In the Mediterranean region, difficult climate conditions and inadequate land management have led to a reduction of the organic matter content of soils. As a solution, municipal solid waste (MSW) compost and sewage (S) sludge were investigated for their effectiveness in maintaining soil fertility. Clayey-loamy soil was amended with 0, 40, and 80 t ha−1 of MSW compost or S sludge and cultivated with Triticum durum. Soil was sampled 15 and 70 days after sowing, and the activities of arylsulphatase, phosphatase, dehydrogenase (DH), β-glucosidase (β-GLU), urease, and catalase (CAT) were assayed. The wheat was harvested after 68 days, then soil properties as well as plant growth and K+ and Na+ contents were determined.
Almost all soil enzymatic activities were significantly (P < 0.01) affected by amendment dose, sampling time, and their interaction. At 15 days, MSW compost had a moderate effect on DH, β-GLU, and CAT activities under both applied doses. A significant increase of all the measured activities was observed after 70 days at either 40 t ha−1 or 80 t ha−1 (ranged between 16%-160% and 10%-81%, respectively), likely providing a long-term nutrient release. The activities of arylsulphatase, phosphatase, DH, CAT, and β-GLU (only with the lower dose) were strongly enhanced at 15 days after S sludge treatment. After 70 days, an increase of the enzymatic activities occurred with S sludge, although its beneficial effect was reduced mainly at 80 t ha−1 presumably because of the presence of micropollutants in the sludge. Plant growth was significantly improved by 40 and 80 t ha−1 of compost (93% and 126%, respectively); however, less impact was observed with S sludge. Overall, the results suggest that addition of MSW compost could enhance the fertility of degraded soils and promote plant growth.
1Laboratoire d'Adaptation des Plantes aux Stress Abiotiques, Centre de Biotechnologies, Technopole Borj Cedria, BP 901, Hammam Lif 2050, Tunisia. Dr.Abdelbasset Lakhdar is corresponding author. E-mail: email@example.com
2Centre de Recherches et Technologies des Eaux, Technopole Borj Cedria, BP 273, Soliman 8020, Tunisia.
3Dipartimento di Scienze del Suolo, della Pianta, dell'Ambiente e delle Produzioni Animali, Università di Napoli Federico II, via Università 100, 80055 Portici, Italy.
Received July 10, 2010.
Accepted for publication October 18, 2010.
This work was supported by the Tunisian Ministry of Higher Education, Scientific Research and Technology (LR02CB02).