The current status of water resources in the U.S. Central High Plains necessitates adopting water conservation practices to move toward a sustainable agricultural economy. Identifying proper irrigation scheduling techniques is a conservative practice to maintain the sustainability of the agricultural systems. However, conducting field experiments is time and money consuming. Thus, the utilization of crop models, such as AquaCrop, could be a convenient alternative to field experiments. The FAO AquaCrop model was calibrated and validated for simulating forage sorghum yield response to various deficit irrigation conditions in a semi-arid region. Afterwards, the model was used to investigate the efficiency of the pre-season and in-season irrigation scheduling scenarios. In this study, the soil water status at the planting time was considered as the indicator of the pre-season irrigation level. Therefore, the pre-season irrigation scenarios were arranged as the replenishment of soil water deficiency at the time of planting at up to 30, 50, and 100% of the soil’s total available water for the first 60 cm of soil depth and the same replenishment levels for the entire crop root zone (150 cm soil depth). Then, AquaCrop long-term (37 years) simulations of forage sorghum biomass and irrigation water use efficiency reactions to three levels of maximum allowable depletion (MAD) (40, 55, and 70%) were compared to three fixed irrigation interval (4, 6, and 10 days) scenarios by considering six pre-season irrigation conditions (36 scenarios). The scenarios analysis found the 10-day irrigation interval and the MAD levels of 55% and 70% to be the most efficient irrigation scheduling strategies if combined with pre-season irrigation that brought the crop root zone (0–150 cm soil depth) to field capacity. Moreover, the 40% MAD application was the least efficient strategy. This study’s outputs can be a baseline for establishing forage sorghum irrigation scheduling in the U.S. Central High Plains. However, exploring the interactions of irrigation scheduling strategies with other irrigation and agronomic practices, such as salinity management and fertilizer application, is highly recommended.

The Zayandeh-Rud watershed of Iran has had water scarcity for decades, giving rise to pressures toward limiting water allocation for the agriculture sector. Marginal waters can be an alternative source for irrigated agriculture in water-scarce regions if adequately managed. One of the critical hazards for sustainable agriculture and the environment is the accumulated salinity–sodicity problem as a consequence of irrigating with unconventional waters. Applying additional water beyond the crop water requirement, known as leaching application, has been suggested as a solution to this problem. A physical model was built to investigate the effects of the severe sodicity and salinity conditions of irrigation water by creating 250 mm diameter soil columns (27 columns) filled with sandy clay loam soil. The severity of the irrigation water’s sodicity (sodium adsorption ratios (SAR): 5.27, 16.56, and 28.57) and its interactions with various leaching fractions (0%, 15%, and 30%) on critical soil chemical characteristics and corn yield were studied. Implementing a 30% leaching fraction reduced the SAR and salinity in the soil’s first layer (0–10 cm) when irrigating with saline–hyper-sodic water (SAR = 28.57 and ECiw = 9 dS/m). However, an elevated level of sodicity accumulation in the soil profile was observed, emphasizing the importance of adding calcium and magnesium amendments during the irrigation season. A noticeable increase in the efficiency of leaching applications in reducing accumulated salts and the sodicity level in the corn rootzone was detected with higher levels of irrigation water sodicity. The reduction in the accumulated salinity and sodium in the first soil layer due to implementing a 30% leaching fraction resulted in a 223.3% increase in the total biomass of silage corn. Applying a 30% leaching fraction also increased the corn biomass by 58% and 114.56% when irrigating with waters with 5.57 and 16.56 SAR values. The effectiveness of a 15% leaching fraction for enhancing the soil and crop conditions was significantly lower than that of the 30% leaching fraction. Nevertheless, in case of unavailability of sufficient water supply for irrigation purposes, applying a 15% leaching fraction could mitigate the consequences of sodic water irrigation. The results demonstrate that in the absence of the proper calcium amendments, the implementation of leaching management could still be effective in enhancing corn production under sodic water irrigation conditions.