Crop Yield decreases significantly

[JC]

Dear Community,

I write to you because I am calibrating crop yield. My crop is planted in the year 1 and then only harvested for 5 to 7 years, and then harvested and killed, and planted again.

In the model, the crop yield decreases significantly after the first year, which doesn't happen in real life. I was using only BIOE and input of P, N and organic fertilizer to calibrate it, but I am sure that there is something else really impacting the crop yield and I have no clue what parameter might causing this. Any idea?

Many thanks to aeveryone!