"Start graze" works on a single day

[Matteo Longo]

Hello,

I'm trying to simulate grazing with EPIC but the "start graze" command seems to only harvest biomass on that date instead of starting the harvest and continuing until the "stop graze" date. What am I doing wrong? 

Thank you,

Matteo

[Luca]

Dear Matteo,

The first thing that comes to my mind is that, after the first grazing event, the plant growth is very slow and the amount of biomass available for grazing remains below the minimum amount required to allow a grazing event to occur again. Check if you have this limit (GZLM in the control table) set to a large value or set it to a very low values (for instance 0.1) and see if the model simulates more grazing operations.

Let me know,

Luca

[Matteo Longo]

Dear Luca, 

Thank you for your reply. Actually I had already set  GZLM  to 0.01 t/ha. Moreover, the total biomass is quite large (up to 27 t/ha). About the other parameters,  the number of cows equals 7 and the fraction of time cows in the feed area is 0.8 (I do not understand if this last parameter works just on APEX). I attached the .DCS file.

Thank you for your help,

Matteo

[Luca]

Matteo,

Can you share your input and output files with me?

Luca

[Luca]

Matteo,

To solve the problem you are having in your simulation you have to insert the "grazing rate" (as kg of dry matter ingested per hectare per animal) in the column EFM of the tillage table (TILLCOM.DAT file) instead of adding this information in the ORHI column. Using the information reported in the EFM, the model will then calculate the equivalent value of ORHI in the case of grazing.

This problem is caused by an error in the user manual that has never been updated to reflect the modifications introduced in the model source code.

Best regards,

Luca

[Matteo Longo]

Dear Luca,

Thank you for your help. Following your suggestions it does work now!

Bests,

Matteo