泥处理处置路径碳排放分析

根据联合国政府间气候变化专门委员会(IPCC)提供的核算准则,结合生命周期评价(LCA),对我国常见的污泥处理处置路径包括填埋、焚烧、热解、好氧堆肥、厌氧消化和湿式空气氧化进行了碳排放核算,并对敏感因子污泥有机质含量进行了影响分析.结果表明,对于有机质含量40%~50%的脱水污泥(含水率80%),净碳排放排序为填埋>焚烧>热解>厌氧消化>好氧堆肥>湿式空气氧化;而对于有机质含量60%~70%的脱水污泥,排序为填埋>焚烧>热解>好氧堆肥>湿式空气氧化>厌氧消化.对不同污泥处理处置组合路径进一步分析表明,独立焚烧相对于污泥水泥窑协同处置和燃煤电厂混烧碳排放更低.水解-厌氧消化-土地利用组合路径因提高有机质利用率而降低碳排放.1t脱水污泥处理处置全生命周期碳排放分析的结果表明,当污泥有机质含量低于60%时,上述路径都会产生2.07~494.45kg CO₂eq/t不等的碳排放;当污泥有机质含量达到60%时,热水解-厌氧消化-土地利用组合路径可以实现负碳排放,为-37.91kg CO₂eq/t,厌氧消化及湿式空气氧化路径接近于零碳排放;当有机质含量达到70%时,湿式空气氧化､厌氧消化及组合路径均可以实现负碳排放.     

我国陆地表层土壤的238Pu水平和溯源分析

基于我国陆地表层土壤样品中²³⁸Pu本底水平数据缺少的问题,分析了采自全国多个地区陆地表层土壤样品中²³⁸Pu的比活度.结果表明,我国陆地表层土壤样品中²³⁸Pu比活度很低,范围在0.007~0.045Bq/kg,²³⁸Pu/^239+240Pu活度比范围为0.032~0.041,这些数值均与周边国家和中纬度地区的报道值接近.根据二元模型对我国陆地表层土壤的²³⁸Pu来源进行分析,结果表明我国表层土壤样品中²³⁸Pu主要来源于核试验的全球沉降和SNAP-9A的沉降.     

Impact of litter removal on soil characteristics under a Pinus caribaea stand

ABSTRACT

Forest productivity is dependent on soil quality, which in turn is related to litter; yet there is limited understanding of the relationships between litter and soil quality. The effects of litter removal treatment on tree growth and soil properties were examined in a Pinus caribaea stand with the aim of providing an understanding of consequences of litter removal on soil patterns. This knowledge is important for planning appropriate long-term forest management. Three pairs of 30 × 30 m² plots (each pair a control and treatment) were established in the center of a P. caribaea stand in April 2002. The controls were left undisturbed with an intact litter layer, while litter was removed monthly from treated plots. The diameter and height of the P. caribaea decreased and soil quality was degraded over the experimental period in litter-removed (treated) plots. Litter removal also produced a significant increase in soil bulk density at 0–20 and 20–40 cm depths. The capillary porosity, capillary moisture capacity, and natural water content in controls at 0–20 and 20–40 cm depths were significantly greater than treated plots. The non-capillary porosity in controls at the 0–20 cm depth was also significantly higher than treated plots. The organic carbon, total nitrogen (N), total potassium (K) and alkalized N content in each layer, and available P and exchangeable K at 0–20 and 40–60 cm depths in control plots were significantly greater than litter-removed plots. The numbers of bacteria at 0–20 and 40–60 cm depths and of fungi at 20–40 and 40–60 cm depths were higher in control than treated plots. The number of actinomyces and urease, catalase, and acid phosphatase activities in controls at each depth were significantly greater than litter-removed plots.     

Development of a framework for fire risk assessment using remote sensing and geographic information system technologies

Forest fires play a critical role in landscape transformation, vegetation succession, soil degradation and air quality. Improvements in fire risk estimation are vital to reduce the negative impacts of fire, either by lessen burn severity or intensity through fuel management, or by aiding the natural vegetation recovery using post-fire treatments. This paper presents the methods to generate the input variables and the risk integration developed within the Firemap project (funded under the Spanish Ministry of Science and Technology) to map wildland fire risk for several regions of Spain. After defining the conceptual scheme for fire risk assessment, the paper describes the methods used to generate the risk parameters, and presents proposals for their integration into synthetic risk indices. The generation of the input variables was based on an extensive use of geographic information system and remote sensing technologies, since the project was intended to provide a spatial and temporal assessment of risk conditions. All variables were mapped at 1 km² spatial resolution, and were integrated into a web-mapping service system. This service was active in the summer of 2007 for semi-operational testing of end-users. The paper also presents the first validation results of the danger index, by comparing temporal trends of different danger components and fire occurrence in the different study regions.     

高浓度废水可调式厌氧处理技术

以酒精发酵和有机化工混合废水为研究对象,通过对原厌氧工艺的改进,成功地研发了"可调式Ⅰ级全糟发酵/DDG+Ⅱ级UASB+Ⅲ级IC"厌氧工艺,实现了废水有机负荷和进入方式的随机调节。运行结果表明:新工艺运行稳定,有机负荷提高1倍,沼气产率提高39%~56%,厌氧阶段出水COD由原工艺的2000 mg/L降低到500 mg/L左右,COD去除率由93%上升到99%。     

贵州中部喀斯特山地三种优势灌木养分分布

选择贵州喀斯特山区广泛分布的灌木林和灌草丛生态系统,探讨了三种优势灌木养分分布格局及其与土壤的关系。结果表明：（1）三种优势灌木叶片和果实的氮和钾元素含量高于茎干和根系,果实和茎干的磷含量比其他器官高,而钙镁主要集中在茎干和叶片。（2）在灌草丛中,三种灌木根系和茎干的N：P之间差异显著且变异很大,而在灌木林中,三种灌木根系的N：P比值变异较大,但它们之间没有差异。（3）根际有效态养分含量与叶片养分含量呈正相关关系,叶片磷与根际有效态磷显著正相关     

不同水分条件下三裂叶豚草叶解剖结构的生态适应性

三裂叶豚草（Ambrosia trifida）是世界公害杂草,于20世纪30年代传人我国后,对我国人民的生产生活和生态系统造成了严重危害。本研究以我国北方地区主要分布的入侵植物三裂叶豚草为对象,采用盆栽实验的方法及石蜡切片技术,在Zeiss Image．A,光学显微镜下研究不同土壤水分条件下三裂叶豚草叶片解剖结构的变化。结果表明：三裂叶豚草在90％土壤相对含水量处理下叶片厚度、上下表皮厚度均增加,是细胞储水量增加,细胞体积增大的结果;在50％、30％土壤相对含水量处理下三裂叶豚草叶片变薄、栅海比值增大,是典型的节约型干旱适应,同时叶肉栅栏细胞层数增加、栅栏细胞密度增大,表现出强壮型干旱适应特征;干旱胁迫程度越大,三裂叶豚草叶显微结构变化越大。不同水分条件下三裂叶豚草解剖特征总体可塑性值为0．39,具较高可塑性,其中叶片厚度、上表皮厚度、下表皮厚度、栅栏组织与海绵组织的厚度比（P／S）、栅栏细胞密度等指标较栅栏组织厚度、海绵组织厚度具有更大可塑性,表明这些因素对三裂叶豚草成功入侵有较大作用。     

马鬃岭自然保护区土壤碳蓄积的研究

以金寨马鬃岭自然保护区为研究对象,布置56个采样点,分析该区森林土壤有机碳质量分数时空分布特征和碳储量。结果表明：研究区有机碳含量丰富,随着土壤深度、植被类型、海拔高度的变化而变化。0~20cm土层有机碳质量分数最高为90.88 g·kg-1,平均为32.47 g·kg-1,土壤有机碳质量分数随着深度的增加而递减,表层有机碳变化幅度高于深层土壤,不同测点递减的程度不同;有机碳质量分数随海拔高度的增加呈递增趋势;土壤有机碳质量分数存在明显的季节变化,表层土壤秋季有机碳质量分数最高,冬春季次之,夏季最低,越往表层季节变化越明显。0~20 cm土层有机碳密度平均为6.52 kg.m-2,0~100 cm土层有机碳平均密度为23.26 kg.m-2,有机碳密度分布与有机碳质量分数分布基本一致。0~20 cm土层土壤碳储量为2.258×105~2.265×105 t,0~100 cm土层土壤碳储量为6.91×105~8.76×105 t,碳储量丰富。最后提出该自然保护区封山育林,对温室气体减排意义重大。     

疏勒河中下游绿洲胡杨林土壤水盐的空间变化特征与成因

胡杨林对保护疏勒河中下游绿洲脆弱的生态平衡具有决定性作用。认识疏勒河中下游绿洲胡杨林土壤水盐的空间变化特征与成因有利于胡杨林保护和更新复壮,促进研究区绿洲可持续发展。研究基于河西走廊疏勒河中下游绿洲天然胡杨林下8个采样点720个土壤样品,应用地统计学和数理统计学方法研究了胡杨林土壤水盐的空间变化特征及其原因。结果表明:研究区土壤含水量随深度而增加,土壤全盐量变化与之相反,两者在80 cm土层之上变化剧烈,之下变化平缓;且明显存在着自中游向下游土壤含水量逐渐减小,土壤全盐量逐渐增大的空间差异。土壤水盐含量变异明显,但均属于中强度变异。自然和人为因素共同作用造成研究区土壤水盐空间分布差异显著。     

芨芨草草丛肥岛特征

论文通过对祁连山区芨芨草草丛肥岛特征研究,结果表明:①芨芨草草丛肥岛冠幅下土壤养分高于空地。②土壤有机质、 全氮、 全磷、 速效氮、 速效磷、 速效钾、 速效锌、 速效锰和速效铁含量从草丛中心到距草丛边缘100 cm变化的整体规律是先减小后增加;但距草丛边缘100 cm含量低于草丛中心。③土壤全钾含量、 pH值和速效铜含量从草丛中心到距草丛边缘100 cm变化规律为:全钾含量在各土层变化各异;pH值变化0~10 cm和10~20 cm土层升高,20~30 cm土层则降低;速效铜含量0~10 cm和10~20 cm土层持续下降,20~30 cm土层先减小后增加,并在距草丛边缘40 cm含量最低。总体而言,芨芨草草丛肥岛的各种土壤养分变化规律不是完全一致的。