Effects of Different Irrigation Levels and Nitrogen Fertilization on Some Physiological Characteristics of Potato

Abstract Water and nitrogen are agricultural inputs that are widely used in potato production areas. Excessive and inappropriate use of these two important inputs causes rapid consumption of water resources and results in inappropriate nitrogen leakage. In potato production, understanding the effects of water and nitrogen on the physiological properties will help to overcome these difficulties. This study was therefore conducted to determine the effects of different nitrogen and irrigation levels on the physiological (photosynthesis rate, leaf area index, leaf chlorophyll content, leaf temperature) characteristic of potato. Field experiments were conducted during the 2021 and 2022 main potato cropping seasons to select the suitable combination of irrigation and fertilization levels for potato production in the Nigde Province of the Central Anatolia Region of Turkey. The study conducted in a factorial design with six nitrogen fertilization rates and three irrigation levels. The experiment included no nitrogen (control, N0), 100 kg N ha − 1 (N1), 200 kg N ha − 1 (N2), 300 kg N ha − 1 (N3), 400 kg N ha − 1 (N4) and 500 kg N ha − 1 (N5) and I1 = 100%, I2 = 66%, I3 = 33% of Field Capacity (FC). All the measurements were taken at five different times (40, 50, 60, 70, 80 days) after emergence. The results revealed that nitrogen treatments improve the crop physiology traits by increasing the photosynthetic rate, chlorophyll content and leaf area index, except the leaf temperature, compared with the control (no-nitrogen treatments) while the full irrigation (I1) treatment recorded the highest photosynthesis and leaf area index values. I1N3 was the most efficient treatment for both photosynthesis and leaf area index. The increase in irrigation treatments resulted in a decrease in leaf chlorophyll and leaf temperature (Pt). Leaf chlorophyll content tended to increase with increasing nitrogen, but leaf temperature did not show a regular increase or decrease. The highest N and I interaction for leaf chlorophyll content and leaf temperature were obtained from I3N0 treatment. This study identifies the most appropriate nitrogen and irrigation application for optimum physiological yield of the potato for crop producers. The study used only one commercial potato cultivar (agria), so more research should be carried out on several cultivars in order to arrive at a more conclusive conclusion, since it may be that this result is unique to agria potato cultivars only. In addition, both biochemical and physiological assessments in comparison with tuber yield should be conducted using different nitrogen and irrigation levels to assess their correlations.