Suitability assessment and projected impact of climate change on rice yield in two Agro-ecological zones in southkivu, Democratic Republic of Congo

Rice is one of the five most important staple foods in South-Kivu, with high and increasing demand. The gap between the demand and supply has led to increasing importation of rice in the region. Changes in climate are likely to further increase this gap. A study was conducted in South-Kivu to i) determine suitable areas for optimum rice growing and ii) determine the impact of historical and future climate on paddy rice yield in two agro-ecolgical zones (Kavumu and Luberizi) in the region. GIS-based multicriteria analysis techniques were used in ArcGIS 10.2 to identify suitable areas for rice growth in the two locations while the Agricultural Production Systems Simulator Model (APSIM) was used to simulate the impact of historical and future climate change scenarios (Mid and end-century, Representative Concentration Pathways 4.5 and 8.5) on rice yield. The results obtained from this study indicate that Kavumu and Luberizi catchments cover 1744 ha and 16036 ha respectively and generally only a small portion of the two locations are at most moderately suitable for rice growth (7.51% and approximately 20% of the catchment in Kavumu and Luberizi, respectively). The marginally suitable class represented 72.88% and 36.09% of the catchment in Kavumu and Luberizi respectively. The most limiting factors to rice production in both catchments were temperature, nutrient retention capacity and erosion hazard. During the last 30 years (1980-2010) rice biomass significantly (p<0.001) declined in both catchments while rice grain yield remained stable (p>0.05) in Kavumu but significantly declined in Luberizi over time (p<0.001). Both rice biomass and grain yield are projected to increase with climate change in Kavumu, except for the end-century under RCP 8.5 while in Luberizi it is projected that there will be a decline in rice biomass and a slight increase in grain yield followed by a decline in the end-century under RCP 8.5.