Response of potato growth and yield to potassium fertigation with a subsurface drip system

Abstract Water and fertilizer significantly impact potato ( Solanum tuberosum L.) growth and yield, necessitating an efficient field supply system. This study examined the effects of irrigation and fertigation on potato growth and yield using a subsurface drip system consisting of a pipe buried 40 cm underground. The water required for fertigation was 243 mm ha −1 . Fertigation treatments with water were applied as topdressing through the subsurface drip system with potassium (K) fertilizer concentrations of I (only applied irrigation), K 20, K 50, and K 70 kg ha −1 . Plants fertigated with 50 kg ha −1 (K50) absorbed the most potassium. Absorption did not increase with higher potassium levels; instead, potassium accumulated in the residual soil, linked to the soil's cation exchange capacity. Although potato growth was not significantly different among K treatments, it was highest in the K50 treatment. Yield was also highest with K50 and did not increase with >50 kg ha −1 of potassium. Subsurface drip irrigation had the most substantial impact on yield. While irrigation remained influential during fertigation, its effect diminished as fertigation effectiveness increased up to 50 kg ha −1 of potassium. Irrigation alone increased yield by 32.2% compared with the control, while K50 fertigation increased yield by 56.7%. Overall, this study demonstrates that subsurface drip fertigation with potassium optimizes potato yield, offering a sustainable approach for resource management in agriculture.