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Biochar effects on nitrous oxide and methane emissions from soil
Published in Johannes Lehmann, Stephen Joseph, Biochar for Environmental Management, 2015
Lukas Van Zwieten, Claudia Kammann, Maria Luz Cayuela, Bhupinder Pal Singh, Stephen Joseph, Stephen Kimber, Scott Donne, Tim Clough, Kurt A. Spokas
The biotic and abiotic mechanisms responsible for biochar induced mitigation of soil N2O emissions remain elusive (Van Zwieten et al, 2009; Cayuela et al, 2013; Clough et al, 2013). These mechanisms will most likely be a function of both the biochar and soil properties and their interaction. Biochar application in soil may affect N2O emissions by changing: (i) soil physical properties (e.g. gas diffusivity, aggregation, water retention) (Quin et al, 2014); (ii) soil chemical properties (e.g. pH, Eh, availability of organic and mineral N and dissolved organic C, organo-mineral interactions); and (iii) soil biological properties (e.g. microbial community structure, microbial biomass and activity, macrofauna activity, N cycling enzymes) (Cayuela et al, 2013; Harter et al, 2013; Van Zwieten et al, 2014). Such changes in soil properties could influence N mineralization-immobilization, turnover and nitrification or denitrification processes in the soil. Many of these potential effects on soil properties may relate to the chemical composition of biochar (low molecular weight organic compounds, aliphatic to aromatic C ratio, intrinsic N content and form, ash content, acid neutralizing capacity) and physical characteristics (specific surface area, sorption properties, particle size). Over time, the developing negative charge on biochar surfaces (Cheng et al, 2006) and subsequent interactions with native organic matter and clay minerals (Joseph et al, 2010; Lin et al, 2012a; Fang et al, 2014a, b) may further contribute to the mitigation of soil N2O emissions.
On the stability of unsaturated soil slopes
Published in H. Rahardjo, D.G. Toll, E.C. Leong, Unsaturated Soils for Asia, 2020
The energy status of pore water is described by making use of the concept of soil water potential in soil physics or soil thermodynamics. Precise definitions of total potential and its various component potentials were provided by the International Soil Science Society (ISSS) in 1963 and slightly modified in 1976. Total potential of soil water can be divided into three components: ψt=ψp+ψg+ψo
Nitrates in groundwater in the southeastern USA
Published in Domy C. Adriano, Alex K. Iskandar, Ishwar P. Murarka, Contamination of Groundwaters, 2020
Transport of NO3-N vertically through soil and subsoil materials depends on water movement. Soil physical properties such as particle size distribution and porosity largely control water movement rates. Preferential flow through macropores may also greatly influence the rate and extent to which NO3-N moves to groundwater. More research is needed on water and solute transport pathways through the root zone and vadose zone of southeastern soils. Better understanding of water movement both at the local and regional scale will aid in devising management strategies which protect groundwater quality.
Effects of Crude Oil on Geotechnical Specification of Sandy Soils
Published in Soil and Sediment Contamination: An International Journal, 2021
Mojtaba Ostovar, Reza Ghiassi, Mohammad Javad Mehdizadeh, Nader Shariatmadari
The soil structure consists of soil physical texture and interaction forces between particle and pore fluid. The mechanical forces are affected by the shape of the particles and the manner of placement, as well as the nature of the particles of the soil. In this regard, the characteristics of the pore fluid that surrounds the particles of the soil can contribute to the shear strength of the soil. The physicochemical effects in fine-grained soils, affected by the kind of minerals that form the soil particles, and the electrochemical interaction of these minerals with the particle-surrounding pore fluid, forms the double-layer (Ratnaweera and Meegoda 2006).
Energy budgeting and productivity response of cotton-wheat cropping system to mechanical sub-soiling
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Harjeet Singh Brar, Manpreet Singh
Soil compaction from heavy field traffic is a well-known problem worldwide (Naderi-Boldaji et al. 2018), which deteriorates soil physical conditions by increasing sub-soil bulk density, reducing soil porosity, decreasing water infiltration rate and lesser nutrient availability (Jin et al. 2007), which ultimately reduce crop root growth, crop productivity and profitability (Medvedev 2009). Sub-soiling/deep tillage can overcome these ill effects of soil compaction by loosening the soil and breaking the hardpan below the plow layer (Jin et al. 2007). This operation may increase energy consumption due to its high energy requirement.