Whole farm soil greenhouse gas fluxes among smallholders cropping systems in Upper Eastern Kenya

Abstract

Limited studies have evaluated whole-farm soil greenhouse gas fluxes from smallholder cropping systems in Kenya. In this study, we evaluated soil greenhouse gas fluxes from different cropping systems in Kenya. The five cropping systems under study were i) sole maize, ii) maize intercropped with beans, iii) coffee, iv) banana, and iv) agroforestry. Gas was sampled using a static chamber arranged linearly in a complete randomized design replicated thrice per cropping system. Gas concentration determination was done using the gas-chromatography approach. Cumulative annual fluxes varied significantly CH₄ (P<0.0001, p=0.05), CO₂ (P=0.0007, P<0.0001), and N₂O (P<0.0001, P<0.0001) in farm one and two respectively across the cropping systems. The annual cumulative fluxes ranged from 5.8 to 13.2 tCO₂-C ha^-1yr^-1 and 0.29 to 1.53 kg N₂O-N ha^-1yr^-1, and 1.39 to -0.25 kg CH₄-C ha-1 yr^-1 across farms and cropping systems. We observed the lowest uptake of CH₄ in the banana cropping system (-0.82± 0.10 and -0.25± 0.9 kg CH₄-C ha^-1yr^-1 from the farm and two, respectively. The different cropping systems among the smallholder farmers in Central Highland of Kenya contribute to varied GHG emissions. The results obtained from our study are in conjunction with the previous findings in SSA. Our findings are pivotal in GHG estimation from agroecosystems and coordination of low GHG emissions in different cropping systems in Africa.