1. General Model Information
Name: SOS - Spreadsheet Oriented Simulation.
Main medium: terrestrial
Main subject: biogeochemistry, agriculture
Organization level: ecosystem, biocoenosis
Type of model: compartment model, ordinary differential equations
Keywords: crop science, soil science, environmental science
MSci H.T.C. Simota.
Research Institute of Soil Science and Agro-chemistry (RISSA), Dept. of Soil Physics, Blvd. Marasti 61, R-71331 Bucharest, ROMANIA.
The SOS model is designated for calculating the effect of soil water balance on agricultural production potential for selected crop-soil-climate combinations. SOS consists in a number of macro-functions developed under a spreadsheet environment. The production system is defined by crop species, soil type, hydrologic conditions and weather during the growing season. The user has two choices selecting the algorithms for the estimation of the water balance elements significant for crop studies, depending on the quality and the amount of available input data. The first one uses monthly values of rainfall and precipitation and a soil profile having one (averaged) layer. The other one is based on the travel time approach using daily weather data and a layered soil profile. The model has the ability to deal with various crop rotations, including fallow. As optional tools are included a weather daily data generator (using monthly averages of air temperature and precipitation) and an algorithm for the evaluation of the pedotransfer functions using soil data obtained in simple soil survey studies (texture, bulk density, organic carbon). The effects of the land slope and exposition on the ground level solar radiation are included in the weather data generator.
Purpose of the model:
Model parentage: The algorithm for water balance elements dynamics on a monthly base was developed by Thornthwaite, C.W., & J.R.Mather. 1957. Instructions and tables for computing potential evapotranspiration and the water balance. Drexel Institute of Technology. Publications in Climatology, X(3), Centerton, New Jersey. SOS uses for crop development algorithms from EPIC*, SWATRE and BACROS* models.
Source of the AbstractCAMASE Register of Agro-ecosystems Models
II. Technical Information
Operating System(s): IBM-PC compatible with a 486 processor or better and 8 Mb RAM. Math co-processor is highly recommended.
Costs: : No.
Programming Language(s): Microsoft VisualBasic under Excel 5.0 environment.
III. Mathematical Information
Rate variables: Net solar radiation, potential/actual evaporation and transpiration, actual infiltration rate, runoff, water fluxes between soil layers, soil water root sink rate, drainage.
State variables: Air temperature, soil water content, dry matter (total and per plant organ), water use efficiency.
Soil physical properties per layer, standard meteorological variables, initial soil water content, crop type and cultivar, sawing date and depth. Input check in model: Yes.
Soil water profile dynamics, biomass per plant organs, crop yield, root system development, water balance elements (evaporation, transpiration, drainage, runoff), number of workable days.
Basic spatial unit: Ha.
Time interval of simulation: 1 Month or 1 day depending on the input data quality.
V. Further information in the World-Wide-Web
VI. Additional remarks
Parentage: The algorithm for water balance elements dynamics on a monthly base was developed by Thornthwaite, C.W., & J.R.Mather. 1957. Instructions and tables for computing potential evapotranspiration and the water balance. Drexel Institute of Technology. Publications in Climatology, X(3), Centerton, New Jersey. SOS uses for crop development algorithms from EPIC*, SWATRE and BACROS* models.
Last review of this document by: T. Gabele: Dec 17 1997
Status of the document:
last modified by
Joachim Benz Mon Jul 2 18:31:37 CEST 2007