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Biofuel production from algal biomass
Published in Ozcan Konur, Bioenergy and Biofuels, 2017
Jonah Teo Teck Chye, Lau Yien Jun, Lau Sie Yon, Sharadwata Pan, Michael K. Danquah
The first generation of biofuels, such as bioethanol, biobutanol, and biodiesels, is usually produced using edible, conventional crops (Ullah et al., 2015). They may be produced either by utilizing feedstock via starch fermentation of crops such as wheat, barley, potato, corn, sugar beet, and sugarcane (mostly used), or chemically by using rapeseed, sunflower, soybeans, palm, coconut, and animal fats as feedstocks (Lee and Lavoie, 2013; Maity et al., 2014). The important characteristics of first-generation biofuels include their ability to be blended with petroleum-based fuels and their efficiency in internal combustion engines, as well as the compatibility with flexible fuel vehicles (FFVs). However, the principal disadvantage of using food-based crops as feedstock is the concomitant increase in food prices due to the concealed crisis of food shortage (Naik et al., 2010). Additionally, the crop feedstock requires large agricultural areas to produce sufficient quantities of biomass, which invites competition between food and biofuel production. In terms of environmental issues, this increased agriculture yield and subsequent harvesting may lead to enhanced land clearing, loss in biodiversity due to habitat destruction, water depletion, and air pollution (Brennan and Owende, 2010).
Carbon: Soil Inorganic
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Global Resources and Universal Processes, 2020
Land clearing generally results in increased water runoff and soil erosion. This process or any other process such as tillage that increases erosion serves to remove the surface soil horizons. Since these horizons are generally depleted in IC relative to less weathered, deeper horizons, erosion causes an apparent increase in the IC content of the top 1–2 m of carbonate-containing soils. This may result in erroneous estimates of changes in soil IC when comparing the top 1 m of disturbed vs. native vegetation sites. In terms of carbonate dissolution, the impact of land clearing is not certain. After clearing, there is increased runoff, thus decreased surface infiltration, favoring less dissolution of carbonates from the surface horizons. This effect may be compensated by the decreased water consumption (lower evapotranspiration) after clearing, resulting in increased deep recharge and possibly greater carbonate dissolution or less reprecipitation at depth, depending on the volumes of water. Depending on how much biomass remains after clearing, there is likely a short-term increase in soil CO2 followed by a longer-term reduction, favoring less carbonate dissolution in the soil.
Groundwater regulation in case of overdraft: national groundwater policy implementation in north-west China
Published in International Journal of Water Resources Development, 2019
Eefje Aarnoudse, Bettina Bluemling, Wei Qu, Thomas Herzfeld
Irrigated agriculture on the alluvial plains of the Hei River basin is mainly located at the river’s middle reaches, which belong to three different counties of Zhangye Prefecture. Here, groundwater use for irrigation intensified only recently. In 2002, the central government launched a pilot project in Zhangye to promote water saving. The associated policy measures focused primarily on reducing farmers’ surface water use and triggered intensified groundwater use (Zhang, Zhang, Zhang, & Wang, 2009). Zhangye counted around 4,500 groundwater wells for irrigation in 2002 (Zhang & Zhang, 2008). Reliable figures on the current number of groundwater wells and estimates on the amount of groundwater pumped are not publicly available (staff water management H1). Village heads reported between 30 to 70 wells per village in the more downstream areas. All reported wells were drilled in the 1990s and 2000s by farmers. Despite spatially heterogeneous groundwater level developments, the groundwater level dropped continuously at the outer edges of the Zhangye sub-basin by 0.1–0.5 m/y from 1986 to 2007 (Nian, Li, Zhou, & Hu, 2014). Recently Zhangye is increasingly facing severe sand storms and desertification, which is associated with (among other things) land clearing for agriculture, often enabled by groundwater pumping (Luo, Qi, & Xiao, 2005; Nian et al., 2014).
Quantitative analysis of soil erosion causative factors for susceptibility assessment in a complex watershed
Published in Cogent Engineering, 2019
Taofeeq Sholagberu Abdulkadir, Raza Ul Mustafa Muhammad, Khamaruzaman Wan Yusof, Mustafa Hashim Ahmad, Saheed Adeniyi Aremu, Adel Gohari, Abdurrasheed S Abdurrasheed
In Cameron Highlands Malaysia, soil erosion is a serious environmental challenge due to extensive urban development, intensive agricultural activities, massive land clearing and indiscriminate deforestation. Some of the challenges currently experienced are deteriorating water quality, reservoir sedimentation, landslides, etc. Increasing human-environment interactions coupled with natural topography have increased the ecological disturbances. Sustainable management practices that will dampen these challenges include quantification of erosion, analysing its spatial distribution, identifying critical locations and evaluating its susceptibility. Susceptibility mapping measures the relative probability of erosion occurrence at a certain location compared to others under the influence of causative factors (CFs). Previous studies showed a lack of specific guidelines in selecting CFs for adequate susceptibility analysis. Thus, some crucial dynamic CFs are often not considered. This study quantitatively evaluates the impacts of the addition of dynamic CFs to frequently used non-redundant CFs for accurate susceptibility mapping using remote sensing, geographic information system and statistical techniques.
Reducing the ecological footprint of urban cars
Published in International Journal of Sustainable Transportation, 2018
Bonnie McBain, Manfred Lenzen, Glenn Albrecht, Mathis Wackernagel
The modeling of the global urban car transport sector that we describe here is set in the context of a larger global Ecological Footprint model that is outlined in more detail in McBain et al. (2017) and Lenzen et al. (2013). The key groups of variables that inform the Ecological Footprint and Biocapacity in the larger model are land use (built, cropping, grazing, plantation, and forest), agricultural productivity (in response to land degradation, technological change, and climate change), and climate change (the net emissions produced from the stationary energy sector, the transport sector, agricultural emissions, land clearing, and forest sequestration).