Our school in Nairobi is developing well and has also generated some new regular income for our Kenyan co-workers (it is our policy that foreigners like me do not generate any income from the school and work entirely as volunteers only).

I'm teaching in China at present, but not agriculture. They need me to teach english. It sure beats farming! Being somewhat well-heeled, like you, I can also afford to render my services much more cheaply than others. That's good for China, just as your philanthropic attitude is good for Africa.
Incidentally, the accommodation depicted by your photagraphs looks akin to that where I'm living in central China, except for the plies of rotting household waste lying around and the discarded pet dogs surviving off it!