Sustainable soil fertility management in Benin: learning from farmers

Abstract

The perception of farmers from the Atacora and Save regions of Benin was studied about the causes and consequences ofland degradation and corrective actions for sustaining soil fertility. Research methods in this diagnostic study included group discussions, using non-standardized unstructured interviews and participant observations. Farmland degradation leading to declining yields, and land tenure arrangements were identified as the main constraints on the sustainability of agriculture. In both regions the farmers stated that climatic changes (less and more irregular rainfall), run off, erosion, and overexploitation of farmlands caused land degradation. Soil fertility status was assessed on the basis of dicotyledonous weeds, soil texture and colour, and soil fauna (earthworm casting activity). Farmers have adapted their cropping systems to the local environment by developing traditional and new strategies and activities that could contribute to maintain or enhance crop productivity. These strategies include animal manure, inorganic fertilizer, crop rotation, a five-year fallow, extensive cropping systems with cassava or egusi melon, and emigration. Land tenure arrangements between landlords and migrants affect strategies that can be applied to maintain soil fertility. The importance of building mutual trust and the need to experiment with different land tenure arrangements are indicated. A framework for interactive research where knowledge is collectively generated is proposed in order to test the effectiveness and applicability of some of these local innovations not yet well understood by conventional science.

Cassava: The Drought, War and Famine Crop in a Changing World

“…Cassava requires little active management after the first 4-6 months following planting (i.e., after canopy establishment and closure [86]) and is compatible with many types of intercrops [21,36,135]. In Africa, for example, cassava is often grown as an intercrop on subsistence farms on marginal land [20,36,136,137]. Access to agricultural inputs, such as fertilisers and pesticides are often limited or non-existent in such situations [138].…”

“…However, intercropping has the benefit of increasing the diversity of food consumed, which has implications for human capacity to detoxify cyanide in the diet (see Section 3.4). Cassava is also grown as an imitation fallow, i.e., a cassava crop is planted instead of leaving the land to rest and the discarded plant material is mulched into the soil [137,139,140]. Using cassava as an imitation fallow allows for agricultural intensification without rapid degradation of soil quality [139].…”

Responses of Upland NERICA Rice to Fertiliser Application and Fallow Management in Different Agro-Ecological Zones of Benin Republic

“…Meanwhile, when taking rotation factor alone there were highest yield was obtained with natural fallow in the Sudano-Guinea zone. Saidou et al (2004) reported that the cereals production in the Sudano-Guinea region is sustained when cereals benefit from the residual effect of fertiliser applied to the previous crops. In our study, there was no fertiliser application in the preceding crop to rice possibly inducing higher soil nitrogen mining by the pre-crops and consequently no yield benefits by the following rice.…”

Promoting Cassava as an Industrial Crop in Ghana: Effects on Soil Fertility and Farming System Sustainability

“…The use of cassava for soil fertility regeneration is not only peculiar to Wenchi. Reference [7] also reported on the extensive use of cassava for soil fertility regeneration in some parts of Benin. While the natives widely apply bush fallowing, and rotation involving long duration crops such as cassava and pigeonpea for maintaining the fertility of their farmlands, migrants who do not own land in the communities but depend largely on sharecropping and land renting for gaining access to land for farming use short-term rotational strategies such as rotations involving short duration crops such as cowpea and groundnuts (Table 2).…”

“…In the forest/savannah transitional agroecological zone of Ghana, farmers often rotate maize with cowpea and when they observe decline in productivity, the land is cropped to cassava for a period ranging between 12 to 18 months after which the maize/cowpea rotation is resumed [6]. Farmers in Benin also use cassava as a "strategy for regenerating soil fertility" [7], and the term used for cassava cultivation in Benin "jachère manioc" literally means "cassava fallow". According to [8], cassava is frequently grown on marginal soils.…”