Phosphorus Fertilizer Rate for Fresh Market Potato Cultivars Grown in Tropical Soil with Low Phosphorus Availability

Knowledge on phosphorus (P) response of main potato cultivars is essential to rational fertilization management and maximize yield, mainly in tropical soils that usually have low P availability. An experiment was conducted to evaluate the effect of P fertilization rates (0, 125, 250, 500, and 1000 kg P2O5 ha(-1)) on leaf nutrient concentrations, tuber yield and size distribution, as well as applied P-use efficiency (APUE) in the potato cultivars Agata and Mondial. The results indicated that it is not necessary to evaluate the P-nutritional status and adjust P recommendations on a cultivar basis because P fertilization resulted in similar increases in the leaf P concentration of both cultivars, and the cultivars responded to the same P rate (500 kg P2O5 ha(-1)). However, Mondial had a higher APUE and was more responsive than Agata to the same P rate. A leaf P concentration of 2.9 g kg(-1) was superior to 2.5 g kg(-1) as the lower limit of the P sufficiency range for Agata and Mondial.