Nutritional status and physiological parameters of maize cultivated with sewage sludge

ABSTRACT The use of sewage sludge as a source of nutrients and organic matter for agricultural soils is a well-established practice. However, few reports highlight the effect of the nutrients and potentially toxic elements provided by organic wastes application on the plant physiological parameters, such as photosynthetic activity and stomatal conductivity. We performed a greenhouse experiment with maize exposed to a dystrophic red Latosol amended with mineral fertilizer and different rates of sewage sludge with the following objectives: i) assess the nutrients and metal uptake translocation and distribution in plants and ii) evaluate the relationship between plant physiological parameters and yield indicators under the study conditions. The application of sewage sludge increased the soil organic matter, pH, and the amounts of available Ca, S, and Mg, comparing to the mineral fertilizer treatment. The plants promote a higher translocation of macronutrients to the shoots in the sewage sludge treatments, which results in higher photosynthetic activity, stomatal conductivity, and maize yield parameters. Moreover, the trace elements, which can cause toxicity in small concentrations, were founded mainly in the roots, which indicates a plant defense mechanism.