Interactive study of phosphorous 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.