Assessing the effects of management and hydro-edaphic conditions on rice in contrasting East African wetlands using experimental and modelling approaches

Lowland rice yields in East Africa remain low despite favourable hydro-edaphic conditions as benefits from improved cultural management vary between and within wetland types interactions are poorly understood. Hence, multi-year agronomic field experiments were established to assess the differential responses of lowland (rainfed 0 60 kg N ha ?1 , irrigated 120 + PK ) position a floodplain Tanzania (fringe middle positions) an inland valley Uganda (valley-fringe, mid-valley valley-bottom positions). We then calibrated validated Agricultural Production System Simulator (APSIM), evaluated importance external water table data model input assessed relative effects stress on yield affected by type position. Yields 3.2–9.2 Mg attained 1.9–6.3 valley, highlighting substantial scope boost beyond current regional means around 2 . The estimated grain both wetlands well experimental uncertainty during validation ( n = 12, r 0.76, RMSEa= 0.92 floodplain; 18, 0.71, 0.72 valley). Results further emphasised for sound performance they evidently alleviated seasonal droughts. Simulated abiotic patterns additionally highlighted differences positioning wetlands. While soil was generally main constraint, comparably more pronounced supplemental irrigation thus beneficial yield. Hydro-edaphic favoured production floodplain’s fringe with lower stress, while large spatial-temporal variabilities prevented distinct delineation based toposequential positions valley. • Improved practices can African substantially. APSIM adequately simulated using data. Low constraint but fertiliser significant. Water beneficial. modulated yields, particularly floodplain.