Differences on nitrogen availability in a soil amended with fresh, composted and thermally-dried sewage sludge

Tarrasón D., Ojeda G., Ortiz O., Alcañiz J.M. (2008) Differences on nitrogen availability in a soil amended with fresh, composted and thermally-dried sewage sludge. Bioresource Technology. 99: 252-259.
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Doi: 10.1016/j.biortech.2006.12.023

Resum:

Anaerobically-digested sludge called fresh sludge (F), composted sludge (C) and thermally-drying sludge (T), all from the same batch, were applied to the surface of a calcareous Udic Calciustept with loamy texture. Dosage equivalent was 10 t ha-1 of dry matter. The concentration of mineral nitrogen (ammonium and nitrate) in the soil was measured in order to estimate the effects of the post-treatments to which the different kinds of sewage sludge are subjected in relation to the availability of N in the surface layer of the soil. The most significant differences in NH4-N and NO3-N concentrations due to the transformation of the organic matter were observed during the first three weeks following soil amendment. Thermally-dried and composted sludge initially displayed higher concentrations of ammonium and nitrate in soil. Five months after the amendment, soil applied with fresh sludge showed the highest concentrations of NH4-N and NO3-N (6.1 and 36.6 mg kg-1, respectively). It is clear that the processes of composting and thermal-drying influence the bioavailability of nitrogen from the different types of sewage sludge. © 2007 Elsevier Ltd. All rights reserved.

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