词:土壤侵蚀;模拟溅蚀;土壤呼吸、土壤有机碳、退耕还草

Other Abstract

Soil respiration is an important ecological process of terrestrial ecosystem carbon
cycling , Erosion influence the global carbon budget in the terrestrial ecosystem. But the
variation of soil respiration under conditions of erosion and its influencing factors is unclear.
Based on the analysis on the characteristics of eroded soil respiration ,we simulated the splash
erosion and explored the factors that affect the splash erosion of soil respiration ,then we
selected alfalfa farmland under pasture conditions and to understand the impact of soil erosion
on soil organic carbon storage volume.
Relying on Chang Wu station and based on similar vegetation and management
conditions , we monitored the soil respiration , soil temperature and soil moisture changes in
( 2011 - 2013 )in sloping and plateau orchard surface , the variation and interannual variations
and differences in factors of non-seasonal erosion and erosion under conditions of soil
respiration was analysis; then we simulated the splash erosion in Chinese Academy of
Sciences and Water Conservation artificial rainfall hall. we set a fixed rainfall intensity
conditions:Covered by the rail network as non- splash erosion and non-covered as the splash
erosion. After rainfall, we monitored the soil respiration , soil temperature, soil moisture and
changes in soil particle aggregates to research splash erosion on soil organic carbon
mineralization decomposition of its influencing factors. From March 2011 to December 2012,
CO2 efflux from the soil surface was measured from 8:00 to 10:00 am in clear days by a
Licor-8100 closed chamber system (Li-COR, Lincoln, NE, US). Also, soil temperature and
soil moisture at the 5cm depth was measured using a Li-Cor thermocouple and a hand-held
frequency-domain reflectometer(ML2x, Delta-T Devices Ltd, UK) at each PVC collar,
respectively.
The main results are as follows:
Compared with the plateau surface , soil respiration in sloping orchard is reduced
but the Q 10  is higher.
Soil respiration in Plateau Orchard and sloping Orchard are differences . Average soil
respiration rate in Plateau orchard is 2.11 μmol • m -2 s -1 , above the hillside orchard (1.60 μmol
• m -2 s -1 ) 32%, and usually after April , the soil respiration gap between the two treatments
begins to increase , to October , the gap decreases , which , in 2013 the biggest difference
between the two soil respiration rates , up to 40 %. Average cumulative soil respiration in
Plateau orchard is 570.58 g CO 2 • m -2 , above the slope orchard (443.39 g CO 2 • m -2 ) 29%. In
2013, the cumulative respiration differences was maximum as 50% and the smallest
difference in 2012 , is 16 %.
The influencing factors of soil temperature , soil moisture are also differences : the
average soil moisture content in plateau (16.86%) is 20% higher than slope orchard surface
( 14.08% ); during the three years of observation, highest average soil temperature in slope
was 15.74 ℃, higher than the plateau surface (15.02 ℃) 5%, which in 2011 and 2013 , the
average soil temperature in hillside orchard is above Plateau orchard, and in 2012, the average
soil temperature in plateau surface orchard and hillside orchard is close ( Plateau 15.83 ℃,
sloping 14.50 ℃).
Soil respiration was significantly exponentially with the soil temperature , but the
relationship between soil moisture and soil respiration is more complicated. Despite the soil
respiration in plateau surface is above the hillside orchard , but the temperature coefficient of
sensitivity Q 10 in hillside orchard is above the plateau surface orchard, average Q 10 in hillside
orchard was 1.79 , higher than the plateau surface orchard ( 1.67 ) 7%.
Splash erosion influences the soil respiration rate , and reduces soil carbon
reservoir capacity.
Under the same rainfall intensity (90 mm/h), the soil respiration rate are differences
between non- splash erosion and splash erosion , and the gap is a certain related to the rainfall
duration :
soil respiration under splash erosion conditions is higher than non- splash erosion
conditions , the gap in 10 minutes rainfall duration is greater than 5 minutes duration. In 5
minutes rainfall duration , the soil respiration rate in the two treatment are both between 0.75
~ 1.65 μmol • m -2 s -1 , the average soil respiration rate of the non-covered condition is 1.25
μmol • m -2 s -1 , and the average soil respiration rate of the covered one is 1.20 μmol • m -2 s -1 ,
which is 4% higher than the former . in the Initial measurement of soil respiration , only little difference between two treatments (1%), the maximum difference was in the morning on
September 5 , the soil respiration in plateau is higher than the slope orchard of 14%.
Under 10 minutes rainfall duration, soil respiration rate in two treatments is both
between 0.97 to 1.61 μmol • m -2 s -1 , all 10 sets of data showed that the splash erosion
respiration rate is higher than the non-splash treatment. The average soil respiration rate of the
non-covered treatment is 1.42 μmol • m -2 s -1 , and the covered treatment is 1.21 μmol • m -2 s -1 ,
which is 17% higher than the former . In 10 minutes duration, the difference between the two
treatment in soil respiration was significantly higher than five minutes rainfall. In the initial ,
the maximum difference is up to 28% , and with the extension of the measurement time , the
minimum difference is just 6 %.
Under conditions of splash erosion , soil aggregates crushing impact the
decomposition of organic carbon mineralization
In Splash erosion process, raindrops would have an impact on the soil aggregates
particles. and mainly affects the soil aggregate of size 0.01 mm or below. Soil aggregates
particles content in this size is higher than the non-splash one. Before the rain , soil aggregates
content of 0.01 mm or below was 32.5%, and after the raindrops hit, soil aggregates dispersed,
the soil particles smaller than 0.01 mm were both increased : in 5 minutes rainfall duration,
soil aggregates content of 0.01 mm or below of the covered increased to 36.3% ,and the the
exposed treatment to 37.5% ,respectively 12% and 14% increase compared with the one
before rain; and under 10 minutes rainfall , soil aggregates content of 0.01 mm or below of
covered is 35.5% ,and the non-covered is 36.2% , respectively 9 % and 11 % increased
compared with the one before rain. Meanwhile , compared with the two treatments we can
draw : for the non-covered soil hit by the raindrops directly ,the growth in the amount of soil
particles of 0.01 mm or below is slightly higher than the covered one, and respectively 3%
and 2% under five minutes and 10 minutes of rainfall.
Splash erosion impact the surface soil mineralization rates , and rainfall duration is also a
factor affecting CO 2 emission : under 5 minutes rainfall , the average CO 2 emission of the
covered soil treatment was 29.58 ml/kg, and the non-covered treatment improved to 39.01
ml/kg, 32% higher than the former ; under 10 minutes rainfall , the average CO 2 emission of
the covered soil treatment was 39.80 ml/kg, and the non-covered treatment improved to 42.31
ml/kg, 6% higher than the former; the CO 2 emission is increasing as rainfall duration
prolonged: in covered conditions, CO 2 emission of the 10 minutes rainfall is 35% higher than
5 minutes , and in non-covered treatment , CO 2 emission of the 10 minutes is 9% higher than
5 minutes .
Since returning cultivated land for 27 years, the Q 10 and the mean grassland soil
respiration was higher than paired cropland. The converstion of cropland to grassland
inhanced the SOC.
Since returning cultivated land for 27 years, the mean grassland soil respiration(3.55
μmol•m -2 s -1 ) was averaged 2.61 times higher than paired cropland soil respiration(1.36
μmol•m -2 s -1 )and the cumulative CO 2 -C emissions in grassland (981 g C m -2 ) was 2.75 times
higher than that in cropland (357 g C m -2 ). In 2011, the temperature sensitivity of grassland
(Q 10 ) improved by 24.5% compared with cropland, and in 2012 it reduced to 2.4%. We found
marked differences in soil characteristics related to different land-use: the mean grassland
SOC(10.5g•kg -1 ) was averaged 61.5% higher than paired cropland SOC(6.5g•kg -1 )and the
SMBC (204mg•kg -1 ) was averaged 34% higher than cropland (152mg•kg -1 ). Soil moisture
from 0 ~ 5 depth was much drier in cropland and significantly different between cropland and
grassland except for winter. However, there were no clear differences between soil
temperatures. SOC and soil moisture differences between cropland and grassland can explain
the soil respiration difference caused by land-use change, which was confirmed by the
validation results.
Key Words:soil erosion; erosion simulation;soil respiration; SOC; conversion

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8993
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
郭慧敏. 侵蚀条件下土壤呼吸变化特征 及其影响因素[D]. 北京. 中国科学院研究生院,2014.
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