Influence of Biosolids Rate on Chemical Properties of an Oxisol in São Paulo, Brazil

Abstract

Organic residues may cause major health and environmental problems. This is the case in our study area, where more than 10 billion L per year of residential and industrial waste are produced. Land application of biosolids can be an economical solution by recycling waste and can provide valuable fertilizer if used correctly. The aim of this work was to study the effect of biosolids on the chemical properties of an Oxisol. The experiment was located at Ilha Solteira northwest of São Paulo State, Brazil. The soil was cropped to Sorghum bicolor. The field experimental design consisted of random blocks with six treatments and four replications of each treatment. Biosolids were surface applied to four treatments at rates of 5, 10, 20, and 40 Mg ha 21 on a dry matter basis; in addition, a treatment with mineral fertilizer and a control were included. One year after biosolids application, soil samples were taken at 0 -10, 10 -20, and 20 -40 cm. Organic matter content (Walkley -Black) and pH (CaCl 2 ) were routinely determined. Cation exchange capacity, exchangeable bases (Ca, Mg, K), and P were determined by exchange resin extraction. No significant Extractable phosphorus (P) and potassium (K) increased with increasing biosolids rate in the top 20 cm, whereas calcium (Ca) and (Ma) magnesium content were not significantly influenced by biosolids. Soil pH decreased with increasing biosolids application. The sewage sludge application did not influence the sorghum production in the first year of culture, under unfavorable soil moisture conditions, but it influenced the dry matter.

Evaluación de dosis de biosólidos urbanos en maíz bajo condiciones de invernadero

“…Su disposición final se ha convertido en un problema ambiental que viene en aumento desde la última década del Siglo XX (Gavalda et al, 2005). Las opciones para disponer los biosólidos incluyen la incineración, el depósito en rellenos sanitarios y el reciclaje como abonos orgánicos para uso agrícola (Alves et al, 2006). La utilización de biosólidos como mejoradores de suelos agrícolas puede ser viable ambiental y económicamente, y se considera una opción sostenible para su disposición final.…”

“…Their final disposal has become an environmental problem that has been increasing since the last decade of the 20th century (Gavalda et al, 2005). The options to dispose of biosolids include incineration, landfill and recycling as organic fertilizers for agricultural use (Alves et al, 2006). The use of biosolids as agricultural soil improvers may be environmentally and economically viable and is considered a sustainable option for final disposal.…”

Effects of incubation times and moisture regimes on pH values and exchangeable cations in acid sulfate soils as influenced by application rates of basic slag

“…To maintain a reasonably goodconditioned soil for growing crops, the soil should be amended at saturated soil condition followed by the application of BS at 33 t ha -1 . The BS was also reported effective in increasing soil pH as well as maintaining favorable soil conditions (Abbaspour et al 2004;Alves et al 2006;Khan et al 2006b). …”

Assessment of long-term effects of basic slag in reclaiming acid sulfate soil

“…Throughout the incubation period, it was noticed that the potentiality of basic slag as a liming material will be effective for reducing the acidity of acid sulfate soil for long time. Abbaspour et al (2004); Alves et al (2006) and Khan et al (2006) reported that the basic slag was also effective in increasing soil pH as well as maintained favorable soil conditions. The effects of basic slag and duration of incubation time on the changes in EC of supplied acid sulfate soil is represented in Fig.…”