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Africa’s need to double food production and feed the burgeoning human population, without compromising its natural resource base, has raised the momentum for sustainable agricultural intensification on the continent. Many studies describe agronomic practices that can increase productivity on existing agricultural land without damaging the environment and without increasing the agricultural carbon footprint. However, there is limited information on specific practices with the greatest potential to contribute to sustainable intensification on smallholder farms in sub-Saharan Africa, while simultaneously keeping the carbon footprint low. The objectives of this review were to (1) identify good agronomic practices with potential for contributing to sustainable intensification across sub-Saharan Africa, (2) synthesize available information on benefits and synergies from these technologies, and (3) discuss bottlenecks in their adoption in order to obtain insights that inform the formulation of supportive policies. Agroforestry, cereal-legume intercropping, conservation agriculture, doubled-up legume cropping, fertilizer micro-dosing, planting basins, and push-pull technology were identified as key agronomic innovations widely promoted in sub-Saharan Africa. We show that these innovations can build synergies and increase resource use efficiency while reducing agricultural carbon footprint. We outline the benefits, trade-offs, and limitations of these practices and discuss their potential role in strengthening food sovereignty and climate change adaptation and mitigation.

It remains a challenge for agricultural research-for-development (AR4D) institutions to demonstrate to donors which technologies contribute significantly to poverty reduction due to a multitude of impact pathways. We attempt to overcome this challenge by utilizing the potential outcomes framework and quantile treatment effects analytical approaches applied on panel household data collected from Central Africa. Our findings show that adoption of AR4D technologies reduced the probability of being poor by 13 percentage points. A large share of this poverty reduction is causally attributable to adoption of improved crop varieties (32%) followed by adoption of post-harvest technologies (28%) and crop and natural resource management (26%), with the rest 14% attributable to unidentified and/or unmeasured intermediate outcomes or factors. The findings further indicate that relatively poor farm households benefit from adopting improved crop varieties more than the relatively better-off households. Correspondingly, the relatively better off households benefit from adopting post-harvest technologies enhancing crop commercialization much more than the relatively poor households. The findings reveal interesting policy implications for successful targeting of agricultural interventions aimed at reducing rural poverty.

Low levels of nitrogen (N) and phosphorus (P) in soils in sub-Saharan Africa (SSA) limit maize (Zea mays) production in smallholder farms. We tested the hypothesis that desmodium (Desmodium intortum (Mill.) Urb.), a fodder legume, and food legumes commonly grown with maize in Western Kenya avail N and P and improve the performance of maize in intercrops. We measured available N and P in 15 cm topsoil at 4, 8 and 12 weeks after planting (WAP), and corresponding maize shoot weight in three seasons: 2017 long rains (LR), 2017 short rains (SR), and 2018 LR at Thomas Odhiambo Campus of icipe at Mbita Point in western Kenya. Treatments were additive 1:1 maize-legume intercrops; maize-bean (Phaseolus vulgaris L.), maize-cowpea (Vigna unguiculata (L.) Walp.), maize-crotalaria (Crotalaria ochroleuca G. Don), maize-desmodium, maize-green gram [Vigna radiata (L.) Wilczek] and maize-groundnut (Arachis hypogaea L.), and maize monocrop as a control, replicated four times in a complete randomized design. This experiment was established in 2003 and treatments were repeated every season on the same plot (for 31 seasons up to 2018 LR). At the beginning (year 2003), experimental plots were infested with 100 g of striga seeds per 250 g soil. Across the three last seasons corresponding to this study, we observed an increase in available N in maize-desmodium plots compared to maize monocrop plots. Available P measured at 4, 8 and 12 WAP in 2017 SR and at 4 WAP in 2018 LR was higher in maize-desmodium than in maize monocrop at the same sampling times (P

Push-pull is one of the sustainable intensification technologies for the control of stem-borers, striga weed and fall armyworm. Even though the effectiveness of push-pull in addressing these constraints has been evaluated under different agro-ecological conditions and on research stations, performance of the technology relative to other common maize-based cropping systems in farmers’ fields and the impact of the push-pull age is not yet understood. We hypothesized that, a) maize grain yield and aboveground biomass from push-pull system is higher than other common maize farming systems; b) duration of use of push-pull, and climatic conditions have an influence on its efficacy; and c) the presence of legumes in maize farms positively affects system performance. We compared maize grain yield, aboveground biomass and striga emergence of push-pull system with common maize farming systems: (1) maize monocrop (2) maize-bean intercrop, (3) maize-cowpea intercrop, (4) maize-green gram intercrop, and (5) maize-groundnut intercrop in 45 farms in three contrasting sites (Vihiga, Siaya and Bondo) in western Kenya. Push-pull increased maize grain yield by 2.33 and 1.77 Mg ha−1 in Vihiga in 2017 long and short rains, and 2.15 Mg ha−1 in Bondo in 2018 long rains, and aboveground biomass by between 2.84 Mg ha−1 in Vihiga in 2018 long rains and 8.94 Mg ha−1 in Bondo in 2018 long rains. Striga emergence declined in push-pull systems by up to 100 % and its performance varied with sites and seasons. Farms that had practiced push-pull for less than 2 years had a higher number of striga than farms which had practiced it for more than 2 years for the first season; the number decreased and was similar to that for farms which had practiced push-pull for above 2 years in the two subsequent seasons. Farms with legumes had similar maize grain and aboveground biomass as maize monocrop in all sites and seasons, and higher number of striga in Siaya in 2017 short rains and 2018 long rains, and Vihiga in 2018 long rains. These findings show that push-pull is similar or superior to other maize farming systems in terms of maize grain and biomass production; and that while its performance is influenced by agro-ecological conditions, its efficacy in controlling striga increases over time, and its productivity is not compromised over time on the same farm.