In irrigated areas, the annual means and cycles of these soil moisture additions correlate well with irrigation, while these correlate less with the precipitation bias. Therefore, it is concluded that in irrigated areas, it is more likely that the soil moisture additions are caused by irrigation than by the precipitation bias. In non-irrigated areas, a weak statistical relation between soil moisture additions and precipitation bias is present. As irrigation influences the water balance in atmospheric reanalysis systems, it is recommended to include this process in the reanalysis models. Moreover, as irrigation has an influence on the local and regional atmosphere, this influence should be taken into account when interpreting atmospheric data over strongly irrigated areas.