Chemical composition of prickly pear cactus (Opuntia stricta Haw) irrigated with saline water in semi-arid soils

Abstract

The objective of this study was to investigate the effect of application of saline water in different soils on the accumulation of sodium and potassium in different structures of prickly pear cactus (Opuntia stricta Haw) variety ‘Orelha de elefante mexicana’. The experiment was laid out in a randomized-block design with treatments arranged in a 3 × 4 factorial arrangement (three soil types: chromic Luvisol, Solonetz and Fluvisol × four irrigation water salinity levels: 0.75, 3.0, 5.25 and 7.50 dS m-1, at 25 °C), using three replicates. At 360 days after planting, the plants were harvested, dried in a forced-air oven, ground and digested. After the digested samples were obtained, the sodium and potassium contents of each plant structure were determined by flame emission spectrometry, using a flame photometer. The soil types significantly influenced the potassium content in the mother and primary cladodes, whereas the salinity levels did not influence the potassium content in any of the plant structures. Higher sodium contents were found in the roots as compared with the other structures, but which did not differ statistically between the soils. Under salt stress, sodium tended to accumulate in the roots and mother cladodes. Chromic Luvisol is the most recommended soil for growing prickly pear cactus ‘Orelha de elefante Mexicano’ in salt stress conditions.