Mitigation of Greenhouse Gas Emissions with Biochar Application in Compacted and Uncompacted Soil

Ján Horák,Lukáš Trakal,Martin Lukac,Vladimír Šimanský,Tatijana Kotuš,Tereza Hnátková

doi:10.3390/agronomy12030546

Abstract

Biochar may offer a substantial potential as a climate change mitigation and soil improvement agent; however, little is known about its effects in fertile soils subjected to standard agricultural practices. The aim of this short-term (60 days) lab experiment, under controlled temperature and soil moisture regimes, was to investigate the interaction between soil compaction and fertiliser and biochar addition in relatively fertile Luvisol. Three different biochar types and two soil compaction levels were investigated to describe their interactive effect on soil greenhouse gas emission (GHG). A very strong effect of soil compaction on N2O emission (+280%) and an interaction with biochar were found. The cumulative N2O emissions from the compacted soil were higher (from +70 to +371%, depending on the biochar type) than the uncompacted soil. Soil compaction resulted in a faster onset and a faster decrease of N2O production. Biochar did not affect the temporal dynamics of N2O evolution from either soil. The addition of digestate/crop biomass biochar has resulted in a significant increase in CO2 evolution both in compacted and uncompacted soils, compared to softwood from spruce (mixture of branches and wood chips) and wood pallets from softwood (spruce without bark) biochar. In the compacted soil, NH4+ availability was positively related to N2O efflux, and CO2 emission was positively correlated to both NH4+ and SOC content. An increase in GHGs as a result of an increase in NH4+ availability was seen both in compacted and uncompacted soils, while the rates of N2O emission were modified by biochar type. Our results show a strong interaction between biochar and soil conditions and a strong effect of biochar type on GHG emissions from agricultural soils.

Highlights

Agricultural soils are one of the most important anthropogenic sources of greenhouse gas emission (GHG) emissions to the atmosphere [1]
This study aimed to evaluate the effects of two factors on GHG emissions from agricultural soil: biochar addition and soil compaction
Our results suggest that some biochar types offer the promise of mitigating GHG emissions from agricultural soils, the effects can be different in compacted and uncompacted soils

Summary

Introduction

Agricultural soils are one of the most important anthropogenic sources of GHG emissions to the atmosphere [1]. According to the IPCC [2], agriculture generates 11% of global GHG emissions due to soil and nutrient management and livestock farming. Heavy vehicular traffic accompanying these operations increases the risk of soil compaction in arable soils [3,4,5], with a consequent change in GHG emissions [6]. Soil compaction strongly affects soil properties; soil particles are pushed together at the expense of pores. The degree of soil compaction in a specific soil is affected by its texture [3,7], humic substances content [12], and the presence of soil water [13,14]

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Discussion

Conclusion