The potato tuber contains a lot of water, the average water content is nearly 80%, the stem and leaves are luxuriant, and the transpiration is large. Therefore, during the whole growth period, especially into the potato bearing period, it is necessary to absorb a lot of water, and the lack of soil water is difficult to produce. It is generally believed that for every 1kg of dry matter formed, 300-600kg of water is consumed.
Tuber formation stage is the period of the most water demand, in the early and full tuber forming stage, the soil water content of 70-80% of the maximum field water capacity is more suitable.
Tuber formation and rapid expansion period, tuber peak period of water consumption accounted for more than half of the total water demand of the whole growth period, soil water content to maintain the maximum field water capacity of about 70%. Therefore, the early maturing varieties need the most water from the bud stage to the end of flowering, the stems and leaves grow rapidly, the tubers form in large quantities. The whole stage from flowering to stem and leaves stop growing belongs to tuber swelling stage, and the water requirement period is longer than that of early maturing varieties.
