Can Phosphorus and Calcium Inputs Improve Tuber Yield and Quality of Potato Grown on Soil Rich in the Both Nutrients in Northeast Florida?.

A survey conducted with potato growers in the Hastings area in northeast Florida indicated that the local commercial potato farms had high levels of extractable phosphorus (P) and calcium (Ca) in the soil. The objective of this research was to evaluate chipping potato (cv. ‘Atlantic’) yield and quality under different application rates of P and gypsum (CaSO₄·2H₂O). A three-year field study was conducted at the University of Florida Institute of Food and Agricultural Ssciences Hastings Agricultural Extension Center, FL in the three growing seasons of 2015, 2016 and 2017. The study included six rates of P (0, 45, 90, 135, 179, 224 kg/ha of P₂O₅) and two rates of gypsum (0, 560 kg/ha) by employing a randomized complete block design with four replications. Mehlich-3 extractable soil P and Ca were 230 and 481; 185 and 553; and 185 and 532 mg/kg on average for the three consecutive growing seasons, respectively. Specific gravity and tuber internal and external quality were not improved by P and gypsum applications in all of the three growing seasons. There were not any significant differences in total yield between the treatments. Total average tuber yield was 55, 50 and 49 Mg/ha in 2015, 2016 and 2017, respectively. The results suggested that applications of P and Ca fertilizers do not contribute to improving potato yield and tuber quality on the soils with high contents of P and Ca in this study.