Spatio-temporal variation of wheat and silage maize water requirement using CGMS model

Document Type : Research Paper


1 Academic member of water engineering department, Razi University, Kermanshah, Iran.PhD student, ITC faculty, University of Twente, the Netherlands.

2 Assistant professor, water engineering department, Razi University, Kermanshah, Iran

3 Associate professor, ITC faculty, University of Twente, the Netherlands

4 Professor, Plant Production Systems Group, Wageningen University, the Netherlands


The Crop Growth Monitoring System (CGMS) has been applied for spatial
biophysical resource analysis of Borkhar & Meymeh district in Esfahan province,
Iran. The potentially suitable area for agriculture in the district has been divided into
128 homogeneous land units in terms of soil (physical characteristics), weather and
administrative unit. Crop parameters required in the WOFOST simulation model for
winter wheat and silage maize, have been calibrated based on experimental data from
the study area. The study area has been classified into three cropping calendar zones
based on average annual temperature, altitude and latitude. For each zone, a sowing
date has been defined for each crop as the starting point of crop growth simulation.
Growth of these crops has been simulated for the potential situation in each land unit
for 20 years of historical daily weather data. Daily potential evapotranspiration and
irrigation requirements of each crop per land unit have been calculated in a postsimulation,
on the basis of model outputs. Outputs of the model are crop yield
(marketable yield and total biomass) and irrigation requirements per decade. Spatial
and temporal variation in irrigation requirements has been analyzed. The temporal
variation in crop water requirements is larger than the spati3al variation.