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Availability, fractionation and leaching potential of phosphorus from sewage sludge and manure -amended soils
Abstract
Experiments have been conducted on measuring the combined effects of (1) time after sludge application, (2) temperature of equilibration, and (3) soil properties (principally pH and texture) on P availability and chemical fractions. Plant-available P (measured by iron-oxide strip extraction) was highest in the coarse textured soil. Plant-available P decreased from 20 to 60 d after application, probably due to combined effects of chemical fixation and biological immobilization, but increased thereafter. Plant-available P in all soils was lower at 37°C than at 25°C over the entire incubation period. This difference might reflect greater immobilization of P by microorganisms at 37°C. Sludge P was predominantly found in the non-occluded P (Fe and Al-bound P) fraction which is biologically-available, and thus may contribute to eutrophication if eroded into surface waters. A parallel study was carried out on the contribution of 4 different manures to soil P fractions and their potential for leaching into the soil. Beef feedlot, sheep feedlot, turkey house, and composted paunch manures were applied to a central Nebraska soil in alternate years from 1991 to 1997 in amounts approximating replacement of P removed by irrigated corn. Highest available P (Bray and Kurtz-1) was in turkey manure-amended plots. In all cases, P accumulated in the 0–15 cm tillage zone. All inorganic P fractions increased with manure application, but Ca-P decreased as a percentage of total inorganic P. Based on depth of increase of various P fractions, non-occluded P is the form most likely to move downward from the zone of application. Phosphorus movement was most apparent in compost-amended soil.
Subject Area
Soil sciences|Agronomy
Recommended Citation
Akhtar, Muhammad, "Availability, fractionation and leaching potential of phosphorus from sewage sludge and manure -amended soils" (1999). ETD collection for University of Nebraska-Lincoln. AAI9952671.
https://digitalcommons.unl.edu/dissertations/AAI9952671