Hierarchical classification of environmental factors and agricultural practices affecting soil fauna under cropping systems using Bt maize

The population dynamics of soil organisms under agricultural field conditions are influenced by many factors, such as pedology and climate, but also farming practices such as crop type, tillage and the use of pesticides. To assess the real effects of farming practices on soil organisms it is necessary to rank the influence of all of these parameters. Bt maize (Zea mays L.), as a crop recently introduced into farming practices, is a genetically modified maize with the Cry1Ab gene which produces a protein toxic to specific lepidopteran insect pests. To assess the effects of Bt maize on non-target soil organisms, we conducted research at a field site in Foulum (Denmark) with a loamy sand soil containing 6.4% organic matter. The study focused on populations of springtails (Collembola) and earthworms (Oligochaeta) from samples taken at the beginning and at the end of the maize crop-growing season during 2 consecutive years. Farming practices, soil parameters, the biological structure of soil communities, and the type and age of the crop at the time of sampling, were used as attributes to predict the total abundance of springtails and biomass of earthworms in general and the abundance or biomass for specific functional groups (epigeic, endogeic and anecic groups for earthworms, and eu-, eu to hemi-, hemi-, hemi to epi- and epiedaphic groups for Collembola). Predictive models were built with data mining tools, such as regression trees that predict the value of a dependent variable from a set of independent variables. Regression trees were constructed with the data mining system M5′. The models were evaluated by qualitative and quantitative measures of performance and two models were selected for further interpretation: anecic worms and hemi-epiedaphic Collembola. The anecic worms (r²=0.83) showed preferences for less clay and more silt soil with medium pH but were not influenced directly by farming practices. The biomass of earthworms was greater in early autumn than in spring or late autumn. Biomass of hemi-epiedaphic Collembola (r²=0.59) increased at the end of the maize growing season, while higher organic matter content and pH tended to increase their biomass in spring. Greater abundance of Collembola was also noted in early autumn if the crop was non-Bt maize. The models assessed by this research did not find any effects of the Bt maize cropping system on functional groups of soil fauna.     

矿业废弃地再利用空间结构优化的技术体系与方法

为了合理确定矿业废弃地再利用的用途、数量比例和空间布局,释放其再利用潜力,保障矿产资源型城市未来发展所需各项用地,构建了矿业废弃地再利用空间结构优化的技术体系,即先进行复垦适宜性评价,而后进行数量结构优化,最后进行空间结构优化。提出了数量结构优化和空间结构优化的思路和方法,数量结构优化应将再利用为各种地类的矿业废弃地的面积与区域内原有的相同地类的面积进行整合,综合考虑土地利用的生态、经济、社会效益,同时将土地复垦适宜性评价的结果作为主要约束条件;将数量结构优化的结果作为空间结构优化的约束条件,将矿业废弃地视为一种独立的地类参与整个区域的土地利用空间结构优化,通过区域土地利用空间结构优化的结果来确定矿业废弃地再利用的最优空间布局,同时结合土地复垦适宜性评价的结果对其进行检验和修正。采用比较分析法,选择基于GIS的模糊综合评价法作为土地复垦适宜性评价的方法;数量结构优化采用基于生态位的线性规划模型,空间结构优化采用CLUES模型。最后,以北京市门头沟区为例进行了实证研究。结果表明,该技术体系、方法和模型有效地实现了矿业废弃地再利用数量结构和空间结构的协同优化。该研究可为矿产资源型城市矿业废弃地再利用的实践提供理论借鉴。     

冰藏鲢的鲜度变化对其鱼糜凝胶作用的影响

通过比较不同冰藏时间的鲢所制鱼糜在各种加热温度下的凝胶化和凝胶劣化的特性,考察了鲢的鲜度变化与鱼糜凝胶作用能力的关系。实验结果表明：冰藏０￣９天鲢鱼糜,在３０℃低温一段加热时凝胶的形成与链鲜度关系不大;８５℃一段加热时,凝胶化能力随鲜度下降而降低;３０￣８５℃二段加热与３０℃一段加热相比,两者凝胶破断强度之间的差值随鲢鲜度的下降而减小;６０℃加热条件下,凝胶劣化程度随原料鲜度下降而明显加剧。据此可见：鲜度对鲢鱼糜凝胶作用能力的影响主要表现在凝胶劣化方面。８５℃高温一段加热和３０￣８５℃二段加热的凝胶强度之所以受鲜度下降而影响,都是由于加热时经过了易劣化的６０℃温度区所致。从总体上看,鲢肉蛋白质在冰藏条件下较为稳定,保持较强的凝胶化能力。     

采煤废弃物对作物生长的影响

通过室内栽培试验,研究了煤矸石和粉煤灰作为培养基对作物生长的影响。结果表明:(1)粉煤灰物理性质不适于作物生长,对作物长势影响最大,在粉煤灰排放场不覆土直接种植作物不可取;(2)煤矸石和粉煤灰会对作物产生重金属污染,尤其是细颗粒煤矸石的污染最大;(3)充填采煤废弃物复垦应该保证足够的覆土厚度。     

矿山废弃地土壤基质改良研究

矿山废弃地对生态环境有着极大的破坏作用,危及人类的生存与健康,并影响到区域生态经济的可持续发展。矿山废弃地的生态修复和重建,已被看作是矿区土地修复的主要组成部分,而在生态恢复的植被重建过程中,基质改良是生态恢复的核心问题。研究借鉴目前国内外土壤基质改良的方法,较系统地介绍了矿山废弃地土壤基质物理、化学、生物改良技术措施。最后提出我国矿山废弃地土壤改良方法的选用原则：遵循因地制宜、就地取材,结合以往的研究成果,借鉴国际矿区土地复垦和生态修复的成功经验,研究废弃物土壤化演化的自然规律和机理,最终实现人工辅助的土壤化演化。     

不同自燃性煤氧化阶段的表征差异

对3种不同自燃倾向性煤样进行低温氧化实验,利用CO体积分数与煤体温度间变化的计算模型,求解出活化能和煤氧化过程发生转变的特征温度,同时结合热重-差示扫描量热（TG-DSC,theremogravimetric analysis-differential scanning calorimetry）实验结果,分析了不同自燃性煤氧化特性和活化能的低温表征规律。结果表明：1）低温氧化阶段,CO生成量、耗氧量和耗氧速率随着煤自燃倾向性增强而增大;不同煤样在实验过程中出现同样的CO生成量和耗氧速率急剧上升的温度拐点,且煤的自燃性越强,该拐点温度越低,同时CO体积分数的变化具有明显的阶段性。2）不同自燃性煤氧化阶段活化能变化规律存在显著差异,当各煤样的温度到达活性温度时,活化能快速减少,且活化能变化点对应于煤氧化过程发生转变的特征温度点。3）根据煤特征温度和活化能的变化规律,把煤低温氧化进程分为4个阶段,分别为表面氧化、氧化自热、加速氧化和深度氧化。     

Understanding ‘resource’ conflicts in Papua New Guinea

Abstract: Papua New Guinea, with its heavy dependence on natural resources, limited economic development in the past two decades, poor record of governance and high‐profile separatist conflicts such as the Bougainville civil war, appears to be an exemplar of the ‘Resource Curse’ theory – the notion that natural resources actively undermine economic development. Using a number of examples from a range of scales, this paper argues that what appear to be ‘resource’ conflicts in Papua New Guinea are actually better conceived as conflicts around identity and social relationships. The very different conceptualisation of natural resources in most Melanesian societies – as elements of the social world as much as any external environmental sphere – means that resources become a conduit for local social and political agendas and tensions to be expressed. The nature of traditional conflict in Melanesian societies is discussed as a guide to the better management and resolution of what appear to be ‘resource’ conflicts in Papua New Guinea.     

煤矸石山植被恢复影响因子初探——以山西省阳泉市280煤矸石山为例

对山西省阳泉市280煤矸石山小气候特征、地形条件、煤矸石理化性质、水分和生物特点进行了调查分析.结果表明.煤矸石山的小气候特征表现为以干热和干旱为主.煤矸石自燃致使地温产生较大异常,局部自燃的煤矸石坡面地表温度远高于植物生长的正常温度范围.煤矸石山坡度大,堆积松散,易产生坡面侵蚀.表层煤矸石经侵蚀后,植被根系周围缺乏附着物,生长势逐渐变弱.煤矸石物理特性与黄土相比,其持水能力差,有效水分含量低,缺乏下层水分补给,直接影响到植物正常生长.自燃后的煤矸石pH值降低,表层煤矸石养分状况差,微生物种类和数量均偏少.煤矸石山植物生长状况显示,地表温度、侵蚀状况、酸性和含水量是影响植物生长的重要因子.地温高于50 ℃或pH值小于5的地区植物均不能生长.植物盖度在含水量小于15%的区域较含水量为20%的区域下降约10%～20%.在侵蚀区植物盖度下降约30%.     

Nitrogen recovery in reclaimed mine soil under different amendment practices in tandem with legume and non-legume revegetation: A review

Nitrogen (N) supply is the major limiting nutrient in most reclamation schemes. In reclaimed mine soil (RMS), examining the N dynamics can be especially informative for understanding constraints on recovery that restrict revegetation success. Scholarly studies worldwide have focused on exogenous N incorporation to alleviate N shortages in the agriculture, and forestry sectors. Currently, growing concerns for the negative consequences of mining have highlighted N deficiency as one of the most significantly identified abiotic limits. Only a few researchers have focused on the N transformation mechanisms in drastically altered mine soils. The review comprises the last 10 years’ research on mine reclamation approaches using legume and non-legume plant communities. Also the capacity of different amendments to alleviate N shortages in mine soils is emphasized. The major findings of the present review suggest: (i) Revegetation using legume and non-legume species is a self-sustaining and economical alternative to mineral N fertilizer application; however, they cannot fully activate the biological N cycle in RMS. (ii) A more biological amendment-assisted revegetation would enhance the key concepts of “soil-biomass N balance” and would be ideal for N recovery in imbalanced mine soil. Altogether, grass-legume seeding offers a potentially valuable mine reclamation tool for managing N and addressing the challenges of sustainable development.     

Phosphorus and iron erosion from non-vegetated sites in a post-mining landscape,Lusatia, Germany: Impact on aborning mining lakes

Particulate phosphorus (P) can be transported via soil erosion in overland flow to waters, where it provides a long-term source of P for aquatic biota, and can accelerate freshwater eutrophication. Hence, knowledge of P sources is important for good environmental management. However, data on P, and related Fe, losses from various structures of a post-mining landscape are lacking. A year-long monitoring, and ten short rainfall simulations on plot scale, at ridges and rills and a combination of them, revealed high erosion from bare lignite mining dumps at Schlabendorf-North, Lusatia, Germany. The mean annual soil erosion rate from the year-long monitoring site was 18 × 10⁶ kg km^− 2 yr^− 1, corresponding to 0.034 g m^− 2 min^− 1. The erosion rates were lowest at rill plots (1.9–4.4 g m^− 2 min^− 1), intermediate at ridge plots (14.3–37.1 g m^− 2 min^− 1), and highest at a combined rill and ridge plot (48.7–63.4 g m^− 2 min^− 1). These differences in extent were due to small scale differences in morphology and extreme water repellency. The hydrophobicity leads to very low infiltration, thus generating surface runoff even at low rainfall intensities. Loss rates of P and Fe, as deduced from the year-long erosion rate, were 470–650 kg km^− 2 yr^− 1, and 37.9 × 10³–71 × 10³ kg km^− 2 yr^− 1 respectively. However, these P inputs from lignite mining dump erosion, consisting of P-poor (17–90 μg g^− 1) tertiary spoil materials, into aborning mining lakes, are negligible since they are accompanied by high Fe inputs, which favour an efficient P co-precipitation in the water column.