Sunflower nutrition irrigated with domestic sewage treated

Abstract

This study aimed to evaluate the nutritional status of the sunflower (Helianthus annus L.) irrigated with domestic effluents. The study was performed in a pilot sewage treatment plant, where the treatments were composed by the combination of two factors: types of water (A1 - effluent treated by UASB reactor; A2 – effluent treated with digester decant and anaerobic filtering; A3 – effluent treated with anaerobic filtering; and A4 – water supply) and irrigation depths (L1 - equal to the crop evapotranspiration (ETc) and L2 – 1.2 ETc. The experimental design was in randomized blocks, in a 4 x 2 factorial scheme, with four replications. At 96 days after sowing, the leaves, capitulum, and achenes were collected for the concentration evaluation of N, P, K, Ca, Mg and S. The analyses of variance were performed based on the concentration of the nutrients in the respective organs; when significant, they were analyzed by orthogonal contrasts. The sunflower nutritional status was influenced by the types of treatment for the domestic sewage, especially regarding N, Ca and S, and by the irrigation depths; the sunflower crop presented a better nutritional balance when irrigated with treated domestic effluents; with the application of the water supply only, the nutritional supply of the P and S, is necessary.

Hydrogen peroxide as a saline stress attenuator in okra (Abelmoschus esculentus L.)

“…Stomatal closure is a strategy to prevent water loss to the environment and maintain high water status in the cell (DIAS et al, 2019). Decrease in gs in plants grown under water salinity has also been observed in other crops, such as cowpea (OLIVEIRA et al, 2017) and zucchini (DANTAS et al, 2021).…”

“…The experimental design used was randomized blocks, in a 5 × 3 factorial arrangement, referring to five levels of electrical conductivity of water -ECw (0.3; 1.3; 2.3; 3.3 and 4.3 dS m -1 ) and three concentrations of hydrogen peroxide -H 2 O 2 (0, 25 and 50 μM) with five replicates and one plant per plot. Due to few studies with H 2 O 2 in vegetables, the concentrations used were based on studies carried out with zucchini (DANTAS et al, 2021), passion fruit (RAMOS et al 2021) and passion fruit (Silva et al, 2019), while salinity levels were based on SOARES et al (2020).…”

“…However, the effects of salt stress may vary on each crop, depending on irrigation and fertilization management, edaphoclimatic conditions, species or even development stages (LIMA et al, 2016;SOARES et al, 2021). In this context, alternatives have been sought to mitigate the effects caused by salt stress on plants, among which the exogenous application of hydrogen peroxide (H 2 O 2 ) at low concentrations has proven to be promising in the acclimatization of plants to salt stress (SEMIDA, 2016, SILVA et al, 2019ANDRADE et al, 2022) In addition, H 2 O 2 acts as a signaling molecule in plants under biotic and abiotic stresses, favoring greater accumulation of soluble proteins and carbohydrates that can act as organic solutes, performing the osmotic adjustment of plants under salt stress, thus allowing greater water absorption (ANDRADE et al, 2019;DANTAS et al, 2021;SILVA et al, 2021).…”