1. General Model Information
Name: RECAFS 1.0 - Modelling resource competition and cycling in agroforestry systems.
Main medium: terrestrial
Main subject: forestry, agriculture, hydrology
Organization level: ecosystem
Type of model: ordinary differential equations
Keywords: evapotranspiration, light interception, light consumtion, nitrogen consumtion, trees, planting pattern, Penman-Monteith equation, herbage growth
Ir. J.G. Conijn.
Research Institute for Agrobiology and Soil Fertility (AB-DLO), Dept. Agrosystems Research, P.O.Box 14, 6700 AA Wageningen, THE NETHERLANDS.
Basically, the model simulates the absorption of light, water and nitrogen by
each species, the dry matter production as a function of the absorbed
resources and the effect of resource depletion by both species upon the
availability of light, water and nitrogen. The tree population, as described
in the model, consists of a number of trees planted in a rectangular planting
pattern. The area per tree has been subdivided into 3 subareas and the
herbaceous development of each subarea is simulated separately. Light
interception by the trees and remaining light availability at ground level for
each subarea is simulated and the production of both species is calculated by
using the LUE approach. The potential soil evaporation and the potential herb
transpiration per subarea are calculated with the Penman-Monteith equation.
For simulating the potential tree transpiration, the WUE approach has been
applied. Actual water uptake is modelled as a function of soil water status
and root length distribution of both species. A simple soil water balance
(storage overflow concept) with a number of horizontal layers has been
incorporated separately for each subarea. Lateral soil water movement is thus
not modelled. Uptake of nitrogen has been related to availability in the soil,
root length distribution and the demand for nitrogen of living plant biomass.
Net nitrogen mineralization is calculated in dependence of carbon-nitrogen
ratios in the soil organic matter. Growth of several plant parts is simulated
by partitioning the biomass production of each species among its plant parts.
Death of plant parts has also been modelled providing carbon and nitrogen
input for the soil organic matter. Modelling objectives are: 1. to predict the
herbage growth underneath and outside the tree crown. 2. to simulate the
effects of a tree population on water and nutrient availability of the
agro-ecosystem. 3. to calculate the production possibilities of a mixed
culture of trees and herbs.
Purpose of the model:
Source of the Abstract CAMASE Register of Agro-ecosystems Models
II. Technical Information
Operating System(s): VAX computer, IBM compatible PC/AT >= 640 Kb RAM; ROM
Costs: : Dfl. 270,=.
Programming Language(s): Microsoft FORTRAN.
III. Mathematical Information
Rate variables: Light absorption, water uptake, nutrient uptake/partitioning, dry matter production/partitioning, leaf area growth, rooted depth extension, senescence, soil organic matter input (C & N), organic mater decomposition, net nitrogen mineralization, infiltration and redistribution of soil water, soil nutrient flow.
State variables: Dry weight, N content of leaves, stems, roots and generative organs of the herbaceous species for each subarea (3), dry weight, N content of leaves, stems, branches, roots and generative organs of the tree species, leaf area of both species, root length distribution, water and mineral N content per soil layer, C and N content of the soil organic matter.
Geographical latitude, daily weather data, plant and tree density, tree crown size and form, nutrient input rates, morpho-physiological characteristics of tree and herb species, volumetric soil water content at airdry, wilting point and field capacity, initial amount of C and N in soil organic matter, decomposition constants, critical N/C ratios. Input check in model: No.
Values of all state and rate variables and their cumulative values
Time interval of simulation: 1 day.
Conijn, J.G. 1997. Inventorization of grass growth simulation models for the benefit of research into carbon and nitrogen flow in grassland.Inventarisatie van grasgroeisimulatiemodellen ten behoeve van het onderzoek naar koolstof- en stikstofstromen in grasland. Report Research-Institute-for-Agrobiology-and-Soil-Fertility. 1997, No. 71, 22 pp.; 1 appendix; 24 ref.., Wageningen
V. Further information in the World-Wide-Web
VI. Additional remarks
Last review of this document by: T. Gabele: Dec 10 1997
Status of the document:
last modified by
Joachim Benz Mon Jul 2 18:31:37 CEST 2007