Use of Olive Mill Pomace Biochar as a Support for Soil Microbial Communities in an Italian Sandy Soil

Abstract

Soils with low organic matter and modest biological activity exhibit a reduced capacity to produce goods and services. The use of biochar as a soil amendment has been suggested as a way to increase soil productivity thanks to its physical and chemical characteristics. These properties lead to its possible use as a structural support and a habitat for microorganisms. This study investigated the role of biochar, produced from olive mill pomace at the Mediterranean Agronomic Institute of Bari by a slow pyrolysis process, as a carrier of two microbial communities extracted from a fertile soil and a commercial compost. This study aims to highlight the relationship between the physical structure of biochar and the potential microbial community and to evaluate the use of charged biochar as a carrier of microflora. The inoculation of agricultural soil with biochar seems to have no effect on the total aerobic heterotrophic microflora evaluated with the plate count method. Nevertheless, scanning electron microscope (SEM) images show the presence of biofilm, thus suggesting an early stage of colonization. Despite the short time of incubation of microbial charged biochar in the studied soil, the microbial biomass C and N increased, suggesting a beneficial effect of this amendment.

Potential short-term negative versus positive effects of olive mill-derived biochar on nutrient availability in a calcareous loamy sandy soil

“…Previous studies have demonstrated that the biochar produced from OMSW is a promising sorbent/immobilizing agent for removing heavy metals from aqueous solutions or to remediate heavy metal contaminated soils [26, 29]. Additionally, the enhancing effects of OMSW biochar on soil microbial biomass C and N, and alteration of the structure of the bacterial community has been reported by other authors [30, 31]. However, to date, there is no available information on the effects of OMSW-derived biochar on nutrient availability in alkaline sandy soils.…”

Potential short-term negative versus positive effects of olive mill-derived biochar on nutrient availability in a calcareous loamy sand soil

“…Therefore, converting OMSW into biochar could reduce surface pollution on one hand, and the produced biochar could serve as a soil conditioner for enhanced soil productivity on the other hand. Previous studies have demonstrated the enhancing effects of OMSW-derived biochar on soil microbial biomass C and N, and alteration of the structure of the bacterial community in soil [ 25 , 26 ]. However, to date, there is no available information on the effects of OMSW-derived biochar on nutrient availability in alkaline sandy soils.…”