RZWQM2 is an enhancement of the Root Zone Water Quality Model (RZWQM), created on users' requests. Main components of the model were extensively validated and improved, and several new components added. As a result, RZWQM2 is an advanced, but practical, model of root zone processes that influence water quality, soil water storage, efficient water use, and crop production. It is unique in its major emphasis on simulating the effects of major agricultural management practices on physical, chemical and biological system processes; plant growth and development; and, the movement of water, nutrients, and pesticides to runoff and through the crop-root zone to shallow groundwater. The model allows simulation and evaluation of a wide spectrum of management practices, such as no-tillage and residue cover vs. conventional tillage; rates, methods, and timings of application of water, fertilizers, manures, and various pesticides; and different crop rotations. The model contains the special features of tile drainage and rapid transport of surface-applied chemicals through soil macropores to deeper depths, groundwater and tile flow. The benefits of RZWQM2 are that this provides a comprehensive whole-system approach to evaluate management effects on water (& soil) quality and crop production, compared with simpler models that look at potential leaching of chemicals in isolation.
The model requires daily weather data (maximum and minimum daily temperature, solar radiation, wind speed, relative humidity, and rainfall), soil texture, soil bulk density, soil hydraulic properties (if known), and recorded management practices. It runs on a daily time step with exception of water and chemical movement that is on a sub-hourly time step. RZWQM2 is a one-dimensional model with a pseudo 2-dimensional drainage flow and water table fluctuation.
RZWQM2 versions are delivered through the web, http://arsagsoftware.ars.usda.gov/ . It has been transferred to users through personal discussions, training sessions, and collaborative testing/applications; The science in the model is documented in a book, which can be purchased at http://www.wrpllc.com/books/rzwqm.html
RZWQM2 has all the following features:
1. State-of-the-science simulation of management effects on plant-soil systems;
2. Simulation of a tile drainage system and water table fluctuation;
3. Simulation of macropore/preferential flow in soils;
4. Option to use a generic plant growth model, quick plant modules or DSSAT4.0 crop models;
5. Capability of simulating surface energy balance and its effects on the plant-soil systems;
6. Extended soil profile simulation to 30 meters;
8. User friendly Windows Interface to facilitate input/output management for model parameterization;
9. Built-in database for soil, plant, pesticides, and weather generator inputs;
10. Rule-based implementations of management practices;
11. On-line help system and Documentation Directory with User Guide and supporting pdf?s to guide model parameterization.
RZWQM2 is a one-dimensional model designed for a uniform soil and management.
Technical Support Contact: RZWQMSupport@ars.usda.gov
For more information, visit this page.
Operating System: Windows 98 and later.