CSM-IXIM

CSM-IXIM or simply IXIM , the Maya word for maize, is a more mechanistic maize model available in DSSAT since v4.5. The model IXIM was developed by accumulating and testing together a number of CERES-Maize model improvements. The modular version of CERES-Maize, was used for that purpose.

IXIM simulates expansion and senescence of individual leaves using a thermal time framework and for each leaf, estimates instantaneous C assimilation as limited by temperature, leaf age and leaf position. Canopy respiration is next estimated, based on organ composition, and the resulting potential crop growth rate calculated. Compared to CERES-Maize, IXIM also includes differences in the simulation of assimilate partitioning, ear growth, kernel number, grain yield, and plant N acquisition and partitioning. The model includes new algorithms to estimate PAR from solar radiation, and light absorption by individual leaves through the canopy.

More recently, the simulation of additional processes have been improved and/or added. This includes crop N demand and partitioning, as well as N remobilization and allocation into the grain. Concerns derived from climate change projections and elevated temperatures have been addressed. Lizaso et al. (2017) incorporated new thermal time calculation, and the simulation of the anthesis-silking interval. Also based on previous work the explicit and distinct impact of heat on pollen and silks was described together with the overall impact on grain yield.

Some studies using CSM-IXIM:

- Yakoub, Abdallah et al. “Testing and improving the maize models in DSSAT: Development, growth, yield, and N uptake.” (2017).

- Lizaso, Jon I. et al. “Modeling the response of maize phenology, kernel set, and yield components to heat stress and heat shock with CSM-IXIM.” (2017).