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1.
以广州市1992年,2000年、2005年TM、ETM遥感影像资料为数据源,在GIS技术支持下,对处于广州市南部边缘的番禺区近1 3年来的土地利用/覆盖变化过程进行了定量研究.结果显示番禺区在1992～2005年间建设用地、园地、水域大幅增加,耕地大量减少,林地、未利用地有增有减;各类型之间的转化主要表现为耕地向建设用地、园地、水域大量转移:研究区土地利用程度逐年增加,范围不断扩大.表明番禺区对广州大都市的生产功能、缓冲功能,生态功能的影响力不断加大.  相似文献   

2.
丁字湾地区是山东半岛蓝色经济区划9大核心区之一,是胶东经济圈一体化建设的焦点,发展远景广阔。本文选取2005年、2010年、2016年三期TM影像进行遥感解译研究丁字湾地区土地利用变化特征及其空间分布。研究结果表明,丁字湾地区土地利用类型以耕地为主,2005—2016年间建设用地、草地的面积显著增加,水域、海域面积大幅减少。土地的转移主要发生在"建设用地与耕地、耕地与水域、养殖盐田与海域、草地与养殖盐田"之间。城乡建设的不断发展,也给丁字湾地区带来了海岸侵蚀、海水入侵等生态环境负面影响。建议在湾口地区开展"退围还海、退养还滩、退耕还湿"等海岸整治修复工作后,发展人地环境和谐的生态旅游经济。  相似文献   

3.
江苏省近30年来的土地利用变化的区域差异分析   总被引：2，自引：1，他引：1  
本文利用4个时相(1985年、1995、2000年和2005年)的遥感数据,提取了江苏省三大区域(苏南、苏中、苏北)的土地利用变化转换矩阵表,分析了江苏省的土地利用区域差异,并进行人口、城市化、农业结构调整因子、政策对土地利用差异的驱动机制分析。通过土地利用变化转换矩阵表统计得到:耕地的流出面积、城镇用地面积和农村用地面积的扩大面积从南到北呈梯度递减,且随着时间的推移,区域性差异越来越显著。在驱动力分析中发现:苏南地区大量耕地存在浪费利用与超前非农化的问题在社会经济没有进入高度发达的时期之前,经济社会越是发达,人口的增长越落后于耕地的减少在城市化过程中,城市越发达,城镇人口密度的增长对耕地向城镇用地的流入的影响越小"苏南模式"是致使土地利用区域差异的重要因素。  相似文献   

4.
武汉城市圈是全国首批“两型社会”改革试验区之一,而且是中部崛起战略和长江经济带发展战略的重点区域。为了正确认识武汉城市圈土地利用时空变化特征,以及政策因素对土地利用变化的影响,本文基于2000、2005、2010和2015年4期武汉城市圈土地利用现状数据,结合GIS空间分析、数理统计、单一土地利用动态度、土地利用转移矩阵和综合土地利用动态度方法,对武汉城市圈2000-2015年以及3个5年期土地利用变化的总体特征、转化方向和区域差异特征进行研究,并分析政策因素对土地利用变化的驱动作用。结果表明：① 总体特征上,2000-2015年耕地、草地、林地和未利用地面积持续减少,建设用地和水域面积不断增多。② 变化方向上,2000-2015年以耕地、林地转化为建设用地和水域为主要特征,2000-2005年以耕地向水域和建设用地转化为主,2005-2010年以耕地向建设用地、水域,林地向建设用地转化为主,2010-2015年以耕地、林地和水域向建设用地转化为主。③ 区域时空差异上,综合土地利用动态度最大的区域集中在武汉城市圈的中部;从单一土地利用动态度看,耕地主要分布在武汉城市圈周边地区;建设用地主要集中在武汉城市圈中部;水域集中在武汉城市圈的仙桃市;林地主要在潜江市、云梦县;草地主要为英山县。④ 政策驱动因素分析上,中部崛起、两型社会、长江经济带发展战略等政策对土地利用变化具有重要影响。  相似文献   

5.
城镇扩张的多源遥感图像动态监测分析   总被引：1，自引：1，他引：0  
遥感动态监测城镇扩展己成为一个重要的研究和应用领域。利用ASTER和TM多源多时相遥感影像和地形数据,以福建省漳州市区为示范区,对城镇建筑用地扩张进行了遥感监测。研究认为,对于ASTER影像,综合利用光谱知识、多时相植被指数、城镇建筑用地的地形分布等建立分类决策规则,可以有效提取城镇建筑用地信息(精度不低于90%);研究提出用较新时相影像获取的城镇建筑用地限定较早时相影像城镇建筑用地提取范围的思路,拓展了TM影像三指数法的应用范围,以此保证了较早时期TM影像城镇信息的有效提取。  相似文献   

6.
基于青岛市区2005年4月和2015年4月的TM影像,利用ENVI中监督分类法,结合人工目视解译,得出2005年和2015年青岛市区土地利用类型分布情况。利用土地利用类型动态模型,分析了10年间青岛市土地利用类型的变化规律。认为2005—2015年,青岛市土地利用类型产生了较大的变化,建设用地、耕地、水面、草地、林地的面积变化显著。其中,建设用地面积增加200.98 km~2;耕地面积减少105.89 km~2;水面面积减少76.68 km~2;草地面积减少69.53 km~2;林地面积增加54.45 km~2;未利用土地面积减少。说明青岛市区处于土地利用发展的时期,政府应该注重土地资源的合理利用。  相似文献   

7.
准确预测未采样区域SOC密度,是研究SOC演变趋势和探索土壤固碳作用对缓解全球气候变化的基础。采用泛克里格法(Universal Kriging,UK)和土壤类型法(pedological professional knowledge-based method,PKB),分别对长兴县水稻土有机碳密度进行了预测,其中,UK直接以长兴水稻土剖面资料为源数据、PKB以长兴水稻土剖面数据和长兴1∶5万数字土壤图为源数据进行预测。根据平均绝对误差(MAE)及均方根误差(RMSE)大小,评价了两种方法在县域尺度土壤有机碳密度空间预测效果。结果表明:UK的MAE(31.2)、RMSE(52.5)均大于PKB的MAE(24.7)、RMSE(43.1),说明PKB法的预测效果较好,UK法相对较差。研究表明,对土壤类型、土壤母质,以及剖面点位置等信息的综合考虑能使PKB法更好地表达土壤属性的空间特征,也更适于县域尺度土壤有机碳密度的空间预测。  相似文献   

8.
土地利用变化监测方法有很多种,本文提出了一种基于IDRISI平台进行土地利用变化监测的方法。以北京市昌平区为研究区域,对2001年和2005年昌平区土地利用数据进行统一土地利用类型和格式转换,输入IDRISI中的LCM模块得到2009年的预测土地利用图,并与基于TM遥感卫星影像解译的2009年图进行精度对比,在此基础上预测研究区2020年建设用地状况。结果表明:基于IDRISI中的LCM模块进行土地利用变化预测具有较高的精度。预测结果显示昌平区2020年建设用地总面积增长了13.2%,过程中存在建设面积大量侵占耕地、植被的现象。文章建议研究区在今后的发展中应做到限制建设用地面积的快速增长,提高其土地利用集约度,严守耕地红线,提升土地产能。  相似文献   

9.
以1986、1996和2006年三期Landsat TM影像为基本数据源,采用最大似然法分类,并以同期高分辨率的SPOT5影像进行分类后处理,最后分类后变化检测法监测了福州市1986~2006年的土地利用变化及其转移模式。结果表明,福州市近20年间土地利用发生了较大的变化,城乡建筑用地处于快速增长阶段,而耕地数量却在不断下降。经济发展、人口增长、政府决策等因素是福州市土地利用发生变化的主要驱动力。  相似文献   

10.
本文以成都市为例,应用1996和2002年两期的TM影像资料,对该市6年来的土地利用变化情况及其特点进行了研究,分析出该市各类土地利用数量变化的幅度、速度、区域差异以及土地利用空间变化的主要类型、分布特征和区域方向。结果表明:①从1996年至2002年,成都市土地利用结构变化较大,主要表现为耕地、未利用土地的大量减少和林地(园地)、城镇、居民建设用地的大幅度增加,而水域、草地面积变化不十分明显;②6年间,成都市不同土地利用类型之间的相互转化比较复杂,其主要发生在耕地、林地(园地)、城镇、居民建设用地及未利用土地之间;③成都市各类土地利用变化类型分布呈现出明显的区域差异性。同时,相同土地利用变化类型在不同区域的空间分布状况也存在着较大的差异。  相似文献   

11.
Global and local climate changes could disturb carbon sequestration and carbon stocks in forest soils. Thus, it is important to characterize the stability of soil organic matter and the dynamics of soil organic carbon (SOC) fractions in forest ecosystems. This study had two aims: (1) to evaluate the effects of altitude and vegetation on the content of labile and stabile forms of organic carbon in the mountain soils; and (2) to assess the impact of the properties of soil organic matter on the SOC pools under changing environmental conditions. The studies were conducted in the Karkonosze Mountains (SW Poland, Central Europe). The content of the most labile fraction of carbon (dissolved organic carbon, DOC) decreases with altitude, but the content of fulvic acids (FA), clearly increases in the zone above 1000 m asl, while the stabile fraction (humins, non-hydrolyzing carbon) significantly decreases. A higher contribution of stabile forms was found in soils under coniferous forests (Norway spruce), while a smaller - under deciduous forests (European beech) and on grasslands. The expected climate change and the ongoing land use transformations in the zone above 1000 m asl may lead to a substantial increase in the stable humus fraction (mainly of a non-hydrolyzing carbon) and an increase in the SOC pools, even if humus acids are characterized by a lower maturity and greater mobility favorable to soil podzolization. In the lower zone (below 1000 m asl), a decrease in the most stable humus forms can be expected, accompanied by an increase of DOC contribution, which will result in a reduction in SOC pools. Overall, the expected prevailing (spatial) effect is a decreasing contribution of the most stable humus fractions, which will be associated with a reduction in the SOC pools in medium-high mountains of temperate zone of Central Europe.  相似文献   

12.
The dynamics of soil organic carbon(SOC)in cropland is one of the central issues related to both soil fertility and environmental safety. However, little information is available at county level regarding the spatiotemporal variability of SOC in the southwestern mountainous region of China. Thus, this study aimed to explore spatiotemporal changes of SOC in the cultivated soil layer of dry land in Mojiang County,Yunnan Province, China. Data were obtained from the second national soil survey(SNSS) of 1985 and soil tests for fertilizer application carried out by the Mojiang Agricultural Bureau in 2006. The ANOVA test was applied to determine any significant differences between the datasets, while semivariogram analysis was performed on geostatistics via an ordinary Kriging method in order to map spatial patterns of soil organic carbon density(SOCD). The results revealed that SOCD in the cultivated soil layer significantly decreased from 3.93 kg m~(-2) in 1985 to 2.89 kg m~(-2) in 2006, with a total soil organic carbon stock(SOCS) decrease of 41.54×10~4 t over the same period. SOCS levels fell most markedly in yellow-brown soil at a rate of51.52%, while an increase of 8.70% was found in the analysed latosol. Geostatistical analysis also showed that the recorded changes in SOCD between 1985 and2006 were spatially structured. The decreasing trend might be attributed to the combined action of intense cultivation, major crop residue removal without any protective tillage measures, unreasonable fertilization and natural climatic diversity inducing a large decrease in SOC in the studied cultivated dry land region of Mojiang County. Therefore, management measures such as protective tillage should be undertaken in order to enhance soil C sequestration.  相似文献   

13.
1INTRODUCTIONDesertification is one of the most serious land degrada-tion, which results in the deterioration of physical, che-mical, and biological characteristics of soils (UNEP, 1992). Soil organic carbon (SOC) was considered to be a key index in evaluation of soil quality, soil degradation and soil C sequestration(SCHLENGSINGER etal., 1990; FENG etal., 2002; WANG etal., 2003). Many researchers have reported the correlations among desertification restoration, soil C s…  相似文献   

14.
Labile organic carbon (LOC) is one of the most important indicators of soil organic matter quality and dynamics elevation and plays important function in the Tibetan Plateau climate. However, it is unknown what the sources and causes of LOC contamination are. In this study, soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and LOC were analyzed based on different soil horizons and elevations using turnover time in an experimental site (3700 m to 4300 m area) in Sygera. SOC and LOC in higher-elevation vegetation types were higher than that of in lower-elevation vegetation types. Our results presented that the soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) were positively correlated with SOC. The content of easily oxidized carbon (EOC), particulate organic carbon (POC) and light fraction organic carbon (LFOC) decreased with depth increasing and the content were the lowest in the 60 cm to 100 cm depth. The total SOC, ROC and POC contents decreased with increasing soil horizons. The SOC, TN, MBC and MBN contents increased with increasing altitude in the Sygera Mountains. The MBC and MBN contents were different with the changes of SOC (p<0.05), meanwhile, both LFOC and POC were related to total SOC (p<0.05). The physical and chemical properties of soil, including temperature, humidity, and altitude, were involved in the regulation of SOC, TN, MBC, MBN and LFOC contents in the Sygera Mountains, Tibetan Plateau.  相似文献   

15.
Land cover type is critical for soil organic carbon(SOC) stocks in territorial ecosystems. However, impacts of land cover on SOC stocks in a karst landscape are not fully understood due to discontinuous soil distribution. In this study, considering soil distribution, SOC content and density were investigated along positive successional stages(cropland, plantation, grassland, scrubland, secondary forest, and primary forest) to determine the effects of land cover type on SOC stocks in a subtropical karst area. The proportion of continuous soil on the ground surface under different land cover types ranged between 0.0% and 79.8%. As land cover types changed across the positive successional stages, SOC content in both the 0–20 cm and 20–50 cm soil layers increased significantly. SOC density(SOCD) within 0–100 cm soil depth ranged from 1.45 to 8.72 kg m-2, and increased from secondary forest to primary forest, plantation, grassland, scrubland, and cropland, due to discontinuous soil distribution. Discontinuous soil distribution had a negative effect on SOC stocks, highlighting the necessity for accurate determination of soil distribution in karst areas. Generally, ecological restoration had positive impacts on SOC accumulation in karst areas, but this is a slow process. In the short term, the conversion of croplandto grassland was found to be the most efficient way for SOC sequestration.  相似文献   

16.
Accurate estimate of soil carbon storage is essential to reveal the role of soil in global carbon cycle. However, there is large uncertainty on the estimation of soil organic carbon (SOC) storage in grassland among previous studies, and the study on soil inorganic carbon (SIC) is still lack. We surveyed 153 sites during plant peak growing season and estimated SOC and SIC for temperate desert, temperate steppe, alpine steppe, steppe meadow, alpine meadow and swamp, which covered main grassland in the Qinghai Plateau during 2011 to 2012. The results showed that the vertical and spatial distributions of SOC and SIC varied by grassland types. The SOC amount mainly decreased from southeast to northwest, whereas the SIC amount increased from southeast to northwest. The magnitude of SOC amount in the top 50 cm across grassland types ranked by: swamp > alpine meadow > steppe meadow > temperate steppe > alpine steppe > temperate desert, while the SIC amount showed an opposite order. There was a great deal of variation in proportion of SOC and SIC among different grassland types (from 55.17 to 94.59 for SOC and 5.14 to 44.83 for SIC). The total SOC and SIC storage was 5.78 Pg and 1.37 Pg, respectively, in the top 50 cm of soil in Qinghai Province. The mixed linear model revealed that grassland types was the predominant factor in spatial variations of SOC amount while grassland types and soil pH accounted for those of SIC amount. Our results suggested that the community shift of alpine meadow towards alpine grassland induced by climate warming would decrease carbon sequestration capacity by 6.0 kg C m2.  相似文献   

17.
Soil organic carbon (SOC) was considered to be a key index in evaluation of soil degradation and soil C sequestration. To discuss the spatial-temporal dynamics of SOC in arable layer in reversed desertification area, a case study was conducted in Yulin City, Shaanxi Province, China. Data of SOC were based on general soil survey in 1982 and repeated soil sampling in 2003. Soil organic carbon content (SOCC) was determined by K2Cr3O2-FeSO4 titration method, and soil organic carbon density (SOCD) was calculated by arithmetic average and area weighted average method, respectively. On average, SOCC and SOCD of the arable layer in the study area from 1982 to 2003 had increased 0.5 Ig/kg and 0.16kg/m2, respectively. Considering main soil types, the widest distributed Arid-Sandic Entisols had lowest values and increments of SOCC and SOCD during the study period; while the second widest Los-Orthic Entisols had higher values and increments of SOCC and SOCD, compared to the mean values of the whole region. The results indicated that reversed desertification process was due to the modification of land use and management practices, such as natural vegetation recovery, planting grass, turning arable land to grassland, and soil and water conservation etc., which can improve SOCC and SOCD and thus enhance soil C sequestration.  相似文献   

18.
Land use change is one of the major factors that affect soil organic carbon(SOC) variation and global carbon balance. However, the effects of land use change on SOC are always variable. In this study, using a series of paired-field experiments, we estimated the effects of revegetation types and environmental conditions on SOC stock and vertical distribution after replacement of cropland with poplar(Populus tomentosa) and korshinsk peashrub(Caragana korshinskii) in three climate regions(Chifeng City, Fengning City and Datong City of the ′Beijing-Tianjin Sandstorm Source Control′(BTSSC) program area. The results show that SOC sequestration rate ranges from 0.15 Mg/(ha·yr) to 3.76 Mg/(ha·yr) in the soil layer of 0–100 cm in early stage after cropland afforestation in the BTSSC program area. The SOC accumulation rates are the highest in Fengning for both the two vegetation types. Compared to C. korshinskii, P. tomentosa has greater effects on SOC accumulation in the three climate regions, but significantly greater effect only appears in Datong. The SOC density increases by 20%–111% and 15%–59% for P. tomentosa and 9%–63% and 0–73% for C. korshinskii in the 0–20 cm and 20–100 cm soil layers, respectively. Our results indicate that cropland afforestation not only affects SOC stock in the topsoil, but also has some effects on subsoil carbon. However, the effect of cropland afforestation on SOC accumulation varied with climate regions and revegetation types. Considering the large area of revegetation and relatively high SOC accumulation rate, SOC sequestration in the BTSSC program should contribute significantly to decrease the CO2 concentration in the atmosphere.  相似文献   

19.
A crucial region for China's ‘Grain-forGreen Policy' is located within a traditional farmpastoral area, between 2000 to 3000 m above sea level, on the eastern Qinghai-Tibetan Plateau.However, the responses of soil organic carbon(SOC) to different land-use patterns in this region are unclear. Here, we determined the SOC(0–20 cm) content of grasslands and forests that are being converted from farmlands, as well as in abandoned arable land and arable land in this region. The factors influencing the reclaimed lands were analyzed along altitudes from 2030 to 3132 m. Our results showed that SOC content was higher for grassland and abandoned arable land than forest and arable land. The SOC content increased with the increase in altitude for total land-use patterns. Further, the grassland and abandoned arable land had higher SOC content than the forest with almost parallel trends along the increase in altitude. However, the proportion of regulated factors of altitude and species richness varied among forest, grassland, and abandoned arable land. Our results indicated that the land-use pattern of returning farmland to grassland and abandoned arable land was more effective in terms of the SOC storage in the superficial layer in this altitude range in the Qinghai-Tibetan Plateau, thereby being beneficial to optimizing land management in this region.  相似文献   

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