hut104
commented
1 year ago Hi, If I understand the problem, you expect eucalypt production to reach 400m3/ha at 7 years of age with only 100kg/ha of fertiliser nitrogen but the model is requiring 1500kg/ha of fertiliser nitrogen. 1) How are you determining the 1500kg/ha requirement? have you created a virtual fertilser trial? 2) I assume that these are block plantings and not high growth rates for tree belts. 3) To achieve these sorts of yields in the absence of significant fertiliser application you will require relatively high soil fertility. You may need to investigate your soil organic matter configuration. 4) Given that you require high rates of fertiliser application, you may be simulating very large nitrogen losses. I suggest that you output simulated values for denitrification and leaching losses, accumulate these over the rotation and determine where the fertiliser nitrogen is going. Also output soil nitrogen (total N, including mineral and organic pools) to determine if and where nitrogen is stored within the soil profile. 5) If you cannot find the nitrogen in losses of soil stores, I suggest that you check that the fertiliser applications are actually operating correctly (ie the scripts are actually applying the nitrogen you specify).
stale[bot]
What is your question?
I am using the default eucalyptus crop with the Apsim NG model, and I noticed that in order to remove all the nitrogen deficiency during the crop cycle (7 years), I need to apply a very large amount of nitrogen (+ 1500 kg/ha of nitrogen). The problem is that this does not match reality, since for yields greater than 400 m3/ha, a maximum of 100 kg/ha of nitrogen is applied.