Use of treated wastewater in irrigation: productive and nutritional aspects of millet and chemical properties of clay and sandy loam soils

This experiment analyzed the effect of the treated wastewater (TWW) use via irrigation on the production of dry matter and content of nutrient and sodium (Na) in millet (Pennisetum glaucum (L.) R. Br.) and on the chemical properties of clay soil (CS) and sandy loam soil (SLS). The study was conducted in 5 x 2 factorial scheme, consisting of five TWW concentrations (0, 25, 50, 75, and 100%), combined with two soil types (CS and SLS). Cultivation in clay soil contributes to the increase of dry matter and nutrient content in millet, compared to cultivation in sandy loam soil. Increased TWW concentration in irrigation water raised dry matter production and nutrient uptake in millet plants, favoured by increased nutrient availability, cation exchange capacity, and base saturation on both soils. In clay soil, the millet plants irrigated with 100% TWW showed a root dry matter production 44% lower than those treatments irrigated with 75% TWW, which may be associated with an increase in soil salinization and sodification. TWW can be sustainably used in millet irrigation, being 75 and 100% the recommended concentrations in the irrigation of clay soil and sandy loam soil, respectively.

Automated summary

This experiment found that using treated wastewater (TWW) for irrigation can enhance dry matter production and nutrient uptake in millet in clay soil, but excessive TWW concentration may lead to soil salinization.