基于GIS和RULSE的三峡库区土壤侵蚀量估算分析

以三峡库区为研究对象,在GIS技术支持下,利用野外实测及DEM、土地利用、土壤类型、植被覆盖等数据,对修正后的通用土壤流失方程(RUSLE)中各因子进行量化分析,从而对三峡库区土壤侵蚀量进行估算,并对土壤侵蚀强度进行分级;在此基础上计算不同坡度、土地利用类型、土壤类型下的土壤侵蚀综合指数。结果表明,三峡库区年均土壤侵蚀量为19 364.71×104 t/a,平均土壤侵蚀模数为2 741.48t/(km2.a),属于中度侵蚀;68.57%的区域为微度侵蚀或轻度侵蚀,强度以上侵蚀主要分布在库区的东部,面积占库区的14.43%,侵蚀量却占总侵蚀量的58.67%,是预防和加强水土流失治理的重点区域。     

基于RUSLE的藉河示范区土壤侵蚀时空动态特征研究

探究区域土壤侵蚀变化特征,为区域水土保持效益评价、土壤侵蚀防治提供依据。基于GIS和RS技术,采用降雨数据、DEM数据、土壤数据以及遥感影像等数据,运用RUSLE模型,定量分析了藉河示范区1997-2015年土壤侵蚀时空动态特征。结果表明:4个时期土壤侵蚀模数分别为1 326.18、2 790.39、2 025.23和1 366.32 t/(km~2·a),呈现先加剧后改善的趋势。土壤侵蚀以微度侵蚀和轻度侵蚀为主,在2005年之前,土壤侵蚀以向更高侵蚀等级转移为主,2005年之后以向更低侵蚀等级转移为主。不同坡度等级上,出现随坡度增加,土壤侵蚀先趋于严重后缓和的特征,15°～45°的坡度上是研究区土壤侵蚀主要分布坡段。不同海拔等级上,土壤侵蚀随海拔升高呈现先增加后降低的趋势,在中海拔区(1 562～1 782 m)和中低海拔区(1 335～1 562 m)土壤侵蚀分布面积最广、强度最大,此类区域是藉河示范区土壤侵蚀防治的重点区域。     

基于土壤侵蚀预测模型对石城县域低效林的判别及研究

基于遥感影像数据、地形数据和小班调查数据,采用修正通用土壤流失方程和三因子法相结合的土壤侵蚀预测模型,对石城县域林地土壤侵蚀模数进行等级划分,建立低质低效林的评价体系,并进行空间分布和土地利用特征研究。结果表明:低质低效林主要分布在研究区东北和东南区域,占整个研究区内林地面积的31.48%,属于劣质立地条件下的低质低效林;研究区内微度侵蚀面积占比最大,接近总面积的93%,另外强烈侵蚀以上等级的侵蚀面积为5.56 km~2,占整个研究区总面积的0.351%;土壤侵蚀总量方面,稀疏林地以2.92%的侵蚀面积对研究区总侵蚀量的贡献率达到了4.80%,总侵蚀量占比几乎是侵蚀面积占比的2倍。研究结果旨在丰富低质低效林判别理论,同时为低效林改造提供科学依据。     

利用“3S”技术进行区域土壤侵蚀研究——以四川省泸定县冷碛镇为例

为解决当前区域土壤侵蚀量快速调查的问题,以四川省泸定县冷碛镇为研究区,直接引入修正土壤流失方程(RUSLE),利用遥感影像和其他非遥感数据,选取了合适的影响因子,快速地获取了该区域的土壤侵蚀状况,并研究了土壤侵蚀与土地利用的相互关系。研究结果表明:冷碛镇大部分土地属于微度和中度侵蚀,少量土地属于极强烈和剧烈侵蚀;侵蚀强度大的区域多为植被覆盖度低得区域,如:未利用土地和部分无作物覆盖耕地。该研究为冷碛镇的土地利用和水保决策提供了依据。     

基于Hadoop的区域土壤侵蚀强度计算GIS设计与实验

在开源分布式计算框架Hadoop的基础上,选择大凌河流域为研究区,构建降雨侵蚀力、土壤可侵蚀性、坡长等土壤侵蚀因子栅格数据分布式存储策略,利用MapReduce编程模式设计实现通用水土流失方程RUSLE的算法程序进行土壤侵蚀强度计算,并扩展Geoserver的栅格文件读取功能,增大对HDFS栅格文件的读取支持,实现土壤侵蚀强度计算结果的快速发布。结果表明,该系统可实现大数据量、高分辨率土壤侵蚀因子栅格数据的区域土壤侵蚀强度快速计算,可较好满足区域土壤侵蚀预测预报的时效性要求;程序运行过程中计算任务本地化效果明显,显著降低了计算过程中的网络传输压力,网络使用率约22%,且系统性能可通过增加计算节点进一步提升。本研究可为大数据量、高分辨率栅格数据下区域土壤侵蚀强度计算及发布GIS设计开发提供指导,为大凌河流域土壤侵蚀监测提供科学依据。     

沙棘造林对吴起县土壤水蚀的影响

为定量评价沙棘造林后的水土保持效益,文章以沙棘造林的典型县域为研究对象,基于3S技术与RUSLE土壤侵蚀模型,分析评价了该县沙棘造林前后土壤侵蚀的时空变化。结果表明:吴起县实施沙棘造林后10年来,水土流失明显减少,较高强度土壤侵蚀的土地面积大幅度减少。①沙棘造林后土壤侵蚀分布以中度侵蚀最多,其面积占吴起县国土总面积的43.62%,而沙棘造林前土壤侵蚀以极强烈侵蚀为主,占吴起县国土总面积的42.76%。②沙棘造林后全县平均土壤侵蚀模数为5285t/km2.a,属于强度侵蚀,其沙棘造林前平均土壤侵蚀模数为9779t/km2.a,属于极强烈侵蚀,为沙棘造林后的1.85倍,沙棘造林后全县每年可减少土壤侵蚀量1402万t。     

基于GIS的南小河沟流域土壤侵蚀 数据库建立案例研究

南小河沟流域是属于黄土高原沟壑区的一条典型小流域，对该流域土壤侵蚀情况的调查和收集的数据，需要建立数据库对其进行有效管理。通过GIS平台，利用高分辨率卫星影像及1∶10 000地形图，对该流域的土地利用、植被覆盖状况及坡度组成等情况进行调查，建立土壤侵蚀数据库，为流域的进一步治理和管理提供本底数据。      

基于SRTM的地形因子提取方法研究

地形是影响土壤侵蚀的重要因子,在侵蚀估算模型中常用坡度和坡长(LS)来衡量,在大区域上常基于数字高程模型(DEM)提取.SRTM作为大区域尺度上质量高、易获取的高程数据,在全球土壤侵蚀评价中得到广泛应用.但现有地形因子提取算法要求高程和栅格单元的单位(通常为m)一致,需对SRTM进行坐标变换才能使用.针对大区域上SRT...     

浅论区域水土流失模型设计及参数采集方法

在已有区域试验研究和观测数据、水土流失因子研究成果基础上,基于坡面土壤侵蚀机理对区域水土流失过程进行分析,基于结合GIS空间分析功能,进行了区域尺度上水土流失模型设计的初步尝试,并提出了模型所需参数的提取方法及精度要求,本模型在延河流域试运算结果反映了接近现实的土壤侵蚀时空分布趋势和分异。     

东江流域洪灾风险空间模糊综合评价

通过分析东江流域形成洪水灾害的主要影响因素,构建了流域洪灾风险评价指标体系,利用层次分析法确定了各评价指标的权重,基于GIS技术运用模糊综合评价方法对东江流域洪水灾害风险进行了综合评价.结果表明:东江流域洪灾风险度最高的地方为河源市区、惠州市区、惠阳区以及龙岗等经济较发达地区;而较安全区域则位于流域中上游经济发展较为落后的山区.评价结果与往年大洪水造成的灾害区域基本吻合,表明基于格网的空间模糊综合评价方法用于洪灾风险评价是可行的,评价结果也是合理的.     

湖北省城市土地集约利用度时空变异分析

以湖北省12个地级以上城市的土地利用数据为依据,利用特尔菲法和层次分析法建立评价指标体系,采用集约度模型进行了综合评价,并探讨分析了湖北省城市土地集约利用潜力时空变异特征。结果显示,湖北省城市土地集约利用程度较低,在评价期内总体上呈下降趋势,在空间上形成了东部以武汉市、西北以十堰市、西南以宜昌市为中心向周围地区递减的态势,区域差异较明显。基于此,提出了政策建议。     

甘肃陇东地区农田水利可持续发展探讨

介绍了陇东地区农业资源的基本状况,从塬面山区2个方面探讨了农田水利建设可持续发展对策。提出了适合塬地的发展农田灌溉基本方式,针对山区退耕还林提出了农林、农草相结合的措施,以及治理水土流失、水资源短缺的相应措施。     

Assessing multi-criteria approaches with environmental, economic and social attributes, weights and procedures: A case study in the Pampas, Argentina

Soil erosion control is a major issue in agriculture. The no till system of soybean production has been widely adopted; however, soil erosion may increase due to pasture and forestry land convertion to cropland in the marginal Pampas, Argentina. The aim of this paper is to assess the conflicts and trade-off among environmental, economic and social interests by using three continuous multi-criteria approaches and a set of different weights. Different land uses, crops, pastures, forestry and soil and water conservation practices at the basin scale in the marginal Pampas were assessed. The basin (423 km²) was discretised into 176 sub-basins to focus the management strategy on 5th and 6th order streams. Minimum basic information was obtained using intensive field observations and satellite images. The basin hydrology, soil erosion, sediment delivery and vegetated filter strip models and GIS were used to quantify the technical coefficients. Thirteen decision factors and six criteria (peak run-off, annual erosion, sediment, investment, gross margin and employment) were used in the optimisation trials. Weighted goal programming, lexicographic goal programming, compromise programming and a sensitivity analysis of weights were performed. The results showed a high impact of soil and water management practices on the environmental factors and a strong conflict between environmental and economic interests. The three multi-criteria approaches also showed that it is possible to obtain a good level of goal achievement with different plans. These plans should include: soil conservation practices; crop rotation (of a 2:1 soybean-to-corn ratio); gully and channel erosion control; regulation ponds; and pasture and agro-forestry areas. This goal achievement is mainly limited by public and private investment. Sensitivity analysis of the decision-maker weights shows differences among the values achieved by the criteria and their trade-off. Thus, the weight value of each criterium should be supported by the negotiation-consensus process.     

陕西省杨凌区绿色食品产地环境质量监测与评价

通过对陕西省杨凌区绿色食品产地环境中的大气、灌溉水、土壤进行调查、采样,对土壤中有机质、全氮、有效磷、速效钾、重金属元素,以及灌溉水中总汞、总镉、总砷、总铅、六价铬、氟化物、粪大肠菌群、石油类等成分进行检测,根据调查和监测结果对环境现状进行了综合评价,得出杨凌区3 357 hm2的设施蔬菜、猕猴桃、葡萄、西瓜、甜瓜、草莓等生产基地的大气、土壤、灌溉水各项检测指标符合绿色食品产地土壤环境质量标准,适合发展绿色农产品生产。     

土壤热特性参数空间变异性与拟合方法研究

采用3S技术相结合的方法,在陕西省泾惠渠灌区研究了土壤热特性参数区域尺度的空间变异性,结果表明:土壤热容量、热扩散率及土壤导热率在该区域尺度下属于中等变异,土壤热扩散率和导热率的空间异质性较强,而土壤热容量的空间异质性相对土壤热扩散率和导热率表现较弱,三者均具有较强的空间依赖性。土壤热容量、热扩散率及土壤导热率的最优拟合模型分别为指数、球型、高斯模型,推荐三者的采样间距分别为2.67、3.68、2.76 km,推荐该区域范围内土壤热特性参数空间变异采样间距的最优值为3 km。在描述土壤热特性参数空间变异特征的基础上,建立利用土壤物理基本参数拟合土壤热特性参数的简单公式,并验证了此方法的适用性,决定系数R2达0.80以上,利用此方法能够实现土壤热特性参数的空间变异特征在复杂程度上的定量化。     

A regional soil survey approach for upgrading from flood to sprinkler irrigation in a semi-arid environment

Increasing pressure on water resources in Spain is forcing farmers to move from flood to pressurized water application. Initial recommendations for this upgrading require soil survey information, especially in areas prone to soil salinity. In this article a 3158 ha soil survey at a scale of 1:25,000 is presented. Soil series are split in phases based on the texture of the surface layer, slope, and salinity. Available water holding capacity (AWHC), to a depth of 1.5 m or to a lithic or paralithic contact, texture and coarse components in the surface horizons, and salinity mapped as discrete soil units are combined to develop a regional soil suitability map for irrigation upgrade. To minimize soil erosion and salt mobilization in the soils, our recommendations are: (i) maintain and improve flood irrigation on 296 ha, (ii) develop standard sprinkler irrigation on 2261 ha, and (iii) move to high frequency sprinkler irrigation on 601 ha. This research demonstrates the importance of soil survey as part of the decision making process for upgrading the regional irrigation systems.     

Systematic design and evaluation of crop rotations enhancing soil conservation, soil fertility and farm income: a case study for vegetable farms in South Uruguay

Rapid changes in the social and economic environment in which agriculture is developing, together with the deterioration of the natural resource base threatens sustainability of farm systems in many areas of the world. For vegetable farms in South Uruguay, survival in the long term depends upon the development of production systems able to reduce soil erosion, maintain or improve physical and biological soil fertility, and increase farmer’s income to socially acceptable levels. We propose a model-based explorative land use study to support the re-orientation of vegetable production systems in South Uruguay. In this paper we present a new method to quantitatively integrate agricultural, environmental and socio-economic aspects of agricultural land use based on explicit design objectives. We describe the method followed to design and evaluate a wide variety of land use activities for Canelón Grande (South Uruguay) and we illustrate the usefulness of this approach in an ex-ante evaluation of new farming systems using data from 25 farms in this region. Land use activities resulted from systematic combination of crops and inter-crop activities into crop rotations, different crop management techniques (i.e., mechanisation, irrigation and crop protection) and animal production. We identified and quantified all possible rotations and estimated inputs and outputs at crop rotation scale, explicitly considering interactions among crops. Relevant inputs and outputs (i.e., soil erosion, balance of soil organic matter and nutrients, environmental impact of pesticides, labour and machinery requirements, and economic performance) of each land use activity were quantified using different quantitative methods and following the target-oriented approach. By applying the methodology presented in this paper we were able to design and evaluate 336,128 land use activities suitable for the different soil types in Canelón Grande and for farms with different availability of resources, i.e., land, labour, soil quality, capital and water for irrigation. After theoretical evaluation, a large subset of these land use activities showed promise for reducing soil erosion, maintaining soil organic matter content of the soil and increasing farmer’s income, allowing improvement of current farming systems in the region and providing a widely diverse set of strategic options for farmers in the region to choose from. This method can be used as a stand-alone tool to explore options at the field and farm scale or to generate input for optimisation models to explore options at the farm or regional scale.