Assessing and improving organic matter, nutrient dynamics and profitability of smallholder farms in Ethiopia and Kenya: proof of concept of using the whole farm model FarmDESIGN for prioritization of GIZ development interventions - Paul, Birthe K.; Birnholz, Celine A.; Timler, Carl J.; Michalscheck, Mirja; Koge, J.; Groot, Jeroen C.J.; Sommer, Rolf (2015)