There are few studies that have assessed greenhouse gas (GHG) effluxes under dryland agriculture, especially in South Africa. Subsequently, limited data in the sub-Saharan region impedes the formulation of policies on GHG mitigation and adaptation. Therefore, the need to study effluxes of carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) was salient. The objective of the study was to assess GHG effluxes across seasons in conventional tillage (CT) and no-till (NT) systems under nitrogen (N) fertilizer management. Gases were sampled using static PVC chambers and sampling was done by inserting a 25-mL polypropylene syringe into the chamber septa and slowly removing the gas. Samples were analysed for CO2, CH4 and N2O using gas chromatography. In winter, CH4 effluxes were higher under NT than CT for each application rate (p < 0.05). N2O efflux was higher (p < 0.05) under CT at 120 and 240 kg N ha(-1) compared to NT in summer. The CO2 effluxes of CT were higher (p < 0.05) than NT at all N application rates and seasons. Higher GHG effluxes in summer than winter was attributed to higher soil temperature and moisture. CO2 and N2O emissions were positively correlated to tillage with CH4 negatively correlated, but it has to be noted that not only the intensity of tillage influenced effluxes, but also climatic conditions played a huge role in determining the direction of effluxes. Conservation tillage is climate smart and, in this case NT at 120 kg N ha(-1), can be recommended because it sustained less effluxes especially during summer.