Chemical and biological properties of a sandy loam soil amended with olive mill waste, solid or liquid form, in vitro

Nikolaos Gougoulias,Alexandros Papachatzis,Eleftheria Stergiou,Adamantia Chouliara,Nikolaos Chouliaras,Ioannis Vagelas

doi:10.1186/2251-7715-2-13

Nikolaos Gougoulias, Alexandros Papachatzis + Show 4 more

Open Access

https://doi.org/10.1186/2251-7715-2-13

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Abstract

AbstractBackgroundThe profitable use of the large amounts of olive oil mill wastes produced in Greece, as source of soil organic matter, might be probably beneficial to soil microorganism activity.ResultsA high rate of organic matter biodegradation was observed in soil samples amended with the liquid form of olive mill wastewater, whereas the vice versa results were obtained with the solid form. When the soil was amended with a mixture of both olive mill waste forms, liquid (L) and solid (S), the organic matter of the solid waste (S) showed a well-improved biodegradation; the available forms of P, K, Zn, Mn, and Cu were increased, especially in treatments where the olive mill wastewater, liquid form, was threefold in comparison to the solid form. Moreover, the soil amended with the solid (S) form of olive mill waste reduced bacterial growth significantly, and both waste forms act negative impacts to soil-borne fungi belonging to the genusRhizopus.ConclusionsThe results of this work demonstrated the high potential of olive mill waste, solid or liquid form, added to sandy loam soil in an incubation experimentin vitro. The better results for soil quality were obtained when a combining mixture of these materials was added in the ratio 1:3 (solid/liquid).

Highlights

The organic matter as a soil fraction is regulating the biological activity of soils, so a satisfactory content in organic material dominates the soil fertility (Economou et al 1980; Chouliaras et al 1998; Gougoulias et al 2010).Very important amounts of olive mill waste are produced in olive cultivation areas, ranging between 1.75 × 106 and 2.25 × 106 tons/year of olive mill wastewater for Greece (Kyriazopoulos 2005); the profitable use of these organic materials as soil amendments are beneficial both to soil improvement and environmental protection
When the two kinds of waste were added separately, a strong resistance to biodegradation has been proved by solid waste; the organic matter of solid waste is better decomposed under the effect of the olive mill wastewater, when the two waste sorts are added together
The salinity elevation is more affected by olive mill wastewater application, and it is important to remark the increased presence of available forms of P, K, Zn, Mn, and Cu in the soils amended with the mixture of solid + olive mill wastewater, in the ratio 1:3 (S/L)

Summary

Introduction

The organic matter as a soil fraction is regulating the biological activity of soils, so a satisfactory content in organic material dominates the soil fertility (Economou et al 1980; Chouliaras et al 1998; Gougoulias et al 2010). Very important amounts of olive mill waste are produced in olive cultivation areas, ranging between 1.75 × 106 and 2.25 × 106 tons/year of olive mill wastewater for Greece (Kyriazopoulos 2005); the profitable use of these organic materials as soil amendments are beneficial both to soil improvement and environmental protection. The profitable use of the large amounts of olive oil mill wastes produced in Greece, as source of soil organic matter, might be probably beneficial to soil microorganism activity

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