Evaluation of Drip‐Irrigated Water‐Saving Cultivation and Stage‐Specific Irrigation Withholding in Sweetpotato

This study evaluated drip‐irrigated water‐saving cultivation and stage‐specific irrigation withholding effects on yield and tuber quality in sweetpotato ( Ipomoea batatas ). A field experiment included conventional furrow irrigation (CK), drip‐irrigated water‐saving cultivation (T1), late‐stage irrigation withholding (T2), midstage irrigation withholding (T3), and mid‐ to late‐stage irrigation withholding (T4). Compared with CK, T1 reduced irrigation water input by 21.9%, while the difference in marketable tuber yield was not statistically significant despite a numerically lower mean yield under T1. Most fresh tuber quality traits and sensory acceptance of steamed tubers were also not significantly affected. Based on irrigation water input, yield‐based irrigation water productivity was 6.3% higher in T1 than in CK. Among the drip‐irrigated treatments, late‐stage irrigation withholding (T2) had limited effects on marketable tuber yield, whereas midstage (T3) and mid‐ to late‐stage (T4) irrigation withholding reduced tuber number and marketable tuber yield. Irrigation withholding, particularly in T4, increased total soluble solids and sucrose content but reduced starch content, whereas midstage irrigation withholding altered selected starch pasting properties, mainly peak time and pasting temperature. These results suggest that drip‐irrigated water‐saving cultivation reduced irrigation water input, while no statistically significant differences were detected in marketable tuber yield or most fresh tuber quality traits under the present field conditions. In contrast, the midgrowth stage appeared to be particularly sensitive to water limitation, with negative effects on tuber formation and marketable tuber yield.