I realize, it´s difficult to identify landuses in Nepal from aerial images.
For instance this: http://www.myholidaynepal.com/blog/images/blogimage/Jhoor-Tokha-Kathmandu-Nepal-20120530123012.jpg
We see terraced landuse=farmland with trees in between.
This may be sometimes identified as a scrub or Forest, when trees have more density. With other words we need an catalogue with aerial images and hints how to make digitalization of such areas.
I think also additionally tagging of such areas would be helpful to differentiate different kind of farmfields.