And the best of times this is not: The ill effects of a years-long drought have been exacerbated by the tradition of grazing herd animals indiscriminately over a large region, so that topsoil never replenishes.

FORBES: Magazine Article

Settled Pokomo farmers and semi-nomadic Orma pastoralists have clashed intermittently for years over access to grazing, farmland and water in the coastal region.

BBC: Kenya: Tana River clashes leave dozens dead

The International Livestock Research Institute says large parts of Africa may soon be too dry for grazing, leading to conflicts between rival cattle herders or, as in Sudan's Darfur region, between herders and settled farmers.

ECONOMIST: Africa's population