Modeling the Impact of Field Irrigation Management on Soil Water-Nitrate Dynamics: Experimental Measurements and Model Simulations

• Published in: Eurasian soil science 2023-12, Vol.56 (Suppl 2), p.S354-S365
• Main Authors: Shahadha, Saadi Sattar, Zeki, Suhair Luay, Dawood, Ibrahim Abbas, Salih, Riyadh M., Salim, Ahmed Hatif
• Format: Article
• Language: English
• Subjects: Analysis; Cereal crops; Crop yield; Crop yields; Crops; Dynamics; Earth and Environmental Science; Earth Sciences; Geotechnical Engineering & Applied Earth Sciences; Groundwater; High temperature; Irrigation; Irrigation practices; Irrigation systems; Irrigation water; Leaching; Moisture content; Nitrates; Root zone; Roots; Simulation methods; Soil; Soil depth; Soil moisture; Soil Reclamation; Soil surfaces; Soil water; Sprinkler irrigation; Strategic planning (Business); Surface irrigation; Water content; Water management; Water quality; Water requirements; Water, Underground; Wheat industry
• ISSN: 1064-2293; 1556-195X
• DOI: 10.1134/S1064229323600768

Irrigation systems and watering rates in Iraq often exceed crop water requirements, which yield high soil nitrate (NO 3 ) leaching out of the effective depth of crop roots. This work was conducted to discover the impact of different irrigation management conditions on the soil water-nitrate dynamics to develop management practices for minimizing soil NO 3 leaching out of the effective crop roots. The Root Zone Water Quality Model (RZWQM2), which integrates water-nitrate dynamics and related processes, can assist in improving the acknowledgment of soil water-nitrate dynamics. A field experiment was conducted at A-l‑Raeeid Research Station, Baghdad, Iraq; with a wheat crop irrigated by sprinkler and surface irrigation systems at different watering rates of 30, 50, and 70% of the available soil water. RZWQM2 was used to explore the interactions between irrigation practices and soil nitrate dynamics. The model satisfactorily worked for the study field conditions after the calibration process and simulated the impact of irrigation management on the soil water-nitrate dynamics. The results indicate that the high watering rate of irrigation led to a higher amount of soil water content and soil nitrate in the surface soil depths for both irrigation systems. Sprinkler irrigation yielded 0 mg/cm 2 /day nitrate flux toward the groundwater for all watering rates, whereas surface irrigation produced 314, 94, and 183 mg/cm 2 /day for the watering rate of 30, 50, and 70%, respectively. Hence, the best irrigation management strategy for the local area of high temperatures is increasing the number of irrigation events with low application rates to achieve an appropriate balance of high crop yield and low nitrate leaching toward the groundwater.