Add parametercategory about management practices

[orianebro]

For the moment, it lacks a parameter category about management practices.

[pradal]

Can you give us some example? Which type of parameters do you want to annotate as management one?

[orianebro]

For example parameters concerning nursery and transplanting.

[cyrillemidingoyi]

Use constant if the parameter is not related to species or genotypic or soil