A multi-criteria evaluation of organic amendments used to transform an unproductive shrubland into a Mediterranean dehesa

Tarrasón D., Ortiz O., Alcañiz J.M. (2007) A multi-criteria evaluation of organic amendments used to transform an unproductive shrubland into a Mediterranean dehesa. Journal of Environmental Management. 82: 446-456.
Enllaç
Doi: 10.1016/j.jenvman.2006.01.002

Resum:

Environmental and health problems associated with the use of digested sewage sludge hinder its application and encourage the introduction of additional treatments such as composting and thermal drying. The aim of this paper is to assess the possibility of using three different types of sewage sludge (digested, composted and thermally dried) to improve soil fertility and enhance the transformation of an unproductive shrub land into a Mediterranean dehesa for grazing purposes and also to reduce wildfire risk. In total, 10 t ha-1 of dry matter of three types of sewage sludge were spread on the soil surface of 4×5 m field plots, and then seeded with a mixture of grasses. Effects on soil fertility and plant growth were monitored over 2 years. The results show that all three types of sludge application had a significant effect on vegetation cover, herbaceous biomass (2767.7±716.1 and 1735.0±299.7 kg ha-1 for digested sludge amended and control plots, respectively) and tree growth (0.41±0.108 cm year-1 on amended trees, 14.6% more than control trees). This study proposes the use of multi-criteria analysis to identify the most suitable fertilization alternatives and to assist in the decision-making process of sludge recycling. Because of the high degree of uncertainty and conflicting objectives associated with these decisions, multi-criteria evaluation tools make a valuable contribution to decision-making processes concerning sewage sludge applications. According to multi-criteria results, the composted sludge alternative is the most suitable. This is because all the objectives are achieved: an improvement in the properties and functions of the soil with a positive vegetation response as well as minimal economic cost and risk of toxicity. © 2006 Elsevier Ltd. All rights reserved.

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Fractal analysis of soil water hysteresis as influenced by sewage sludge application

Ojeda G., Perfect E., Alcañiz J.M., Ortiz O. (2006) Fractal analysis of soil water hysteresis as influenced by sewage sludge application. Geoderma. 134: 386-401.
Enllaç
Doi: 10.1016/j.geoderma.2006.03.011

Resum:

The impact of three types of surface applied sewage sludge from the same lot (fresh, composted, and thermally dried) on the water retention properties of a loam soil (Udic Calciustept) and a loamy sand soil (Typic Haplustalf) from central Catalonia (NE Spain) was investigated using fractal analysis. First, we proposed a composite fractal model that covers both the low and high suction regimes. This model has four fitting parameters: D1 (the pore-solid fractal dimension), D2 (the surface fractal dimension), A1 (a compound parameter that includes D1, the density of water, bulk density, particle density, and the air/water displacement suction), and A2 (a compound parameter that includes D2, and the critical suction and water content separating the low and high suction regimes). This model was fitted to the main wetting and drying branches of soil water retention curves obtained from small-disturbed samples using the chilled mirror dew point method. The equation fitted the data extremely well with adjusted R2 values ≥ 0.99 (p < 0.0001). Analysis of variance (ANOVA) was performed on the resulting parameter estimates. Few significant effects were observed for the loamy sand soil. In contrast, all of the model parameters, except D1, were significantly affected by hysteresis and/or the sludge treatments for the loam soil. Values of A1 and A2 from the main drying branch were significantly higher than corresponding estimates from the wetting branch. This trend was reversed for D2, indicating that pore surfaces are smoother after wetting, as compared to initially dry surfaces. The fresh, composted and thermally dried sludge treatments all significantly increased the A1 parameter relative to the untreated loam soil, possibly by decreasing bulk density. The fresh and thermally dried sludge treatments also significantly increased the A2 parameter. All three sludge types increased D2 relative to the control when this parameter was determined from the main wetting branch of the water retention curve. In contrast, D2 estimated from the main drying branch was not influenced by any of the sludge treatments. These analyses indicate that the effects of sewage sludge on hysteresis of the soil water retention curve were still present 2 years after surface application in the case of the loam soil. © 2006 Elsevier B.V. All rights reserved.

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Nitrogen losses in runoff waters from a loamy soil treated with sewage sludge

Ojeda G., Tarrasón D., Ortiz O., Alcañiz J.M. (2006) Nitrogen losses in runoff waters from a loamy soil treated with sewage sludge. Agriculture, Ecosystems and Environment. 117: 49-56.
Enllaç
Doi: 10.1016/j.agee.2006.02.017

Resum:

Sludge from the same waste-water treatment plant, processed in different ways, was applied superficially to plots of a soil developed on marls (Udic calciustept) at doses equivalent to 10 t ha-1 of dry matter. The concentration of mineral nitrogen (ammonium, nitrate) in runoff waters was measured to assess the effects of composting and thermally drying of sludge on the pollution of surface waters. Significant differences of NH4-N and NO3-N concentration in both runoff waters and soil only appeared during the first five runoff events after sludge application. Thereafter, runoff volume decreased remarkably, possibly due to vegetation growth. The treatment with composted sludge contributes mainly to NO3-N runoff, whereas the NH4-N was predominant in runoff from plots of thermally-dried sludge. The treatment with fresh sludge provided NH4-N and NO3-N to surface runoff in similar amounts. The electrical conductivity of the runoff was not greatly affected by the surface application of the sewage sludges. © 2006 Elsevier B.V. All rights reserved.

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Bioaccumulation of heavy metals in Dactylis glomerata L. growing in a calcareous soil amended with sewage sludge

Ortiz O., Alcañiz J.M. (2006) Bioaccumulation of heavy metals in Dactylis glomerata L. growing in a calcareous soil amended with sewage sludge. Bioresource Technology. 97: 545-552.
Enllaç
Doi: 10.1016/j.biortech.2005.04.014

Resum:

The total and DTPA-extractable concentrations of Pb, Ni, Zn, Cu, Cr and Cd were measured in a calcareous soil amended with different doses of sewage sludge under field conditions. The same metals were also measured in the roots and leaves of Dactylis glomerata at the end of the first vegetative period after the sludge was added. The root concentrations of all the metals were unrelated to their concentrations in the soil. Leaf concentrations of Zn and Cr correlated with total (Zn) and DTPA-extractable (Zn and Cr) concentrations in the soil. DTPA extraction did not appear to be very useful for evaluating the bioavailability of metals in this kind of soil as it gave very low correlation coefficients with leaf content (r = 0.684, P = 0.0049 for Zn and r = 0.557, P = 0.0249 for Cr). Concentrations of Pb, Ni, Cu, and Cd in roots and leaves of Dactylis glomerata were unrelated to the total or DTPA-extractable concentrations in the sludge-amended soil. © 2005 Elsevier Ltd. All rights reserved.

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El paper dels sòls de Catalunya en el canvi climàtic. A: Llebot J.E. (editor) Informe sobre el canvi climàtic a Catalunya, Consell Asesor per al Desenvolupament Sostenible, Generalitat de Catalunya.

Alcañiz JM, Boixadera J, Felipó MT, Ortiz O, Poch RM (2005) El paper dels sòls de Catalunya en el canvi climàtic. A: Llebot J.E. (editor) Informe sobre el canvi climàtic a Catalunya, Consell Asesor per al Desenvolupament Sostenible, Generalitat de Catalunya. Institut d’Estudis Catalans, 1ª edición, abril 2005, Barcelona, pp. 555-608.

Escorrentía y granolumetría de sedimentos en suelos tratados con diversoss tipos de lodos de depuradora.

Ojeda G, Alcañiz JN, Ortiz O, Tarrasón D (2003) Escorrentía y granolumetría de sedimentos en suelos tratados con diversoss tipos de lodos de depuradora. Edafología 10: 135-145

Avaluació de treballs de rehabilitació de sòl en àrees afectades per activitats extractives a Catalunya: criteris de qualitat de la restauració.

Alcañiz JM, Ortiz O (2003) Avaluació de treballs de rehabilitació de sòl en àrees afectades per activitats extractives a Catalunya: criteris de qualitat de la restauració. Orsis 18:63-75.

Runoff and losses by erosion in soils amended with sewage sludge

Ojeda G., Alcaniz J.M., Ortiz O. (2003) Runoff and losses by erosion in soils amended with sewage sludge. Land Degradation and Development. 14: 563-573.
Enllaç
Doi: 10.1002/ldr.580

Resum:

In order to promote the transformation of a burnt Mediterranean forest area into a dehesa system, 10 t ha-1 of dry matter of the same sewage sludge in three different forms: fresh, composted and thermally-dried, were added superficially to field plots of loam and sandy soils located on a 16 per cent slope. This application is equivalent to 13·8 t ha-1 of composted sludge, 50 t ha-1 of fresh sludge and 11·3 t ha-1 of thermally-dried sludge. The surface addition of a single application of thermally-dried sludge resulted in a decrease in runoff and erosion in both kinds of soil. Runoff in thermally-dried sludge plots was lower than in the control treatment (32 per cent for the loam soil and 26 per cent for the sandy soil). The addition of any type of sludge to both soil types also reduces sediment production. Significant differences between the control and sludge treatments indicate that the rapid development of plant cover and the direct protective effect of sludge on the soil are the main agents that influence soil erosion rates. Results suggest that the surface application of thermally-dried sludge is the most efficient way to enhance soil infiltration. Copyright © 2003 John Wiley and Sons, Ltd.

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Organic matter dynamics in soils with different types of sewage sludge amendments.

Tarrasón D, Ortiz O, Ojeda G, Alcañiz JM (2002) Organic matter dynamics in soils with different types of sewage sludge amendments. In Faz (ed) Sustainable Use and Management of Soils in Arid and Semiarid Regions, Vol. II, pp. 201-202.

Effects of three types of sewage sludge on soil erodibility.

Ojeda G, Alcañiz JM, Ortiz O, Tarrasón D (2002) Effects of three types of sewage sludge on soil erodibility. In Faz (ed) Sustainable Use and Management of Soils in Arid and Semiarid Regions, Vol. II, p. 110-111.

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