不同覆被下红壤坡地地表径流及其养分流失特征

通过对南方红壤坡地农作区、茶园、柑橘园、退化区和恢复区5种不同利用方式所产生的地表径流量的全年连续观测及其径流水中养分含量分析,结果表明:覆被植物群落类型单一化和农事耕作都能增加地表径流量、次数和增加养分流失,5种类型地表径流量不论是月平均径流量还是年总径流量,其大小关系为农作区*>茶园*>柑橘园>退化区>恢复区*,产流次数也是恢复区最少,其余4种类型基本一致;径流水中总P、K 、Ca2 、Mg2和SO42-流失量以农作区达到最大,茶园和柑橘园次之,然后是退化区和,恢复区的径流各养分流失量量少,耕作区的总P、K 、Ca2 、Mg2 和SO42-流失量大于非耕作区,覆被植物群落类型少的总P、K 、Ca2 、Mg2 和SO42-流失量大于覆被植物群落类型复杂.综合考虑,红壤坡地用来耕作可以加剧水土和土壤养分流失,自然植被对红壤坡地保持水土和养分效果最佳,如果种植经济价值较高的果林和药、茶、草等需采用复种方式,避免单一种植和减少人工扰动,以便维持坡地土壤利用的可持续性.     

不同土地利用模式下红壤坡地雨水产流与结构拟合

模拟主要利用方式构建的垫面为主导因子,采用径流场实测方法,通过4年(1998-2001年)实地观测试验,剖析不同下垫面对雨水地表径流的影响.研究表明:降雨和下垫面是影响地表径流特征的主导因素;年降雨量与地表径流量和系统水土流失量呈正相关.不同垫面地表径流产量有显著性差异;雨水径流过程的土壤和养分流失有相似的表现.在假定雨水年份的基础上,提出"利用坡地集雨优势,构建与单元生态系统水循环平衡相适应的坡地农林复合生态系统,通过水平衡生态建设来维系生态系统的水分平衡"观点.以集雨区水量平衡为基础,从分析坡地水文过程入手,以坡地不同生态系统雨水分配、降雨过程地表径流产量、径流过程的土壤及养分流失量为参数,以生产灌溉对集雨的要求、坡地不同生态系统对雨水侵蚀的承载力、坡地雨水运移过程对环境和区域洪涝灾害的影响为约束条件,拟合出红壤丘岗坡地农林复合生态系统构建适宜的土地利用结构:人工林占30%,人工草地占15%,果药茶园占30%,耕地占20%,自然保护区占5%.该用地比例(结构)既满足于地貌单元(集雨区)生态系统利用坡地集雨维持系统水循环平衡的要求,也满足于坡地农林复合生态系统的可持续性保护的要求.     

喀斯特坡地不同地表微地貌产流产沙模拟研究

通过人工模拟喀斯特坡地不同地表微地貌特征和地下岩溶裂隙构造,结合野外自然降雨试验,研究不同雨型、雨强,不同地表微地貌和地下孔(裂)隙度对坡地土壤侵蚀的影响。结果表明:(1)地表累积产流、产沙量均高于地下累积产流、产沙量,且地表产流量以裸地达到最大,草地、裸岩次之,地下产流则与之相反。(2)地表、地下累积产流量随着降雨量的增大整体上呈现出波动增长的趋势,地下产流量的波动要小于地表产流量的波动,地表累积产流量、产沙量总体上大于地下累积产流量、产沙量,地表、地下累积产流量、产沙量与降雨量之间出现了较为显著的正相关。(3)随着降雨强度的增大,地表、地下累积产流、产沙量出现波动增长,并在雨强为10.04 mm/h时地表、地下累积产流量达到最高峰。(4)随着孔(裂)隙度的增大,地表、地下累积产流量不断增加,地表累积产沙量先减后增,地下累积产沙量不断增加。(5)6—8月地表累积产流量和累积产沙量均为裸地>裸岩>草地,地下累积产流量草地>裸岩>裸地,地下累积产沙量草地>裸地>裸岩。     

红壤丘岗坡地土地利用与土壤水分的时空变化关系

利用连续2a土壤水分定位观测数据，对红壤丘岗坡地不同土地利用类型与土壤水分时空关系的研究结果表明：（1）生长季（3—10月）不同土地利用类型之间0—90cm深土壤平均含水量差异显著，丰水年的差异比平水年大。（2）不同水文年同一土地利用类型土壤水分季节变化差异明显。丰水年土壤水分含量较高，年内变化较平稳，土壤基本处于湿润状态；而平水年土壤水分先升高后显著降低再缓慢升高，出现明显的干湿交替。（3）从丰水年到平水年土壤水分的剖面结构类型没有发生改变，湿地松区属波动型，其他4种土地利用类型属增长型。（4）土壤水分沿坡位的年内变化始终是坡上大于坡下，持续干旱能减少土壤水分沿坡位分布的变化幅度。     

不同草篱种植模式对土壤侵蚀的控制效应

选取我国南方红壤丘陵区5种等高草篱种植模式,结合径流小区法和稀土元素示踪技术,开展不同草篱控制坡地水土流失、减少地表径流的效应研究,分析等高草篱对坡面侵蚀空间分布的影响.结果发现,径流小区土壤流失量显著受降雨量影响,不同草篱种植模式下,各径流小区的平均土壤流失量和地表径流量较对照组(裸坡)均显著降低(P＜0.05),其中麦冬双行草篱处理平均土壤流失量和地表径流量最小,分别为4 047 g和1 554 L,对照组(裸坡)最大,分别为19 793 g和2 403 L;麦冬双行草篱在控制坡面土壤流失和径流方面效果最佳;通过平均土壤流失量和平均径流量的二次线性拟合模型发现,随着地表径流量的变化,不同处理下土壤流失量的边际值存在差异;坡面中、下部是侵蚀泥沙的主要溯源地,产生了接近总流失量85%的泥沙;草篱改变了降雨过程中坡面内部土壤因沉积作用导致的再分布,但对整个坡面土壤侵蚀的空间分布规律无明显影响.     

模拟酸雨下自然红壤与污染红壤中Cd,Cu,Zn的释放特征

通过对2个自然红壤和2个污染红壤的模拟酸雨土柱淋溶试验,研究了酸雨作用下红壤中重金属Cd,Cu,Zn的释放特征与影响因素,比较了自然红壤与污染红壤重金属释放特征的差异,结果表明,自然红壤中Cd,Cu,Zn的释放量均随酸雨淋溶量增加而线性增加,累积释放量有Zn＞Cu＞Cd的规律,并且随酸雨酸度增加而增加,3种重金属释放量之间存在显著的线性关系,在污染红壤中,Cd的释放随着酸雨淋溶量的增加呈现对数型增长,Cu的释放模式仍为直线型增长,而Zn的释放在弱酸性酸雨作用下为直线型增长,在强酸性酸雨作用下则为对数型增长,3种重金属释放鼍之间存在非线性关系,污染红壤中重金属释放量顺序为Cd＞Zn＞＞Cu,大约26%-76%的外源Cd和11%-68%的外源Zn被酸雨淋溶释放,但99%以上的外源Cu被土壤吸附,同时,3种重金属累积释放量均与淋出液中H+离子累积量呈现显著的对数关系;Cd和Zn与TOC累积释放量之间呈现显著的对数关系,Cu与TOC呈现显著的乘幂关系,在酸雨作用下,自然红壤由于重金属释放最很小,出现重金属污染的可能性较小;但污染红壤中大量Cd和zn的释放可能导致土壤,水体系统发生重金属污染.     

红壤坡地生态系统恢复过程植被群落的演变

应用样方调查方法,对湘北红壤坡地有人为干扰和无人为干扰两种方式下植被恢复情况进行了初步调查分析,结果表明:无人为干扰的坡地植被恢复在11年间经历了缓慢恢复和快速恢复两个阶段,不同坡位群落生物量稳步增长,正在逐步形成具有稳定群落结构的自然生态系统;人为干扰坡地植被恢复缓慢,由于水土流失,上坡位地下部生物量呈下降趋势,中坡位和下坡位地下部的生物量都大幅度的增加,此外人为干扰使得乔木类植物无法正常生长,从而不能形成具有明显垂直结构的稳定生态系统.     

植物篱对红壤坡耕地的水土保持效应及其机理研究

在浙江诸暨红壤丘陵山区的野外径流小区条件下,设计5种不同植物篱种植模式,结合自然降雨、人工模拟暴雨试验、稀土元素(REE)示踪、土壤抗蚀性评价等方法,研究植物篱的减流减沙效应和控制机理.结果显示,与裸坡相比,自然降雨下麦冬双行植物篱处理地表径流量降低39.4％,土壤流失量降低65.8％,效果最佳.降雨前土壤含水量能显著影响径流和土壤流失的发生特征.土壤容重和孔隙度可作为衡量植物篱控制水土流失效应的最佳指标.根据17个抗蚀性指标建立植物篱条件下红壤抗蚀性的综合评价指标体系,评价结果表明土壤综合抗蚀性由高到低依次为麦冬双行、黄花菜+麦冬双行、黄花菜双行、麦冬单行、黄花菜单行和裸坡.不同坡位植物篱对土壤抗蚀性的影响存在差异,侵蚀泥沙主要来源集中在中下坡位.     

基于GIS与QuickBird影像的小流域土壤侵蚀定量评价

基于GIS技术和QuickBird遥感影像,采用修正的通用土壤流失方程RUSLE作为评价模型,计算了清水沟小流域土壤侵蚀量,并结合土壤侵蚀强度分级标准,生成流域土壤侵蚀强度等级图;利用GIS的叠置分析功能,定量分析了土壤侵蚀与坡度和土地利用之间的关系,并针对不同水保措施预测了水土保持治理效果.结果表明清水沟小流域土壤侵蚀模数为75.02 t·hm-2·a-1,属强度侵蚀区,年水土流失量2.6×104 t;流域64.5%的泥沙来自于占流域面积仅28%的极强度和剧烈侵蚀区域;经分析,流域土壤侵蚀模数与坡度呈显著正相关,不同土地利用类型的土壤侵蚀模数大小排序依次为难利用地＞建设用地＞坡耕地＞园地＞草地＞林地;退耕还林是降低土壤侵蚀强度与减少水土流失量的主要途径.     

基于遥感和GIS的青藏铁路生态累积效应研究

采用遥感和GIS技术,通过生态系统功能偏离累积指数、景观格局干扰累积指数、植被退化指数、生态阻隔累积指数和区域生态累积效应指数研究青藏铁路建设和运营对沿线生态系统的累积影响.结果表明,铁路建设和运营对沿线0～1 km直接影响区的生态服务功能、景观格局、植被覆盖和生态流均造成一定的累积影响,但以景观格局和生态流受到的影响最大,且对拉萨至唐古拉段的影响大于唐古拉至格尔木段,主要表现为对农田、草地、河流湿地和荒漠生态系统的影响.从铁路沿线＞1～5和＞5～10 km范围的间接或协同累积影响来看,拉萨至唐古拉段明显高于唐古拉至格尔木段.铁路建设运营对＞1～5 km范围的农田、荒漠和河流湿地生态系统仍存在一定负面影响,且以农田生态系统受到的负面累积影响最大,主要表现为拉萨和格尔木城市扩张对农田生态系统的干扰和占用.     

森林土壤固碳机理研究进展

全球碳平衡中,土壤有机碳储量为2000 Pg,植被碳储量500 Pg,大气碳储量785 Pg,土壤中有机碳变化是影响大气温室气体含量的重要因素。中国人工林总量世界第一,可以通过造林树种的选择,增加森林土壤的碳汇功能,它主要通过4种机理来实现,包括稳定性有机-矿物复合体的形成、持久性封存的深层碳的增加、耐分解有机物成份的积累、以及土壤团聚体结构中碳的物理性保护。中国近年来对木材的需求上升,导致大量短轮伐期人工林的种植,采伐、火烧炼山、施肥与整地等营林措施对土壤碳汇功能形成重大影响。因而,通过加强对中国人工林土壤固碳机理的研究,通过人为措施实现具有较强固碳能力的森林类型,从而提高人工森林生态系统的固碳能力,它对中国减排增汇战略具有重要意义,而加强对不同营林措施对碳汇功能影响的研究是中国当前面临的重大课题。     

Evaluating losses in ecosystem services in nature reserves in Sichuan,China

Nature reserves have developed rapidly over the decades in China and play a significant role in the function of ecosystem services. The function of ecosystem services in nature reserves, however, has tended to decline in recent years due to natural hazards and human activities. Based on land use, the variation of ecosystem services value (ESV) during 2000–2010 in national nature reserves in Sichuan was evaluated. We analyzed the comprehensive effects of natural disasters and human activities on the decline of ESVs. Total ESV in the national nature reserves in Sichuan was approximately 2741.35 million US$ in 2000, 2616.81 million US$ in 2005, and 2499.06 million US$ in 2010, representing a decrease of 242.29 million US$, or 8.84%, in the decade. Forestland, grassland, wetland, and water bodies played vital roles in the function of ecosystem services, with an aggregated ESV of 99% of the total. The largest proportion of the total ESV was the protection of biodiversity at 48.6%. ESV of all land use types and single ecosystem services continued to decline during 2000–2010. A mechanism of adaptable risk prevention should be established, and unreasonable human activities should be avoided to protect ecosystems and to improve the functions of ecosystem services.     

中国水稻土碳循环研究进展

文章首先分析了水稻土在碳循环研究中的地位和重要性，进而对我目水稻土碳循环的研究现状作了较为详尽的阐述，对其主要研究结论进行了深入的剖析。中国大而积的水稻土自1980年以来显示出有机碳库增加现象，说明水稻田对大气CO2可能产生汇效应。水耕熟化过程足有机碳的积累过程，水稻土的碳密度是早作土碳密度的2-3倍。水稻土的同碳能力与土壤的微团聚体的粒径有关。但对于水稻土中有机碳的分布和结合状态与农业管理措施、水稻土质量变化、农业生态环境变化的关系仍不清楚。因而建议就这一问题从土壤物理学、化学和生物学的相互作朋与土壤微团聚体中矿物质、有机质和微生物的相互结合关系的层面上进行多学科研究。同时提出了今后我困水稻土碳循环的重点研究方向和领域，即从整体和系统的角度来研究碳循环和平衡，从不同的时空区域来研究碳循环的过程和强度。     

Is the antipredatory response in behaviour reflected in stress measured in faecal corticosteroids in a small rodent?

Predation risk has been shown to alter various behaviours in prey. Risk alters activity, habitat use and foraging, and weight decrease might be a consequence of that. In mammals, studies on physiological measures affected by risk of predation, other than weight, are rare. We studied in two separate laboratory experiments foraging, hoarding behaviour and expression of stress measured non-invasively from the faeces in the bank vole (Clethrionomys glareolus), a common boreal rodent. Voles were exposed to predation risk using odours of the least weasels (Mustela nivalis nivalis). Distilled water served as control. In the first experiment, we found that foraging effort, measured as sunflower seeds taken from seed trays filled with sand, was significantly lower in trays scented with weasel odour. Both immediate consumption of seeds and hoarding were affected negatively by the weasel odour. Females hoarded significantly more than males in autumn. In the second experiment, the negative effect of weasel odour on foraging was consistent over a 3-day experiment, but the strongest effect was observed in the first night. Foraging increased over the time of the experiment, which might reflect either energetic compensation during a longer period of risk, predicted in the predation risk allocation hypothesis, or habituation to the odour-simulated risk. Despite decreased foraging under predation risk, stress measured as corticosteroid metabolite concentration in vole faeces was not affected by the weasel odour treatment. In conclusion, we were able to verify predation-risk-mediated changes in the foraging effort of bank voles but no physiological stress response was measured non-invasively, probably due to great individual variation in secretion of stress hormones.     

中国公众参与环境管理的研究

回顾了中国公众参与环境管理的发展历程,分析了公众参与环境管理存在的问题。针对公众参与环境保护管理的有效性的影响因子,例如主观因素、传统背景、时效因素及执行技巧等进行一系列的探讨,并根据公众参与计划的设计构思、公众参与计划的关键两方面的讨论,提出增加公众参与环境保护管理有效性的一些建议。     

生物扰动在水层-底栖界面耦合中的作用

综合评述了生物扰动在水层-底栖界面耦合中的作用研究进展和热点问题,并进行了展望。国际上十分重视水层-底栖界面耦合过程的研究并已有一定基础,生物扰动作为海洋生态学的重要内容之一早在20世纪50—60年代就已开展了工作,但直到10余年前才真正开始定量研究,进入了实验模拟、现场观测与建立模型相结合的新阶段。国内的生物扰动研究尚处于起步阶段,加上技术方法落后,一直未能取得突破性进展。目前国内外关于水层-底栖界面生物扰动效应研究基本上都在海洋中开展,尤其在河口、近岸和浅海水域进行,湖泊和河流研究明显薄弱。作为水生态动力学的重要分支和前沿领域,生物扰动研究具有广阔前景。急需针对我国水域特点,引进先进的现场观测和室内测试手段,进一步揭示水层-底栖界面耦合过程中的生物扰动机制,更精准和更详细地掌握水域中各种物质的生物地球化学循环的全过程,为控制水体内源污染释放、富营养化治理和生态建模等提供科学依据。     

Lead in a residential environment in Jamaica

The background levels of lead in Jamaica in soils and sediments, estimated at 37 mg kg^–1, are relatively high compared with world averages. Several areas have values in excess of this due to mineralisation and pollution. One such is the residential Hope Flats/Kintyre area in which levels of lead up to 2.5% are found in the soils and up to 8 g kg^–1 in the water of the nearby Hope River. The blood lead levels of a sample of children were in the range 5.7–57 g dl^–1. The high lead levels suggest a potential health risk, particularly for the children. This can be minimised by programmes which include community education, case management and abatement to reduce the lead exposure.     

硝基芳香化合物的植物作用研究进展

硝基芳香化合物是环境中难以降解的污染物之一。因其用途广泛,大量残留于土壤,水体和大气中,造成的环境污染日趋严重。多种植物对该类污染物具有吸收、富集和代谢降解作用,利用植物对其环境污染进行治理是一种有效的方法。文章在总结国内外有关硝基芳香化合物的植物作用研究基础上,重点阐述了植物对硝基芳香化合物的吸收、转运和代谢过程,分析了吸收、代谢机理以及影响吸收的因素;硝基芳香化合物的理化特性、浓度和植物自身特性及其它外界条件都会影响植物对该类化合物的吸收,植物可以通过体内降解、体外联合代谢、根部释放酶催化的机制实现该类化合物的降解。目前,硝基芳香化合物进入植物细胞膜的机理认知不足,模拟模型缺乏有力数据验证;代谢机制中参与反应的酶、化合物等体系和反应产物环境特性仍不明确,植物修复可行性缺乏有力证据。未来将在模型预测构建、降解机理和修复工程的实际应用方面作进一步探究,以形成系统的认知,为硝基芳香化合物污染土壤和农产品的生态风险评价以及植物修复提供理论依据。     

Employment of passive sampling in monitoring indoor air quality in selected residences in a Tri-city area in Poland

Time-weighted average concentrations of selected volatile compounds were measured in chosen residences in a Tri-City area of Poland by means of passive sampling. The results were compared to those obtained by dynamic technique – sorption tubes filled with Tenax TA sorbent. Results obtained by employing the two techniques were similar. Total volatile organic compound (TVOC) parameters were also determined. An attempt was also made to evaluate the influence of outdoor air pollutants on indoor air quality.     

Bioavailability of trace metals in brownfield soils in an urban area in the UK

Thirty-two brownfield sites from the city of Wolverhampton were selected from those with a former industrial use, wasteland or areas adjacent to industrial processes. Samples (<2 mm powdered soil fraction) were analysed, using inductively coupled plasma–atomic emission spectrometry (ICP–AES) for 20 elements. Loss on ignition and pH were also determined. A five-step chemical sequential extraction technique was carried out. Single leach extraction with 0.12 M hydrochloric acid of Pb, Cu and Zn in soil was determined as a first approximation of the bioavailability in the human stomach. Some of the sites were found to have high concentrations of the potentially toxic elements Pb, Zn, Cu and Ni. The partitioning of metals showed a high variability, however a number of trends were determined. The majority of Zn was partitioned into the least chemically stable phases (steps 1, 2 and 3). The majority of Cu was associated with the organic phase (step 4) and the majority of Ni was fractionated into the residue phase (step 5). The majority of Pb was associated with the residue fraction (step 5) followed by Fe–Mn oxide fraction (step 3). The variability reflects the heterogeneous and complex nature of metal speciation in urban soils with varied historic histories. There was a strong inverse linear relationship between the metals Ni, Zn and Pb in the readily exchangeable phase (step 1) and soil pH, significant at P < 0.01 level. There was a significant increase (P < 0.05) in the partitioning of Cu, Ni and Zn into step 4 (the organic phase) in soils with a higher organic carbon content (estimated by loss on ignition). Copper was highly partitioned into step 4 as it has a strong association with organics in soil but this phase was not important for the partitioning of Ni or Zn. The fractionation of Ni, Cu and Zn increased significantly in step 3 when the total metal concentration increases (P < 0.01). The Fe–Mn oxide fraction becomes more important in soils elevated in these metals, possibly due to the scavenging of metals by oxides. Cu and Pb extracted by HCl was statistically similar to the sum of the metals in steps 1 to 4 (P < 0.01) and HCl available Zn was statistically similar to the sum of Zn in steps 1 to 3 (P < 0.01). Step 4 (the organic phase) was not an important phase for Zn, so it was concluded that any Cu, Zn and Pb present in soil in a nonresidue phase would be potentially available for uptake into the human system once soil has been ingested.