Increasing water productivity in arid regions using low-discharge drip irrigation: a case study on potato growth

Potato is sensitive to excess or deficit irrigation and therefore requires the efficient use of water, especially in arid regions. Low-discharge drip irrigation has been suggested as an efficient irrigation method, providing an optimal amount of water and fertilizer directly to the root zone. However, field studies using a continuous irrigation system with low discharge have rarely been reported, in particular for arid regions. The main objective of the current study was to optimize the irrigation regime of low-discharge drip irrigation under potato growth. Specifically, we examined combinations of dripper discharge, dripper spacing, and irrigation doses. We report the results from two subsequent years of potato growth in the Arava Desert, Israel. The results obtained suggest that the lower the irrigation dose, the higher the water productivity (i.e., yield/dose), regardless of the dripper discharge (first year 0.6 vs. 1.6 L h⁻¹ and second year 0.6 L h⁻¹) or spacing (first year 20 vs. 40 cm and second year 25 vs. 50 cm). In terms of economic viability and/or food production, the results of this study imply that one may consider using low irrigation doses relative to the optimal. Specifically, for a given field, the total tuber yield will be smaller. However, if available agricultural lands are not a limiting factor (such as in the Arava Desert), higher yields can be obtained with a small irrigation dose in a larger area, with no significant reduction in tuber quality.