PP cotton-wrapped subsurface drip irrigation can increase potato yield and sustainability in arid regions

Although subsurface drip irrigation (SDI) is widely used for shallow-rooted crops in arid regions, it still suffers from exogenous clogging, and effective, systematic physical protection measures are lacking. Therefore, a 3 × 4 two-factor factorial field experiment was conducted in a potato field in Mizhi, Shaanxi Province, China, with three irrigation levels and four drip tape anti-clogging measures, yielding 12 treatment combinations. The comprehensive effect of these two factors on the root-zone soil moisture–nutrient environment, potato yield, tuber quality, and economic returns were evaluated. The results showed that SDI with a polypropylene (PP) cotton-wrapped drip tape (D3) significantly improved the root-zone moisture and nutrient environment in arid potato fields, similar to traditional drip irrigation, while maintaining stronger adaptability under drought. Under 75%–85% crop evapotranspiration ( ET c ), the PP cotton-wrapped drip tape achieved a soil moisture content of 19.00% and a soil moisture uniformity of 98.47%. It further improved the uniformity and stability of soil moisture and NO 3 - -N distribution. Yield and water productivity ( WP ) were improved by about 10%, and economic returns increased by about 19.5%, making it the optimal strategy in terms of overall benefits. In addition, a yield prediction model (R² = 0.89, r = 0.94) was developed based on leaf area index (β = 0.90), irrigation amount (β = 0.61), NO 3 - -N (β = 0.45), and soil moisture uniformity (β = −0.06). This model provides a quantitative tool to simplify monitoring indicators and implement precise irrigation scheduling. Structural equation modeling further confirmed the significant effects of irrigation amount (β = 0.91***) and anti-clogging measure (β = −1.28***) on potato performance. However, tuber quality was negatively correlated with economic returns (β = −0.24*), revealing an inherent trade-off between yield and quality. This study offers a new perspective and important reference for designing underground anti-clogging measures for SDI in potatoes and other shallow-rooted dryland crops on the Loess Plateau and in similar arid regions.