Including area history (and fosfate saturation)

[Wardlorenz]

Hi,

For my project we are running the niche model for an area that will be converted from agricultural use to a natural (non) fertilised landscape.

While there is tools for including current use and nitrogen fertilisation, is there a way people have included historical fertilisation or land use?
This mostly regarding the more persistent ions like fosfate.

One of the measure that might be taken in the conversion of agricultaral land to forest (and the opposite elsewhere) is scraping off the nutriënt rich top soil of the agricultural fields, and replacing them by the non fertilised soil of nearby ( to be converted) forest and vice versa.

Nitrogen will most likely not be a limiting factor in the conversion, however remaining fosfate in the deeper soil layers is likely to be.

Is there a way niche has or can been used to model / calculate the effects of these type of conversions?

Thanks for any feedback!

Kind regards,

Ward

[cecileherr]

Hello Ward,

Unfortunately NICHE Flanders does not include a module to take the phosphorus fertilization history of a plot into account. Adding a few basic decision rules for phosphorus-enriched zones is certainly not impossible but would require some research (reference values for the different vegetations), development and testing. There are no concrete plans to add this functionality anytime soon.

With the present NICHE version (2.0), nature development on former arable land is a typical case where the NICHE predictions will need to be adapted: if you use the current nitrogen fertilization for such land plots (that is, mostly no fertilization), NICHE will predict the potential development of vegetation types that are absolutely unable to thrive in these soils where the phosphorus concentrations are still high.

Therefore you will probably want to correct the NICHE predictions afterwards: for the vegetations limited to phosphorus-poor conditions you will need to remove the zones where you expect/measured too high P concentrations from the NICHE predictions. An extra GIS routine with a few decision rules (e.g. different thresholds depending on the vegetation type) should do the trick.

Your example (top layer of agricultural soil replaced by non-fertilized soil for nature development) is a much more specific case: based on the rooting depth of the vegetation, groundwater regime, the phosphorus measurements at different depths, ... you will have to determine whether the phosphorus can still be available to your target vegetation.
I am afraid this is too specific to be included in a model for now.

So unfortunately no quick and ready solution to your problem.
I wish you success with your task though