• Energy Research
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• 15. Life on land close
• Journal of Environmental Management close

Forest soil acidification caused by acid deposition is a serious threat to the forest ecosystem. To investigate the liming effects of biomass ash (BA) and alkaline slag (AS) on the acidic topsoil and subsoil, a three-year field experiment under artificial Masson pine was conducted at Langxi, Anhui province in Southern China. The surface application of BA and AS significantly increased the soil pH, and thus decreased exchangeable acidity and active Al in the topsoil. Soil exchangeable Ca2+ and Mg2+ in topsoil were significantly increased by the surface application of BA and AS, while an increase in soil exchangeable K+ was only observed in BA treatments. The soil acidity and active Al in subsoil were decreased by the surface application of AS. Compared with the control, soluble monomeric and exchangeable Al in the subsoil was decreased by 38.0% and 29.4% after 3 years of AS surface application. There was a minimal effect on soluble monomeric and exchangeable Al after the application of BA. The soil exchangeable Ca2+ and Mg2+ in the subsoil increased respectively by 54% and 141% after surface application of 10 t ha-1 AS. The decrease of soil active Al and increase of base cations in subsoil were mainly attributed to the high migration capacity of base cations in AS. In conclusion, the effect of surface application of AS was superior to BA in ameliorating soil acidity and alleviating soil Al toxicity in the subsoil of this Ultisol.

Weighting scheme definition represents an important step in assessment of adaptive capacity to climate change with indicator approach since it defines the trade-offs among indicators or components and can be source of uncertainty. This study aims to assess smallholder farmers' adaptive capacity to climate change by using a mixed weighting scheme that reflect farmers' perceived importance of adaptive capacity components to inform policy makers. To achieve that objective, the sustainable livelihood framework was adopted and indicator approach was used for the assessment. The mixed weighting scheme were defined by using both equal weights and experts judgement methods during the assessment process. The mixed weighting scheme index is compared to the case where equal weights are applied in the assessment process and an uncertainty analysis was performed on relative standard deviation through a Monte Carlo simulation. Primary Data were collected from 450 farmers in two communities in northern Benin with a structured questionnaire and through focus groups discussion. The results show that smallholder farmers in both communities do not have the same perceived importance of adaptive capacity components. The index scores show that farmers have in majority low adaptive capacity. When weighted product aggregation method is used, there is more uncertainty related to the index computed with the mixed weighting scheme, but it leads to the same characterisation when compared with the index computed with the equal weights. It is recommended that mixed weighting scheme should be preferred for the assessment of adaptive capacity and weighted product aggregation method should be used.

The world's largest alpine pastures are found on the Tibetan Plateau, where considerable climate changes and human impacts have been experienced. Identifying their contributions to terrestrial productivity is essential if we are to adapt to, or mitigate the effects of, climate change. In this work, we begin by showing how the current warming and wetting of the climate over the last three decades has favored plant growth, as consistently captured by satellite observations and 15 models. However, the interactions between climate factors explain less of the variation in greenness observed by satellites after the 2000s, implying non-climatic influences. Next, we show that there is a significant negative impact of livestock grazing on pasture greenness, especially in peak summer. Official statistics across 72 counties verify these negative impacts, especially in poorer pastures with a higher density of grazing livestock. The variation in grazing density has a stronger negative effect on vegetation growth during the early part of the growing season after the 2000s, as compared with that before the 2000s. We found a compensatory effect of grazing and climate on alpine grassland growth, and the grazing regulates the response of vegetation greenness to climate change by modulating the dependency of vegetation growth on temperature. Thus, we suggest there is a weakening influence of climate on the greenness of alpine pastures, largely due to a strengthening influence of management, which should be considered by both the scientific community and policymakers.

Alpine grasslands on the Qinghai-Tibetan Plateau are sensitive and vulnerable to climate change and human activities. Climate warming and overgrazing have already caused degradation in a large fraction of alpine grasslands on this plateau. However, it remains unclear how human activities (mainly livestock grazing) regulates vegetation dynamics under climate change. Here, alpine grassland productivity (substituted with the normalized difference vegetation index, NDVI) is hypothesized to vary in a nonlinear trajectory to follow climate fluctuations and human disturbances. With generalized additive mixed modelling (GAMM) and residual-trend (RESTREND) analysis together, both magnitude and direction of climatic (in terms of temperature, precipitation, and radiation) and anthropogenic impacts on NDVI variation were examined across alpine meadows, steppes, and desert-steppes on the Qinghai-Tibetan Plateau. The results revealed that accelerating warming and greening, respectively, took place in 76.2% and 78.8% of alpine grasslands on the Qinghai-Tibetan Plateau. The relative importance of temperature, precipitation, and radiation impacts was comparable, between 20.4% and 24.8%, and combined to explain 66.2% of NDVI variance at the pixel scale. The human influence was strengthening and weakening, respectively, in 15.5% and 14.3% of grassland pixels, being slightly larger than any sole climatic variable across the entire plateau. Anthropogenic and climatic factors can be in opposite ways to affect alpine grasslands, even within the same grassland type, likely regulated by plant community assembly and species functional traits. Therefore, the underlying mechanisms of how plant functional diversity regulates nonlinear ecosystem response to climatic and anthropogenic stresses should be carefully explored in the future.

Globalization as a mechanism to connect people at distance and share knowledge has been flourishing. Simultaneously, environmental degradation has been increasing, as reflected in global warming. Through three dimensions, the economic, the social and political, and two measures, de jure and de facto, this study provides a disaggregated analysis of the effect of globalization on the critical issue of global warming for 25 European Union countries from 1990 to 2016. To emphasize globalization, the countries analysed were evaluated by two measures of globalization, de jure and de facto, resulting in their classification as high or low globalized countries de jure and de facto. Furthermore, energy consumption, economic growth and efficiency were included in an Autoregressive Distributed Lag model performed with the Driscoll-Kraay estimator. Robustness was checked using a Feasible Generalized Least Squares estimator. The results revealed that, overall, globalization increases environmental degradation, with the de jure measure having greater influence on high-globalized countries and the de facto measure having greater influence on low-globalized countries. Bearing in mind the increase in worldwide emissions driven by globalization, practices such as the relocation of polluting industries from high globalized countries should be discouraged. Incentives to harmonize global environmental restrictions could contribute to decarbonization worldwide.

Understanding the differences in the responses of river hydrology and water quality to climate and land use changes is particularly crucial for the development and management of water resources in the future. This study was carried out to assess the isolated and coupled effects of future climate change and land use change on the flow and nutrient load of the Xitiaoxi watershed in southeast China by applying the calibrated Hydrological Simulation Program Fortran model. Four representative concentration pathways released by the Intergovernmental Panel on Climate Change and two projected land use change scenarios were used to simulate future conditions. The results indicate that climate change would result in flow increased with an average variation of 25.2% in the future, and the increased flow would be mainly concentrated on the high flow part of the total flow duration curve. Climate change would also induce seasonal shifts to nutrient load. The effects of land use change showed that nutrient load was more sensitive than flow, made Orthophosphate load increase by 2.8%-154.7%, and flow increase by 7.2%-15.1%. The results for coupled climate and land use changes indicate that flow and nutrient load would be more affected by climate change than by land use change. Climate and land use changes may amplify or weaken each other's effects on flow and nutrient load, which suggests that both should be incorporated into hydrologic models when studying the future conditions. The results of this study can help decision-makers guide management practices that aim to minimize flow and nutrient load.

Urban land development alters landscapes and carbon cycle, especially net primary productivity (NPP). Despite projections that NPP is often reduced by urbanization, little is known about NPP changes under future urban expansion and climate change conditions. In this paper, terrestrial NPP was calculated by using Biome-BGC model. However, this model does not explicitly address urban lands. Hence, we proposed a method of NPP-fraction to detect future urban NPP, assuming that the ratio of real NPP to potential NPP for urban cells remains constant for decades. Furthermore, NPP dynamics were explored by integrating the Biome-BGC and the cellular automata (CA), a widely used method for modeling urban growth. Consequently, urban expansion, climate change and their associated effects on the NPP were analyzed for the period of 2010-2039 using Guangdong Province in China as a case study. In addition, four scenarios were designed to reflect future conditions, namely baseline, climate change, urban expansion and comprehensive scenarios. Our analyses indicate that vegetation NPP in urban cells may increase (17.63 gC m(-2) year(-1)-23.35 gC m(-2) year(-1)) in the climate change scenario. However, future urban expansion may cause some NPP losses of 241.61 gC m(-2) year(-1), decupling the NPP increase of the climate change factor. Taking into account both climate change and urban expansion, vegetation NPP in urban area may decrease, minimally at a rate of 228.54 gC m(-2) year(-1) to 231.74 gC m(-2) year(-1). Nevertheless, they may account for an overall NPP increase of 0.78 TgC year(-1) to 1.28 TgC year(-1) in the whole province. All these show that the provincial NPP increase from climate change may offset the NPP decrease from urban expansion. Despite these results, it is of great significance to regulate reasonable expansion of urban lands to maintain carbon balance.

We examined the potential of Azolla japonica as a remediating plant for leachate channels and post-accumulation use as fertilizer for landfill slope. The harvested biomass of Azolla after one month grown in leachate was 254% that of the initial biomass and the predicted annual harvestable biomass of Azolla using a growth model was 32 times that of the initial biomass. Na, Fe, Mn, Mg, and P were accumulated in Azolla at very high concentrations. Such rapid increase of biomass and high accumulation rates suggest that this plant could be an excellent remediating plant. The post-harvest use of Azolla as compost was studied for the management and use of phytoaccumulating Azolla. Metal contents of Azolla compost were below permissible limits for co-composting material. Nitrogen, organic matter, P, and Mg content of the Azolla compost improved the soil condition of the landfill and enhanced ecophysiological responses of the plants. The application of Azolla compost can improve management of sanitary landfills, including the restoration of vegetation. Considering its ease of harvesting, high accumulation rates, harvestable biomass and suitability for composting, Azolla can provide a suitable solution for sustainable management of leachate channels and landfill slopes.