Grain and Foliar Nutritional Responses of Corn ( Zea mays L.) to Sewage Sludge Soil Application

Corn is one of the major crops in Brazil where acidic soils poor in available nutrients limit grain productivity in the country. Alternative sources of nutrients have been in demand and land application of sewage materials is a cost-effective practice that returns to agricultural soils nutrients removed with harvests. Based on such a scenario, we have tested the performance of a tertiary domestic sewage sludge combined with chemical sources of Ca, Mg, and K to produce corn grains. A field trial was set on a flat area of Oxisol soil to fulfill an experimental design of nine sewage sludge application rates established on randomized blocks in triplicate. Results have shown that increasing rates of sewage sludge have positively influenced productivity and incremented protein and lipids in grains, although it has negatively affected carbohydrate contents in grains that could be attributed to insufficient K availability in the soil at sewage sludge application rates higher than 6.1 dry Mg ha −1 . Sewage sludge was more effective to supply some micronutrients and N than P and S to corn plants. However, it could produce nutritious grains as long as chemical sources of Ca, Mg, and K were supplementarily applied to soils at sufficient rates. Graphical Abstract