The Soil as a Reactor PDF Download

Author: Jörg Richter
Publisher:
ISBN:
Category : Soil chemistry
Languages : en
Pages : 210

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Book Description
The approach followed in this book. Statics and kinetics. Dynamic approach. Balance approach. The system in thermodynamics. Fundamentals of the theory of potential. The macroscopic approach. Aggregation and buffering. The term "model". Classifying the processes in the soil. The organization of this book. Heat conduction in soils. Significance of heat dispersion in soils. Phenomena of heat dispersion. Examples of daily temperature courses in soils. Example of an annual course of the temperature. Heat conductivity and capacity in relation to soil composition and structure. Deriving the transport equation using local balance and principle of causality. Local balance for matter and energy without transformation. One-dimensional transport equation of matter and energy in a rigid system with continuous pores. The equation for heat transport. Analytical solutions of the heat transport equation with constant aT. The stationary case. Sudden change in temperature as boundary condition. Oscillating temperature as boundary condition. Numeriacal solution of the heat transport equation with constant aT. Heat balance of the soil and heat conversion. Estimating the soil-absorbed energy. Heat to evaporate 1 mm water. Gas regime of soils. The significance of the gas regime in the soil. Phenomena in soil gas regime. Profiles of CO2 and O2 concentrations in the soil. Cycles and depth profiles of CO2 production. Parameters of the gas regime in soils. The apparent diffusion coefficient Ds. The storage of gases in the soil. Quantitative description of the gas regime in soils. Extending the transport equation. Partial pressure and diffusive gas transport. Solving the equation of gas regime. An analytical solution for the stationary case. Numerical solution for a stationary example. Applications of the gas transport and gas regime equation. The measurement of the diffusion coeficient Ds. The "tortuous" macropore as a structure model. Vapour flow in the soil. Micro-anoxia as a problem of aeration, and the redoxpotencial Eh. Soil water regime. The significance of soil water; annual balances. Phenomena of soil water flow. Water tension and water content profiles in the soil. Flows at the boundary area and in the soil. Hydraulic conductivity and the moisture retention curve. The hydraulic conductivity K( m). The moisture retention curve m(0). The water regime equation. The local water balance. The equation for the water flow qw. The hydraulic potential h. Different formulations of the water transport equation. Characteristic flow conditions of water in the bare soil. Equilibrium and quasi-equilibrium. Stationary and quasi-stationary conditions. Non-stationary flow. Applications and numerical solutions for the water regime equation. Moisture equilibrium in the soil. stationary flow in the soil during drying in summer. Solution methods for non-stationary flow. Simple water regime models for the flat, homogeneous cropped soil; the root uptake function P(z,t). Calculating the evapotranspiration E. The water regime of a wheat field on a loess-Parabraunerde. Regime of matter in soils. Significance of "matter" in the soil. Extension of the transport the transport models. Phenomena of ion flows. Movement of non-interacting ions during winter. Movement of interacting ions during winter. Paramenters of solute transport. Transport parameter: effective dispersion coefficient Db. Quantity/intensity relation for compenents that do interact with the soil matrix; the specific storage capacity B. Specific storage capacity C (and the diffusion coefficient D). Coupled transport flows of components that do not interact with the soil matrix. General description of coupled transport. Transport of dissolved non-interacting components in the soil. Particle charge. Introduction to reaction dynamics. Fundamentals of the course of reactions. Order of elementary reactions in homogeneous systems. A special case: second-order reactions of sigmoidal shape. Complex reactions in homogeneous systems. Heterogeneous reactions (interactions with the surfaces of solids). Models for reactive components and ions in the soil. Dynamic description of interactions of substances with the solid phase. Description of interactions of ions with charged surfaces of the solid phase (ions-exchange). Simple regime models of substances in the soil. Models for nitrification and simultaneous movement of nitrogen. Simulating the nitrogen regime of loess field soils during winter. A site model for the displacement of physically interacting ions for the example potassium. Simulating the degradation of herbicides in soils. Simulating the behaviour of heavy metals in the soil. "Complete"models of material components regime. Looking ahead. Beyond the assumptions. The soil as a non-rigid solid. Mechanical deformations and changes of the state of stress. Mechanical cause-and-effect relations. Changes of the parameters with mechanical deformations. The explicit modelling of nutrient uptake by plants. Field and regional models. Simulating solute transport in heterogeneous pore systems. Geostatistical formulation of spatial variability. Combining deterministic and stochastic approaches: Monte-Carlo simulation of salt transport. Alternative approaches: plate and compartment models. Modelling soil development. Appendix. Numerical solutions for non-stationary water transport and for solute transport under stationary flow conditions. Vertical solute movement under stationary flow conditions. Vertical water transport. Difference formulationwith the help of the Taylor equation. Gas solubilities in water. Conversion of units. List of symbols and indices.