Validation of SALTMAD model for simulating soil moisture and faba bean productivity under deficit irrigation and integrated fertilization in the semi-arid regions
Authors:   National Research Centre, Agricultural and Biological Research Institute, Water Relation and Field Irrigation Department, 12311, Cairo, Egypt, Eid Abdelraouf Ramadan , Fathy Maher ,   National Research Centre, Agricultural and Biological Research Institute, Water Relation and Field Irrigation Department, 12311, Cairo, Egypt, El-Sayed Ayman ,   National Water Research Center, Drainage Research Institute, 13621/5, El-Qanater El-Khayreya, Egypt, Hafez Mohamed ,   Land and Water Technologies Department, Arid Lands Cultivation Research Institute (ALCRI), City of Scientific Research and Technological Applications (SRTA-City), New Borg El-Arab, 21934, Egypt, El Shirbeny Mohammed Ahmed ,   National Authority for Remote Sensing and Space Sciences (NARSS), Cairo, Egypt, Reda Amr Mohammed ,   Rice Department, Field Crops Research, ARC, Sakha, Kafr El-Sheikh 33717, Egypt, Mady Ahmed Yehia ,   Ain Shams University, Faculty of Agriculture, Soil Science Department, 11241 Cairo, Egypt
Published: November 2023

Lack of water is the main problem facing agriculture and crop production in arid and semi-arid regions. Deficit irrigation is widely used to optimize water application efficiency under drought conditions in arid areas. The purpose of the work is to estimate the efficiency of SALTMAD model for simulating soil moisture dynamics, water application efficiency, and seed yield under three Deficit Irrigation Strategies (DIS) [DIS1 (100% Full Irrigation (FI)), DIS2 (80% FI), and DIS3 (60% FI)] with six treatments of Integrated Nitrogen-Fertilization (INF) including [INF1 (100% MN + 0% ON), INF2 (80% MN + 20% ON), INF3 (60% MN + 40% ON), INF4 (40% MN+ 60% ON), INF5 (20% MN + 80% ON) and INF6 (0% MN + 100% ON)]. Moreover, the best strategy of deficit irrigation with the best treatment of integrated nitrogen fertilizer will be selected for improving soil hydro-physical properties, water productivity, and seed yield in semi-arid soil regions without any water stress. Field experiment was conducted during 2020/2021 and 2021/2022 at the Research Farm of National Research Center (NRC) at Nubaryia Region, Al Buhayrah Governorate, Egypt. Soil hydro-physical properties including infiltration rate (IR), and soil moisture dynamics were measured in the field. In addition, soil moisture dynamics, water application efficiency, seed yield, and water productivity of bean were simulated using the SALTMAD model and compared with thatmeasured in the field under the above conditions. The results observed that the best treatment that led to increased water application efficiency and seed yield was at DIS2 (80% FI) with INF4 (40% MN+ 60% ON) compared to DIS1 (100% FI), and DIS3 (60% FI). In this strategy, seed yield productivity increased by 43.4% in the first season, and 34.7% in the second season as well as saving irrigation water by up to 20% for cultivated faba bean in sandy soil without any water stress. The usage of balance a combination of mineral and organic fertilizers can be used to compensate for deficit irrigation by improving infiltration rate, water holding capacity, water application efficiency, and seed yield. The SALTMAD model can be used to simulate soil moisture dynamics, water application efficiency, seed yield, and water productivity with little calculation error under different deficit irrigation strategies and integrated nitrogen fertilization in arid and semi-arid areas with sandy soil.