| To examine the effects of different straw returning methods on soil acid\|hydrolysable organic nitrogen and potato yield in rainfed potato fields in the semi\|arid region of Northwest China, a field experiment was conducted from 2022 to 2023 with four treatments: bare land (CK), plastic film mulching (PM), crushed straw returning (SR), and whole\|straw strip mulching (SM). The study analyzed soil total nitrogen (TN), acid\|hydrolysable organic nitrogen fractions—including amino acid nitrogen (AAN), ammonium nitrogen (AN), hydrolysable unknown nitrogen (HUN), and amino sugar nitrogen (ASN)—as well as the C/N ratio, soil organic matter (SOM) content, and potato yield. The results showed that SR and SM treatments significantly enhanced the accumulation of TN and total hydrolysable nitrogen (HN) in the 0~60 cm soil layer. Specifically, SM increased TN and HN by 4.33% and 12.51%, respectively, compared to SR. In contrast, PM negatively affected TN and HN accumulation in the 0~60 cm layer, reducing them by 7.85% and 8.48% relative to CK. The concentrations of acid\|hydrolysable organic nitrogen fractions across all treatments followed the order: AAN > AN > HUN > ASN. Both SR and SM treatments increased the contents of AAN, AN, and ASN to varying degrees. Compared to CK, PM and SR elevated the soil C/N ratio in the 0~60 cm layer in 2023, while SM reduced it. SR and SM significantly improved SOM content in the 0~60 cm layer, with SR exhibiting a 9.82% higher SOM than SM. However, PM reduced SOM content in the 0~20 cm layer by 5.32% compared to CK. In 2023, potato yields under SR and SM treatments increased significantly by 23.97% and 16.81%, respectively, compared to CK, with benefit\|cost ratios rising by 18.85% and 21.31%. In conclusion, whole\|straw strip mulching (SM) more effectively enhances soil nitrogen supply capacity, improves soil fertility, and increases potato yield, making it the recommended straw\|returning practice for rainfed potato fields in semi\|arid regions. |