Irrigation is inevitable in the study regions due to erratic rainfall and its large spatial and temporal variations that do not address the wheat water requirement during the growing season (Davarpanah & Ahmadi 2021). Irrigation water was supplied from surface water in the S1 and S2 fields and from deep groundwater in the S3 and S4 fields. The electrical conductivity of irrigation water was less than 2.5 dS m⁻¹ in the four locations. Surface irrigation, as the common irrigation method in the four studied regions, was practiced to irrigate the fields. The local irrigation schedule fulfilled by the farmers is four to six irrigation events during the growing season depending on the water availability and rainfall amount and frequency in the regions (Table 2) (Davarpanah & Ahmadi 2021; Solgi et al. 2022). For instance, the growing season 2018–2019 was a wet year, and therefore lower irrigation amounts and less irrigation events were needed (Solgi et al. 2022). Moreover, all irrigation practices were carried out according to the local irrigation strategies of the farmers. The total applied irrigation volume during the whole growing season is given in Table 2. The average depth of applied irrigation water in each irrigation event varied between about 90 and 120 mm resulting from the applied irrigation volume and the number of irrigation events (Table 2).