ORIGINAL RESEARCH
Isotopic Evaluations of Dynamic and Plant Uptake of N in Soil Amended with 15N-Labelled Sewage Sludge
Rajia Kchaou1, Mohamed Naceur Khelil1, Fatma Gharbi2, Saloua Rejeb1, Belgacem Henchi2, Teresa Hernandez3, Jean Pierre Destain4
 
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1Institut National de Recherche en Génie Rural, Eau et Forêts BP 10, 2080 Ariana, Tunisia
2Département de Biologie, Faculté des Sciences de Tunis, 2092 Tunis, Tunisia
3Centro de Edafologia y Biologia Aplicada del Segura, (CSIC), Apartado 4195, 30080 Murcia, Spain
4Centre Wallon de Recherches Agronomiques, 4 rue Bordia, 5030 Gembloux, Belgium
 
Pol. J. Environ. Stud. 2010;19(2):363–370
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ABSTRACT
Field experiments were conducted to evaluate the use of a novel 15N isotope technique for comparing the dynamics of N derived from sewage sludge applied to sorghum to the dynamics of N derived from the commercial fertilizer, urea. The treatments included a control, sludge applied at three rates (3, 6 and 9 t/ha, or 113, 226 and 338 kg N/ha) and N-urea applied at three rates (150, 250 and 350 kg N/ha). Recovery of 15N-labelled sludge was similar for the different nitrogen rates applied, with a mean value of 27%. However, the recovery of 15N-urea decreased as the rate of N application increased (from 38% to 27%). Approximately 22% and 19% of the 15N from sludge and urea, respectively, remained in the 0-60 cm layer of soil, most of which was present in the 0-20 cm layer. Furthermore, losses of 15N-labelled fertilizer were not affected by the N fertilization source, and the greatest losses, which were measured in response to the highest N application rate, were 59%.
eISSN:2083-5906
ISSN:1230-1485