Hi
when i use landuse greenfield it’s turn into water?? on my Garmin Oregon 550
link http://www.openstreetmap.org/?lat=55.8928&lon=12.38321&zoom=17&layers=M
Are you sure greenfield is really what you want ?
“landuse=greenfield” means it was some agricultural land that is now destined for development, i.e. houses or industrial/commercial buildings are about to be build on this site.
If the land is still used agriculturally it would be landuse=farmland or landuse=pasture.
If it really is a greenfield it depends on the maker of the Garmin-Map how landuse greenfield is mapped onto a Garmin mapfeature. Then you would need to add or edit the TYP-file to change the way the Garmin unit displays this feature.
Where did you get the Garmin map from?
Micha H.
homemade map 
gonna try use landuse=pasture, its a field whit cows