Changes in Soil Particulate Organic Matter, Microbial Biomass, and Activity Following Afforestation of Marginal Agricultural Lands in a Semi-Arid Area of Northeast China

Afforestation of agricultural lands has been one of the major land use changes in China in recent decades. To better understand the effect of such land use change on soil quality, we investigated selected soil physical, chemical and microbial properties (0–15 cm depth) in marginal agricultural land and a chronosequence of poplar (Populus euramericana cv. ‘N3016’) plantations (5-, 10-, 15- and 20-years old) in a semi-arid area of Northeast China. Soil bulk density significantly declined after conversion of agricultural lands to poplar plantations. Soil total organic carbon (TOC) and nitrogen (TN) concentrations, microbial biomass C (MBC) and potential N mineralization rate (PNM) decreased initially following afforestation of agricultural lands, and then increased with stand development. However, soil metabolic quotient (qCO₂) exhibited a reverse trend. In addition, soil particulate organic matter C (POM-C) and N (POM-N) concentrations showed no significant changes in the first 10 years following afforestation, and then increased with stand age. These findings demonstrated that soil quality declined initially following afforestation of agricultural lands in semi-arid regions, and then recovered with stand development. Following 15 years of afforestation, many soil quality parameters recovered to the values found in agricultural land. We propose that change in soil quality with stand age should be considered in determining optimum rotation length of plantations and best management practices for afforestation programs.     

2013年眉山市东坡区主城区降水化学组成特征

为了更好地了解眉山市东坡区主城区降水的化学组成特征,本文于2013年在东坡区环境监测站所在点采集到32场降水,并采用离子色谱仪、原子吸收分光光度计以及流动注射分析仪等分析降水中水溶性无机离子组份浓度,同时使用电导率仪测定降水的电导率,通过对这些数据的分析,总结得出:降水电导率加权年均值为100μs/cm,加权年均总离子浓度为982.21μeq/L,这两数的值均高于国内部分主要城市。另外,降水中主要组份依次是SO2-4、Ca2+、NO-3和NH+4,四者占总离子浓度的87%。NO-3/SO2-4质量浓度比的年均值为0.27,远小于1,说明本地区降水污染主要来自固定污染源。最后使用SPSS 19.0软件对降水中主要水溶性无机离子浓度进行相关性分析,推断出某些离子可能来自相同的污染源。     

Solar and Tidal Modulations of Fecal Indicator Bacteria in Coastal Waters at Huntington Beach,California

The coastal waters at many beaches in California and the United States are afflicted with fecal pollution, which poses a health risk for people exposed to the water through recreational activities such as swimming, surfing, and diving. Identifying sources of pollution is complicated by oceanographic transport/mixing processes and the nonconservative behavior of microorganisms exposed to sunlight and hostile marine conditions. This article investigates the variation of fecal indicator bacteria (FIB) concentrations in the surf zone and the adjacent coastal marsh by applying autocorrelation and cross-correlation analyses that illustrate solar and tidal modulations. A steady state bioreactor model was developed to explain solar inactivation in the surf zone, whereas a dynamic model was applied to explain tidally influenced disturbances in the coastal marsh. These models applied to intensive monitoring datasets on FIB and environmental variables have provided insights into the biologic and physical processes controlling coastal water quality, specifically the influence of sunlight and tides on bacterial levels.     

Characteristics of Coastal Dune Topography and Vegetation in Environments Recently Modified Using Beach Fill and Vegetation Plantings,Veneto, Italy

Human actions can contribute to degradation of coastal environments or they can increase the likelihood that these environments will be restored. Beach nourishment provides a basis for restoration, but ways must be found to add habitat improvement to projects designed for shore protection. This study examines how beach nourishment projects can help reinstate dune landscapes in locations where beaches and dunes had been replaced by static shore protection structures. Dune topography and vegetation on three nourished sites on the northern Adriatic Coast of Italy are compared to a reference site to evaluate changes after beach fill was emplaced. Results reveal how nourishment projects used for shore protection can restore the space available for dunes to form, increase the likelihood of sediment transfers inland and increase the diversity of topography and vegetation. Beach raking prevents formation and growth of hummocky, incipient backshore dunes that would otherwise evolve into a naturally functioning foredune. Sand-trapping fences can speed the process of foredune development but can be counterproductive if they interfere with transport to beach grass (Ammophila littoralis) planted landward of them. Shore protection structures can provide stability and more time for dune evolution on eroding shores, resulting in greater species richness and longer retention of ecological niches. These structures need not be required if re-nourishment occurs frequently enough to provide a beach wide enough to protect against storm wave uprush.     

Distribution and Significance of Epipsammic Algae in the Coastal Shore (Ibeno Beach) of Qua Iboe River Estuary, Nigeria

The distribution of epipsammic phytoplankton in the coastal shore (Ibeno beach) of Qua Iboe River estuary was studied in the early summer (between October and December) of 1998. The results revealed the presence of Actinoptychus undulatus, Aphanizomenon flos-aquae, Astasia fustis, Chromulina globosa, Cocconeis pediculus, Cymatopleura solea, Cymbella lanceolata, Euglena intermedia, Lyngbya majusculata, Microcystis sp., Nodularia spumigena, Navicular rhynocephala, Oscillatoria nigroviridis, Pinnularia viridis, Rhoicosphenia curvata, Trachelomonas volvocina and Urceolus cyclostomus in the sandy beach. The mean species density of the epipsammic algae encountered in the beach ranged from 16 to 7600 organisms per hectare. The density, however, decreased with increase in sampling distance from the low tide level. Actinoptychus undulatus was the most abundant and widely distributed phytoplankton while Aphanizomenon flos-aquae was the least encountered species. The occurrence of A. flos-aquae and other toxin producing cyanobacterial species of Lyngbya majusculata, Microcystis sp., N. spumigena and O. nigroviridis in the sandy beach are of serious health significance.     

成都市大气颗粒物工业和民用污染源的调查分析与对策

针对成都市大气中颗粒物污染现状,对烟(粉)尘排放的来源,烟(粉)尘排放的重点行业,烟(粉)尘排放的分布地区做了调查,并结合颗粒物污染的分布区域对照分析,提出了相应对策。     

川北高台原区废弃煤矿枯水期矿井涌水水化学特征及成因分析

对废弃煤矿矿井涌水的水化学特征及成因进行分析,可为保护矿区地下水环境提供理论支撑.基于地质背景,通过对比枯水季节川北高台原区废弃煤矿矿井涌水与背景泉点水化学指标,并采用聚类分析方法对矿井涌水中离子指标进行统计,进而对其特征及成因进行了研究.结果表明:地层中黄铁矿中硫元素氧化是矿井涌水水化学特征变化的开端,受研究区矿井涌...     

资阳市空气可吸入颗粒物的污染水平及变化规律

本文对资阳市两年间城区环境空气中PM10的监测数据进行分析,揭示了该污染物的时空分布特征及变化规律,并有针对性的提出了一些防治对策.     

Environmental degradation of the Obra-Renukoot-Singrauli Area,India, and its impact on natural and derived ecosystems

Summary Vast stretches of the Obra—Renukoot—Singrauli region were once covered with natural forests. The tribal dwellings were small and interspersed. However, there has been rapid industrialisation in recent years. Quarrying for limestone, the establishment of a cement factory, thermal power stations and the construction of the G.B. Pant Sagar reservoir have resulted in a rapid build up of human population, the displacement of the original population, deforestation and conversion of natural forest ecosystems into savanna and marginal croplands. The converted ecosystems are under immense biotic stresses such as lopping, grazing, etc.The rainfall is meagre and erratic, the soils are highly weathered and impoverished, consequently the natural forests, as well as the derived ecosystems, are fragile. Signs of desertification are widespread. A rapid depletion in the wildlife has occurred. The establishment of thermal power stations and chemical and cement factories has also resulted in large scale gaseous air pollution, particularly of SO₂ and HF, pollution due to particulate matter through fly ash and cement dust, and that due to liquid effluents. Surface coal mining has caused extensive damage to the natural ecosystems with growing dumps of overburden. The latter needs to be stabilised.This integrated research project on environmental degradation and its impact on air, soil, water and vegetation was divided into five sub-projects, each supervised by a principal investigator. These sub-projects were: (i) Industrial air pollutants and their effects on ecosystem structure and function; (ii) Analysis of structure and functioning of forest ecosystems; (iii) Analysis of structure and functioning of savanna and agroecosystems; (iv) Analysis of structure and functioning of watershed and water-bodies; and (v) Impact of land-use system, socio-economic- demographic conditions, and environmental perception and behavioural management. In these studies dynamics of plant biomass, productivity and nutrients, and biochemical—physiological responses of plants to pollution were emphasised. Environmental perceptions of the native and displaced populations were also studied.The paper outlines a range of recommendations which should help to improve the environmental quality of the region.This article summarises a Man and the Biosphere research project which was sponsored by the Ministry of Environment and Forests of the Government of India. The team of principal investigators comprised Professors J.S. Singh, D.N. Rao, R.S. Ambasht, K.P. Singh, B.S. Gupta and M. Agrawal. The study was coordinated by Professor J.S. Singh, Professor of Botany at Banaras Hindu University.     

成都市居民生活与第三产业污染源调查分析

居民生活与第三产业污染源是影响城市大气环境质量的重要因素之一。本文对居民生活与第三产业污染源进行了调查分析。了解其对成都市大气环境的影响程度，为成都市大气环境质量控制策略提供依据。     

Chemical properties of soils in relation to forest composition in moist temperate valley slopes of Garhwal Himalaya, India

The present study was undertaken in moist temperate forest of Mandal-Chopta area in the Garhwal region of Uttarakhand, India. The aim of the present study was to assess the chemical properties of soils in relation to the forest structure and composition. Twelve forest types according to the altitude, slope aspect, and species composition were selected for the study. Chemical properties of the soil, i.e., total nitrogen (N), available phosphorus (P), available potassium (K), organic carbon (C), soil organic matter (SOM), pH and C:N ratios were analyzed for three different depths viz., (i) ??Upper?? (0?C10?cm), (ii) ??Middle?? (11?C30?cm), and (iii) ??Lower?? (31?C60?cm) in all the selected forest types. Phytosociological and diversity parameters viz. total basal cover (Gha^?1), stem density (Nha^?1), tree species richness (SR), Simpson concentration of dominance and Shannon?CWiener diversity index ( $ \overline{\rm H} $ ) were also calculated for each forest type. Values of N, P, K, C, SOM, C:N ratio and pH ranged from 0.17 to 0.45?%, 2.73 to 20.17?ppm, 40.67 to 261.17?ppm, 2.29 to 4.31?%, 3.95 to 7.43?%, 8.12 to 14.49 and 5.47 to 6.67, respectively. N showed a positive relationship with C and K. P was positively correlated with C and negatively correlated with altitude. P was higher in the soil of lower horizons of all the forest types. K was found to be positively correlated with altitude, C and N. pH of all the forest types was slightly acidic. C was comparatively higher in mixed broad-leaved forest types. No relationship between altitude and C was observed, which may be due to different composition of forest types along the altitudinal gradient and their differential decomposition rates. C content decreased with the depth of the soil. C showed positive correlation with N, P, and K. N showed a positive correlation with Gha^?1. K showed a negative correlation with SR and $ \overline{\rm H} $ . P showed no relationship with the phytosociological parameters. This study also provides the comparisons between the results of chemical analysis of the present study with numerous other previous studies in the temperate Himalayan region of the Uttarakhand. The values of soil chemical properties of the present study in most of the forest types are on the higher end than the values previously recorded for the other similar forests of the region. The possible reason being luxuriant vegetation and undisturbed nature of these forest types, which is evident from higher values of diversity and other phytosociological parameters.     

盘锦地区稻田田面水氮素动态变化及化学氮肥投入阈值研究

以水稻为供试作物,水稻土为供试土壤,采用田间定位试验的方法,以施肥后田面水中的总氮（TN）、NH4^＋-N和NO3^--N浓度为指标,进行了施氮后田面水中氮素释放规律研究。结果表明,施肥后田面水中的总氮（TN）、NH4＋-N和NO3--N浓度随着施肥量的增加而增加,随着时间的推移三者的浓度呈先上升后下降的趋势,一周后趋于稳定;以氮素表观盈余率和植株吸氮量为指标,从环境安全角度研究水稻生产化学氮肥投入阈值,初步确定试验区环境安全化学氮肥投入阈值为189.22～218.98 kg·hm^-2;以水稻产量为指标,进行了粮食安全氮肥投入阈值研究,初步确定试验区水稻生产粮食安全化学氮肥投入阈值为202.24～288.89 kg·hm^-2。综合考虑粮食安全和环境安全,试验区化学氮肥投入阈值为202.24～218.98 kg·hm^-2。     

Predicting Particulate Matter (PM2.5) Concentrations in the Air of Shahr‐e Ray City,Iran, by Using an Artificial Neural Network

Particulate matter (PM), along with other air pollutants, pose serious hazards to human health. The Artificial Neural Network (ANN) is a branch of artificial intelligence that has an ability to make accurate predictions. In this article, the authors describe such methods and how historical data on air quality, moisture, wind velocity, and temperature in Shahr‐e Ray City, located at the southern tip of Tehran, was used to train an ANN to provide accurate predictions of PM concentrations. The availability of such predictions can offer significant assistance to those who are working to reduce air pollution.     

华北农牧交错带气候生产力时空变化特征——以大同市为例

以华北农牧交错带为切入点,选取晋北长城沿线大同市8个气象站点,利用线性趋势分析、5年滑动、M-K检验以及Thormthwaite模型,分析了近38年来大同市气候变化及其气候生产力的演变特征.结果表明:①近38年大同市气温呈现显著增加趋势,且在1994年发生突变.②降水量呈现不显著的减少趋势.③气候生产力呈现缓慢增加趋势,出现南部高于北部,东西方向上呈现由中心向四周递增.④暖湿气候的气候生产力呈现正距平,最适合作物生长;冷干气候的气候生产力呈现负距平,最不适合作物生长.现阶段气候暖干化趋势显著,因此研究气候变化对气候生产力有重要意义.     

泸州市大气降水的化学特征及其防治对策

本文讨论了泸州市2000年3月～2003年2月年度降水的酸碱性、离子组分变化规律与特征，指出泸州市酸雨污染应从总量上控制SO2并从源头上消减SO2的排放量，并预防城市机动车尾气NOx的酸雨沉降污染。     

Land Suitability Assessment in the Catchment Area of Four Southwestern Atlantic Coastal Lagoons: Multicriteria and Optimization Modeling

In the present study, a land suitability assessment was conducted in the basin of four Uruguayan coastal lagoons (Southwestern Atlantic) to analyze the productive development while minimizing eutrophication, biodiversity loss and conflicts among different land uses. Suitable land for agriculture, forest, livestock ranching, tourism and conservation sectors were initially established based on a multi-attribute model developed using a geographic information system. Experts were consulted to determine the requirements for each land use sector and the incompatibilities among land use types. The current and potential conflicts among incompatible land use sectors were analyzed by overlapping land suitability maps. We subsequently applied a multi-objective model where land (pixels) with similar suitability was clustered into "land suitability groups", using a two-phase cluster analysis and the Akaike Information Criterion. Finally, a linear programming optimization procedure was applied to allocate land use sectors into land suitable groups, maximizing total suitability and minimizing interference among sectors. Results indicated that current land use overlapped by 4.7?% with suitable land of other incompatible sectors. However, the suitable land of incompatible sectors overlapped in 20.3?% of the study area, indicating a high potential for the occurrence of future conflict. The highest competition was between agriculture and conservation, followed by forest and agriculture. We explored scenarios where livestock ranching and tourism intensified, and found that interference with conservation and agriculture notably increased. This methodology allowed us to analyze current and potential land use conflicts and to contribute to the strategic planning of the study area.     

Variations in perceptions of danger,fear and preference in a simulated natural environment

Although natural environments can help promote health, they also contain a number of dangers. This study attempted to examine how variations in the physical structure of a simulated natural environment influenced perceptions of both overall and specific types of danger, fear and preference before exploring the relationships between these variables. Three simulated walks through a natural environment differing in levels of prospect-refuge were created for the study. Respondents were randomly assigned to one of the conditions and asked to imagine taking the walk for real. In support of the typology, the results found that the walks with higher levels of prospect-refuge (higher visibility, fewer hiding places and more accessibility) were perceived as less dangerous and fearful and more preferred than walks with lower levels of prospect-refuge. However despite levels of prospect-refuge appearing to impact on the perceived likelihood of encountering a physical danger or becoming lost, they were not found to impact on the perception of encountering a social danger.     

成都市区酸雨变化及降雨化学组成分析

依据成都市1995～2003年城区酸雨监测统计资料,本文对成都市城区酸雨的变化特征、离子化学组成进行了分析。结果表明:城区降水酸度变化呈现出一定的波动性,酸雨频变化表现出较大的波动性;1999年和2000年酸雨年均酸度及频率情况都较好,之后出现反弹;降水中离子含量高,雨水污染严重;降水中CSO2-的比值正在逐步缩小,酸雨状况转变为硫/CNO-34酸型和硝酸型并重的局面,大气污染物中NOx的贡献率正在升高。灰色关联分析表明:降水pH值与雨水中碱性阳离子的关联序为NH+4>Ca2+>Mg2+>K+>Na+;降水pH′值与雨水中酸性阴离子的关联序为Cl->F->SO2-3。4>NO-