Interactions between different types of biochar and soil microbial activity: the effects on the dynamics of labile organic matter and the behaviour of some pesticides

Abstract

Biochar, the particular charcoal obtained through the process of pyrolysis of biomass, has been proposed as a mean of carbon sequestration through soil. It has been also considered useful to improve some relevant properties of the soil fertility and to reduce adverse effects of pollutants. But the use of biochar must ensure, in addition to its conservation, that it does not generate adverse effects on living organisms, on the soil ecosistemic functions, or on the adjacent natural systems. This thesis attempts to contribute to knowledge in this regard, by studying: - The biochar's ability to protect the most labile soil organic matter; - The hypothetic adverse effects caused by biochar once incorporated into the soil, depending on the type of pyrolysis process and doses applied ; and - The modulation of the toxic side effects of some pesticides when incorporated into soils that have received a provision of biochar. To achieve these goals three types of biochars produced from the same starting biomass (pine wood chips) were used to amend soil: biochar produced by slow pyrolysis (PL), biochar obtained from fast pyrolysis (PR) and biochar obtained through the gasification of biomass (PG). The addition of biochar results in changes of the structure and biology of the soil, then in positive or negative modification of its physical and biological balance. Considering that microbial community plays a major regulatory role in the soil, conditioning the most important biotic reactions, microbial biomass and soil respiration were used as indicators of the effects produced by the addition of biochar into the soil. Sorption models were used to assess the ability of biochar to adsorb and protect the most labile soil organic matter. A fully factorial experiment was designed to check the effects of three single factors (biochar, nutrients and glucose addition) and their relationship with the whole SOM mineralization. The results of this work demonstrated that each kind of biochar established different interactions with the soil.

Date of Award	23 Oct 2014
Original language	English
Supervisor	Josep Oriol Ortiz Perpiña (Director) & Josep Maria Alcañiz Baldellou (Director)