Land brokerage is a great game if you love the outdoors and willing to get bitten,stung, scratched and so on.
The land category is broad and can require specialization in just segments of it like lots for homes,rural or mini-farms,shopping center sites,large acreage,motel sites,multifamily sites,industrial land,commercial land,land for residential development and so on.
You can be primarily a listing agent or a buyer's agent but very often you will find yourself in a dual agency situation.
Other areas are land assemblage of multiple tracts, options on land,due dilligence contracts ,resort land,beach parcels and many many more.
Land -like commercial real estate generally requires years of practical experience and much much more knowledge about factors affecting value than normal residential real estate.
Like commercial, there will be many opportunities to invest and make huge commissions but when it is slow -it is real slow -like all of 2008-2009 and possibly 2010.
To learn a lot about rural land, one of my favorite sites is "Landthink.com".