Analysis of Potato Growth, Water Consumption Characteristics and Irrigation Strategies in the Agro-Pastoral Ecotone of Northwest China

The agro-pastoral ecotone in Yinshanbeilu is the main potato-producing region. In recent years, the shift from rainfed to irrigated agriculture has created challenges in understanding potato water consumption patterns, water use efficiency, and irrigation optimization. This study utilized the DSSAT model to simulate soil moisture, leaf area index, and potato yield based on a two-year in situ observational experiment. The study showed that simulated values of the soil water moisture, leaf area index, and yield, with Absolute Relative Error (ARE) of 4.18–5.27%, Normalized Root Mean Square Error (nRMSE) of 5.64–8.65%, and Coefficient of Determination (R2) values of 0.86–0.921, exhibited acceptable accuracy. Simulated results pointed out that potato water consumption ranged between 375.2 and 414.2 mm, with 50–52% occurring during tuber formation to bulking stages, and the average water consumption intensity was 2.62~2.81 mm/d. Based on DSSAT model simulation, this study found that water use efficiency (WUE) reached 162.17–166.20 kg/(hm2·mm), while irrigation water use efficiency (IWUE) varied between 86.1 and 108.1 kg/(hm2·mm). With the highest yield as the target, the recommended irrigation amounts for potato in normal year and dry year were 180 mm and 240 mm. With the highest utilization rate of groundwater resources as the target, the recommended irrigation amounts in normal year and dry year were 162 mm and 192 mm. These findings offer valuable insights for promoting sustainable groundwater use and enhancing water conservation practices in the Yinshanbeilu agro-pastoral ecotone.