遥感技术在我国土壤侵蚀中的研究进展

介绍了利用遥感技术提取土壤侵蚀信息的原理、技术和方法,对我国目前已取得的进展与成就进行了综述,并对目前存在的问题及以后的发展前景进行了展望。     

流域洪水模拟的分布式时变汇流方法及应用

在考虑流域降雨时空变化和流域地形对流域产、汇流影响的基础上,提出了一种流域洪水模拟的新方法——分布式时变汇流方法。该方法在分布式产、汇流模拟过程中,增加了时变因子,克服了传统方法中忽略降雨在时间上变化的影响。此外,该方法还充分利用了GIS和遥感技术,使得模型中的大多数参数均可从DEM、土壤类型图或遥感影像中获取,只需要率定少数敏感参数。尽管模型结构简单,却能反映降雨径流过程的物理机制。因此,它可用于无资料地区的水文预报,便于应用与推广。将该方法用于浙江省皎口水库流域的洪水模拟,结果显示该模型效率高,模拟的流量曲线与实测曲线吻合较好,并且模拟结果不受降雨强度大小的限制。对双峰型或多峰型洪水,该方法不仅能很好地模拟出各峰的形状,而且主次洪峰分明。     

京郊西北地区农地利用与景观格局时空特征

运用遥感与地理信息系统技术,对三年Landsat TM多光谱遥感图像（1989年、1996年、2005年）进行解译判读,获取京郊西北地区各土地利用类型数据。运用土地利用程度时空演变模型、土地利用动态度模型、土地利用重心模型和景观生态学方法,对研究区1989～2005年间农用地利用及景观格局变化进行了分析。结果表明：农用地频繁流转,以耕地流失最为显著,去向主要为城市及建设用地,林地面积增加缓慢,沙荒地向林地转移明显;农用地各类型的新增速率远小于同期的转移速率,而城市及建设用地则相反;1989～1996年间研究区的综合土地利用动态变化率较1996～2005年间的大,变化集中表现在西北城郊过渡区域,城镇用地扩张导致耕地的利用重心不断向西偏南方向转移;研究区农用地景观破碎化程度在增加,各景观类型的平均斑块形状趋于分散和简单,景观多样性、景观均匀度呈现增加趋势,而景观优势度在逐渐减小。以利用农业用地为鲜明特征的城市化过程是影响北京西北地区景观格局演变的直接因素,城市及建设用地的不断扩张使得林地、耕地斑块的平均面积逐渐变小,景观格局连通性降低。     

GIS、RS与3DS MAX在园林三维景观设计中的应用

目前应用计算机进行园林景观设计的方法可以分成两大类:一类应用地理信息系统(G IS)技术,另一类应用传统的图形图像处理软件。前者制约了园林景观的建模和效果展示,后者却忽略了作为园林景观设计基础的地形研究与应用。为了克服上述不足,提出"G[地理信息系统(G IS)]R[遥感(RS)]M[3DSM AX]三维园林"综合方法来进行园林景观设计:先用G IS生成园林设计区域数字高程模型,用RS创建3D数字地形模型,再把3D数字地形模型导入3DS M AX,制作基于三维地形的园林景观模型。该方法应用于广西都乔山森林公园设计,其设计质量和效率明显提高。     

铵、钾同时存在时, 土壤对铵的优先吸附

The water stability of aggregates in various size classes separated from 18 samples of red soils under different managements, and the mechanisms responsible for the formation of water-stable soil aggregates were studied. The results showed that the water stability of soil aggregates declined with increasing size, especially for the low organic matter soils. Organic matter plays a key role in the formation of water-stable soil aggregates. The larger the soil aggregate size, the greater the impact of organic matter on the water stability of soil aggregates. Removal of organic matter markedly disintegrated the large water-stable aggregates (> 2.0 mm) and increased the small ones (< 0.25-0.5mm) to some extent, whereas removal of free iron(aluminium) oxides considerably destroyed aggregates of all sizes, especially the < 0.25-0.5 mm classes. The contents of organic matter in water-stable aggregates increased with aggregate sizes. It is concluded from this study that small water-stable aggregates (< 0.25-0.5 mm) were chiefly cemented by Fe and Al oxides whilst the large ones (> 2.0 mm) were mainly glued up by organic matter. Both free oxides and organic matter contribute to the formation and water stability of aggregates in red soils.     

基于GIS和RS的巢湖流域水土流失评估

基于地理信息系统(GIS)和遥感技术(RS),提取了巢湖流域地表覆盖、水土保持措施、坡度坡长、土壤可蚀性、降雨侵蚀力5个主要影响水土流失的因子,并运用修正的通用土壤侵蚀模型(revised univer-sal soil loss equation,RUSLE)估算土壤侵蚀量,生成水土流失等级分布图,从而完成对巢湖流域水土流失现状和空间分布特征的评估分析.结果表明,巢湖流域水土流失主要为微度侵蚀和轻度侵蚀,分别占流域总面积的93.87％和6.04％.此外,坡度和植被覆盖是影响流域土壤侵蚀的主要因素.研究结果可为巢湖流域水土流失治理及决策提供科学参考.     

黄河流域生态环境脆弱性评价

Using remote sensing （RS） data and geographical information system （GIS）, eco-environmental vulnerability and its changes were analyzed for the Yellow River Basin, China. The objective of this study was to improve our understanding of eco-environmental changes so that a strategy of sustainable land use could be established. An environmental numerical model was developed using spatial principal component analysis （SPCA） model. The model contains twelve factors that include variables of land use, soil erosion, topography, climate, and vegetation. Using this model, synthetic ecoenvironmental vulnerability index （SEVI） was computed for 1990 and 2000 for the Yellow River Basin. The SEVI was classified into six levels, potential, slight, light, medium, heavy, and very heavy, following the natural breaks classification. The eco-environmental vulnerability distribution and its changes over the ten years from 1990 to 2000 were analyzed and the driving factors of eco-environmental changes were investigated. The results show that the eco-environmental vulnerability in the study area was at medium level, and the eco-environmental quality had been gradually improved on the whole. However, the eco-environmental quality had become worse over the ten years in some regions. In the study area, population growth, vegetation degradation, and governmental policies for eco-environmental protection were found to be the major factors that caused the eco-environmental changes over the ten years.     

Total and young organic matter distributions in aggregates of silty cultivated soils

The distribution of organic matter in soil aggregates was investigated by fractionating aggregates and measuring carbon contents. The distribution of recently incorporated organic carbon was analyzed using ¹³C natural abundance. The soils of the experiment, which previously only had C₃ vegetation, were cropped to maize, aC₄ plant, for 6 or 23 years. Aggregate size distributions were determined for silty soils with different organic matter contents. Slaking-resistant macroaggregates were enriched in C as compared to dry-sieved macroaggregates or to microaggregates, and the C content increased with the size of aggregates. The δ¹³C value was used to calculate the amount of C₃-derived and C₄-derived organic carbon in the fractions. The larger carbon contents in stable macroaggregates were due to young C₄-derived organic carbon (<6 or 23 years), and we concluded that young organic matter was responsible for macroaggregate stability.     

基于多光谱数据的荒漠矿区土壤有机质估算模型

目前运用高光谱数据估算土壤有机质的模型精度已经可以达到精准农业的要求,但其数据的整理和运算过程较为复杂且观测尺度较小.为节省资源,提高效率并为多光谱遥感估算土壤有机质积累经验,该文将Landsat8_OLI多光谱遥感影像各波段的反射率数据与地面土壤有机质SOM(soil organic matter)实测数据相结合,利用SPSS软件及多元线性回归分析方法建立基于反射率R、反射率倒数1/R、反射率倒数对数LN(1/R)、反射率一阶导数FDR(first derivative reflectance)的土壤有机质定量估算模型,精度检验后择取最优模型通过多光谱遥感波段运算的方式推广至整个研究区.结果表明:FDR模型的精度更高,RMSE为0.215,F检验结果为4.072,预测值与实际值之间的决定系数R2为0.963.基于该模型估算研究区空间范围的土壤有机质含量,得出土壤有机质含量在0～5 g/kg之间的面积占总研究区的84.065％,＞10 g/kg的面积仅仅为0.001 5％.在4种土地类型中工矿用地SOM平均含量为最高的7.35 g/kg,受开采的煤炭中有机质影响较大.裸地面积2 674.44 km2,占研究区面积的63％,SOM平均含量6.12 g/kg;盐渍地和荒漠林地SOM含量偏低.总之,运用多光谱遥感数据估算干旱区土壤有机质的方法可行,也为遥感估算其他地表参数提供参考.     

基于RS和GIS的川西天然林保护区土壤侵蚀动态研究

利用1989,1999年的TM和2007年SPOT5遥感影像,运用RS和GIS技术对四川省甘孜州道孚县甲斯孔林场土壤侵蚀状况进行了动态监测研究。结果表明,天然林保护工程实施前(1989-1999年),研究区轻度侵蚀区和强度侵蚀区面积不断增加,说明土壤状况整体上处于恶化趋势;实施天然林保护工程后(1998-2007年),强度侵蚀区面积下降,中度侵蚀区面积上升,表明水土保持状况趋于好转,土壤状况恶化趋势得到反转,但改善幅度不够明显。天然林保护工程在促进植被恢复和提高水土保持功能等方面有着积极的作用。     

基于AHP-熵权TOPSIS模型的辽宁省各城市土地承载力评价

[目的]定量分析评价辽宁省各城市土地承载力状况并对其障碍因子进行诊断,为辽宁省土地利用合理开发提供建议,也为区域土地承载力评价研究提供新思路。[方法]以辽宁省14个地级市作为研究区域,基于2018年Landsat 8 OLI遥感影像,进行土地利用分类获得土地各类型用地面积并结合社会经济数据,构建了土地承载力评价指标体系,并利用AHP-熵权TOPSIS模型,对土地资源承载力进行评价。运用障碍度模型对土地承载力障碍因子进行诊断。[结果]辽宁省城市分别呈现不同的承载力状态。盘锦市、大连市以及沈阳市土地承载力相对较高,但社会子系统是制约其土地承载力的主要障碍因素。鞍山市和营口市承载力表现为相对低的状态,其经济子系统的是制约土地承载力提高的主要因素。[结论]辽宁省各城市土地承载力距离其理想状态还有着一定距离,应促进社会、经济、资源3个子系统协调发展进而提高土地承载力。     

引入时相信息的耕地土壤有机质遥感反演模型

土壤有机质(soil organic matter,SOM)是土壤质量评价的重要指标。监测SOM含量及其空间分布对土壤利用与保护、土壤有机碳库估算等具有重要意义。该文以松嫩平原典型区为研究区,采集4种主要土壤类型样本共147个,获取裸土期多时相MODIS地表反射率8 d合成产品,以单期、多期影像所构建光谱指数作为输入量,构建包含含水量变化与有机质含量信息的多光谱指数,建立SOM线性回归遥感反演模型,揭示SOM空间分布规律。结果表明:由于土壤含水量空间差异随时间变化,基于单期影像构建的模型主要输入量发生规律性改变,其中年积日137 d裸土条件最好,反演模型最优;比值光谱指数R61与SOM显著相关,而和含水量相关性极小,适于作为反演模型输入量;基于多期影像构建的模型引入时相信息后,精度与稳定性较单期影像模型显著提高,其中基于年积日137、105 d两期影像光谱指数所建立的多元线性模型最优;松嫩平原SOM呈现由东北向西南递减趋势。     

基于权重最优组合和多时相遥感的作物估产

多时相遥感数据比单一时相携带了更多的反映作物产量的信息,研究如何将多时相遥感信息进行有机融合以提高作物估产精度的方法是具有意义的。权重最优组合（WOC）是一种通过对单个模型权重的最优化,来构建高精度组合模型的原理方法。论文以黑龙江农垦友谊农场大麦产量遥感估算为例,首先利用大麦4个时相的Landsat5 TM影像分别构建单一时相的大麦产量模型,然后利用WOC的迭代算法,通过赋予4个单一时相产量模型以最优权重,生成基于多时相遥感的组合模型估算大麦产量,结果表明：基于WOC和多时相遥感的组合估产模型的决定系数R2与单一时相的相比得到较大改善,估算精度提高明显。同时,通过对WOC获取的各时相单一模型最优权重大小进行分析表明：应用多时相遥感数据进行作物估产时,权重大小能够反映各时相遥感数据所携带的产量信息的多少,这对于如何选择和确定能有效反映作物产量的敏感遥感时相具有一定的指导意义。     

基于RS和GIS的小型城市土地利用动态分析--以杨凌示范区为例

根据1986年,1995年和2003年3期TM遥感影像,利用遥感技术和地理信息系统空间分析方法,研究了1986—2003年间杨凌示范区的土地利用动态变化情况。分析结果显示:(1)在1986—2003年间,耕地面积逐年下降,17 a间下降了20 km2多。1986年,1995年及2003年耕地分别占总土地面积的74%,59.7%和50.8%;而园地面积增加幅度最大,增加了近12 km2,年变化率近10%;林地和交通用地也有了明显的增加,增长幅度分别为7.4%,7.1%;此外,居民点用地也有明显增加。(2)杨凌在1986—1995年间,居民点用地几乎没有变化,而1995—2003年间居民点用地有了大幅度的增加。另外,2003年交通用地比1995年在总土地面积中所占的比例增加了1.6%,这充分说明了杨凌的城市化步伐不断加快。     

基于信息扩散和关键期遥感数据的冬小麦估产模型

农作物估产对于国家制定粮食进出口政策和保障粮食安全具有重要意义。为构建高精度的作物估产模型,探讨了一种将信息扩散原理和关键期遥感数据相结合的农作物遥感估产方法。首先利用信息扩散原理将关键期遥感数据生成的NDVI和实割实测产量数据扩散到多维监控空间,采用模糊合成的方法建立关键期遥感数据和实割实测产量之间的离散关系模型。然后针对模型的稳定性和精度进行交叉验证,并与多元线性回归模型和BP神经网络模型进行对比。结果表明,利用信息扩散方法构建的遥感估产模型稳定性和精度都明显提高,与多元回归方法和BP神经网络方法相比,决定系数分别提高0.180、0.491,均方根误差分别降低173.10、487.79 kg/hm2。该方法能较好地模拟冬小麦遥感估产中归一化植被指数和产量之间的非线性关系,且泛化推广能力优异,为应用关键期遥感数据进行冬小麦估产提供了一种有效方法。     

我国农情遥感监测关键技术研究进展

我国作物的遥感监测已有20年的研究历史。但象中国这样国土辽阔、地形多样、种植结构复杂、农户规模小的国家的国家级农情遥感监测运行系统，在关键技术方面仍然需要加强研究。这些关键技术包括：数据处理、作物识别、面积量算、长势监测、灾害评估、产量估计及运行系统集成等。该文根据作者开发农业部农情遥感监测系统的经验，分析存在的问题，提出解决问题的基本思路。     

流沙河流域土地利用变化研究

流域土地利用/土地覆被变化是区域土地利用变化研究的重要内容。通过数字化1965年的地形图和对1976年、1988年、2003年三期L andsatM SS/TM/ETM卫星影像的解译得到西双版纳流沙河流域土地利用信息,进而在A rc G IS的支持下,采用土地利用转移矩阵和几种景观指数,结合该区域民族分布和传统习俗对流域土地利用变化进行分析。结果表明:流域的自然条件决定了土地利用的空间分布格局,但民族传统习俗的影响也很大:靠近坝区的山区居民以傣族为主,人口密度较大,森林覆盖率却较高;距离坝区较远的山区,主要是山地民族,人口密度小,但森林覆盖率也小,民族因素对森林以及其他土地利用类型的影响要大于人口因素。政策对土地利用的时间变化影响较大,从1965~2003年,流域的土地利用/土地覆被发生了很大变化,1965年、1976年、1988年和2003年4年中流域的主要土地利用类型都是有林地,但有林地面积在减少,受人类活动影响较大的土地利用类型面积在增加,人类活动对土地利用的干扰增强,土地开发利用强度有增大的趋势。     

Effects of iron and organic matter on the porosity and structural stability of soil aggregates

Knowledge of the soil components controlling aggregate formation and stability is fundamental to the conservation of soil structure. In this work, the effects of Fe and organic matter (OM) on the porosity and structural stability of aggregates <4 mm of two cropped soils from Galicia (NW Spain) were determined. Porosity was estimated directly, by mercury intrusion porosimetry, and indirectly, from moisture characteristic and shrinkage curves. The three porosities obtained were similar and indicated that Soil 1, with the highest Fe and OM contents, had lower total porosity and a wider pore-size distribution than Soil 2. As regards structural stability, Hénin and Monnier's test, simulated rainfall and dispersion experiments, and determination of textural tensile strength all indicated Soil 1 to be the more stable soil. Oxidation of OM and selective extraction of Fe, which were most concentrated in the clay and silt fractions, indicated both these components to be important soil aggregants. It is suggested that the higher content of Soil 1 in Fe and OM is responsible for its greater stability.     

Density separation of soil organic matter across three land uses in calcareous soils of Iran

ABSTRACT

The aim of this study was to examine the usefulness of physical and chemical fractionation in quantifying soil organic matter (SOM) in different stabilized fraction pools. Soil samples from three land use types in Lorestan province, Southwest Iran were examined to account for the amount of organic carbon and nitrogen in different SOM fractions. Size/density separation and chemical oxidation methods were applied to separate the SOM fractions including particulate organic matter (POM), Si + C (silt and clay), DOC (dissolved organic C), rSOM (oxidation-resistant organic carbon and nitrogen) and S + SA (sand and stable aggregates). The values obtained for TOC, TN, and HWC were highest in forest lands followed by the range and agricultural lands. Among the SOM fractions, S + SA showed the highest values (5.75, 5.77 and 20.6 g kg^?1 for agriculture, range and forest lands respectively) followed by POM, Si + C, rSOM, and DOC. The concentrations of C and N in the labile fractions obtained the higher values than in the stabilized fractions. Forest lands had the highest amounts of organic C and N among all fractions whereas agricultural lands showed highest values for inorganic C content of soils in different fractions.     

Effect of soil organic matter, electrical conductivity and sodium adsorption ratio on tensile strength of aggregates

The properties of soils affected by salinity and processes involving degradation of soil structure have been partly recognized. However, the effects of saline and sodic conditions on mechanical and physical properties of soils have been studied to a lesser extent. In this research, the effects of electrical conductivity (EC) and sodium adsorption ratio (SAR) on soils possessing various amounts of organic matter were assessed under laboratory conditions. The soils contained a uniform clay type, predominantly Illite. The major difference of the soils was their amount of organic matter content. The treatments consisted of solutions with definite EC and SAR (two levels of EC: 0.5 and 4 dS/m and three levels of SAR: 0, 5 and 15). The amount of tensile strength was dependent on organic matter, EC, and SAR in a way that with the increase of SAR, the tensile strength decreased. In similar SAR, treatments with higher EC exhibited greater tensile strength. Also, the soils with higher organic matter showed greater tensile strength. The analysis of variance showed the significant difference (at 1%) between the mean of parameters analyzed (soil type, sampling depth, EC, and SAR). The order of averages of tensile strength were: permanent pasture (Agropyron elengatum)Festuca arusdinaceae)相似文献