Agricultural innovation and environmental change on the floodplains of the Congo River

Abstract

Climate‐driven environmental changes bring new risks but also opportunities to populations living along the world's major rivers. Based on ethnoecological fieldwork, in this paper we examine how people living in the cuvette centrale of the Congo basin have adopted flood‐recession agriculture on islands in the Congo River, taking advantage of a secular shift since the 1980s in the hydrological regime of the Congo River. Analyses of the hydrological data reveal that this shift decreased flood risk and significantly extended the growing season on the islands, long enough to enable cultivation of fast‐maturing varieties of manioc and other crops. Flood‐recession farming on islands in the river is today not only an important source of food, but also a source of income for women, who are primarily responsible for seasonal cultivation of fields during the low‐water season. Hydrological changes alone are insufficient to explain the adoption of the new agricultural practice; adoption also arose as a result of dynamic interactions among river fishing, trading, and broader socio‐economic forces. Climate‐change models project an increased frequency of extreme floods. Our results suggest that this change may limit island cultivation in the future. More generally, our findings point to the importance of looking beyond single‐factor, solely environmental explanations in studies of climate‐change adaptation.

Hydro‐Morphological Disturbance and Suitability for Temporary Agriculture of Riverine Islands in a Tropical Wandering River

“…Riverine islands provide unique habitat diversity (Gurnell & Petts, 2002;Ward et al, 2000) and, as suggested by the present investigation, unique agro-ecosystems when found in adaptive socio-ecological systems characterized by moderate human pressures on the environment like in the Upper Huallaga. Besides our case study, other evidence has been provided of the productive use of fluvial islands in tropical areas by communities living along the rivers (Comptour et al, 2020;Kotoky et al, 2003;Prashnani et al, 2019;Sarker et al, 2020). This anthropogenic impact can be viewed as moderate, allowing these rivers to still keep their free-flowing character, according to Grill et al (2019).…”

“…For centuries, agricultural practices in floodplains have been adapted to river regimes: in the Amazon region, people take advantage of the proximity to the water source and of seasonal flow pulses (Coomes et al., 2016; Denevan, 1982; Hiraoka, 1985; IIAP, 2018). These strategies also include specific adaptations in relation to fluvial islands, were agricultural, and occasionally other human activities, (Comptour et al., 2020), coexist with flow disturbance and river morphodynamics. Notwithstanding a large number of studies on riverine islands, little literature delved into their agricultural exploitation.…”

“…These studies were based on remote sensing (Prashnani et al, 2019;Ricaurte et al, 2012) and field activities, which are crucial for soil chemical and physical characterization, necessary to determine their agricultural suitability (Troeh & Thompson, 2005). Three emblematic cases of agricultural use of fluvial islands from tropical regions can be listed: the floating islands of the Amazon, consisting of aquatic vegetation on which part of the fine sediment transported by the river is deposited, which, although they often extend over several hectares, last only one season (De Freitas et al, 2015); the chars, the fluvial islands of the Bengali river, which are so stable that they can support around 6 million people, despite increasing threats from climate change (Blitz, 1969;Mondal et al, 2015;Sarker et al, 2019Sarker et al, , 2020; and the fluvial islands of Congo river, where local inhabitants have recently started to cultivate according to flood-recession agriculture, as reported by Comptour et al (2020). The aforementioned studies, therefore, suggest that the agricultural suitability of riverine islands mainly depends on three factors: (a) the balance between fluvial disturbance and islands stability, (b) the quality of their soils, that is, their physical and chemical characteristics, and (c) the selection of flood-resistant crop varieties.…”

Les forêts du bassin du Congo : État des Forêts 2021

“…Si certains champs surélevés sont abandonnés, d'autres sont toujours cultivés. Ils exigent plus de main-d'oeuvre que la culture sur terre ferme, la culture sur brûlis ou l'agriculture de décrue, mais leur rendement est plus élevé et le risque d'inondation est moindre (Comptour et al 2020). Actuellement, les communautés des tourbières pratiquent la chasse, la pêche, le ramassage de produits forestiers tels que les frondes des palmiers pour construire des toitures.…”

Flood‐recession cropping in the mid‐Zambezi Valley: A neglected farming system with potential to improve household food security and income

“…Under this farming system, farmers grow crops outside the rainy season, thus giving them an opportunity to secure food throughout the year and earn additional income. The removal of water and nutrient‐related constraints affords smallholder farmers the opportunity to venture into high‐value crops and earn high incomes (Balana et al, 2019; Comptour et al, 2020; Sidibé et al, 2016). Crops grown under FRC in SSA are diversified and they include food and cash crops (Table 1).…”