Contents lists available at ScienceDirect Agriculture, Ecosystems and Environment journal homepage: www.elsevier.com/locate/agee Soil greenhouse gas fluxes from maize cropping system under different soil fertility management technologies in Kenya Collins M. Musafiri a, *, Joseph M. Macharia b , Milka N. Kiboi c , Onesmus K. Ng'etich a , Chris A. Shisanya b , Jeremiah M. Okeyo c , Daniel N. Mugendi a , Elizabeth A. Okwuosa d , Felix K. Ngetich c a University of Embu, Department of Agricultural Resource Management, P.O. Box 6-60100, Embu, Kenya b Kenyatta University, Department of Geography, P.O. Box 43844-00100, Nairobi, Kenya c University of Embu, Department of Land and Water Management, P.O. Box 6-60100, Embu, Kenya d Kenya Agricultural Livestock and Research Organization (KALRO) - Muguga, P.O. Box 30148 – 00100, Nairobi, Kenya ARTICLE INFO Keywords: Nitrous oxide Methane Carbon dioxide Yield-scaled greenhouse gas emissions Emission factors ABSTRACT Few studies have quantified soil greenhouse gas (GHG) -CH 4 , CO 2 N 2 O – annual fluxes directly from small- holder maize cropping systems under different soil fertility management technologies in Sub Saharan Africa. We quantified soil GHG annual fluxes from smallholder maize cropping systems under four different soil fertility management technologies in the Central Highlands of Kenya. We regularly sampled GHG from 2nd March 2018 to 1st March 2019 (1 year) in three maize farms using a static chamber technique. The fertility management technologies were: inorganic fertilizer, animal manure, animal manure combined with inorganic fertilizer, and a Control (No external input). The experimental design was a randomized complete block design replicated thrice. Cumulative annual soil fluxes ranged from -2.40 kg CH 4 -C ha -1 yr -1 from the control treatment to -1.62 kg CH 4 -C ha -1 yr -1 from the manure combined with inorganic fertilizer treatment, 4810 kg CO 2 -C ha -1 yr -1 from the control treatment to 6576 kg CO 2 -C ha -1 yr -1 from the inorganic fertilizer treatment, and 0.21 kg N 2 O-N ha -1 yr -1 from the control treatment to 0.38 kg N 2 O-N ha -1 yr -1 from the inorganic fertilizer treatment for CH 4 , CO 2 , and N 2 O fluxes, respectively. Fertilizer treatment produced the highest CO 2 emissions (p < 0.001), N 2 O emissions (P < 0.001), and yield-scaled N 2 O emissions (YSE), (0.028 g N 2 O-N kg -1 grain yield). A com- bination of manure and inorganic fertilizer produced the highest CH 4 fluxes (p = 0.035) across treatments. We concluded that a judicious combination of organic resources (animal manure) and inorganic resources (fertilizer) has the potential to enhance food security while mitigating soil greenhouse gas emissions in SSA. 1. Introduction Agricultural ecosystems and climate variability are intertwined. The agricultural systems contribute to climate variability through atmo- spheric greenhouse gas (GHG) emissions such as methane (CH 4 ), carbon dioxide (CO 2 ), and nitrous oxide (N 2 O) (Majiwa et al., 2018). The three GHG have been on the rise over the last few decades, increasing positive radiative forcing that results in the warming effect and resultant climate variability (Myhre et al., 2013). The warming effects could lead to negative climate-related changes such as prolonged drought, reduced rainfall amounts, and erratic rains, which can precipitate a decline in productivity of rain-fed smallholder agriculture leading to food in- security (Herrero et al., 2010; Agovino et al., 2019). Hence, to meet the increasing global food demand for the growing population, there is a need to increase food production while mitigating the effects of GHG emissions (Tilman et al., 2011; Lipper et al., 2014). The global agricultural ecosystems account for 14 %–17 % of the total direct anthropogenic GHG emissions (Ciais et al., 2011; IPCC, 2014). Agriculture plays a vital role in Africa, contributing 26 % of the total GHG emissions (Valentini et al., 2014). The agricultural sector in Kenya contributes approximately 30 % of the total GHG emissions (Kenya Climate-Smart Agriculture Strategy (KCSAS), 2017). Carbon dioxide is the most important GHG, while N 2 O and CH 4, though emitted in small quantities compared with CO 2 , play a substantial role in global warming (Smith et al., 2018). For example, N 2 O, a potent ozone layer depleting tracer gas, has 265 times greater global warming potential (GWP) than CO 2 over 100 years time horizon (IPCC, 2014). Methane is a substantial anthropogenic GHG with a GWP of 28 times higher than https://doi.org/10.1016/j.agee.2020.107064 Received 15 May 2020; Received in revised form 10 June 2020; Accepted 12 June 2020 ⁎ Corresponding author. E-mail address: collins.musafiri15@gmail.com (C.M. Musafiri). Agriculture, Ecosystems and Environment 301 (2020) 107064 0167-8809/ © 2020 Elsevier B.V. All rights reserved. T