<p>Water scarcity in semi-arid regions increases the need for effective field practices to enhance water use efficiency and crop production. This study developed RZWQM2 models with field data collected from experimental sites in the semi-arid region of Iraq during the crop-growing seasons of 2022–2023 and 2023–2024 to predict the effects of combined field practices on water and wheat (Triticum aestivum L.) productivity for two different soil textures. We tested two deficit irrigation practices (50% and 70% reduction of the available soil water) and two tillage practices (conventional tillage and No-till) for sandy and silty clay soils. Our model results showed that, at a 50% deficit irrigation level, water flux into the groundwater was 8% higher in sandy soil and 4% higher in silty clay soil under conventional tillage than under No-till. Conversely, at the same 50% deficit irrigation, No-till resulted in 35% lower NO₃ groundwater leaching in sandy soil and 6% lower in silty clay soil compared to conventional tillage. No-till improved productivity in sandy soil, while conventional tillage was more effective in silty clay soil. Combining deficit irrigation of 70% with tillage practices improves water-wheat productivity and reduces water-nitrate loss. These findings emphasize the importance of selecting the optimal combination of field practices regarding soil texture types to enhance water-crop productivity.</p>