Millet irrigation with treated wastewater: Gas exchange response and nutrient accumulation

Abstract

Wastewater can be considered an excellent nutritional and water source for cultivated plants. However, the presence of high concentrations of salts and toxic compounds can negatively affect crops. The effect of irrigation with different concentrations of treated wastewater on the accumulation of nutrients and gas exchange aspects of millet (Pennisetum glaucum (L.) R. Br.) grown in clay soil and sandy loam soil was analyzed. This study was conducted in a greenhouse (16°40’57,50” S; 43°50’26,07” O; 650 m) in a 5 x 2 factorial design, consisting of five levels of concentration of treated wastewater (0, 25, 50, 75, and 100%), combined with two types of soil (clay and sandy loam). The experiment was designed in randomized blocks with four replicates. The increase in treated wastewater concentration in irrigation water applied to clay soil and sandy loam soil favored the increase of net photosynthesis, transpiration rate, stomatal conductance, leaf chlorophyll content and accumulation of macro- and micronutrients in millet plants. Millet plants grown in clay soil showed an average increase of 23% in gas exchange capacity and 71% in accumulation of macro- and micronutrients, when compared with treatments in sandy loam soil. Therefore, treated wastewater contributes to the increase in gas exchange capacity and greater accumulation of nutrients in millet plants, which represents an alternative for reduced demand for fresh water and use of chemical fertilizers.

Lawn irrigation with domestic wastewater by subsurface drip or sprinkling

“…The increasing grass growth observed with the increasing DW depths is due, in large part, to its nutrient load, considering that at depth of 100% ADEv, applied via drip irrigation, the grasses accumulated up to 10 times more mass when compared with treatment with TW at the same irrigation depth. Domestic wastewater contributed to the greater nutrient accumulation in millet plants, representing an alternative for reducing the demand for water and the use of chemical fertilizers (Reis et al, 2019). Thus, the largest accumulation of dry matter in zoysia grass was provided by the application of the highest DW depth via subsurface dripping.…”

Reuse of Treated Wastewater for Crop Irrigation: Water Suitability, Fertilization Potential, and Impact on Selected Soil Physicochemical Properties

“…Additionally, TWW has the potential to remediate and restore degraded and contaminated sandy soils [12][13][14]. The use of TWW for irrigation could come with some demerits, such as soil salinization, the risk of heavy metals, and the microbial contamination of food crops.…”

Impactos de metais pesados presentes na água e esgoto tratado usados para irrigação de área situada na bacia do rio Vieira e em sistema de cultivo de milheto (Pennisetum glaucum)

“…Embora o uso de água residuária na agricultura promova aumento de produção e disponibilidade de nutrientes no solo (BEN HASSENA et al, 2018;DUBE et al, 2018;REIS et al, 2019), o acúmulo de metais em solos irrigados com água residuárias é uma preocupação por representar riscos ao crescimento e desenvolvimento de plantas e pela possibilidade de bioacumulação nas cadeias tróficas (CHOPRA e PATHAK, 2015). Os metais são poluentes ambientais não biodegradáveis que podem prejudicar a disponibilidade de nutrientes essenciais para o crescimento e desenvolvimento das plantas, além de ter natureza tóxica, neurotóxica, cancerígena, mutagênica ou teratogênica no organismo de animais e seres humanos (EU, 2002;JAHANY e REZAPOUR, 2020).…”