# Calibrate APSIM-Wheat model

Calibration is a common task to use crop model (e.g. APSIM to simulate field experiments. It is also tricky to pick up which parameters are used to optimize. This post summarised my experience to calibrate APSIM Wheat model in classic and next generation.

## Phenology

In general, phenology is the frist target to optimize as it is mainly impacted by temperature (earliness per se, vernalization) and day length.

### Emergence date

Emergence date is simulated by shoot_rate and shoot_lag. In a specific experiments, the emergence date is likely impacted by the local environments (e.g. temperature) and hardly to be calibrated for all experiments through adjusting shoot_rate and shoot_lag. The sowing date could be modified to suit emergence date.

APSIM Classic

Name Description Default value Range
##### Bangyou Zheng
###### Data Scientist / Digital Agronomist

a research scientist of digital agriculture at the CSIRO.