DRYADS and DIFMAS, FORTRAN models for investigating solute uptake and incorporation into vegetation and litter. Environmental Sciences Division publication No. 921
The concepts and FORTRAN algorithms of a model describing solute movement from bulk soil solution into roots (DIFMAS) and a model of solute dynamics and accumulation in plant tissues and litter (DRYADS) are presented. Foliar uptake of solutes and gases are included in the DRYADS code. These models form components in a coupled system of models having hourly resolution of carbon, water, and solute dynamics in terrestrial ecosystems. The input data requirements of the solute models and the methods of coupling these codes with the other component models are given in detail as a guide to users. Applications showing successive hourly, monthly, and annual results illustrate the utility of the models. The DRYADS model sensitivity to both leaf solute permeability and root solute conductivity parameters suggest the importance of careful experimental determination of these plant properties. The tissues of solute entry (leaves, roots) initially accumulate solutes in a fixed form in preference to the more remote tissues (stems, fruits). Model application results suggest that root sapwood is the first major site of trace contaminant accumulation from soil borne pollutants. The algorithms describing solute movement along a concentration gradient in phloem and as mass flow in the xylem transpiration stream result in high mobility of solutes in vegetation. The simulated diurnal pattern of rootsolute uptake showed that more than 85% of solutes are taken up during the daylight hours. The simulations further showed that contaminants had the greatest effect on the litter system. Toxic effects of contaminants on decomposition resulted in lower mineralization losses and higher accumulations of contaminant in litter with continuing deposition.
- Research Organization:
- Oak Ridge National Lab., Tenn. (USA)
- DOE Contract Number:
- W-7405-ENG-26; NSF-INA-AG-389
- OSTI ID:
- 7338298
- Report Number(s):
- ORNL/NSF/EATC-26
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
COMPUTER CODES
D CODES
PLANT TISSUES
METABOLISM
PERMEABILITY
PLANTS
POLLUTION
MATHEMATICAL MODELS
UPTAKE
ALGORITHMS
DAILY VARIATIONS
FORTRAN
GASES
LEAVES
ROOTS
TERRESTRIAL ECOSYSTEMS
BIOMASS
ECOSYSTEMS
ENERGY SOURCES
FLUIDS
MATHEMATICAL LOGIC
PROGRAMMING LANGUAGES
RENEWABLE ENERGY SOURCES
VARIATIONS
550500* - Metabolism
510200 - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)