I have long been a staunch supporter of the USDA Conservation Reserve Program (CRP)
http://www.fsa.usda.gov/dafp/cepd/default.htm This is a long-term lease arrangement and not a conservation easement.
At this time, I cannot endorse conservation easements as a recommended strategy. An easement permanently transfers an ownership interest in the land - generally, it is a split estate interest in the use permitted of that land. (These are commonly mischaracterized as sale of "development rights." Most commonly, they are for a specific purpose, such as riparian or wildlife conservation.) The easement can be bought and sold and is frequently purchased by a federal agency and transferred to a land trust or vice versa.
Conservation Easements commonly have a "third party suit" clause. This allows both the owner of the easement AND any person or organization claiming an interest in the conserved values to sue the underlying landowner to require them to manage in a certain way or eliminate all uses that are not consistent with the protected values, (including a house.) This has resulted in farmers selling "development rights" and losing all the viable commercial use of the land.
http://www.paragonpowerhouse.org/what_you_need_to_know_about_cons.htm &
http://www.wcel.org/wcelpub/10362/10362_5.html To buy out of the easement generally costs far more than the land is worth due to accruing interest.
There can also be various negative tax implications.
There can also be various negative tax implications.
...And they can be HUGE.
I concur; be well