The dominant discourse in sub-Saharan agricultural systems has traditionally focused on rain-fed and irrigated agriculture, ignoring a vast array of farming systems that don’t conform to either of these categories. The largest of these are flood-based farming systems (FBFS) which are estimated to encompass a land area of approximately 30 million hectares across Africa (TWC 2015). As will be discussed during this blog FBFS are highly variable in nature both spatially and temporally, consequently estimations of size are sparsely documented and rarely included in national or regional statistics thus meaning estimations are difficult to make.
What are flood-based farming systems?
FBFS are a highly complex, risk-adverse agricultural strategy utilising seasonal river flows to remove the dependence-induced vulnerability of rain-fed agriculture (Adams 1992). FBFS are classified into different categories based on the nature of flood use and inundation, this blog will focus on flood recession agriculture as it is the most common type of FBFS in sub-Saharan Africa . This type of agriculture revolves around cultivating gently sloping floodplains using rising and/or receding flood water from rivers/lakes to inundate floodplains with fertile silt. In sub-Saharan Africa most cases of flood recession agriculture use post-inundation residual moisture left after flood levels drop to grow things like pulses, however some areas grow crops (i.e. sorghum) in rising water levels (see Figure 1), and some combine both to manage flooding patterns and implement two cropping cycles per flood season (SINF 2015). Flood-recession agriculture is heavily influenced by the topography of the floodplain because of its role in water distribution, with low lying and flatter areas optimal for flood recession agriculture as moisture is retained for longer periods of time and the flood spreads further. Similarly, soil typology determines the retention properties and permeability of the floodplain (SINF 2015).
Why are flood-based farming systems used and what are its relative benefits and drawbacks?
Flood-recession agriculture is a risk-adverse strategy employed in many countries that do not have access or the economic power to import food during periods of rain-fed agricultural failure (i.e. drought). Floodplains can be vast and extremely fertile, allowing them to be cultivated without fertiliser because of the nutrient’s floods leave behind. FBFS can often be the only form of income in isolated, difficult to access semi-arid areas thus representing a key source of income generation and food security in remote areas of sub-Saharan Africa (SINF 2015). It’s suggested that the improvement and expansion of ecologically sympathetic FBFS is likely to prove to be the most sustainable form of water use for sub-Saharan Africa, highlighting the useful services that floods can bring to rural communities across the region. If access to groundwater is available a third cropping season can be applied to more impermeable soils through groundwater irrigation (as covered in the last blog post) (SINF 2015).
Uncertainty regarding time, recurrence and quantity of flood events means these systems are extremely variable and often not maximum productivity. Appropriate management practices such as those developed in the Asian context can increase productivity by lessening said uncertainties, however this facet remains underdeveloped in the sub-Saharan Africa context with extreme uncertainty preventing crop and technique innovation (SINF 2015).
Flood recession agriculture in practice: A case study of northern Ghana
Northern Ghana is rife with food insecurity, with rain-fed agriculture often insufficient to meet household food needs for up to five months a year (Balana et al. 2019). Flood-recession agriculture is practiced on the flood plains of the White Volta River utilising low input low-output conditions. Balana et al. (2019) used optimisation modelling to explore the potential of flood-recession agriculture to extend the cropping season beyond the short-lived rainy season in order to improve food security and small holder income. The study revealed that growing food such as cowpea’s and peanut’s using residual moisture and cash-crops (i.e. tomato and onion) under supplementary irrigation is the optimal combination for flood-recession agriculture in northern Ghana, resulting in an estimated net cash income of US$4344 per hectare compared to US$316 for rain-fed agriculture in low rainfall scenarios (SciDevNet 2019). The full potential of flood-recession agriculture in northern Ghana will only be met if crops are carefully selected, farmers have access to better quality seeds, pest management is integrated and flood recession agriculture is encouraged through policy interventions and institutional support, of which the Ghanaian government is yet to do (Balana et al. 2019).
The future of flood-recession agriculture in sub-Saharan Africa:
As described in the Ghanaian case study above flood-recession agricultures development has immense potential in sub-Saharan Africa, however the techniques and approaches to undertake it remain undervalued and often unknown to lots of smallholders (SINF 2015). Flood-recession agriculture hasn’t been given the appropriate attention by national governments, NGOs and development agencies with infrastructural projects such as groundwater irrigation often at the forefront of the agenda. There is a distinct lack of comprehension and appreciation of the system dynamics and their potential for agricultural development in sub-Saharan Africa (SINF 2015). Flood-recession agriculture needs support and interventions from policy makers such as the creation of water retention structures and drainage as well as access to higher quality seeds and irrigation structures (SciDevNet 2019). It is also crucial that larger infrastructural projects such as hydropower dams and irrigation projects do not continue to be made to the detriment of FBFS downstream without including their value in a cost-benefit analysis (SINF 2015). Flood-recession agriculture requires detailed management practices and an understanding of flood behaviour so capacity building and agricultural extension services (through educational and training centres) are vital if they are to expand across sub-Saharan Africa. ‘Human capital is one of the main challenges and goals for strengthening and exploiting the full potential of FBFS’ (SINF 2015: 37).
Conclusions:
Whilst flood-recession agriculture is usually employed as a risk-adverse strategy to achieve food security, there is a large possibility for the systems to be managed for commercial agriculture. The increasing threat of climate change and increasing pressure on land and water resources across sub-Saharan Africa require alternative systems to rain-fed and irrigated agriculture, of which FBFS are a promising option to tackle the socio-economic and physical challenges faced by rural sub-Saharan Africa (SINF 2015).
What are flood-based farming systems?
FBFS are a highly complex, risk-adverse agricultural strategy utilising seasonal river flows to remove the dependence-induced vulnerability of rain-fed agriculture (Adams 1992). FBFS are classified into different categories based on the nature of flood use and inundation, this blog will focus on flood recession agriculture as it is the most common type of FBFS in sub-Saharan Africa . This type of agriculture revolves around cultivating gently sloping floodplains using rising and/or receding flood water from rivers/lakes to inundate floodplains with fertile silt. In sub-Saharan Africa most cases of flood recession agriculture use post-inundation residual moisture left after flood levels drop to grow things like pulses, however some areas grow crops (i.e. sorghum) in rising water levels (see Figure 1), and some combine both to manage flooding patterns and implement two cropping cycles per flood season (SINF 2015). Flood-recession agriculture is heavily influenced by the topography of the floodplain because of its role in water distribution, with low lying and flatter areas optimal for flood recession agriculture as moisture is retained for longer periods of time and the flood spreads further. Similarly, soil typology determines the retention properties and permeability of the floodplain (SINF 2015).
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| Figure 1. Rice crop grown in a flood-recession agriculture system on the Betsimitatatra floodplains, Madagascar (Wood 2017) |
Why are flood-based farming systems used and what are its relative benefits and drawbacks?
Flood-recession agriculture is a risk-adverse strategy employed in many countries that do not have access or the economic power to import food during periods of rain-fed agricultural failure (i.e. drought). Floodplains can be vast and extremely fertile, allowing them to be cultivated without fertiliser because of the nutrient’s floods leave behind. FBFS can often be the only form of income in isolated, difficult to access semi-arid areas thus representing a key source of income generation and food security in remote areas of sub-Saharan Africa (SINF 2015). It’s suggested that the improvement and expansion of ecologically sympathetic FBFS is likely to prove to be the most sustainable form of water use for sub-Saharan Africa, highlighting the useful services that floods can bring to rural communities across the region. If access to groundwater is available a third cropping season can be applied to more impermeable soils through groundwater irrigation (as covered in the last blog post) (SINF 2015).
Uncertainty regarding time, recurrence and quantity of flood events means these systems are extremely variable and often not maximum productivity. Appropriate management practices such as those developed in the Asian context can increase productivity by lessening said uncertainties, however this facet remains underdeveloped in the sub-Saharan Africa context with extreme uncertainty preventing crop and technique innovation (SINF 2015).
Flood recession agriculture in practice: A case study of northern Ghana
Northern Ghana is rife with food insecurity, with rain-fed agriculture often insufficient to meet household food needs for up to five months a year (Balana et al. 2019). Flood-recession agriculture is practiced on the flood plains of the White Volta River utilising low input low-output conditions. Balana et al. (2019) used optimisation modelling to explore the potential of flood-recession agriculture to extend the cropping season beyond the short-lived rainy season in order to improve food security and small holder income. The study revealed that growing food such as cowpea’s and peanut’s using residual moisture and cash-crops (i.e. tomato and onion) under supplementary irrigation is the optimal combination for flood-recession agriculture in northern Ghana, resulting in an estimated net cash income of US$4344 per hectare compared to US$316 for rain-fed agriculture in low rainfall scenarios (SciDevNet 2019). The full potential of flood-recession agriculture in northern Ghana will only be met if crops are carefully selected, farmers have access to better quality seeds, pest management is integrated and flood recession agriculture is encouraged through policy interventions and institutional support, of which the Ghanaian government is yet to do (Balana et al. 2019).
The future of flood-recession agriculture in sub-Saharan Africa:
As described in the Ghanaian case study above flood-recession agricultures development has immense potential in sub-Saharan Africa, however the techniques and approaches to undertake it remain undervalued and often unknown to lots of smallholders (SINF 2015). Flood-recession agriculture hasn’t been given the appropriate attention by national governments, NGOs and development agencies with infrastructural projects such as groundwater irrigation often at the forefront of the agenda. There is a distinct lack of comprehension and appreciation of the system dynamics and their potential for agricultural development in sub-Saharan Africa (SINF 2015). Flood-recession agriculture needs support and interventions from policy makers such as the creation of water retention structures and drainage as well as access to higher quality seeds and irrigation structures (SciDevNet 2019). It is also crucial that larger infrastructural projects such as hydropower dams and irrigation projects do not continue to be made to the detriment of FBFS downstream without including their value in a cost-benefit analysis (SINF 2015). Flood-recession agriculture requires detailed management practices and an understanding of flood behaviour so capacity building and agricultural extension services (through educational and training centres) are vital if they are to expand across sub-Saharan Africa. ‘Human capital is one of the main challenges and goals for strengthening and exploiting the full potential of FBFS’ (SINF 2015: 37).
Conclusions:
Whilst flood-recession agriculture is usually employed as a risk-adverse strategy to achieve food security, there is a large possibility for the systems to be managed for commercial agriculture. The increasing threat of climate change and increasing pressure on land and water resources across sub-Saharan Africa require alternative systems to rain-fed and irrigated agriculture, of which FBFS are a promising option to tackle the socio-economic and physical challenges faced by rural sub-Saharan Africa (SINF 2015).
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