甘肃省耕地资源转变为建设用地的价值损失评估

依据耕地资源具有的社会保障功能、生态系统服务功能和经济产出功能,初步建立耕地资源的价值评估体系,综合运用市场价值法、替代法、机会成本法和影子价格法等评价方法,估算了甘肃省12个市(州)2007年耕地转变为建设用地所导致的正面效应价值损失。结果表明,由于建设用地占用耕地造成的价值损失相当巨大,2007年全省建设所占用耕地的总面积为1 564.66 hm2,造成的价值损失多达95 904.09万元,各市(州)1 hm2土地的损失都超过了45万元。从价值损失的构成来看,损失的直接使用价值为45 712.77万元,间接使用价值达50 191.32万元。可以看出,耕地资源除为社会提供直接产品价值外,还有巨大的间接使用价值,而且这种价值对人类的贡献比农产品的产出价值更为显著。     

广东省南海市农业土壤中铜锌镍的环境容量

南海市是我国经济最发达的县级市之一,工业门类多,布局分散,工业“三废”对土壤环境产生一定影响。研究结果表明,土壤中铜、锌、镍的容量分别为１８５ ．５８ ｋｇ／ｈ ｍ ２ 、２９２ ．８８ ｋｇ／ｈ ｍ ２ 、６３ ．９２ ｋｇ／ｈ ｍ ２ 。丘陵地区容最较大,其次是基塘区,平原地区较小。重金属污染型企业分布密集的地区环境容量较小。土壤环境容量与元素含量和最大允许含量有关。     

分区达标控制法求解海域环境容量

提出可考虑二维扩散的分式标控制法用于求解海域环境容量。引进贡献度系数将二维容量问题定义为线性规划问题,使各类水功能区在达到所对应的环境标准的前提下各排污口污染允许排放量之和最大。并给出了用二维扩散模型计算贡献质系数的方法。     

入侵植物凋落物浸提液对紫色土吸附金霉素的影响

用3种入侵植物的地上(O)和地下(U)凋落物浸提液(Le)对紫色土进行修饰,采用批处理法研究各Le修饰土样对金霉素(CTC)的等温吸附特征,分析pH值、离子强度和温度对CTC吸附的影响。结果表明：各Le修饰紫色土对CTC的吸附等温线最适用于Freundlich模型描述;当pH值为2,离子强度为0.1 mol/L和试验温度40 ℃时,一年蓬(Conyzaannumus)Le修饰紫色土对CTC的吸附效果最佳,最大吸附量为1.68 mmol/kg~7.94 mmol/kg;当Le修饰比例为100%时,OLe和ULe修饰紫色土对CTC的吸附量均达到最大,且OLe修饰紫色土对CTC的吸附效果相比ULe更佳。     

辽河流域控制单元水环境承载力评估研究——以招苏台河铁岭市控制单元为例

新常态下,亟须开展辽河流域水环境承载力评估,以指导流域生态文明建设.针对辽河流域特点,以招苏台河铁岭市控制单元为例,采取目标—准则—指标层级关系框架建立水环境承载力指标体系,并结合主客观赋权综合法对该控制单元水环境承载力进行评估.结果表明,该控制单元水环境承载力指数介于0.1750～0.5302之间,总体呈超载状态.水...     

HYSTAR Sediment Model: Distributed Two‐Dimensional Simulation of Watershed Erosion and Sediment Transport Using Time‐Area Routing

An erosion and sediment transport component incorporated in the HYdrology Simulation using Time‐ARea method (HYSTAR) upland watershed model provides grid‐based prediction of erosion, transport and deposition of sediment in a dynamic, continuous, and fully distributed framework. The model represents the spatiotemporally varied flow in sediment transport simulation by coupling the time‐area routing method and sediment transport capacity approach within a grid‐based spatial data model. This avoids the common, and simplistic, approach of using the Universal Soil Loss Equation (USLE) to estimate erosion rates with a delivery ratio to relate gross soil erosion to sediment yield of a watershed, while enabling us to simulate two‐dimensional sediment transport processes without the complexity of numerical solution of the partial differential governing equations. In using the time‐area method for routing sediment, the model offers a novel alternative to watershed‐scale sediment transport simulation that provides detailed spatial representation. In predicting four‐year sediment hydrographs of a watershed in Virginia, the model provided good performance with R² of 0.82 and 0.78 and relative error of ?35% and 11% using the Yalin and Yang's sediment transport capacity equations, respectively. Prediction of spatiotemporal variation in sediment transport processes was evaluated using maps of sediment transport rates, concentrations, and erosion and deposition mass, which compare well with expected behavior of flow hydraulics and sediment transport processes.     

Dynamics of Policy Networks. The Case of Organic Farming Policy in the Czech Republic

To better understand the potential for successful and long-term establishment of environmental policy, the aim of this paper is to explore the network dynamics of a policy field that has become well established in the EU: organic farming. We look at the dynamics of the organic farming policy network in the Czech Republic over a period of 10 years by applying a comparative formal network analysis. We focused in particular on the distribution of power between actors and how capacities of policy actors have evolved between 2004 (its year of accession to the EU) and 2014. We conclude that the organic farming policy network in the Czech Republic has been highly dynamic and has changed from one that was decidedly influenced by organic sector organizations to a network centralized around the Ministry of Agriculture. However, the organic farming organization managed to maintain its good reputation for competence in organic farming policy, which creates opportunities for the organization to remain active in the policy debate.     

中亚热带红壤区不同土地利用土壤田间持水量估测

田间持水量是衡量土壤保水性的重要指标,也是进行农田灌溉、作物水管理和水文模型的重要参数,但其测定繁琐而耗时,迫切需要一种简捷精确的估测方法。采集了50个来自稻田和旱地的1 m深原状土壤剖面样,然后基于土壤基本理化性质,利用多元逐步回归方法对土壤田间持水量进行模型预测。结果显示:(1)对于稻田土壤,田间持水量主要受容重和有机碳影响,而对于旱地则主要受土壤质地影响;(2)构建的田间持水量传递函数,对于稻田土壤预测精确度较高,调整的确定系数达到0.79,对于旱地则相对较弱。研究表明土地利用方式对田间持水量精确估测影响较大,利用土壤传递函数法对田间持水量的快速获取有一定参考价值。     

竺山湾流域河湖系统污染物总量控制研究

复杂河湖系统的总量控制需考虑河湖双重控制目标,以太湖西北部竺山湾流域为研究对象,运用排污系数法计算了区域内的入河污染负荷;构建了一维河网和二维湖体水环境数学模型,对水环境数学模型进行了率定;基于多重目标的河网水环境容量计算方法,计算了河网水环境容量,并分配至各控制单元;定量分析了各控制单元各污染物总量达标情况下的削减量及削减率。结果表明:竺山湾流域COD削减量为834.4 t,削减率为13.8%;氨氮削减量为226.1 t,削减率为36.5%;总氮削减量为724.8 t,削减率为55.2%;总磷削减量为108.9 t,削减率为73.4%。论文成果对于开展竺山湾流域污染物总量控制和水环境保护具有重要指导意义,同时为类似的河湖系统水污染物总量控制提供借鉴。     

基于水功能区纳污能力的攀枝花限制排污总量研究

实施水功能区限制纳污红线管理,控制陆域范围污染物排放总量,是保障水功能区水质达标的根本途径。针对现有水功能区划分及管理偏重考虑水体自然属性和完整性,缺乏与行政区划、陆域污染源分布的衔接,提出以水功能区划分成果为基础,综合考虑自然水系、行政区划、污染源分布情况的陆域控制单元划分方法,在此基础上,利用GIS空间分析建立水功能区与陆域控制单元的响应关系,制定基于水功能区纳污能力的陆域污染物限制排放总量方案。以攀枝花市河段为例,将攀枝花市划分为15个控制单元,19个控制子单元进行限制排污总量计算及分配,攀枝花全市COD、氨氮限制排放总量分别为17 437.6 t/a、1 866.0 t/a,与攀枝花市污染物总量控制规划成果基本一致。