• Energy Research
• agricultural and veterinary science... close
• 11. Sustainability close
• Sustainability close

Urban heat islands (UHIs) are an important issue in urban sustainability, and the standardized calculation of surface urban heat island (SUHI) intensity has been a common concern of researchers in the past. In this study, we used the administrative borders (AB) method and an optimized simplified urban-extent (OSUE) algorithm to calculate the surface urban heat island intensity from 2001 to 2017 for 36 major cities in mainland China by using Moderate Resolution Imaging Spectroradiometer (MODIS) images. The spatiotemporal differences between these two methods were analyzed from the perspectives of the regional and national patterns and the daily, monthly, and annual trends. Regardless of the spatial or temporal scale, the calculation results of these two methods showed extremely similar patterns, especially for the daytime. However, when the calculated SUHI intensities were investigated through a regression analysis with multiple driving factors, we found that, although natural conditions were the main drivers for both methods, the anthropogenic factors obtained from statistical data (population and gross domestic product) were more correlated with the SUHI intensity from the AB method. This trend was probably caused by the spatial extent of the statistical data, which aligned more closely with the rural extent in the AB method. This study not only explores the standardization of the calculation of urban heat intensity but also provides insights into the relationship between urban development and the SUHI.

Beef cattle production is an important agricultural activity in Brazil, which influences environmental and resource consumption. This study analyzed greenhouse gas (GHG) emission impacts from 17 farms, representing the Brazil’s productive system and determined possible improvements in the production chain. Methane, nitrous oxide, and carbon dioxide emissions were evaluated using the updated Intergovernmental Panel on Climate Change (IPCC) guidelines for national inventories. The GHG inventory included emissions from animals, feeds, and “cradle-to-farm-gate” operations for animal management. Regression analyses of carbon dioxide equivalent (CO2eq) emissions and productive indices were performed to identify possible GHG emission hotspots. The results varied considerably among the farms. The GHG yield ranged from 8.63 to 50.88 CO2eq kg carcass−1. The productive indices of average daily gain (p < 0.0001), area productivity (p = 0.058), and slaughtering age (p < 0.0001) were positively correlated with GHG yield. However, no correlation was found with the stocking rate (p = 0.21). The production chain could be improved through accurate animal management strategies that reduce the slaughtering age and daily weight gain individually or per area using pasture management and strategic animal supplementation, which could subsequently reduce GHG emissions in beef cattle production.

Municipal solid waste management and poor fertility status of sodic soils are two important issues experienced by all developing nations including India. Disposal of municipal solid waste (MSW) being produced in huge amounts is a challenging task for researchers and policy makers. Reclamation of salt affected soils with chemical amendments is a costly affair for resource-poor farmers. Composting of MSW and its enrichment with microbes is one of the options for its recycling and utilization for the reclamation of salt-affected soils. A field experiment was conducted in sodic soil to study the performance of microbial enriched municipal solid waste compost (EMSWC) alone and in combination with a reduced dose of gypsum on growth, yield, nutrient uptake, and grain quality of rice and wheat. The experiment was conducted for three consecutive years from 2018 to 2019 and 2020 to 2021 at ICAR Central Soil Salinity Research Institute, Research farm, Shivri, Lucknow, India, in sodic soil having pH 9.2, electrical conductivity (EC) 1.14 dSm−1, exchangeable sodium percentage (ESP) 48, and organic carbon 0.30%. There were six treatments consisting of control, recommended dose of gypsum (50% GR), and enriched and un-enriched MSW compost with reduced dose of gypsum (25% GR). Based on the results pertaining to plant growth, yield-attributing characters, and yields, the treatment T6 (application of microbial enriched MSW compost @ 10 t ha−1 in conjunction with gypsum @25% GR) performed the best. Grain yield of rice and wheat (5.45 and 3.92 t ha−1) with treatment T6 was 29.45% and 110.75% higher over control (T1) and 29.45% and 110.06% over the recommended dose of gypsum (T2). Maximum nutrient content and N, P, and K uptake in rice-wheat grain and straw was observed with the treatment T6 (MSW compost plus gypsum @ 25 GR). However, the highest Na content and Na: K ratio in plant parts were recorded in treatment T2. The highest positive net return and benefit to cost (B/C) ratio were observed in treatment T6 followed by T5 and the lowest in treatment T1 (control), whereas negative return was calculated in treatment of gypsum alone (T2). This shows that the cost of sodic soil reclamation with application of gypsum was not recovered until the second year of cultivation. The results of this study showed significant impacts in MSW management for regaining the productivity potential of sodic soils.

Coal mining, an important human activity, disturbs soil organic carbon (SOC) accumulation and decomposition, eventually affecting terrestrial carbon cycling and the sustainability of human society. However, changes of SOC content and their relation with influential factors in coal mining areas remained unclear. In the study, predictive models of SOC content were developed based on field sampling and Landsat images for different land-use types (grassland, forest, farmland, and bare land) of the largest coal mining area in China (i.e., Shendong). The established models were employed to estimate SOC content across the Shendong mining area during 1990–2020, followed by an investigation into the impacts of climate change and human disturbance on SOC content by a Geo-detector. Results showed that the models produced satisfactory results (R2 > 0.69, p < 0.05), demonstrating that SOC content over a large coal mining area can be effectively assessed using remote sensing techniques. Results revealed that average SOC content in the study area rose from 5.67 gC·kg−1 in 1990 to 9.23 gC·kg−1 in 2010 and then declined to 5.31 gC·Kg−1 in 2020. This could be attributed to the interaction between the disturbance of soil caused by coal mining and the improvement of eco-environment by land reclamation. Spatially, the SOC content of farmland was the highest, followed by grassland, and that of bare land was the lowest. SOC accumulation was inhibited by coal mining activities, with the effect of high-intensity mining being lower than that of moderate- and low-intensity mining activities. Land use was found to be the strongest individual influencing factor for SOC content changes, while the interaction between vegetation coverage and precipitation exerted the most significant influence on the variability of SOC content. Furthermore, the influence of mining intensity combined with precipitation was 10 times higher than that of mining intensity alone.

Soil erosion causes land degradation which negatively impacts not only natural resources but also livelihoods of people due to low agricultural productivity. Cambodia is prone to soil erosion due to poor agricultural practices. In this research we use Battambang province as a case study to quantify impact of land use and land cover change (LULC) on soil erosion. This study assessed the impact from LULC changes to soil erosion. LULC change maps were analyzed based on Landsat satellite imagery of 1998, 2008, and 2018, computed in QGIS 6.2.9, while the soil erosion loss was estimated by the integration of remote sensing, GIS tools, and Revised Universal Soil Loss Equation (RUSLE) model. The results showed that the area of agricultural land of Battambang province significantly increased from 44.50% in 1998 to 61.11% in 2008 and 68.40% in 2018. The forest cover significantly decreased from 29.82% in 1998 to 6.18% in 2018. Various soil erosion factors were estimated using LULC and slope. Based on that, the mean soil loss was 2.92 t/ha.yr in 1998, 4.20 t/ha.yr in 2008, and 4.98 t/ha.yr in 2018. Whereas the total annual soil loss was 3.49 million tons in 1998, 5.03 million tons in 2008, and 5.93 million tons in 2018. The annual soil loss at the agricultural land dramatically increased from 190,9347.9 tons (54%) in 1998 to 3,543,659 tons (70.43%) in 2008 and to 4,267,439 tons (71.91%) in 2018 due to agricultural land expansion and agricultural practices. These losses were directly correlated with LULC, especially agricultural land expansion and forest cover decline. Our results highlight the need to develop appropriate land use and crop management practices to decrease land degradation and soil erosion. These data are useful to bring about public awareness of land degradation and alert local citizens, researchers, policy makers, and actors towards land rehabilitation to bring the area of land back to a state which is safe for increasing biodiversity and agricultural productivity. Measures to reduce or prevent soil erosion and the use of conservation agriculture practices, along with water and soil conservation, management, agroforestry practices, vegetation cover restoration, the creation of slope terraces, and the use of direct sowing mulch-based cropping systems should be considered.

An understanding of changes in forest cover and the drivers of forest transition (FT) contributes to the sustainable management of global forests. In this paper, we used the latest global land cover data published by the European Space Agency (ESA) to investigate spatiotemporal variation characteristics of forest cover in developing countries from 1992 to 2015, and then analyzed causal factors of this variation using a binary logistic regression model. Existing studies on FT are mostly based on data from the Food and Agriculture Organization (FAO); this study improves our understanding of FT mechanisms through the use of a new dataset. The results indicate that the forest area in developing countries decreased from 21.8 to 21.3 million km2 from 1992–2015, and the rate of decline slowed after 2004. South America suffered the largest reduction in forest area (505,100 km2), whereas forest area in Africa increased slightly. By 2015, more than 80% of African countries had experienced FT, whereas only half of developing countries experienced forest expansion in South America. The variables affecting FT occurrence differed among continents. On the global scale, the remaining forest coverage and the proportion of forest exports negatively affected the likelihood of FT occurrence, whereas urbanization level had a positive effect.

The effect of soil amendment with biochar has been widely evaluated for its effects in mitigating greenhouse gas emissions (GHG) and remediating polluted soils with metals; however, a synergic understanding of the system, including biochar, soil, and microbial activity, is lacking. In this study, a meta-analysis of 854 paired data from 73 studies demonstrate that biochar application in soil affects GHG emissions and soil metal availability. First, several properties of biochar, soil, and microbial activity were considered as parameters in the meta-analysis. Then, the size effect was evaluated using the percentage of change (Pc) as obtained by the meta-analyzed data. Several parameters were related as influencer factors in GHG emissions and soil metal availability. Notably, biochar addition in soil resulted in a significant CO2 increase in emissions, whereas N2O emissions decreased; these results were directly correlated with microbial activity. Although this trend, demonstrated by the data analysis, differs from results of other studies found in the literature, it also emphasized the need for a deep understanding of the effect of biochar addition to soil (properties, nutrients, gas exchange, etc.) and to microorganisms (activity, diversity, etc.). Furthermore, it was also proved, that soil metal concentration decreases significantly when biochar was added (Cd > Zn > Pb > Cu > Fe). According to the results, biochar addition in soils contaminated with Cd and Cu was related to an increase in the microbial activity; while, soils amended with biochar but polluted with Pb, Zn, and Fe presented a higher inhibition effect on microorganisms. To improve the interpretation of soil amendment with biochar, it would be necessary to standardize the form for reporting results, particularly of the microbial activity and GHG emissions, in order to be used for future comparative studies.