When yield gaps are poverty traps: The paradigm of ecological intensification in African smallholder agriculture

By P. Tittonell, K. Giller. 2013

1,037 citations recorded by the source corpus.

Yield gaps are pervasive in African smallholder agriculture, and are large for almost all crops in all regions. There is consensus that poor soil fertility and nutrient availability are the major biophysical limitations to agricultural production in the continent. We identify two major yield gaps: (1) the gap between actual yields (YA) and the water-limited yield potential (Yw), which is the maximum yield achievable under rainfed conditions without irrigation if soil water capture and storage is optimal and nutrient constraints are released, and (2) The gap between YA, and a locally attainable yield (YL) which corresponds to the water and nutrient-limited yields that can be measured in the most productive fields of resource endowed farmers in a community. Estimates of these two yield gaps are given for major crops, together with a framework for how yield gaps can be estimated in a pragmatic way for different farming systems. The paradigm of ecological intensification which focuses on yield potential, soil quality and precision agriculture is explored for the African context. Our analysis suggests that smallholder farmers are unable to benefit from the current yield gains offered by plant genetic improvement. In particular, continued cropping without sufficient inputs of nutrients and organic matter leads to localised but extensive soil degradation and renders many soils in a non-responsive state. The lack of immediate response to increased inputs of fertiliser and labour in such soils constitutes a chronic poverty trap for many smallholder farmers in Africa. This necessitates a rethink for development policy aimed to improve productivity and address problems of food insecurity.

Subfields: Agronomy and Crop Science, General Agricultural and Biological Sciences

View Paper: https://www.semanticscholar.org/paper/41d3fa29c8c05c9317a7f6645916a972b4bea886

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Citations in the corpus

Sustainable intensification of agricultural systems in the Central African Highlands: The need for institutional innovation (2016, background): “…(a) population is expected to increase 2–3 fold in the next 35 years (United Nations, 2015), (b) yield gaps are among the largest in the world (Tittonell and Giller, 2013), (c) fallow land is virtually absent and the hilly landscape is prone to erosionwhich causes soil fertility challenges…”
Greedy or needy? Land use and climate impacts of food in 2050 under different livestock futures (2017, background): “The impacts of climate change, which are expected to slow increases in agricultural yields at the global level as well as loss of soil fertility (Tittonell and Giller, 2013) also need to be factored in.”
Review: Taking stock of Africa’s second-generation agricultural input subsidy programs (2018, background): “Without proper management, this will likely lead to further soil degradation and lower yield response to fertilizers, despite rising use of hybrid seed (Stoorvogel and Smaling; 1990; Tittonell and Giller, 2013).”
Land pressures, the evolution of farming systems, and development strategies in Africa: A synthesis (2014, background): “There is increasing recognition that raising organic matter, moisture retention, and other forms of soil rehabilitation in addition to greater inorganic fertilizer use are preconditions for sustainable agricultural productivity growth in densely populated rainfed farming systems of Africa (Powlson e”
Small farms and development in sub-Saharan Africa: Farming for food, for income or for lack of better options? (2021, background): “Some authors have suggested that there may be a threshold under which farms become too small to be economically viable (e.g.Harris & Orr, 2013; Tittonell & Giller, 2013).”
Accurate crop yield predictions from modelling tree-crop interactions in gliricidia-maize agroforestry (2017, background): “In much of sub-Saharan Africa there is a projected decline in per capita food availability (Rosen et al., 2012) that is exacerbated by land degradation already affecting a third of the land area (Bai et al., 2008; Tittonell and Giller, 2013; Vågen et al., 2016).”
Tillage and fertilizer effect on maize and soybean yields in the Guinea savanna zone of Ghana (2017, background): “The major causes of the low soil fertility are low levels of nutrient inputs, continuous cropping, overgrazing, deforestation, and poor soil and water conservation measures [1].”
Effects of rising rural population density on smallholder agriculture in Kenya (2014, background): “Moreover, especially in densely populated areas, soils have been continuously cultivated and are facing fertility constraints that make them less responsive to inorganic fertilizer (Drechsel et al., 2001; Marenya and Barrett, 2009; Tittonell and Giller, 2012; Sheahan et al., 2013).”