Words guide

For the thing I'm studying - the decline of small-scale and extensive farming - there are many different words used to talk about it, and according to what wording I choose, I have a completely different approach, different questions.
I tend to use "agricultural marginalisation", this phrase springs from the prespective that the economic difficulties agriculture is facing are a result of economic policy drivers. But in order to talk with people about it in an easily understandable way, I've been using "land abandonment" in my interviews. But land abandonment has a different flavour to it: it is related to land-use and land-use change. The perspective of land-use change does not seem to be addressing the economic and political causes of it, nor the particular situation of farmers. For talking with farmers about the situation I think the most adequate term is "The difficulty farmers have for making a living from agriculture". And this phrase again, leads to different questions than "agricultural marginalisation" or "land abandonment" do. The definitions and phrases used guide the direction of the research...