Where is the code located?

SoilTemperature (aka SoilTemp2)

What needs to be changed?

Three issues have a negative impact on the running time of SoilTemp2:

1. doThomas creates a new string for each layer twice for each soiltemp2 timestep (48 timesteps per simulation day) when calling boundCheck, but This string is often unused. Inlining the bound checking and only creating the string when the check is failed should solve this.
2. The value of latitude read from a traditional met file is obtained from Convert.ToDouble each time it is needed by the model, which is frequently in the case of SoilTemp2. Caching this value in some way ought to provide relief here.
3. The depth above each layer is computed every timestep, but could similarly be cached.

Why does the code need changing?

Switching from CERESSoilTemperature to SoilTemperature more than quadruples the running time of a large (approx 9 million 34 year simulations with 18 layer soil profiles) factorial. Some amount of slowdown should be expected, but this amount seems excessive.