Soil erosion under different vegetation covers in the Venezuelan Andes

This comparative study of soil erosion considered different environments in an ecological unit of the Venezuelan Andes. The soils belong to an association of typic palehumults and humic dystrudepts. Soil losses were quantified by using erosion plots in areas covered by four types of vegetation, including both natural and cultivated environments. The highest soil erosion rate evaluated corresponded to horticultural crops in rotation: reaching a value of 22 Mg ha^–1 per year. For apple tree (Malus sylvestris Miller) plots, soil losses reached values of 1.96 Mg ha^–1 per year. Losses from pasture (Pennisetum clandestinum Hochst. ex Chiov.) plots, without livestock grazing, were as high as 1.11 Mg ha^–1 during the second year of the experiment. The highest soil losses generated from plots under natural forest were equal to 0.54 Mg ha^–1 per year. Environmental factors such as total and effective rainfall, runoff, and some soil characteristics as those related to soil losses by water erosion were evaluated. The type of management applied to each site under different land use type and the absence of conservation practices explain, to a large extent, the erosive processes and mechanisms.     

Triangulation theory applied to conflict over hormone herbicide drift in Natal,South Africa

Policies that arise out of conflict or collaboration between specific interest groups and government agencies are often explained by theoretical constructs that fall under the umbrella of group theory. Triangulation theory is one of these constructs and serves to explain the mutuality of interests that exist between government agencies and interest groups expressed as points linking geometric forms. Conflict tends to occur when competing interest groups are excluded from the linkage, in this case between the opponents and proponents of hormone herbicides in the Tala area in Natal, South Africa. In opposition to the use of hormone herbicides were vegetable farmers and their supporters: in linked support were agricultural interest groups who used hormone herbicides, the manufacturers of the herbicides, and the government agency responsible for agriculture. Because of the influence exerted through mutual support by the proponents of hormone herbicides, the formulation of policy decisions directed towards the resolution of the conflict was delayed. When the minister of agriculture finally intervened, the policy decisions were designed to secure the support of those opposing the use of hormone herbicides by introducing issues that cut across those maintaining the discord.     

Assessment of Lead Exposure in Thohoyandou, South Africa

Lead levels in different environmental media (soil, grass leaves, water, ceramics, pencil, paint, crayons and cosmetics) were determined to assess the major sources of lead exposure in Thohoyandou, South Africa. Soil and plant leaves were used as indicators of Pb pollution from vehicle exhaust emissions. After digestion with concentrated acids (HNO₃, HCl and HClO₄) Pb concentrations were determined in triplicate using a flame atomic absorption spectrometer. The mean Pb concentrations at the kerb of selected busy roads were 205.5 ± 90, 273.0 ± 90 and 312.8 ± 81 μg g⁻¹ and 154.7 ± 67, 182.9 ± 76 and 240.6 ± 66 μg g⁻¹ for soil and plant leaves (dry weight) respectively. These concentrations were substantially higher than the values found on soils 50 m away from the roads (97.4 ± 11 μg g⁻¹). Pb concentrations in plants collected further away from the road (50 m) were substantially lower (71.8 ± 9.0 μg g⁻¹). The observed levels on soil are lower than the UK critical value of 500 μg g⁻¹ for gardens and allotments; and 2000 μg g⁻¹ for parks and open space as well as the Canadian values for agricultural (375 μg g⁻¹), residential (500 μg g⁻¹ and industrial (1000 μg g⁻¹). From these data it was clear that Pb concentrations in soil samples were substantially higher than the levels obtained for plant leaves. The Pb levels in green crayons, blue crayons, pencils (from China & Germany), were 10650 ± 75.2, 8200 ± 52.4, 1160 ± 50.2, 79 ± 10.1 μg g⁻¹ for the inner contents; and 4870 ± 58.1, 5650 ± 55.5, 1950 ± 46.6, 60 ± 12.9 μg g⁻¹ for the outer surface paint respectively. The ceramics showed Pb levels of 630 ± 50.3 μg g⁻¹ (saucer) and 560 ± 32.2 μg g⁻¹ (cup), while the inner contents and outer surface paint showed 480 ± 32.4 and 318 ± 21.2 μg g⁻¹ of Pb respectively. Early morning tap water flush gave a Pb level of 20.6 ± 5.6 μg Pb l⁻¹. This value is higher than the WHO and FDA maximum permissible concentrations of 10 μg l⁻¹ and 15 μg l⁻¹ respectively.     

Estimation of Regional, Local and Site-specific Profitability of Soil Conservation for the Wheat-Sheep Zone of New South Wales, Australia

Information about the net benefits of land degradation treatment is required at the relevant management level, such as regional, local or site-specific, to assist decision makers in the allocation of funds to soil conservation. In this paper, estimates of regional opportunity costs of erosion and costs of treatment are used to derive benefit-cost ratios to assess the profitability of gully erosion treatment for localities in the wheat-sheep zone of New South Wales. These results are then used to develop site-specific models which predict benefit-cost ratios of treatment from land attributes including gully length, slope, soil type and land use. These predictive models form the basis of a rapid appraisal method to aid soil conservation decisions.     

Jute bioblanket as a soil rehabilitation strategy in Sorocaba,Brazil: Soil chemistry and SWOT approaches

Soil erosion and the invasion of exotic plant species are major constraints to achieve sustainable development around the world. Currently, we find few products devoted concomitantly to combatting soil erosion as well as the establishment of unwanted exotic plants. In this paper, we introduce a new product, called herein a bioblanket, that protects the soil and impedes the establishment of exotic plant species. This product is of simple design, and to manufacture it, we use two biodegradable materials: jute tissue and grass wastes. We designed this product to combat soil erosion and the germination and establishment of new, unwanted, invasive plant species. In this paper, we describe our evaluation of how successful this product was in terms of improving the chemical attributes of soil. We also identified the product's potentialities and weaknesses by means of strengths, weaknesses, opportunities, and threats (SWOT) analysis. The bioblanket ameliorated the chemical attributes of the soil, as evidenced especially by the neutralization of acidity (8.5%) and aluminum toxicity (33%), and by an increment in nutrients concentration. We argue that after adequate treatment and management, the residues of plants that are normally considered unwanted materials can be transformed into a raw material to control the propagation of unwanted plant species, and concomitantly control soil erosion while improving the chemical conditions of the soil. The improvement of the soil chemical attributes was one of the main positive effects reported through the SWOT analysis. In addition, the SWOT analysis revealed some features that need improvement in future generations of the product, but we argue that these features do not impede the benefits for the use of the product in its present form.     

Trends in Vegetation Degradation in Relation to Land Tenure, Rainfall, and Population Changes in Peddie District, Eastern Cape, South Africa

Spatial and temporal variations in vegetation are examined in relation to land tenure, population increase, and rainfall variation in a part of Peddie district, Eastern Cape. Sequential aerial photographs between 1938 and 1988 are analyzed to determine trends in vegetation and population change in three different land-tenure units. The areal extent at each date of four distinct vegetation categories is determined using PC ARC/INFO GIS. Long-term annual rainfall trends for the area are analyzed and juxtaposed with vegetation changes. Extensive ground-truthing exercises are carried out to verify the present condition of vegetation condition in terms of cover and species composition. Differences in land-tenure systems are discerned as the dominant factor controlling variations in vegetation degradation. The study also reveals that neither population changes nor rainfall variations can explain the observed trends in vegetation degradation. Earlier injudicious land-use practices, sustained since the turn of the last century, may provide plausible explanations for the trends and present status of vegetation degradation in the area.     

Simultaneous adoption of integrated soil fertility management technologies in the Chinyanja Triangle,Southern Africa

Empirical scientific evidence indicates that there is still room for increasing food production by improving land productivity. This study aimed at identifying the key determinants that govern farmers’ decisions to adopt multiple components of integrated soil fertility management (ISFM) in a maize mixed cropping system of the Chinyanja Triangle, Southern Africa. Revealed preferences of ISFM components were collected from 320 randomly selected households and multivariate probit (MVP) model was used to analyse the simultaneous effects on adoption based on biophysical plot and household‐level socioeconomic attributes. The results show that farmers’ choices of a set of ISFM components are determined by a mix of factors that address the trade‐offs and synergies among them. Non‐farm income, moderate land quality perception, and education influence simultaneous technology adoption, while gender and crop loss increase the likelihood of farmers’ decisions to adopt independent options. Having other sources of income supports co‐adoption of inorganic fertilizer, residue incorporation, and crop rotation. Input/output market access, access to information, financial sources, and climate variability also play pivotal role in technology adoption. These results indicate that resource availability, learning costs, finances, and risk aversion need to be considered when designing and promoting ISFM technologies as a package.     

Cost‐benefit analysis of soil remediation in Israeli industrial zones

Industrial zones are the main source of soil pollution in Israel. Due to the upcoming approval of the bill on soil contamination and remediation in Israel, it is important to assess the economic feasibility of soil remediation. This study examines the economic feasibility of an extensive remediation project of all contaminated industrial zones in Israel. The estimated economic benefits include both direct benefits, resulting from the increase in the land value of the contaminated site, and indirect benefits, arising from the increase in nearby property values. A cost‐benefit analysis showed a cost benefit ratio of 1:14. Nonetheless, the direct benefits were found to be lower than the costs. Thus, the question of funding requires collaboration between government and the private sector.     

攀西-六盘水地区生态环境的整治对策

通过对攀西-六盘水地区水文、地质、矿产、气候、人文等诸方面情况的调查研究,分析了造成该地区生态环境严重破坏的原因,结合“攀西-六盘水地区生态环境保护与综合整治规划”,提出了区内主要城市环境污染的治理,崩塌、滑坡、泥石流和水土流失的整治措施,以及实施此规划的对策,最终达到对资源的综合开发与保护,实现生态系统良性循环的目的。     

Eco‐efficiency,self‐sufficiency and sustainability in transport: The limits for Brazilian sugarcane ethanol policy

This paper examines the historic development of the Brazilian sugarcane ethanol sector and the largely successful attempt to create a sustainable, renewable fuel for the transport sector. The policy that resulted from this process is an example of meeting the need for sustainable transport through the consideration of location‐specific characteristics and appropriate policy. The paper then questions the current and expected trajectory of the sugarcane ethanol sector with the focus on one key question: can sustainability be exported? In this analysis, the paper identifies new threats to the sustainability of Brazilian sugarcane ethanol and potential “opportunity costs” incurred in further development and internationalization of the sector. The paper concludes that exporting sugarcane ethanol may bring unanticipated deleterious consequences, which in turn means that both policy and theory need to be more precise about how sustainable transport is defined and bounded by time and space.     

Multi‐Decadal Remote‐Sensing Analysis of Irrigated Areas in the Lower Rio Grande Valley,New Mexico

A time series of estimates of irrigated area was developed for the Lower Rio Grande valley (LRG) in New Mexico from the 1970s to present day. The objective of the project was to develop an independent, accurate, and scientifically justifiable evaluation of irrigated area in the region for the period spanning from the mid‐1970s to the present. These area estimates were used in support of groundwater modeling of the LRG region, as well as for other analyses. This study used a remote‐sensing‐based methodology to evaluate overall irrigated area within the LRG. We applied a methodology that involved the normalization of vegetation indices derived from satellite imagery to get a more accurate estimation of irrigated area across multiple time periods and multiple Landsat platforms. The normalization allows more accurate evaluation of vegetation index data that span several decades. An accuracy assessment of the methodology and results from this study was performed using field‐collected crop data from the 2008 growing season. The comparisons with field data indicate that the accuracy of the remote‐sensing‐based estimates of historical irrigated area is very good, with rates of false positives (areas identified as irrigated that are not truly irrigated) of only about 4%, and rates of false negatives (areas identified as not irrigated that are truly irrigated) in the range of 0.6‐2.0%.     

两种不同生态区坡改梯对土壤氮磷含量影响的研究

分别在干热河谷生态区和华西雨屏生态区的坡改梯地区设置试验小区和对照试验区,通过采集土壤样品进行室内分析,研究在不同的坡位、不同的季节变化下两种生态区实施坡改梯措施对土壤养分保持的效果.干热河谷生态区以清溪小流域为例,华西雨屏生态区以凤鸣小流域为例.试验结果表明,在两个生态区的坡改梯工程试验区,空间上,各个坡位氮磷养分的...     

An Assessment of Forest Cover Trends in South and North Korea, From 1980 to 2010

It is generally believed that forest cover in North Korea has undergone a substantial decrease since 1980, while in South Korea, forest cover has remained relatively static during that same period of time. The United Nations Food and Agriculture Organization (FAO) Forest Resources Assessments—based on the reported forest inventories from North and South Korea—suggest a major forest cover decrease in North Korea, but only a slight decrease in South Korea during the last 30 years. In this study, we seek to check and validate those assessments by comparing them to independently derived forest cover maps compiled for three time intervals between 1990 and 2010, as well as to provide a spatially explicit view of forest cover change in the Korean Peninsula since the 1990s. We extracted tree cover data for the Korean Peninsula from existing global datasets derived from satellite imagery. Our estimates, while qualitatively supporting the FAO results, show that North Korea has lost a large number of densely forested areas, and thus in this sense has suffered heavier forest loss than the FAO assessment suggests. Given the limited time interval studied in our assessment, the overall forest loss from North Korea during the whole span of time since 1980 may have been even heavier than in our estimate. For South Korea, our results indicate that the forest cover has remained relatively stable at the national level, but that important variability in forest cover evolution exists at the regional level: While the northern and western provinces show an overall decrease in forested areas, large areas in the southeastern part of the country have increased their forest cover.     

Effects of Land‐Use and Land‐Cover Change on Evapotranspiration and Water Yield in China During 1900‐20001

Abstract: China has experienced a rapid land‐use/cover change (LUCC) during the 20th Century, and this process is expected to continue in the future. How LUCC has affected water resources across China, however, remains uncertain due to the complexity of LUCC‐water interactions. In this study, we used an integrated Dynamic Land Ecosystem Model (DLEM) in conjunction with spatial data of LUCC to estimate the LUCC effects on the magnitude, spatial and temporal variations of evapotranspiration (ET), runoff, and water yield across China. Through comparisons of DLEM results with other model simulations, field observations, and river discharge data, we found that DLEM model can adequately catch the spatial and seasonal patterns of hydrological processes. Our simulation results demonstrate that LUCC led to substantial changes in ET, runoff, and water yield in most of the China’s river basins during the 20th Century. The temporal and spatial patterns varied significantly across China. The largest change occurred during the second half century when almost all of the river basins had a decreasing trend in ET and an increasing trend in water yield and runoff, in contrast to the inclinations of ET and declinations of water yield in major river basins, such as Pearl river basin, Yangtze river basin, and Yellow river basin during the first half century. The increased water yield and runoff indicated alleviated water deficiency in China in the late 20th Century, but the increased peak flow might make the runoff difficult to be held by reservoirs. The continuously increasing ET and decreasing water yield in Continental river basin, Southwest river basin, and Songhua and Liaohe river basin implied regional water deficiency. Our study in China indicates that deforestation averagely increased ET by 138 mm/year but decreased water yield by the same amount and that reforestation averagely decreased ET by 422 mm/year since most of deforested land was converted to paddy land or irrigated cropland. In China, cropland‐related land transformation is the dominant anthropogenic force affecting water resources during the 20th Century. On national average, cropland expansion was estimated to increase ET by 182 mm/year while cropland abandonment decreased ET by 379 mm/year. Our simulation results indicate that urban sprawl generally decreased ET and increased water yield. Cropland managements (fertilization and irrigation) significantly increased ET by 98 mm/year. To better understand LUCC effects on China’s water resources, it is needed to take into account the interactions of LUCC with other environmental changes such as climate and atmospheric composition.     

Survey of land degradation in New South Wales,Australia

A survey of land degradation was undertaken in New South Wales, Australia during 1987–1988. The aims of the survey were to assess the location, extent, and severity of ten forms of degradation and to present the data in map and statistical form. Sample points were located on a regular grid. The method was designed so that data could be acquired from aerial photographs, expert local knowledge, and limited field checking. Individual statewide maps were prepared for each form of degradation. Map data were shown in pixel form. Sheet and rill erosion and soil structure decline were confined mostly to lands used for cropping. Gully erosion was commonly found across the state, while mass movement was confined to steeper lands. There were three severe areas of dryland salinity; irrigation salinity was mapped in parts of the southern irrigation lands. Induced soil acidity was severe in some cropping and pasture lands. Absence of tree regrowth was a noticeable feature of lands used for cropping. The survey enabled community awareness of the problems of land degradation to be increased, in addition to assisting regional land managers in resource allocation. The survey also provided the basis for the future location of sites that could be used to monitor the trends in the status of land degradation.     

Assessment of Use,Reuse, and End‐of‐Life Disposal and X‐Ray Fluorescence Analysis Screening of Waste Mobile Phones in Nigeria

Insights into consumer behavior, hazards of inappropriate disposal, and opportunities to reclaim valuable resources     

A case study of the opportunities and trade-offs associated with deproclamation of a protected area following a land claim in South Africa

Reconciling conservation and social justice imperatives is a major challenge facing many postcolonial states worldwide. Where historically disenfranchised communities have laid legal claim to protected areas, the typical resolution has been collaborative management agreements between the state and claimant communities. The real outcomes of such strategies for people and ecosystems have been seriously questioned, although alternative approaches are seldom explored. Here, we reflect on one such alternative that was pursued in a case in South Africa, where the land was handed back to the community and a replacement protected area created. Our objective was to explore the opportunities and trade-offs associated with this approach for communities and conservation agencies alike, and to compare these to typical collaborative management outcomes. Methods included key informant interviews, focus group discussions and household surveys. We find that, surprisingly, this approach created more benefits for the conservation agency than for claimant communities. Indeed, the community experiences bore a striking resemblance to those experienced in collaborative management settings: intra-community conflict, confusion over leadership and serious questions about the boundaries of the “community”. Processes aimed at redressing past injustice in disputes over conservation land, regardless of the approach adopted, must bring with them a strong commitment to building institutional and leadership capacities within communities, and pay serious attention to the ways in which equity and social justice can be fostered after the settlement of a land claim. Settlement agreements are frequently treated as the final step towards social justice, but are in fact just the beginning.     

Water‐Yield Reduction After Afforestation and Related Processes in the Semiarid Liupan Mountains,Northwest China1

Abstract: The increase of coverage of forest/vegetation is imperative to improve the environment in dry‐land areas of China, especially for protecting soil against serious erosion and sandstorms. However, inherent severe water shortages, drought stresses, and increasing water use competition greatly restrict the reforestation. Notably, the water‐yield reduction after afforestation generates intense debate about the correct approach to afforestation and forest management in dry‐land areas. However, most studies on water‐yield reduction of forests have been at catchment scales, and there are few studies of the response of total evapotranspiration (ET) and its partitioning to vegetation structure change. This motivates us to learn the linkage between hydrological processes and vegetation structure in slope ecosystems. Therefore, an ecohydrological study was carried out by measuring the individual items of water balance on sloping plots covered by different vegetation types in the semiarid Liupan Mountains of northwest China. The ratio of precipitation consumed as ET was about 60% for grassland, 93% for shrubs, and >95% for forestland. Thus, the water yield was very low, site‐specific, and sensitive to vegetation change. Conversion of grassland to forest decreased the annual water yield from slope by 50‐100 mm. In certain periods, the plantations at lower slopes even consumed the runon from upper slopes. Reducing the density of forests and shrubs by thinning was not an efficient approach to minimize water use. Leaf area index was a better indicator than plant density to relate ET to vegetation structure and to evaluate the soil water carrying capacity for vegetation (i.e., the maximum amount of vegetation that can be supported by the available soil water for an extended time). Selecting proper vegetation types and plant species, based on site soil water condition, may be more effective than the forest density regulation to minimize water‐yield reduction by vegetation coverage increase and notably by reforestation. Finally, the focuses in future research to improve the forest‐water relations in dry‐land areas are recommended as follows: vegetation growth dynamics driven by environment especially water conditions, coupling of ecological and hydrological processes, further development of distributed ecohydrological models, quantitative relation of eco‐water quota of ecosystems with vegetation structures, multi‐scaled evaluation of soil water carrying capacity for vegetation, and the development of widely applicable decision support tools.     

An energetic life cycle assessment of C&D waste and container glass recycling in Cape Town,South Africa

This study presents the results of a comparative life cycle assessment (LCA) on the energy requirements and greenhouse gas (GHG) emission implications of recycling construction and demolition (C&D) rubble and container glass in Cape Town, South Africa. Cape Town is a medium sized city in a developing country with a growing population and a rising middle class, two factors that are resulting in increased generation of solid waste. The City is constrained in terms of landfill space and competing demands for municipal resources.The LCA assessment was based on locally gathered data, supplemented with ecoinvent life cycle inventory data modified to the local context. The results indicated that recycling container glass instead of landfilling can achieve an energy savings of 27% and a GHG emissions savings of 37%, with a net savings still being achieved even if collection practices are varied. The C&D waste results, however, showed net savings only for certain recycling strategies. Recycling C&D waste can avoid up to 90% of the energy and GHG emissions of landfilling when processed and reused onsite but, due to great dependence on haulage distances, a net reduction of energy use and GHG emissions could not be confidently discerned for offsite recycling. It was also found that recycling glass achieves significantly greater savings of energy and emissions than recycling an equivalent mass of C&D waste.The study demonstrated that LCA provides an important tool to inform decisions on supporting recycling activities where resources are limited. It also confirmed other researchers’ observations that strict adherence to the waste management hierarchy will not always result in the best environmental outcome, and that more nuanced analysis is required. The study found that the desirability of recycling from an energy and climate perspective cannot be predicted on the basis of whether such recycling conserves a non-renewable material. However, recycling that replaces a virgin product from an energy-intensive production process appears to be more robustly beneficial than recycling that replaces a product with little embodied energy. Particular caution is needed when applying the waste management hierarchy to the latter situations.