1. General Model Information


Acronym: NCSWAP

Main medium: terrestrial
Main subject: biogeochemistry
Organization level: ecosystem
Type of model: compartment model
Main application:
Keywords: soil-crop-water biosystem, Nitrogen, ammonium, nitrate, soil transformation, decomposition,mineralization, immobilization, nitrification, denitrification


John A. E. Molina
Department of Soil, Water and Climate
439 Borlaug Hall, University of Minnesota
St Paul, MN 55108
Phone: 612-625-6259
Fax: 612-625-2208

J. A. E. Molina, D. R. Linden, R. Richards


J. A. E. Molina, D. R. Linden, R. Richards


NCSWAP is a simulation model of the soil-crop-water biosystem. The model integrates water flow dynamics crop growth, N and N transformations, tillage and residue effects, soil temperature, and solute transport. It can be used by researchers for prediction of nitrification and denitrification, N mineralization and immobilization, soil moisture, plant available NO3-N and NH4-N, N leaching, plant uptake of N and Water, crop yield, root growth, and N fertilizer dynamics.

NCSWAP uses the crop as a biological integrator of the exogenous (managerial and meteorological) and soil status variables. It compares crop yield from a reference yield which is modified to account for the influence of water, nitrogen, and temperature. The reference crop yield is defined as controllable inputs by the kinetics of plant mass growth and nitrogen percentage, for a given set of air temperatures and a specific field site. NCSWAP simulates water carbon and nitrogen dynamics in the soil profile through the concept of water, nitrogen, and temperature stress, expressed as reduction factor functions.

Author of the abstract:


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

Daily air min and max temperature; daily precipitation; daily

III.2.1 Input

Daily air min and max temperature; daily precipitation; dailyirrigation; weekly average soil temperature; weekly pan evaporation; soil bulk density; soilhydraulic conductivity at saturation; water content at field capacity, at saturation, and at waterstress point; initial content of nitrate-N and ammonium-N for each soil horizon; initial level andC/N ratio for pool I and II; nitrification rate; date and amount of inorganic and organic Napplications; tillage events; irrigations; parameters defining the mass increase and N percentageof the reference crop; days of planting, emergence, maturity, and harvest; plant population; rootgrowth and root mass partition in the soil profile; and dry matter shoot to root ratio. Dry mass, nitrogen accumulation, nitrogen management effects, nitrate-N

III.2.2 Output

Dry mass, nitrogen accumulation, nitrogen management effects, nitrate-Nconcentration in soil water for different application rates, computed net N mineralization of soilorganic matter, computed yield, cumulative nitrate leached, simulated N dynamics

Spatial Scale: Field: Site specific; does not integrate over landscape

IV. References

D. E. Clay, C. E. Clapp, D. R. Linden, and J. A. E. Molina.1985 Nitrogen-tillage-residue management: Observed and simulatedinteractions among soil depth, nitrogen mineralization, and corn yield. Plant and Soil 84: 67-77.
D. E. Clay, C. E. Clapp,J. A. E. Molina, and D. R. Linden. 1989 Nitrogen-tillage-residuemanagement: Simulating soil and plant behavior by the model NCSWAP.Soil Science Vol 147, No. 5, pp 319-325.
L. Grimm, J. A. E. Molina, C. Rosen, and S. Haiti. 1993 Simulation ofNitrogen and water dynamics in an irrigated potato field. Department of Soil Science, University of Minnesota, St. Paul, MN Soil Series 137
Lengnick, L.L, R.H. Fox. 1994 Simulation by NCSWAP of Seasonal Nitrogen Dynamics in Corn .1. Soil Nitrate. Agronomy Journal 86: 1, 167-175 Lengnick,L.L, R.H. Fox. 1994 Simulation by NCSWAP of Seasonal Nitrogen Dynamics in Corn .2. Corn Growth and Yield. Agronomy Journal 86: 1, 176-182
Jabro, J.D., J.M. Jemison, Jr., L.L. Lengnick, R.H. Fox, and D.D. Fritton. 1993. Fieldvalidation and comparison of LEACHM and NCSWAP models for predicting nitrateleaching. Transactions of the ASAE 36(6):1651-1657.

V. Further information in the World-Wide-Web

VI. Additional remarks

NCSWAP can be used to evaluate the soil-crop-water biosystem under avariety of different climate conditions and different crops.

Last review of this document by: John A. E. Molina and T. Gabele: 17. 09. 1997 -
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:46 CEST 2002

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