Push-pull technology improves maize grain yield and total aboveground biomass in maize-based systems in Western Kenya

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.