Fractionation of Phosphorus in Sludge‐Affected Soils

Abstract

Phosphorus accumulated in sludge‐treated soils was chemically fractionated by a sequential extraction procedure. Samples used for the study were obtained from experimental plots of a sludge land application site, where composted sludges at rates 0, 22.5, 45, and 90 t ha−1 y−1, and liquid sludges at rates of 0, 3.75, 7.5, and 15 cm/y have been applied for 5 y. There were also experimental plots whose liquid sludge treatments were terminated after 3 y. The experimental field was cropped with winter barley (Hordeum vulgare) after the sludge applications.In soils not treated with sludges, the Ca‐bound P accounted for 50–60% of the total P. An accumulation of Al‐ and Fe‐bound P occurred in all sludge‐treated soils. In the top 15 cm of surface soil, after 5 y of composted sludge treatment at a rate of 90 t ha−1 y−1 (1980), the Al‐ and Fe‐bound P was > 60% of the total P. Concentrations of water‐soluble P in sludge‐treated soils also increased. There were indications that the organically bound P in sludge‐treated soils was the most likely form to leach. Three years after the termination of sludge applications, there was little change in the distribution pattern of sludge‐borne P in the soil profile.

Mapping and Estimation of Chemical Concentrations in Surface Soils using LANDSAT TM Satellite Imagery

“…This confirms the report of Chang et al (1983) that five continuous years of biosolids application in two California soils at 0, 22.5, 45 and 90 ton per hectare increased the total P concentration of surface soil (0-15 cm) from 515-540 mg/kg to 1092-1312, 1657-2163 and 2617-3470 mg/kg, respectively. Similarly Maguire et al (2000) reported that the concentration of total soil P in surface soils (0-20 cm) of biosolid amended soils was 738 mg/kg, or nearly double the values in unamended soils, where the total soil P was 403 mg/kg.…”

Analysis of physiochemical characteristics influencing disposal of pit latrine sludge in Nakuru Municipality, Kenya

“…High TP concentration in the sludge sourced from detergents may affect decomposition because they have a negative impact on microbial activities with some of these detergents being biocides; hence inhibiting microbial activities in the FS which may be beneficial to the degradation processes (Block et al, 2001;Kawasaki et al, 2002). Phosphorous immobilizes other chemicals like zinc and copper that are essential for microbial life, making the reported concentrations a cause of concern to the beneficial microorganisms for faecal sludge degradation (Chang et al, 1983). The documented TP concentrations justify the need for further treatment of the FS as the current concentration would lead to algal growth, odour and oxygen depletion if the sludge is disposed into water bodies.…”

Nutrient transfer by runoff from sewage sludge amended soil under simulated rainfall

“…2. Actually, after sludge spreading, mineral forms of phosphorus are likely to link to iron or aluminium present in soil (Chang et al, 1983), while organic forms are rapidly hydrolysed, both in acid or basic soils (Hinedi et al, 1989). Most sludges induce a decrease in the binding capacity of soil to phosphate ions, as soon as they are incorporated into soil, but it is not the case for limed sludges, which lead to an increase of this binding capacity.…”