Potatoes require regular, uniform watering during the growing season for optimal productivity. Potatoes are sensitive to water shortages due to the plant's shallow root system and large leaf area. Water shortages during establishment can limit emergence and early vine growth. Inconsistent watering at flowering impacts stolon initiation and number. Water deficits during tuber bulking limits size, shape and contributes to reduced tuber quality (necrosis, black spot, hollow heart, heat sprouting). Over-watering encourages foliar and root diseases, impacts tuber quality, delays senescence and skin set, and interferes with harvest.
Common irrigation methods include furrow, sprinkler and in some areas drip irrigation. Regardless of the system used, the goal of soil water management is to maintain adequate soil moisture while avoiding extreme or excessive fluctuations. The amount of water applied during an irrigation event depends of the infiltration rate and water-holding capacity of the soil. Specific guidelines on irrigation depend on soil type, stage of growth, and local conditions (temperature, RH, wind). Soil water
status should be monitored regularly to maintain consistent soil water using a resistance block such as the Irrometer Watermark sensor. Place sensors throughout the field and at several depths to get an accurate measure of soil water content. Start irrigations at 15-25% depletion during vegetative growth. During tuber initiation and tuber bulking, soil should be maintained at 80-90% of available soil water (10-20% depletion) for optimal production.