Effects of Repeated Application of Municipal Sewage Sludge on Soil Fertility, Cotton Yield, and Nitrate Leaching

Abstract

Th e eff ects of sludge application on soil properties and cotton (Gossypium hirsutum L.) response were investigated in an Inseptisol in central Greece. Digested sludge was incorporated in the 0 to 15 cm soil depth at rates of 10, 30, and 50 Mg ha -1 , and repeated for four consecutive years. Sludge treatments were compared to an inorganic fertilizer application and an untreated control in a completely randomized design with four replications. Sludge application increased soil organic matter, associated nutrients and improved physical properties. However, soil electrical conductivity increased with increasing sludge application to levels that may aff ect growth of salt-sensitive crops and warns against long-term application that may impair essential soil functions. Th e multifold increase of Olsen P and nitrate N beyond crop needs is a reason of concern for surface runoff and nitrate leaching below the root zone at the higher sludge application rates. Sludge application of 10 Mg ha −1 was suffi cient to improve soil chemical properties with less risk of water contamination. Cotton responded to sludge application by increased nutrient uptake and yield, which indicated that sludge could replace inorganic fertilizer needs even at the lower application rate. However, fl uctuations of nutrient uptake and yield between growing seasons were of greater magnitude than those caused by sludge application. Multiple regression analysis revealed that P uptake was the major limiting factor for determining cotton yield.

Sales Solubles Y Metales Pesados en Suelos Tratados Con Biosólidos

“…These results coincide with those obtained by Samaras et al (2008) in a field experiment in Greece, where they applied increasing biosolids doses and found increases in soluble salts to levels that may affect the growth of salinity-sensitive crops.…”

“…Además, un alto contenido de bicarbonatos induce la precipitación de Ca 2+ y Mg 2+ , originando acumulación de sodio en la solución del suelo, el cual al adsorberse a las arcillas provocará la sodificación de éste. Los resultados anteriores coinciden con los obtenidos por Samaras et al (2008) en un experimento de campo en Grecia, donde aplicaron dosis crecientes de biosólidos y encontraron incrementos de sales solubles a niveles que pueden afectar el crecimiento de cultivos sensibles a la salinidad.…”

Soil and seedling response to dehydrated septic tank sludge versus forest floor additions at a disturbed site

“…However, at sludge application rates exceeding vegetation requirements, nitrate (NO 3 -) and phosphate ) can leach below the rooting zone and contaminate groundwater (Samaras et al 2008) or eventually reach surface waters, thus promoting eutrophication (Correll 1998). Such problems would be expected in regions receiving heavy rainfall where the nutrient runoff potential is high (Fredriksen et al 1973;Grey and Henry 2002).…”

Sediment, Nutrient, and Bacterial Runoff from Biosolids and Mineral Fertilizer Applied to a Mixed Cool- and Native Warm-Season Grassland in the Ozark Mountains

“…Among the benefits, biosolids provide recycled nutrients to soils and can serve as an alternative or a substitute to costly mineral fertilizers (MF). In addition to providing nutrients, biosolids provide organic matter to soil [4,5], increase infiltration [6], potentially improve soil quality [5,7,8], and increase agronomic productivity [5,7,[9][10][11][12]. Using biosolids as a substitute for MF also helps reduce energy use which would have been associated with production and transportation of MF.…”