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1.
基于土壤剖面测定数据计算中国土壤有机碳贮量   总被引:10,自引:0,他引:10  
Soil organic carbon (SOC) storage under different types of vegetations in China were estimated using measured data of 2 440 soil profiles to compare SOC density distribution between different estimates, to map the soil organic carbon stocks under different types of vegetation in China, and to analyze the relationships between soil organic carbon stocks and environmental variables using stepwise regression analyses. Soil organic carbon storage in China was estimated at 69.38 Gt (1015 g). There was a big difference in SOC densities for various vegetation types, with SOC distribution closely related to climatic patterns in general. Stepwise regression analyses of SOC against environmental variables showed that SOC generally increased with increasing precipitation and elevation, while it decreased with increasing temperature. Furthermore, the important factor controlling SOC accumulation for forests was elevation, while for temperate steppes mean annual temperature dominated. The more specific the vegetation type used in the regression analysis, the greater was the effect of environmental variables on SOC. However, compared to native vegetation, cultivation activities in the croplands reduced the influence of environmental variables on SOC.  相似文献   

2.
Soil organic carbon(SOC) is an important component of farming systems and global carbon cycle. Accurately estimating SOC stock is of great importance for assessing soil productivity and modeling global climate change. A newly built 1:50 000 soil database of Zhejiang Province containing 2 154 geo-referenced soil profiles and a pedological professional knowledge-based(PKB) method were used to estimate SOC stock up to a depth of 100 cm for the Province. The spatial patterns of SOC stocks stratified by soil types,watershed(buffer analysis), topographical factors, and land use types were identified. Results showed that the soils in Zhejiang covered an area of 100 740 km2 with a total SOC stock of 831.49 × 106 t and a mean SOC density of 8.25 kg m-2, excluding water and urban areas. In terms of soil types, red soils had the highest SOC stock(259.10 × 106t), whereas mountain meadow soils contained the lowest(0.15 × 106t). In terms of SOC densities, the lowest value(5.11 kg m-2) was found in skel soils, whereas the highest value(45.30 kg m-2) was observed in mountain meadow soils. Yellow soils, as a dominant soil group, determined the SOC densities of different buffer zones in Qiantang River watershed because of their large area percentage and wide variation of SOC density values.The area percentages of various soil groups significantly varied with increasing elevation or slope when overlaid with digital elevation model data, thus influencing the SOC densities. The highest SOC density was observed under grassland, whereas the lowest SOC density was identified under unutilized land. The map of SOC density(0–100 cm depth) and the spatial patterns of SOC stocks in the Province would be helpful for relevant agencies and communities in Zhejiang Province, China.  相似文献   

3.
Tillage effect on organic carbon in a purple paddy soil   总被引:18,自引:0,他引:18  
The distribution and storage of soil organic carbon (SOC) based on a long-term experiment with various tillage systems were studied in a paddy soil derived from purple soil in Chongqing, China. Organic carbon storage in the 0-20 and 0-40 cm soil layers under different tillage systems were in an order: ridge tillage with rice-rape rotation (RT-rr) 〉 conventional tillage with rice only (CT-r) 〉 ridge tillage with rice only (RT-r) 〉 conventional tillage with rice-rape rotation (CT-rr). The RT-rr system had significantly higher levels of soil organic carbon in the 0-40 cm topsoil, while the proportion of the total remaining organic carbon in the total soil organic carbon in the 0-10 cm layer was greatest in the RT-rr system. This was the reason why the RT-rr system enhanced soil organic carbon storage. These showed that tillage system type was crucial for carbon storage. Carbon levels in soil humus and crop-yield results showed that the RT-rr system enhanced soil fertility and crop productivity. Adoption of this tillage system would be beneficial both for environmental protection and economic development.  相似文献   

4.
B. ZHONG  Y. J. XU 《土壤圈》2011,21(4):491-501
Estimation of soil organic carbon (SOC) pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time.Although development of the U.S.Soil Survey Geographic Database (SSURGO),currently the most detailed level with a map scale ranging from 1:12 000 to 1:63 360,has involved substantial government funds and coordinated network efforts,very few studies have utilized it for soil carbon assessment at the large landscape scale.The objectives of this study were to 1) compare estimates in soil organic matter among SSURGO,the State Soil Geographic Database (STATSGO),and referenced field measurements at the soil map unit;2) examine the influence of missing data on SOC estimation by SSURGO and STATSGO;3) quantify spatial differences in SOC estimation between SSURGO and STATSGO,specifically for the state of Louisiana;and 4) assess scale effects on soil organic carbon density (SOCD) estimates from a soil map unit to a watershed and a river basin scale.SOC was estimated using soil attributes of SSURGO and STATSGO including soil organic matter (SOM) content,soil layer depth,and bulk density.Paired t-test,correlation,and regression analyses were performed to investigate various relations of SOC and SOM among the datasets.There were positive relations of SOC estimates between SSURGO and STATSGO at the soil map unit (R2=0.56,n=86,t=1.65,P=0.102;depth:30 cm).However,the SOC estimated by STATSGO were 9%,33% and 36% lower for the upper 30-cm,the upper 1-m,and the maximal depth (up to 2.75 m) soils,respectively,than those from SSURGO.The difference tended to increase as the spatial scale changes from the soil map unit to the watershed and river basin scales.Compared with the referenced field measurements,the estimates in SOM by SSURGO showed a closer match than those of STATSGO,indicating that the former was more accurate than the latter in SOC estimation,both in spatial and temporal resolutions.Further applications of SSURGO in SOC estimation for the entire United States could improve the accuracy of soil carbon accounting in regional and national carbon balances.  相似文献   

5.
城郊土壤不透水表面有土壤机碳转化及其相关性质的研究   总被引:2,自引:0,他引:2  
Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts, thereby resulting in negative effects on soil function and urban environment. Soil samples were collected at 0-20 cm depth in Nanjing City, China, in which seven sites were selected for urban open soils, and fourteen sites with similar parent material were selected for the impervious-covered soils, to examine the effect of impervious surface on soil properties and microbial activities, and to determine the most important soil properties associated with soil organic carbon (SOC) transformation in the urban soils covered by impervious surfaces. Soil organic carbon and water-soluble organic carbon (WSOC) concentrations, potential carbon (C) and nitrogen (N) mineralization rates, basal respiration, and physicochemical properties with respect to C transformation were measured. Installation of impervious surface severely affected soil physicochemical properties and microbial activities, e.g., it significantly decreased total N contents, potential C mineralization and basal respiration rate (P 〈 0.01), while increased pH, clay and Olsen-P concentrations. Soil organic carbon in the sealed soils at 0-20 cm was 2.35 kg m-2, which was significantly lower than the value of 4.52 kg m-2 in the open soils (P 〈 0.05). Canonical correlation analysis showed WSOC played a major role in determining SOC transformation in the impervious-covered soil, and it was highly correlated with total N content and potential C mineralization rate. These findings demonstrate that installation of impervious surface in urban area, which will result in decreases of SOC and total N concentrations and soil microbial activities, has certain negative consequences for soil fertility and long-term storage of SOC.  相似文献   

6.
中国土壤氮含量、空间格局及其环境控制   总被引:4,自引:0,他引:4  
Soil holds the largest nitrogen (N) pool in terrestrial ecosystems, but estimates of soil N stock remain controversial. Storage and spatial distribution of soil N in China were estimated and the relationships between soil N density and environmental factors were explored using data from China's Second National Soil Survey and field investigation in northwest China and the Tibetan Plateau. China's soil N storage at a depth of one meter was estimated at 7.4 Pg, with an average density of 0.84 kg m^-2. Soil N density appeared to be high in southwest and northeast China and low in the middle areas of the country. Soil N density increased from the arid to semi-arid zone in northern China, and decreased from cold-temperate to tropical zone in the eastern part of the country. An analysis of general linear model suggested that climate and vegetation determined the spatial pattern of soil N density for natural vegetation, which explained 75.4% of the total variance.  相似文献   

7.
Understanding how spatial scale inffuences commonly-observed effiects of climate and soil texture on soil organic carbon (SOC) storage is important for accurately estimating the SOC pool at different scales. The relationships among climate factors, soil texture and SOC density at the regional, provincial, city, and county scales were evaluated at both the soil surface (0-20 cm) and throughout the soil profile (0-100 cm) in the Northeast China uplands. We examined 1022 profiles obtained from the Second National Soil Survey of China. The results indicated that the relationships between climate factors and SOC density generally weakened with decreasing spatial scale. The provincial scale was optimal to assess the relationship between climate factors and SOC density because regional differences among provinces were covered up at the regional scale. However, the relationship between soil texture and SOC density had no obvious trend with increasing scale and changed with temperature. There were great differences in the impacts of climate factors and soil texture on SOC density at different scales. Climate factors had a larger effect on SOC density than soil texture at the regional scale. Similar trends were seen in Heilongjiang and eastern Inner Mongolia at the provincial scale. But, soil texture had a greater effect on SOC density compared with climate factors in Jilin and Liaoning. At the city and county scales, the inffuence of soil texture on SOC density was more important than climate factors.  相似文献   

8.
黄土高原小流域土壤有机碳空间变异性研究   总被引:12,自引:0,他引:12  
Soil organic carbon (SOC) has great impacts on global warming, land degradation and food security. Classic statistical and geostatistical methods were used to characterize and compare the spatial heterogeneity of SOC and related factors, such as topography, soil type and land use, in the Liudaogou watershed on the Loess Plateau of North China. SOC concentrations followed a log-normal distribution with an arithmetic and geometric means of 23.4 and 21.3 g kg-1, respectively, were moderately variable (CV = 75.9%), and demonstrated a moderate spatial dependence according to the nugget ratio (34.7%). The experimental variogram of SOC was best-fitted by a spherical model, after the spatial outliers had been detected and subsequently eliminated. Lower SOC concentrations were associated with higher elevations. Warp soils and farmland had the highest SOC concentrations, while aeolian sand soil and shrublands had the lowest SOC values. The geostatistical characteristics of SOC for the different soil and land use types were different. These patterns were closely related to the spatial structure of topography, and soil and land use types.  相似文献   

9.
发生分类与中国土壤系统分类的参比基准研究   总被引:7,自引:0,他引:7  
Soil classification is the foundation for exchange and extension of research findings in soil science and for modern management of soil resources. This study explained database and research methodology to create a cross-reference system for translating the Genetic Soil Classification of China (GSCC) into the Chinese Soil Taxonomy (CST). With the help of the CST keys, each of the 2 540 soil species in GSCC has been interpreted to its corresponding soil order, suborder, great group, and sub-group in CST. According to the methodology adopted, the assigned soil species have been linked one another to their corresponding polygons in the 1:1000 000 digital soil map of China. Referencibility of each soil species between the GSCC and CST systems was determined statistically on the basis of distribution area of each soil species at a high taxon level of the two systems. The soils were then sorted according to their maximum referencibility and classified into three categories for discussion. There were 19 soil great groups in GSCC with maximum referencibility 〉 90% and 22 great groups between 60%-90%. These soil great groups could serve as cross-reference benchmarks. There were 19 great groups in GSCC with maximum referencibility 〈 60%, which could be used as cross-reference benchmarks until new and better results were available. For these soils, if the translation was made at a lower soil taxon level or on a regional basis, it would improve their referencibility enabling them to serve as new cross-reference benchmarks.  相似文献   

10.
Soil carbon mapping is extremely useful in assessing the effect of land management practices on soil carbon storage. Applications of neutron-gamma analysis in scanning mode for mapping of soil carbon are discussed. A Global Positioning System(GPS) device and softwares required to simultaneously acquire gamma signals and geographical positions during scanning operations were added to an existing measurement system. The reliability of soil carbon measurements in scanning mode was demonstrated to be in agreement with results acquired from static mode. The error analysis indicated that scanning measurements can be conducted with the same accuracy as static measurements in approximately one fourth the time. To obtain results suitable for mapping analogous to traditional chemical analyses(i.e., ± 0.5 in weight percent or ± 0.5 w%), scanning time over a given site should be ca. 15 min using the current measurement system configuration. Based on this measurement time, a reasonable towing speed of 3–5 km h-1, the necessity for complete site coverage during scanning, the number of sites(within the surveyed field), and the required total measurement time can be estimated. Soil carbon measurements for 28 field sites(total area ca. 2.5 ha) were conducted in ca. 8 h. Based on acquired data,a soil carbon distribution map was constructed utilizing various softwares. The surveyed field area included an asphalt road that had carbon readings higher than the surrounding land. The clarity with which these carbon-rich zones were delineated on the constructed map represents evidence supporting the veracity of this method. Neutron-gamma analysis technology can greatly facilitate timely construction of soil carbon maps.  相似文献   

11.
Abstract

Soil profile data are the basis for estimating soil organic carbon (SOC) storage and any changes in SOC storage, which are of great significance in terms of global climate change. Estimates based on various profile data have been made for SOC storage in China. Modeling studies have given contrasting results on changes in SOC storage in Chinese croplands. A certain number of measured soil profile data are needed to validate the modeled results. In the present study, we examined the relationships between sample size, population variance and detection limit using the central limit theorem and the statistical properties of the normal distribution. Based on the profile dataset from the Second National Soil Survey in China, we calculated that to derive a reliable estimate of the overall mean SOC density for all the soils of China, a sample size of 4,000 soil profiles is needed. In this case, a reliable estimate is defined as having a 95% confidence interval and allowing a ±5% detection limit of SOC. The necessary sample size for cropland soils is 1,250. Our results indicate that approximately 100 samples only are needed to validate a modeled SOC loss of 20–30% in cropland soils in China. By aggregating the soil profiles in the dataset into soil orders and calculating the variance of each soil order, we show that the sample sizes in the dataset are insufficient to give reliable estimates on the carbon densities of most soil orders; thus, we conclude that there is considerable uncertainty in the SOC distribution maps resulting from the Second National Soil Survey.  相似文献   

12.
不同植被下中国土壤有机碳的储量与影响因子   总被引:79,自引:0,他引:79       下载免费PDF全文
基于第二次土壤普查和新疆土壤调查等 2 4 4 0个典型土壤剖面数据和 1∶4 0 0万中国植被图 ,对中国不同植被类型下的 1 0 0cm和 2 0cm厚度土壤有机碳密度和储量进行估算 ,绘制了土壤有机碳储量的地理分布图 ,并且对土壤有机碳储量与生境条件之间的关系进行统计分析。结果表明 :不同植被类型下的土壤有机碳密度存在显著差异 ,草甸和森林最高 ,灌木和农田次之 ,再其次是草原 ,最低的是荒漠 ;基于植被分类计算的我国 1 0 0cm和 2 0cm厚度土壤有机碳总储量分别为 6 9.38Gt和 2 3.81Gt。 1 0 0cm深度土壤碳储量在森林、农田、灌丛、草甸、草原、荒漠植被下分别为 1 7.39Gt、1 4 .6 9Gt、1 3.6 2Gt、1 2 .2 2Gt、7.4 6Gt、3.93Gt;土壤有机碳储量的空间分布差异明显 ,具有明显地域性 ,青藏高原东南地区、阿尔泰山和天山山地等高寒草甸、灌丛草甸区是土壤有机碳储量最高的地区 ,其次是东北地区北部的针叶林、草甸区和我国南方的亚热带阔叶林区 ,土壤有机碳储量最低的地区是西北地区和藏北高原的荒漠、草原干旱区 ;在不同生态系统中环境变量对土壤有机碳储量的影响是不同的 ,在温带草原年平均温度是土壤有机碳储量主要控制因素 ,而对于针叶林海拔是导致土壤有机碳储量变异的主导因子 ;随着研究尺度的细化 ,环境变  相似文献   

13.
浙江省土壤发生分类与系统分类参比及制图研究   总被引:3,自引:1,他引:2  
利用新建立的浙江省1∶5万土壤数据库,对土壤发生分类土种与中国土壤系统分类亚类进行了参比,编制了土壤系统分类亚类分布图.结果表明,发生分类基层分类单元归属较为清楚,但高级单元关系较为复杂.99个土属有62个参比归属唯一,277个土种有252个参比归属唯一,通过参比将大比例尺土壤普查成果转换成系统分类体系是可行的,可以满足1∶10万的系统分类亚类制图要求.浙江省土壤参比后归属于8个土纲,以雏形土土纲面积最大,占总面积的31.3%;人为土次之,占总面积的21.4%,有机土面积最小.在系统分类土纲层次,土壤区域分布规律较为明显.研究结果对指导土壤系统分类具有一定的参考价值,也为省域范围的系统分类制图提供了范例.  相似文献   

14.
中国土壤有机碳密度和储量的估算与空间分布分析   总被引:141,自引:5,他引:136       下载免费PDF全文
基于 1∶40 0万的《中华人民共和国土壤图》和第二次土壤普查数据 ,运用地理信息系统技术 ,对中国土壤有机碳密度及储量做出估算 ,并且分析了土壤有机碳密度的空间分布差异。结果表明 :10 0cm深度的土壤有机碳密度介于 1 19kgm- 2 到 176 46kgm- 2 之间 ,2 0cm深度的土壤有机碳密度介于 0 2 7kgm- 2 到53 46kgm- 2 之间 ;10 0cm和 2 0cm深度的土壤有机碳储量分别为 84 4Pg (1Pg =10 15 g)和 2 7 4Pg ;土壤有机碳密度具有高度的空间变异性 ,东北地区、青藏高原的东南部、云贵高原等森林、草甸分布的地区有机碳密度最高 ,准噶尔盆地、塔里木盆地、阿拉善高原与河西走廊、柴达木盆地等沙漠化地区的土壤有机碳密度最低 ;土壤有机碳密度的空间分布主要受气候、植被以及人类活动的影响  相似文献   

15.
分别在长江中下游地区3处超级稻育种试验基地,选择多年连续种植超级稻和未种植超级稻的稻田,于水稻收获后采集表土未破坏土壤样品,采用低能量超声波分散法分离得到不同粒径的团聚体颗粒组,研究超级稻连续种植后有机碳含量变化及其有机碳在团聚体颗粒组中的分配,探讨连续种植超级稻对土壤有机碳和团聚体稳定性的影响。结果表明:连续种植超级稻后,水稻土表土有机碳含量均下降,降幅介于3%-14%;团聚体颗粒组组成以2000-200μm和200~20μm粒径为主,有机碳在2000—200μm和〈2μm两个粒级中最高;连续种植超级稻后2000~200μm大团聚体颗粒组质量分数提高,土壤团聚体稳定性增强。连续种植超级稻后有机碳含量下降可能是土壤短期的一种响应机制,长期来看并不改变水稻土的固碳潜力。  相似文献   

16.
云南省土壤有机碳储量估算及空间分布   总被引:4,自引:2,他引:2  
根据云南省第二次土壤普查资料,采用土壤类型法估算了云南省主要土壤类型的有机碳(SOC)密度和储量,并对云南省土壤有机碳密度的空间分布差异和影响土壤有机碳储量的主要因子进行了分析。结果表明,云南省0-20 cm土层平均SOC密度为59.77 t/hm2,SOC储量为2.30×109 t;0-100 cm土层平均SOC密度为159.95 t/hm2,SOC储量为6.15×109 t,占全国储量的7.28%,占全球陆地生态系统SOC储量的0.41%;其中SOC储量占前4位的土壤类型为红壤、黄棕壤、赤红壤、棕壤,不同深度下4者之和约占云南省总储量的60%。在土壤有机碳密度空间分布上,SOC密度分布最高的区域为云南省西北部和东北部地区,其次是西部的横断山脉和东部的云南高原地区,而以紫色土为主的中北部地区SOC密度则最低。由于降雨量、温度、海拔和土地利用类型的共同影响,导致了区域内的SOC密度分布不均,其中降雨量、温度和海拔等自然因素是影响SOC密度分布的主要因子。  相似文献   

17.
为探明坡耕地土壤有机碳空间分布特征,对紫色土丘陵区坡耕地不同部位土壤有机碳及活性有机碳顺坡和深度分布进行分析。结果表明:坡耕地上坡土层深度仅为22.3cm,中坡和下坡土层深度约为上坡的2.09倍和3.30倍;与上坡比较,中坡和下坡土壤容重下降了0.2和0.04,土壤孔隙度增加了19.82%与3.83%。沿坡从上向下土壤有机碳及活性有机碳储量显著增加,下坡土壤有机碳及活性有机碳储量比上坡和中坡分别增加了674.74%,104.09%和958.51%,267.75%;不同部位土壤有机碳及活性有机碳含量随土层深度增加呈降低趋势,中坡和下坡土壤有机碳及活性有机碳含量的深度分布满足Y=alnX+b对数方程,上坡不符合该方程。坡耕地土壤有机碳与其活性有机碳含量呈极显著正相关。土壤沿坡耕地重新分配影响有机碳空间分布格局。  相似文献   

18.
土地利用方式的变化在土壤有机碳(Soil Organic Carbon,SOC)积累的过程中起着非常重要的作用。目前在估算土壤有机碳储量的过程中,一直没有重视土地利用属性。运用基于土壤学专业知识的连接方法 (pedological professional knowledge-based method,PKB法),结合江苏省新沂县1∶20万土壤图,1∶20万土地利用图和1∶20万土壤类型土地利用混合图,估算了各图在不同土壤剖面点数情况下的新沂县SOC储量,并将三者在最佳剖面点数下估算出的SOC储量和SOC密度(SOCD)进行了比较及精度评价。结果表明:在土壤类型图、土地利用图和土壤类型土地利用混合图上进行的PKB法连接时最佳剖面点数均为397点,最佳网格为2 km×2 km;在中比例尺图件上进行PKB法连接估算SOC储量时,综合考虑土壤类型和土地利用类型可以大大提高估算精度,同时土地利用类型属性比土壤类型属性更为重要。研究结果可为在中比例尺条件下提高SOC估算精度提供科学依据。  相似文献   

19.
滇中不同植物群落对紫色土表层土壤碳、氮累积的影响   总被引:2,自引:0,他引:2  
通过连续观测2007-2008年滇中飒马场5种植物群落下紫色土表层土壤理化性质及碳、氮含量的旱雨季变化和层次分布特征,以揭示滇中不同植物群落对紫色土碳、氮累积效应的影响.研究结果表明:植物群落对表层土壤有机碳及其组分、全氮含量、pH及容重有显著的影响.云南松林表层土壤(0-20 cm)有机碳贮存量(24.9 t/ha)显著低于次生常绿阔叶林、桉树林和针阔混交林土壤的.不同植物群落表层土壤(0-20 cm)的全氮贮存量之间没有显著的差异.易氧化有机碳含量的变化是引起各植物群落表层土壤有机碳含量的呈现差异的主要原因.旱雨季变化对各土层易氧化有机碳及总有机碳含量、pH有明显的影响.表层土壤有机碳贮量与地表枯落物碳贮量变化特征之间表现出明显的滞后效应,且二者无显著相关性,表明地表枯落物可能不是影响土壤有机碳碳贮量季节变化的主要因素.  相似文献   

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