Alkalinized sewage sludge application improves fertility of acid soils (original) (raw)

Although it is known that alkalinized sewage sludge raises the pH of acid soils, there is limited knowledge regarding its effects on other soil fertility indicators, such as P and K availability and soil organic C content. Thus, the goal of this study was to evaluate how the application of alkalinized sewage sludge affects the fertility of acid soil. Twenty sewage treatment plants were selected throughout Paraná State (Brazil), and samples of alkalinized sewage sludge and samples of the most representative agricultural soil of the region were collected (covering soils with medium, clayey or very clayey texture). Each soil was incubated for 60 days with doses of sewage sludge (0, 10, 20, 40, and 80 Mg ha-1) from its region and equivalent doses of limestone. The alkalinized sewage sludge was superior to limestone in the correction of soil acidity (pH, Al3+, and H + Al3+) and P and Ca2+ availability. The sludge also increased Mg2+ availability in all soils, K+ in seven soils and organi...