Interactive study of phosphorus and sulfur application in potato for sandy soils

Abstract Phosphorus (P) and sulfur (S) interaction has been unexplored in the potato ( Solanum tuberosum L.) cultivation of Florida sandy soils. This study investigated the potato response to P and S applications regarding yield, quality, and fertilizer use efficiency. The three P (0, 56, and 112 kg P ha −1 ) rates were applied along with five S rates (0, 45, 90, 135, and 180 kg S ha −1 ) at two sites with split‐plot randomized complete block designs in 2021 and 2022. The study found that the S and P application did not affect the soil availability of S and P. The effects of P application and sites were observed, where the addition of P significantly increased the dry below‐ground biomass (BGB), and site with higher soil P had higher dry BGB compared to site with lower soil P. The fertilizer uptake efficiency indices showed that adding P and S reduced the fertilizer recovery efficiency and partial factor productivity. The results indicated that adding P increases the crop yield even in the soils with higher Mehlich‐III (M‐III) extractable P concentration. In higher P soils, the application of the S also influenced the tubers' specific gravity, which was higher at 90 kg S ha −1 . In conclusion, this study observed the effects of P fertilizer application even on sites with M‐III extractable P >250 mg kg −1 . However, the interaction effects of P and S were inconsistent, potentially due to as high as 1200 kg ha −1 sulfate application through irrigation water.