Pineapple ‘D’ leaf nutrient content in response to treated wastewater fertigation

Treated wastewater use in agriculture, in addition to reducing the demand for clean water for irrigation and pollution of rivers and streams, may decrease the fertilizer needs. Therefore, it is an effective solution for pollution control, environmental preservation, and saving of water and fertilizer. The aim of this study was to evaluate the macronutrients, sodium and chlorine content in dry matter of ‘D’ leaf of pineapple plants fertigated with treated wastewater (TWW). The study was designed in randomized blocks with four replications in a split-plot arrangement. The plots consisted of five application rates of TWW, corresponding to 0, 100, 200, 300, and 400% of the maximum annual limit of Na applied to the soil (150 kg ha^‑1), which resulted in irrigation depths of 0, 117.3, 234.1, 351.4, and 468.3 mm of TWW applied, respectively. The split-plots consisted of four pineapple cultivars: ‘Pérola’, ‘Vitória’, ‘Smooth Cayenne’, and ‘IAC Fantástico’. ‘D’ leaf was sampled at forcing date. Content of macronutrients (N, P, K, Ca, Mg, and S), sodium and chlorine in ‘D’ leaf dry matter were evaluated. There were no differences between the cultivars regarding ‘D’ leaf N, P and K contents. ‘D’ leaf contents of S and Cl were higher in ‘Smooth Cayenne’, while differences in Na content among cultivars were observed only at the maximum TWW dosis. The increase of TWW doses promoted an increase in ‘D’ leaf N, P and S contents for ‘Perola’, ‘IAC Fantastico’ and ‘Smooth Cayenne’ cultivars, respectively, but reduced the ‘D’ leaf N content of ‘Smooth Cayenne’.