I think I’ve narrowed it down to the fact that when you add a new crop and add the crop xml file. That xml file calls for usually 6 different distances texture files. So after you add so many crops you reach the max of 255. The only workaround I have figured out is to direct a new crop to a previous xml in the map. Like if I’m adding durum, in the map I direct the xml path to $data wheat.xml. And under foliage I can label it durum but I need to keep the same ID number as wheat has in the map. This will then call for textures that are already in the game and will not add anymore to my limit. It doesn’t seem to cause any issues yet, however I don’t know if that is a good way to structure it.
Another thing you could try is to eliminate so many distance textures per crop. All you really need is a green, brown, and dead distance texture. Also, for certain "flowering" stages of certain crops (like yellow for canola, etc). The distance layers are all optional, so you can make them whatever you want.
At 3-4 textures per crop, you could have 60 - 70 crops on the map which is double what a vanilla map supports. It must be making a texture array for reused texture files to only count as 1. I'm still waiting to hear back from a couple people, but it's not an issue many have run into. In fact, you're the first that's ever mentioned it to me.
Right. There are usually 2-3 green ones, potentially a colored one for flowering stages, a brown one for harvest ready, and a withered one. You really don't need all of the green ones. Those are just different shades of green to match the shade of green in the crop itself. For example, if you had distance2, distance3, distance4 all green, then distance5 brown, and distance6 withered. You could just rename and reference them to distance2 = green, distance3 = brown, distance4 = withered. and save 2 slots per crop done like this.
Also, some states like stubble could just use the green or brown texture depending. A lot of crops leave so little stubble you could just remove the distanceMap attribute from those altogether and have it show the terrain texture in those cases.
And yes, 5 channels = 31 crops (plus 0 or no crop), 6 channels = 63 crops (plus 0 or no crop). Also, all crops by default have 15 total growth states available (though many of them are not used by default).