Push – pull technology increases above-ground biomass and soil organic carbon in smallholder cropping systems in Western Kenya

Mr Pierre Celestin Ndayisaba1, Dr. Charles  Aura Odhiambo Midega1, Dr. Shem  Kuyah2, Dr. Peter  N. Mwangi2, Prof. Zeyaur Rahman  Khan1

1Icipe – International Centre For Insect Physiology And Ecology, Mbita, Kenya, 2Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya, 3Rwanda Agriculture Board, Kigali, Rwanda

Soils of agroecosystems undergo degradation due to depletion of their soil organic matter. This brings about decline of system productivity that negatively affects world food security while contributing to the rise of greenhouse gases in the atmosphere. Contrary, restoring agroecosystems offsets the release of carbon in atmosphere, improves system productivity and food security as well. We compared push – pull technology with commonly found maize – based cropping systems in Western Kenya in terms of above-ground biomass (excluding grain yield) and soil organic carbon in 15 cm soil upper layer. Push – pull technology consists of maize – desmodium intercrop surrounded by Pennisetum purpureum (elephant grass/Napier grass) or Bracharia brizantha to control stem-borers, fall armyworm, and striga. The study was conducted in three sites, Bondo, Siaya, and Vihiga in three seasons, 2017 long and short rains, and 2018 long rains. In total, forty-five replications were assessed every season. Higher biomass was observed in push-pull systems (8.3±1.1 – 11.6±4.8 Mg ha-1) compared to controls: maize monocrop (4.9±0.6 Mg ha-1), maize – bean (5.0±0.9 Mg ha-1), maize – cowpea (8.0±1.1 Mg ha-1), maize – green gram (4.6±1.1 Mg ha-1) and maize – groundnut (5.6±1.9 Mg ha-1); representing an increment of 131.4%, 131.2%, 20.3%, 78.0%, and 86.6%, respectively. Soil organic carbon determined for push – pull (30.9±0.7 Mg ha-1) was 30.0% higher than control cropping systems in general (23.8±0.7 Mg ha-1). The results showed that push – pull technology has relatively more potential to recycle nutrients and restore soils as it builds up soil organic matter and sequesters carbon in its soils. More studies are needed to understand the relative contribution of each cropping system component crop to stored carbon in order to maximize services provided by push – pull technology.


Biography: Mr. Pierre Celestin Ndayisaba is a Ph. D. student at Jomo Kenyatta University of Agriculture and Technology – JKUAT/Kenya since 2016. His research project is ‘Climate change mitigation through improved soil health; carbon sequestration and nitrogen fixation under the push-pull technology as a case study’ at icipe/Kenya, sponsored by DAAD/In-Country/In-Region Scholarships Programme. Mr. Ndayisaba has been involved in different research projects related to cropping systems involving legumes.

SOIL ORGANIC MATTER

7th International Symposium
Soil Organic Matter

6 – 11 October 2019

Hilton Adelaide

Adelaide, South Australia

Australia

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