Agricultural Easement in Iowa

We live on a property in Eastern Iowa in a 1000sq ft home. When we purchased the property our intention was to add on at some point. We are now ready to act. When we look at the cost to make the additions, we approach the cost of a new home.

Our plans have changed and we intend to split the property in half and build a new home on the new property, and rent out our existing home. To do this we need an agricultural easement from an adjacent land owner with at least 40 acres. Once they would sign the agricultural easement paperwork allowing us to build, it would restrict them in the future from splitting their 40 acres in any way. We are surrounded by farmland. If it is to be farmland, there is not much consequence for the land owner to grant us this easement. But at the same time I can understand that land owners reluctance to grant us this easement.

We have approached one land owner already. They initially said yes, but later backed out when we asked them to sign the paperwork.

I am asking the BP group for some guidance on how to approach the next land owner. What are some ways that I could ease the land owners mind on this issue? I realize that $$ always helps, and it may just come down to that. But looking for other suggestions and viewpoints as well.

Thanks!