| To investigate the effects of adding conditioners to fertilizer applications at different fertility stages on the regulation of soil physicochemical properties and potato yields, the main processing potato variety ‘Burbank’ grown in the Zhangjiakou Bashang area was selected as the research subject. A control treatment using traditional fertilizer rates (CK: 10%, 10%, 55%, 25%) was compared with treatments applying fertilizer at different fertility stages-seedling, tuber formation, tuber expansion, and starch accumulation-combined with the addition of a polymer conditioner. This polymer, synthesized from polyvinyl alcohol, polyacrylamide, and manganese sulfate, was designed to have a ‘bailout’ effect on soil and crop performance. Eight treatment groups (T1~T8) were established with varying fertilizer distributions: T1, 10%, 10%, 55%, 25%; T2, 20%, 40%, 30%, 10%; T3, 30%, 30%, 40%, 0%; T4, 30%, 40%, 30%, 0%; T5, 30%, 50%, 20%, 0%; T6, 30%, 70%, 0%, 0%; T7, 20%, 80%, 0%, 0%; and T8, 10%, 90%, 0%, 0% to analyze the effects of the treatments on the soil water\|holding capacity, the distribution of water\|stable clusters, and soil nutrients and yield. The results showed that, compared with conventional fertilization measures, the addition of conditioners under different fertilizer ratios significantly increased soil water holding capacity (saturated water holding capacity, capillary water holding capacity, field water holding capacity) and the content of organic matter, total nitrogen, quick\|acting phosphorus and quick\|acting potassium in the soil layer of 0~60 cm, increased soil water storage capacity and potato yield in the soil layer of 0~100 cm, and lowered the soil bulk density; among them. Among the treatments, T4 resulted in the most significant increase in potato yield (an increase of 46.00%), while soil nutrient content was highest in T1 and T2 (with increases ranging from 9.26% to 158.65%). Soil water\|stable aggregates in all treatments were primarily composed of 0.25~1 mm macroaggregates and 0.053~0.25 mm microaggregates. In the 0~60 cm soil layer, the proportion of macroaggregates larger than 0.25 mm (R0.25), the mean weight diameter (MWD), and the geometric mean diameter (GMD) in the T4 treatment were significantly higher than those in the control (CK), by 76.27%~162.91%, 55.77%~332.69%, and 95.24%~531.25%, respectively. With increasing soil depth, R0.25, MWD, and GMD first increased and then decreased. In conclusion, the fertilization pattern of seedling stage: tuber formation stage: tuber expansion stage: starch accumulation stage = 30%: 40%: 30%: 0% (T4) can effectively improve the soil’s physical structure and water retention capacity, while also increasing potato yield. This makes it a suitable method for water and fertilizer management in the Zhangjiakou Dam area. |