Design of Closed-Circuit Drip Irrigation and Deficit Irrigation Scheduling Under Rotation Irrigation Systems to Improve Yield and Water Productivity of Potato Under Arid Climate Conditions

Abstract

Under the conditions of water scarcity in Egypt, there are many farms that follow the rotation irrigation system which add a large and more than necessary amount of water, as the entire weekly amount of water om only three days. This results in the loss of large amounts of irrigation water below the root zone, carrying with it and washing away the nutrients that are beneficial to the growth of the planted crops, which results in a decrease in crop productivity and water productivity and pollution of groundwater by increasing the washing of the relevant fertilizers dissolved in the escaping water downward. Two experiments were conducted during 2022/2023 and 2023/2024 At the National Research Centre (NRC) research farm in Nubaryia Region, Egypt to study the effect of closed-circuit
drip irrigation (CCDI) system and the weekly irrigation deficit strategy was studied in an attempt to maximize the productivity and water productivity of the potato crop, which is one of the important vegetable crops that is grown in large areas in Egypt. It was found that the value of water emission uniformity with CCDI is greater than the water emission uniformity with the traditional open-circuit
irrigation system (TDIS). The highest value of irrigation water application efficiency was achieved with CCDI when the irrigation deficit was scheduled at 40% of the full weekly irrigation over three days, although irrigation at 40% encountered the greatest soil moisture stress. The lowest value of irrigation water application efficiency was achieved with TDIS when the irrigation deficit was scheduled at 100% of the full weekly irrigation over three days, although irrigation at 100% encountered the least soil moisture stress. The lowest soil water stress values were achieved when designing TDIS with irrigation at 100% of the full weekly irrigation. The highest water stress values were also achieved with the TDIS with irrigation at 40% of the full weekly irrigation. The highest productivity and N-Uptake values were achieved with CCDI with the irrigation strategy at 80% and 60% of weekly irrigation for the rotation irrigation system. Based on achieving the highest value of productivity when studying the results of the interaction between the study factors, the highest value of crop water productivity was when applying CCDI and applying the irrigation deficit scheduling strategy at 60% of the full weekly irrigation to save 40% of irrigation water.