Simulation of the Effect of Sowing Date with the DSSAT (Decision Support System for Agrotechnology Transfer) Model on Maize Grain Yield

Abstract

Background: Climate change, rainfall variability, and inappropriate sowing dates contribute significantly to low maize yields in Togo, highlighting the need to identify optimal planting periods using the DSSAT crop simulation model. Aims: The sowing date is an agricultural practice that involves aligning the maize growth cycle with the rainy season. In recent years, this date has fluctuated due to interannual variability in the arrival of the first rains heralding the start of the agricultural season. Based on the DSSAT model (Decision Support System for Agrotechnology Transfer), this study aims to estimate the optimal sowing date to meet the water requirements of Obatanpa maize grown in the Maritime and Plateaux regions of Togo. Study Design: Thus, thirty-two years' (1990-2022) of climatic data from these two regions were input into the DSSAT model. Place and Duration of Study: The study took place at the laboratory of the Institutional Economics Research Team (ERECI) at the University of Lome in Togo from January to March 2026. Methodology: The methodology comprises two parts: (i) calibration, validation, and evaluation of the model; and (ii) seasonal analysis. The first part consists of comparing the observed values ​​with those of the simulation. The second part consists of carrying out the seasonal analysis, which is the actual simulation that will determine the best sowing date for obtaining optimal yield. Results: The results show that the model is robust and that 15 March in the Maritime and Plateaux regions of Togo is the most optimal of the five (5) sowing dates for Obatanpa maize, yielding 1,080 kg/ha. This date is followed by the fourth sowing date (April 30th) with a yield of 975 kg/ha; The third sowing date (April 15) yielded 958 kg/ha; the second sowing date (March 30) yielded 884 kg/ha; and the fifth sowing date (May 15) yielded 776 kg/ha. Conclusion: The study recommends that producers of this maize variety in these two agricultural regions of Togo sow maize around 15 March.