Nice, I'm German! It's dismissed by the science community for being no viable solution to feed the world, simply because it takes up too much space. Or in different words: The yield per acre is not enough to feed the world in the long term. So we need to either increase the yield or decrease the population.
Agroforestry has a lot going for it in an ecological way but it's suffering the same problem of that the yield isn't very high. On the other hand wood is a valuable resource so it could make sense to use it in areas where wood is a main resource for heating or as a building material. On top of that, agroforestry is something that requires quite a lot of skill and knowledge. So it could be difficult to teach about this method in areas where it is not common to go to school. But that will probably be the same issue with any other solution; if farmers can't or don't want to learn about new techniques/ chemicals/ tools or whatever else is needed or don't have access to it, then that's the first problem that needs to be tackled.
So as you can hopefully see, I'm very torn on the subject of managing lands. On one hand you have people that preach to go "back to the roots" to save the soil, which is great for the soil and the ecology but not viable due to the small yield. On the other hand you have massive amounts of deforestation to farm genetically invariant coconut oil and corn which produces enough to feed the world but destroys the very land that we depend on.
RE: More about the Earth that is "just right" but likely to expire soon...