Fertirrigação do abacaxizeiro com água residuária sanitária tratada

Abstract

The agricultural use of treated wastewater (ART) is an interesting alternative of disposal, since it allows the use of clean water in agriculture, contributing to improve soil physical and chemical characteristics, plant growth and fruit to the high concentration of nutrients present in ART. The objective of this study was to evaluate the use of treated wastewater (ART) in the pineapple fertirrigation and its effects on the growth, production, quality and microbiological contamination of the fruits as well as on the physical and chemical characteristics of the soil. The study was delineated in a randomized complete block design, with four replications, in the subdivided plots scheme, with five treatments for the treated wastewater (ART) in the plots and the four plots of the pineapple cultivars: Pérola, Vitória, Smooth Cayenne and IAC Fantástico. The doses of ART were calculated based on the annual maximum limit of Na contributed to the soil, corresponding to 150 kg ha-1 , applying 0%; 100%; 200%;300% and 400% of this limit, which corresponded to 0; 117.3; 234.1; 351.4, and 468.3 mm of applied ART. The experimental design was a randomized block design with four replications. Plant and fruit growth, yield, post-harvest and microbiological quality of fruits and soil physical and chemical attributes were evaluated. The fertigation of pineapple with treated waste water leads to a greater vegetative growth of the cultivar Pérola. Among the studied cultivars, the Vitória had lower fruit growth after the application of treated wastewater. The fertirrigation of the cultivars Pérola and IAC Fantástico with treated wastewater promotes greater fruit growth. The use of treated wastewater is a viable alternative for the fertigation of pineapple. The cultivar Pérola is more productive than the cultivars Vitória, Smooth Cayenne and IAC Fantástico with the density of planting used. Fertigation with ART in pineapple provides productivity and fruits with similar quality to handling with mineral fertilization and clean water. The increase in the doses of treated wastewater promotes increases in the Na and ISNa content of the soil up to the depth of 60 cm. The pH, MO, K+ , Mg2+, SB, t, T and V presented higher values in the 0.0-0.20 m layer. The content of S, Al and H + Al increased with soil depth. The ART can be used in the pineapple fertirrigation, without compromising the physical and chemical attributes of the soil profile and contributes to the increase of nutrient contents in the soil.