Potato Irrigation Requirements in a Hot Climate Using Sprinkler and Drip Methods1

Abstract

AbstractPotato (Solanum tuberosum L.) is a heat‐ and drought‐sensitive crop, which in hot climates usually requires large water applications for optimum production. Irrigation water in Israel is both limiting in quantity and high in price; thus it is critical to know the water requirement of the crop, as well as how to improve irrigation efficiency. Field experiments were conducted in the Negev (arid) region of Israel on a Typic Camborthid soil to determine the water production functions of potatoes (‘Desiree’) under drip and sprinkler irrigation. Irrigation treatments were based on Class A pan evaporation. The linear production functions relating total yield in metric ton ha−1 to seasonal water application depth (W) in cm were, for sprinkler irrigation: Y = ‐23.5+1.19W, and for drip irrigation: Y = −12.8+1.14W. Similar total maximum yields were obtained with about 8 % less water with the drip as with the sprinkler method (not statistically significant). A single production function for both methods described the yield of marketable tubers: Y = −40.0+1.28W. These functions apply in the relative water application range (water applied over Class A pan evaporation) of 0.3 to 1.0, at which point the function reaches a plateau. Yield was reduced by 12% as soil water potential in the 0 to 0.6 m depth increment changed from −20 to −29 J kg−1 for sprinkler irrigation. Under drip irrigation the soil could dry to −40 J kg−1 without yield reduction, as long as the water supply was adequate. This was explained by the higher root concentration under drip than under sprinkler irrigation.