Biosolid amendment of a calcareous, degraded soil in a semi-arid environment

I Walter,F Martinez,G Cuevas

doi:10.5424/sjar/2006041-177

Abstract

Many soils in the Mediterranean region are subjected to progressive degradation as a result of water erosion. A study was carried out to examine the effects of biosolids on a degraded soil. Single doses of 40, 80 and 120 Mg haE1 of a biosolid were applied to the surface of soil and their effects on its chemical characteristics and on the native vegetation were assessed. Soil macronutrients, micronutrients and heavy metals were tested one and five years after application. Canopy cover, biomass production and mineral composition of native vegetation were also determined. Biosolids increased the content of most nutrients in the soil, although this effect decreased over time. The soil organic matter content did not increase significantly at the beginning of the experiment, although significant differences were observed after five years. The contents of total and extractable heavy metals did not change with time after the application. The native plant biomass production and the canopy cover significantly increased with all the doses applied at the beginning of the experiment, and remained high five years after biosolids application.

Highlights

The need to reduce biosolids waste disposal costs and to increase concentrations of soil nutrients and organic matter has led to the use of biosolids in the amendment and fertilization of both agricultural and natural land.Generally, correct application of biosolids improves the physical, chemical and biological properties of the soil (García et al, 1998; Lindsay and Logan 1998; Walter et al, 2000; Binder et al, 2002; Martínez et al, 2003a; Ros et al 2003), enlarge the carbon sink, and can reduce greenhouse gas emissions (Akala and Lal, 2001; Swift, 2001; Lal et al 2003).Many soils in the Mediterranean region are susceptible to water erosion due to loss of the protective vegetation
Even at the end of the experiment, the electrical conductivity (EC) of the treated plots remained significantly higher than that of the unamended plots, but the values obtained were below toxic levels for plant growth
A greater increase in Soil organic carbon (SOC) was expected because the biosolids contained 253 g kg–1 of organic carbon (Table 1)

Summary

Introduction

The need to reduce biosolids waste (stabilized waste water sludge) disposal costs and to increase concentrations of soil nutrients and organic matter has led to the use of biosolids in the amendment and fertilization of both agricultural and natural land.Generally, correct application of biosolids improves the physical, chemical and biological properties of the soil (García et al, 1998; Lindsay and Logan 1998; Walter et al, 2000; Binder et al, 2002; Martínez et al, 2003a; Ros et al 2003), enlarge the carbon sink, and can reduce greenhouse gas emissions (Akala and Lal, 2001; Swift, 2001; Lal et al 2003).Many soils in the Mediterranean region are susceptible to water erosion due to loss of the protective vegetation. The need to reduce biosolids waste (stabilized waste water sludge) disposal costs and to increase concentrations of soil nutrients and organic matter has led to the use of biosolids in the amendment and fertilization of both agricultural and natural land. Correct application of biosolids improves the physical, chemical and biological properties of the soil (García et al, 1998; Lindsay and Logan 1998; Walter et al, 2000; Binder et al, 2002; Martínez et al, 2003a; Ros et al 2003), enlarge the carbon sink, and can reduce greenhouse gas emissions (Akala and Lal, 2001; Swift, 2001; Lal et al 2003). Plant cover is rapidly established, helping to minimize runoff and reduce water erosion (Rostagno and Sosebee, 2001; Martínez et al, 2003b; Ojeda et al, 2003)

Methods

Results

Conclusion