Drip Tape Placement Depth and Emitter Spacing Impact Phosphorus Availability to Potato Crops Under Phosphorus Fertigation

Abstract Fertigating with phosphorus (P) through drip irrigation has recently emerged as a promising strategy to enhance phosphorus use efficiency (PUE) in potato production. However, due to P’s limited mobility in soil—particularly in the lateral direction—and the relatively sparse root system of potatoes, its uptake remains suboptimal under conventional practices. This study, conducted from 2021 to 2022 in Inner Mongolia, China, investigated whether modifying drip tape depth and emitter spacing could improve the spatial alignment between soil-applied P and potato roots, thereby boosting PUE. Two variables were tested: the depth of drip tape placement and the distance between emitters. Key parameters measured included plant dry weight, leaf area index (LAI), soil Olsen P concentration, root distribution, tuber yield, and partial factor productivity of fertilizer P (PFP P ). Results showed that subsurface drip tape placement at a 10 cm depth or reducing emitter spacing to 15 cm significantly improved root-P alignment. These adjustments led to increased P uptake, higher LAI, greater biomass accumulation, and improved tuber yield and PFP P compared to the conventional setup (surface drip tape with 30-cm emitter spacing). The findings underscore the importance of optimizing drip tape configuration to synchronize P availability with crop demand. Deep placement and closer emitter spacing can significantly enhance PUE and yield in drip-fertigated potato systems, offering valuable guidance for more efficient P management in potato production.