Reclamation of Acid Soils with Biomass Ashes from Pyrolytic Wood Liquefaction

Marina Fernández-Delgado Juárez,Deborah Schönegger,Heribert Insam,Giacomo Pietramellara,Thomas Mazzier,Ginevra Fabiani,María Gómez-Brandón

doi:10.1007/s12649-019-00789-5

Marina Fernández-Delgado Juárez, Deborah Schönegger + Show 5 more

Open Access

https://doi.org/10.1007/s12649-019-00789-5

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Abstract

Fast pyrolysis bio-oil (FPBO) is a liquid biofuel obtained from lignocellulosic residues. Moreover, biomass fly ashes (FAs) containing many minerals and micronutrients are obtained in the production process. Biomass ashes can be used as a lime substitute for amelioration of acid soils by increasing pH, providing nutrients for crop development and stimulating microbial activity. However, ash application might increase N-mineralization and induce nitrate losses via leaching. The main objective of this study was to investigate the applicability of FPBO-recovered FAs as soil amendment and their effects on soil microbial processes, plant development, and to evaluate the effects on soil leaching. In a greenhouse experiment, an acidic soil was amended with 2% of FAs and sown with a regional wheat variety. After 100 days, wheat was harvested and red clover was sown to simulate crop rotation. After 250 days, the soils were analysed microbiologically and physico-chemically. While no differences in plant yields were observed, FAs addition increased several soil chemical pools as well as certain microbiological parameters. Soil pH increased from 4.8 to 7.2, electrical conductivity from 89 to 407 µS cm−1, and the soil available P pool from 13.6 to 81.3 µg g−1 soil. Further, the nitrification rate, nitrate content in the soil leachates increased upon ash addition, in particular during the clover stage of the experiment. Summarized, despite not measurable effects on the plant growth, fly ash appears to enhance chemical and biological properties of soil cropped with wheat and clover without hinting towards negative environmental side-effects.Graphic

Highlights

The increasing need to replace fossil fuels with renewable energy sources and the global concern about CO2 emission has generated a growing interest for using biomass for energy production [1]
The vapours produced during this process are cooled and condensed into a brown liquid called Fast Pyrolysis Bio-Oil (FPBO) that can be used for heating, power generation, and as substitute in conventional diesel engines [3,4,5]
This study reveals that fly ashes (FAs) resulting from the production of FPBO have a potential use as a soil amendment since, in general, no harmful effects were observed from a chemical and microbiological viewpoint

Summary

Introduction

The increasing need to replace fossil fuels with renewable energy sources and the global concern about CO2 emission has generated a growing interest for using biomass for energy production [1]. There are several ways in which biomass such as wood, straw and energy crops can be transformed for energy production including combustion, gasification or a more recent technique known as fast pyrolysis. In this process organic material is rapidly heated under anaerobic conditions to 400–600 °C, a temperature sufficient to breakdown the biomass structure devoid of melting of the inorganic elements [2]. The vapours produced during this process are cooled and condensed into a brown liquid called Fast Pyrolysis Bio-Oil (FPBO) that can be used for heating, power generation, and as substitute in conventional diesel engines [3,4,5]. Wood ash can act as a soil amendment and lime substitute in agricultural [11,12,13,14] and forest soils [15,16,17], especially when these are acidic

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