Models & Applications
The main reason for doing a soil survey is to solve soil management problems. This page contains links to applied soil science, where the soil characteristics that we map in a soil survey are used in predictive models
This model is based on the Morgan concept of modelling the detachment and transport phases separately, and then computing erosion on the basis of the most limiting of these. It simulates erosion on an event basis for fields and small catchments. It uses physical descriptions to describe the process of soil erosion and is fully dynamic. This is a good compromise between overly-empirical models (e.g. RUSLE) and models that attempt too fine a level of process description (e.g. WEPP).
"WEPP is a process-based, distributed parameter, continuous simulation, erosion prediction model for use on personal computers. [It] is applicable to hillslope erosion processes (sheet and rill erosion), as well as simulation of the hydrologic and erosion processes on small watersheds."
The site includes extensive model documentation.
RUSLE is widely-used in the USA, where careful calibration has been
done on soil series, phases, conservation and management practices,
and land uses. It suffers from the fundamental defect of being a
multiplicative model, so any error in parameter estimation is
amplified in the predictions.
From this site you can download the program and documentation. It also includes a slide presentation explaining the model's assumptions.
AGNPS is a tool for evaluating the effect of management decisions affecting a watershed", widely-used in the USA. It accounts for fertilization and animal waste management practices, and predicts water quality at each point in a small watershed.
EPIC is widely used in the USA for conservation planning, mainly at the farm and field level. It includes a generic crop model, water balance, erosion, and nutrient budgets. The Agricultural Policy/Environmental eXtender (APEX) Model extends this to whole farms and watersheds.
"Given hillslope segment lengths, slopes, percent canopy cover, percent surface ground cover, runoff volume, and a soil erodibility value, the model will simulate erosion process along the hillslope and will return runoff volume, sediment yield, interrill detachment, rill detachment, rill deposition, and the mean concentration of sediment in the flow for each hillslope segment."
This page includes the technical papers which explain the algorithm.
Simulates the daily growth of a specific crop, given the selected weather and soil data It is a member of the family of models developed by the Department of Theoretical Production Ecology of the Wageningen Agricultural University (NL); one of the Alterra (Wageningen) models
ECOCROP is mainly concerned with climatic adaptability of plant species, but has some simple soil requirements also.
Ecocrop 1 is a tool to identify plant species for given environments
and uses. The database contains basic crop environmental information
and permits the identification of more than 1700 plant species of
economic importance whose most important climate and soil
requirements match the data on soil and climate entered by the user.
Ecocrop 2 is a tool to record, organize, compare and use crop response studies to environmental and management factors. The database holds crop response information of varieties of 20 crops of world wide economic importance
At this site you can run ECOCROP over the web.
"Simulation model for the soil-water-atmosphere-plant system. The model simulates vertical transport of water, solutes and heat in both the unsaturated and saturated zones. It is designed to simulate the transport processes on the field scale during the entire growing season"; contains a simplified WOFOST; one of the Alterra (Wageningen) models
"a microcomputer software program combining
crop soil and weather data bases and programs to manage them, with crop
models and application programs, to simulate multi-year outcomes of
crop management strategies."
This has had a long life, in its current form it is a project of International Consortium for Agricultural Systems Applications (ICASA): "ICASA's goal is to advance national and international agricultural systems research through the development and application of compatible and complimentary systems analysis tools and methodologies". But it all goes back to CERES-MAIZE... and they still use FORTRAN... (albeit in the FORTRAN Simulation Enviroinment)
This model is a didactic version of the WOFOST crop model, and is especially intended to give insight into dynamic simulation modelling. It can be run in Production Situation 1 (only light and temperature limited) or 2 (also water limited).
Soil degradation is one aspect of land degradation, defined as the loss of function.
A first (1987-1990), rough, inventory of this global problem; produced a 1:10 M map and groundbreaking report classifying land degradation.
Includes an explanation of what exactly do we understand by the term Soil Quality, how to assess a soil's quality according to this definition, how to manage soils for good quality.
A research theme of the Macaulay Land Use Research Institute, Aberdeen, Scotland
From New South Wales (Australia) Agriculture's Advice and topics in soil health.
This is a Windows '95 program which uses a decision tree to
describe a site. Comprehensive on-line help is available to assist
in the site description, and also to explain why the selected site
characteristics are important for determining the probability of Acid
Sulphate Soils being present, or potentially present.
From the irrepresssible team of David Dent (formerly of East Anglia and now at ISRIC) and Bryan Dawson (Loughborough), UK.
Proceedings of a 1997 workshop.
The soil acts as buffer and filter for agro-chemicals and wastes. Many properties of the soil affect this function.
One of the "themes" of the EEA. Includes reports on environmental problems related to soils in Europe, including the reports:
Advisory bulletin with interpretive tables, from the Organic Waste Recycling Unit of New South Wales (Australia) Agriculture.
"GLEAMS (Groundwater Loading Effects of Agricultural Management Systems) was developed to simulate edge-of-field and bottom-of-root-zone loadings of water, sediment, pesticides, and plant nutrients from the complex climate-soil-management interactions."
from Per-Erik Jansson of the Royal Institute of Technology (KTH), Stockholm.
Sophisticated models mostly of soil physics and chemistry.
The soil serves as a foundation, as material for earth structures (dams, landfills),slopes and excavations, retaining structures, and as a medium for remediation of contaminated soil and groundwater. The use of soil for these purposes is called soil engineering.
Absolutely free high-quality introductory course, from the institute where Terzaghi worked.
"The NRCS National Engineering Handbook (NEH) is intended primarily for Natural Resources Conservation Service (NRCS) engineers and technicians. It presents material needed to carry out NRCS responsibilities in natural resources conservation and flood prevention. Part 630, Hydrology, contains methods and examples for:
-- Studying the hydrology of watersheds
-- Solving special hydrologic problems that arise in planning watershed protection and flood prevention projects
-- Preparing working tools needed to plan or design structures for water use, control, and disposal
-- Training personnel newly assigned to activities that include hydrologic studies"
Soils are both affected by, and can affect, global change; their properties are often taken as `early warning' systems.
Explains how to interpret the Digital Soil Map of the World
WOCAT collects, analyses and distributes knowledge about proven and promising Soil and Water Conservation (SWC) practices. The site includes databases and empty databases (for users to contribute); also a world map of WOCAT activities
Detailed description of soil and water conservation practices in the USA
Soil conservation as an integrated part of land use strategy.
These models treat the soil as a porous medium.
A large number of models, mostly public-domain, for water and solutes.
A Microsoft Windows-based modeling environment for analysis of water flow and solute transport in variably saturated porous media (such as soils) in one (vertical) dimension; one of the most popular codes. Free, with an extensive manual; supported by workshops.
"[A] Microsoft Windows based modeling environment for analysis of water flow and solute transport in variably saturated porous media... includes the two-dimensional finite element model HYDRUS2 for simulating the movement of water, heat, and multiple solutes in variably saturated media. The model includes a parameter optimization algorithm for inverse estimation of a variety of soil hydraulic and/or solute transport parameters. The model is supported by an interactive graphics-based interface for data-preprocessing, generation of a structured mesh, and graphic presentation of the results"
Provides reviews and links to a large number of groundwater models, including HYDRUS-2D and MODFLOW.
On-line (and downloadable) calculator from soil texture to hydraulic properties: wilting point, field capacity, bulk density, AWC; from K Saxton at Washington State University. Also includes full-text article explaining the methodology. Warning! use this and all pedo-transfer functions with caution!
More from the Wösten and Lilly team, based on Staringreeks.
These models treat the soil as part of a catchment (watershed) system.
Includes the WMS (Watershed Modeling System) comprehensive hydrologic analysis modeling environment supporting HEC-1, HEC-HMS, TR-20, TR-55, Rational Method, HSPF, and other hydrologic models.
A computer program for irrigation planning and management, from the FAO's Water Resources, Development and Management Service . Calculates reference evapotranspiration, water requirements, and crop irrigation requirements according to FAO Irrigation and drainage paper 56 .
"Hydrologists are often required to predict river flows, for example, when designing flood protection or river management schemes. Where historical records exist, flow indices can be calculated statistically but where there are none, or few records, other methods need to be used. The HOST classification makes use of the fact that the physical properties of soils have a major influence on catchment hydrology."
This methodology has been very successful in the UK, developed at
the Macaulay Institute in Aberdeen.. The basic idea is to re-interpret
existing soil surveys, to extract properties of the soils that are directly
useful in catchment hydrology.
Includes a nice
Scotland, with photos of landscapes and soils for each HOST
[Editorial comment: More work like this, and we'd have a lot less trouble selling the value of soil surveys to society.]
"The model simulates hydrologic, sedimentation, and nutrient and
pesticide transport in a large, complex rural watershed. The model
operates on a continuous time-scale and allows for subdivision of
basins to account for differences in soils, land use, rainfall, etc.
It can predict the effect of management decisions on water, sediment,
and pesticide yield with reasonable accuracy for ungaged rural basins
throughout the United States."
Developed by the Texas Agricultural Experiment Station and the USDA ARS.
"A repository of software and supporting documentation intended to improve the efficiency and standard of catchment modelling... to enable prediction of the multiple impacts of land and water management decisions at a whole-of-catchment scale."
From the CRC for Catchment Hydrology (Australis). Free. Based on the TIME modelling environment. Includes a soil hydrologic properties dataset.
Soil survey is often used to plan or orient land uses. Yet, what do we really mean by "land use"? Here you may find some answers.
From Kees de Bie of
ITC. Allows the user to store structured information on land uses
encountered in fieldwork, and retrieve it for land use classification.
[ed. comment: Since ITC no longer will host this material, we thank the Centre for Ecological Science, Indian Institute of Science for rescuing it and making it freely available.]
Search for models by name, tupe of application (agriculture, hydrology, ...), mathematical type, or keyword. Good description of each model, with links to its own webpage if possible. Includes soil erosion, soil hydrology, etc.
|Author: D G Rossiter||
|E-Mail: email@example.com||Last Updated: 2010_011|