Land Degradation Evaluation in North Hebei Province Based on Remote Sensing and GIS

Land degradation is one of the serious environmental problems that can lead to poverty, and is especially prominent in eco-fragile areas in developing countries and increases the risk of environmental safety. North Hebei Province belongs to an ecologically fragile region in North China, which has great impact on the eco-safety of Beijing and Tianjin. Using Landsat TM data and GIS, this paper evaluates land degradation in North Hebei province of China from the the 1960＇s to 1987 and 2000. Land use/cover change pattern from 1987 to 2000, its regional difference and forest change characteristics will also be analyzed; soil erosion intensity and arable land suitability were also evaluated. Results revealed that land use/cover pattern in this study area did not change greatly from 1987 to 2000. The structure and function of regional land ecosystem was at a level of local improvement and integral deterioration. Land above medium soil erosion intensity reached 21 percent, which was also the area with a serious soil erosion and land degradation problem. Soil erosion and land degradation intensity of grassland was the biggest. For the present arable land, the proportion of high suitability was 13 percent.     

An optimised sequential extraction scheme for the evaluation of vanadium mobility in soils

Reviewing the current state of knowledge about sequential extraction applied for soil vanadium(V) fractionation, we identified an urgent requirement of an sequential extraction(SE) specified for V. Namely, almost all previous SE extracted only 8.4%–48% of total V in soils(excluding residue). Thus, we proposed an eight-step SE for V fractionation in soils according to the knowledge gained from literature and our own dissolution experiments with model minerals. After extracting the mobilisable and adsorbed V with de-ionised water and 5 mmol/L phosphate, 1 mol/L pyrophosphate was applied to gather organic matter bound V which minimised the artefact dissolving Al and Fe(hydr)oxides occurred when using HNO_3–H_2O_2for extraction. Extraction with 0.4 mol/L NH_2OH·HCl was highly selective toward manganese oxides. Fractionation of different crystalline Al and Fe(hydr)oxides associated V with 1 mol/L HCl, 0.2 mol/L oxalate buffer and 4 mol/L HCl at 95°C especially improved the extractability of V incorporated with crystalline phase associated V. The suitability of our new SE scheme was confirmed by its higher selectivity against the target phases and higher extraction efficiencies(55%–77% of total V) with model minerals and 6 soils of different properties than previous SE.     

加速溶剂萃取-液相色谱测定土壤中酞酸酯类化合物

建立了加速溶剂萃取-液相色谱法测定土壤中14种酞酸酯类化合物的方法。结果表明,该方法对14种酞酸酯分离度较好,加标回收率为67.1%~128%,精密度RSD(n=6)为5.2%~15.0%,方法检出限为0.021~0.034 mg/kg。该方法操作简便、准确,具有较好的实用性。     

土壤重金属监测过程及其质量控制

重点探讨了土壤中典型重金属含量监测过程中样品制备、含水率、预处理等因素对分析结果的影响。实验结果表明,充分风干土壤的含水率在2%～3%左右,200目土壤颗粒度可满足分析精度的要求。硝酸-氢氟酸-高氯酸的多元混酸消解体系可实现对土壤重金属的充分溶解,对标准土壤样品中各元素的回收率可达84%～98%。批次内平行样品以及批次间质控样品各元素的相对标准偏差大都小于10%,符合《土壤环境监测技术规范》的要求,表明该研究建立的系统土壤重金属检测方法结果准确可靠。     

马官喀斯特地下水库的渗漏分析

通过对马官地下水库渗漏的大量野外勘测、观测、水化学资料的分析及库区喀斯特发育规律的研究,基本查清了马官地下水库渗漏的原因、渗漏的具体方位、渗漏量,探讨了库盆渗漏与蓄水年限、以及与地下水流的侵蚀、溶蚀的关系;根据研究结果,提出了马官地下水库防渗处理的几点措施。     

Modelling soil organic carbon dynamics in two long-term experiments of north-eastern Italy

Simulation models are widely used to assess the impacts of management and environmental variables on soil organic matter dynamics, to address questions on ecosystem sustainability and carbon cycling under global change. We tested the Century ecosystem model for two long-term experiments in north-eastern Italy: one (SF) comparing nutrient management treatments in small confined plots containing widely contrasting soil types (i.e., sandy, clay and peat) and the other (CR) involving a field study with crop rotation, nutrient, and management intensity variables. The organic matter changes in the SF experiment, showed a strong, linear relationship with C inputs from crop residues and added manures in the sand and clay soils, which was closely mimicked by the model. There was a net loss of soil C for all treatments in the peat soil, but the rate and overall magnitude of C losses were accurately simulated by the model, which suggested that treatment effects on soil C inputs was the major determinant of SOC dynamics in all three soils. In the CR experiment the model reasonably simulated the large initial decline (averaging about 30% of initial levels) in SOC observed in all treatments, as well as mean treatment effects over the course of the experiment. The model predicted a general pattern of higher SOC in the high management intensity, high fertility treatment combinations and lower SOC in the low management intensity, low fertility treatments; however, observed soil C did not show a clear pattern related to the treatments. Simulated soil C contents were linearly related to C input levels in the different treatments while there was no significant relationship between measured soil C and C inputs based on observed data.     

盐生植物碱蓬在土壤修复及废水处理中的研究现状

介绍了我国土壤污染与水污染概况,论述了盐生植物碱蓬的生态学特性及其在土壤修复和废水处理中的研究现状,提出将碱蓬应用于高盐有机污染物的去除这一研究新方向.     

Soil loss due to harvesting of various crop types in contrasting agro-ecological environments

Soil erosion studies on cropland usually only consider water, wind and tillage erosion. However, significant amounts of soil are also lost from the field during the harvest of crops such as sugar beet (Beta vulgaris L.), potato (Solanum tuberosum L.), chicory roots (Cichorium intybus L.), cassava (Manihot spp.) and sweet potato (Ipomoea batatas (L.) Lam). During the harvest soil adhering to the crop, loose soil or soil clods and rock fragments are exported from the field together with these crops.This soil erosion process is referred to as ‘soil losses due to crop harvesting’ (SLCH). Most of the studies investigated SLCH variability and its controlling factors for one crop type in similar agro-ecological environments and for comparable harvesting techniques. In this study, a compilation of SLCH studies was made in order to investigate the effect of crop type, agricultural systems, ecological conditions and harvesting technique on SLCH variability. SLCH rates ranged from few to tens of Mg ha⁻¹ harvest⁻¹ and SLCH was highly variable both in space and time. Comparison of four studies on SLCH for sugar beet revealed that harvesting technique and soil moisture content at harvesting time can be equally important for SLCH variability. The occurrence of soil clods harvested with the crop explained why SLCH was significantly larger for mechanically harvested potato in Belgium compared to manually harvested potato in China. SLCH values for manually harvested sugar beet, potato, cassava and sweet potato in China and Uganda were in general smaller than SLCH values for mechanically harvested sugar beet, potato and witloof chicory roots measured in Belgium and France. However, SLCH may also vary significantly within Europe due to differences in harvesting techniques. Soil moisture content at harvesting time was besides harvesting technique one of the key factors controlling SLCH variability. There were no systematic differences in SLCH between crop types, although the soil–crop contact area–crop mass ratio could explain more than 40% of the means from several SLCH studies.     

炼钢厂炼焦车间土壤中PAHs的超临界流体萃取-色质联用分析方法研究

超临界流体萃取炼钢厂炼焦车间土壤中多环芳烃的最佳萃取条件为４０ＭＰａ，８０℃，０．５％甲醇动态改性液体ＣＯ２１０ｍＬ时，对土样进行超临界流体萃取，色质联用分析，并与索氏萃取法进行比较。土样中能准确定性的多环芳烃４４种，其中能定量分析的３１种。色谱定量的回收率均值为７８．５％￣１０４．１％，相对标准偏差为５．０％￣１５．６％。     

大青山中高山地带阴坡水土保持效益的研究

本文对大青山高土地带阴坡三种不同水土保持林与农地，撩荒地比较，将枯落物持水性、土壤含水量及土壤性质、分散度、导水率进行了分析，阐明了大青山中高山地带阴坡三种不同林分有极强的哟水性、可拦蓄大量的径流；林地土壤含水量高、结构良好、渗透降水能力强，土本难以破坏。可有交地防治山地水土流失的发生。