This article about an irrigation project implemented by some Turkana people, formerly herders, ignores the question of whether agriculture is sustainable in the area in question. I don’t know, but I suspect from the pictures in the related photo essay that there may be a problem with rainfall being reliable enough to sustain crops, even with the irrigation scheme. There may also be issues of lowering water tables in unsustainable ways in an area not intended for farming.
A scholar named Elliott Fratkin has also done work showing that when formerly nomadic people sedentarize, the health and nutrition of their children declines, even if their schooling increases, though in his case studies the people were keeping small individual farms, not large ones. And finally, why does this article mix questions of US agricultural policy with those of the viability of development projects? Sure, US funding matters to development success, but planning reasonable projects counts as much.