Verification and Validation of Ceres-Wheat Model Under Çukurova Conditions

Authors: Atilla YAZAR, Metin SEZEN

Abstract: Plant Growth models have been presently used extensively by engineers and planners in order to evaluate various management alternatives. Plant growth models are tools for predicting crop growth parameters by using mathematical equation of complex environmental dynamics. In this study, CERES-Wheat V2. 1 plant growth simulation model was verified and validated on PANDA wheat variety under Çukurova conditions. Different amounts of irrigation water were applied to wheat. For this purpose a line-soruce sprinkler irrigation system was utulized in the experiment. Wheat rows adjacent to the lateral were denoted as nonwater stress treatment (I1), rows outside the wetted area were denoted as non-irrigated treatment (I5); the plant rows in between the I1 and I5 treatments were taken as the deficit irrigation treaments with linearly decreasing amount. Meteorological data required by the model were obtained from the automatic recording type weather station in the experimental area of the Department of Agricultural Structures and Irrigation of the Çukurova University and from the Meteorological station of Adana province. Throughout the experiment, soil water, phenological growth stages, and leaf area index (LAI), kernel weight, etc. were determined. The simulated results were compared with the observed parameters. Model under predicted the grain yields in fully irrigated treatment and non-irrigated treatment. On the other hand, the predicted yields in other treaments were higher than the actual grain yields. Predicted and observed accumulated dry matter were very similar. Simulated and observed LAI values had similar trend however the time for reaching the maximum LAI was about one month before the observed maximum LAI. The reason for the time delay could be attributed to the genetic coefficients used in the model for PANDA might not represent this variety. Sensitivity analysis were done in this study and a 10% increase in the field capacity and permanent wilting point water contents resulted in no change in the grain yields from the I1, I2, I3 treatments, however caused a 23% grain yield increase in yield of I5 treament. The same changes resulted in 7% increase in the plant biomass.

Keywords: