Soil fertility and mineral nutrition of “Aljezur Sweetpotato”

Abstract

To assess soil fertility, plant nutritional status and to determine the mineral composition of storage roots, 29 plots of "Batata-doce de Aljezur" were selected and soil, leaf and storage root samples were taken and analysed. The results showed that the soils are sandy, with low levels of organic matter, moderately acidic, with high levels of extractable phosphorus and very low levels of extractable boron and exchange Ca⁺⁺; Mg⁺⁺ and K⁺. The mean leaf nutrient contents in the dry matter were as follows: 37.8 g kg^-1 N, 2.6 g kg^-1 P, 24.1 g kg^-1 K, 9.4 g kg^-1 Ca, 6.4 g kg^-1 Mg, 125 mg kg^-1 Fe, 255 mg kg^-1 Mn, 21 mg kg^-1 Zn, 11 mg kg^-1 Cu and 47 mg kg^-1 B. In the storage roots (>50 g), K and Mg were the most exported macro and micronutrient, with average contents of 3.65 g kg^-1 K and 4.49 mg kg^-1 Mg (wet weight).