Effects of Water Deficit on Water and Nitrogen Coupling Management of Potato

This study aimed to explore how regulated water deficits influence potato growth, yield, and the efficiency of both water and nitrogen use under a water-nitrogen integrated management approach. A field experiment was designed to examine the interactive effects of water limitation and nitrogen application on soil moisture dynamics throughout the entire potato growing season. When soil moisture was maintained at 70-80% of field capacity (mild deficit), potato roots developed more vigorously, and despite a slight reduction in aboveground biomass, tuber yields remained comparable to those under full irrigation. A slightly more pronounced water deficit (60-70% of field capacity) further increased WUE, though a minor yield reduction was observed. In contrast, severe water stress (below 60% of field capacity) notably restricted plant growth and led to a substantial decline in yield. The study also found that increasing nitrogen input could partially mitigate the negative impacts of water shortage. However, applying nitrogen in excess not only reduced its utilization efficiency but also heightened environmental risks. These results provide important guidance for optimizing water and nitrogen management in potato cultivation. It is recommended that, in practical applications, a mild to moderate deficit irrigation strategy be employed, with nitrogen fertilizer rates adjusted in response to soil moisture levels to support both resource efficiency and sustainable potato production.