1. General Model Information

Name: ROOTSIM2D: A Two-Dimesional Root Growth Model for Corn

Acronym: ROOTSIM2D


Main medium: terrestrial
Main subject: hydrology, agriculture
Organization level: Ecosystem
Type of model: partial differential equations (finite elements,2D), ordinary differential equations
Main application:
Keywords: root growth, corn, maize, zea mays, soil water flow, solute transport, richard's equation, convection-dispersion equation

Contact:

Laj Ahuja

USDA-ARS, Great Plains Systems Research Unit
P.O. Box E, 301 S. Howes
Fort Collins, CO 80522

phone:
fax:
email: ahuja@gpsr.colostate.edu

http://www.gpsr.colostate.edu/GPSR/

Author(s):

Joe Benjamin and Laj Ahuja

Abstract:

Purpose

A two-dimensional model of corn root growth has been developed and linked to a two-dimensional model for water, heat and solute transport in soils. Th purpose of this model is to research how different management practices influence root growth and utilization of water and nitrogen from different parts of the root zone. This knowledge is then used to identify practices that help the most efficient use of water and nitrogen and minimize leaching below the root zone. The model may also be used by plant breeders to screen new varieties for their root growth.

Scientific Details

Our intermpretation of photographs and line drawings of corn root systems during the growing season was that, as the root system develops, there is a change from a primarily horizontal growth direction early in the life cycle to a primarily vertical growth direction for later stages in the life cycle. We generalized these data to delineate a region to the legft and right, as viewed along the center of the plant row, and downward in which root growth and downward in which root growth may potentially occur. The size of the region is defined by the growth area is defined by the extension rate of the root system and the growth angle from the horizontal. The horizontal extension of the root region is assumed to progress by the extension rate times the cosine of the growth. The vertical extension of the root region is assumed to progress by the extension rate times the sine of the growth angle. The values of these coefficients are dependent upon the corn hybrid and the age of the plant. The increase of root density for a given position in the root zone follows a first-order dynamics; it is proportional to existing density. The decrease in root density due to root death is proportional to the square of the existing density. The net change of density is the difference between the two. The proportionality constants are a function of growth stage. Suboptimal environmental conditions of soil temperature, bulk density and water content influence root growth.

Source: Rootsim2D Home


II. Technical Information

II.1 Executables:

Operating System(s):

II.2 Source-code:

Programming Language(s):

II.3 Manuals:



II.4 Data:



III. Mathematical Information


III.1 Mathematics


III.2 Quantities


III.2.1 Input

III.2.2 Output


IV. References

Benjamin, J.G., L.R. Ahuja, and R.R. Allmaras. 1996. Modeling corn rooting patterns and theireffects on water uptake and nitrate leaching. Plant and Soil, 179:223-232.
Benjamin, J.G., L. R. Ahuja, L. K. Porter, and H.R. Duke. 1996. Nitrogen leaching with alternateand every furrow irrigation and fertilizer bands. Agronomy Abstracts, p. 277.



V. Further information in the World-Wide-Web


VI. Additional remarks


Last review of this document by: T. Gabele June 2001
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:48 CEST 2002

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