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| Subsistence Agriculture |
Subsistence farming, form of farming in which nearly all of the crops or livestock raised are used to maintain the farmer and the farmer’s family, leaving little, if any, surplus for sale or trade. Preindustrial agricultural peoples throughout the world have traditionally practiced subsistence farming. Some of these peoples moved from site to site as they exhausted the soil at each location. As urban centres grew, agricultural production became more specialized and commercial farming developed, with farmers producing a sizable surplus of certain crops, which they traded for manufactured goods or sold for cash.
Subsistence farming persists today on a relatively wide scale in various areas of the world, including large parts of sub-Saharan Africa. Subsistence farms usually consist of no more than a few acres, and farm technology tends to be primitive and of low yield.
Subsistence agriculture is an enormous contributor to rural livelihoods in sub-Saharan Africa (SSA) and correspondingly adds to the countries GDPs. On Average, agriculture contributes between 10–70 % of the national GDP (Biazin et al., 2012) employing at least 65 % of the people in SSA (Zaki et al., 2018). In this region, farmers simultaneously practice crop and livestock production in which manure is used as fertilizer, while crop residues are used as forage. Crops such as maize, cassava, sorghum, millet and rice are widely cultivated for their edible starch as staple food (Hadebe et al. 2017a), whereas horticultural crops, regularly leafy vegetables are cultivated for relish, therefore ensuring household food security. When the produce is in surplus, they are marketed for income. However, despite the contribution of these crops to food security and income, neglected crops, are underrated on their potential multiuse and versatility in cultivation under harsh conditions currently affecting rural agriculture, which includes weed and pest invasion, soil infertility, climate change, and poor market system among many (Drimie, 2016).
Sorghum bicolor (L.) Moench is an important cereal grain after maize, wheat, and rice which makes it one of the top 5 global staple foods (Nasidi et al., 2019; Reddy et al., 2012). Sorghum can mainly be classified into 3 cultivars, namely forage, grain, and sweet sorghum (Rutto et al., 2013; Shukla et al., 2017). The most utilised, and popular, is grain sorghum (Rutto et al., 2013; Nasidi et al., 2019), while forage and sweet sorghum are uncommon. This might be attributed to preference for cultivars that are well marketed and researched with some additional socio-economic advantages (Dahlberg et al., 2011). Moreover, in SSA, sweet sorghum covers only 10% of the total sorghum plantation (Nasidi et al., 2019), which adds to why it is less popular, and underutilised. There is less awareness of this cultivar, which has the potential to assist in improving socioeconomic conditions in SSA, especially with the region facing severe environmental conditions that are expected to worsen with changes in climate (Hadebe et al., 2017b). Sweet sorghum is a feasible solution in being one of the stable and local food crops that can add to other available energy food sources with limited inputs and maximized yield.
Sweet sorghum is a multi-purpose crop that can either be grown for similar purposes of other sorghum cultivars in addition to the uses of its sugary stalks (Erickson et al., 2011). The grains of sweet sorghum can be used as food and beverages while crop residues are given to animals as fodder (Zegada-Lizarazu and Monti, 2012). Normally, sweet stalks are chewed as a snack and, sometimes, farmers sell the stalks in nearby markets to generate some income. However, global interest of sweet sorghum has gathered momentum as a potential biofuel crop assigned to its comparatively low cost, readily fermentable sugars and competence to be cultivated in marginal areas than other biofuel crops (Erickson et al., 2011; Nasidi et al., 2019). However, its significance in biofuel production is still limited in the SSA region, despite considerable efforts being made in countries like Zambia (Janssen and Rutz, 2012), Nigeria (Olugbemi et al., 2018) and South Africa (Mengistu et al., 2016; Malobane et al., 2018, 2020). Other uses of sweet sorghum may include antiseptic production and generation of biogas and electricity energy (Monteiro et al., 2013).
This paper aims to review literature on the cultivation of sweet sorghum in SSA smallholder farming systems, and its potential adaptive capacity under marginal conditions for socioeconomic gains. In doing so, a description of prospective socioeconomic benefits of sweet sorghum is explained, before going deeper into how sweet sorghum can prosper under marginal factors of production that largely affect farming, i.e., water scarcity, soil nutrition, plant population, planting date, and harvesting. However, due to scarcity of research and research articles from this region, most studies encompassed in this review are studies done elsewhere in other regions (North- and South America, Asia, and Europe), which have researched how sweet sorghum can thrive under different marginal agronomic factors.