Citation: Horák, J.; Šimanský, V.;
Kotuš, T.; Hnátková, T.; Trakal, L.;
Lukac, M. Mitigation of Greenhouse
Gas Emissions with Biochar
Application in Compacted and
Uncompacted Soil. Agronomy 2022,
12, 546. https://doi.org/10.3390/
agronomy12030546
Academic Editor: Jinyang Wang
Received: 30 November 2021
Accepted: 18 February 2022
Published: 22 February 2022
Publisher’s Note: MDPI stays neutral
with regard to jurisdictional claims in
published maps and institutional affil-
iations.
Copyright: © 2022 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
agronomy
Article
Mitigation of Greenhouse Gas Emissions with Biochar
Application in Compacted and Uncompacted Soil
Ján Horák
1,
* , Vladimír Šimanský
2
, Tatijana Kotuš
1
, Tereza Hnátková
3,4
, Lukáš Trakal
3
and
Martin Lukac
5,6
1
Faculty of Horticulture and Landscape Engineering, Institute of Landscape Engineering, Slovak University of
Agriculture, 949 76 Nitra, Slovakia; xkotus@uniag.sk
2
Department of Soil Science, Faculty of Agrobiology and Food Resources, Institute of Agronomic Sciences,
Slovak University of Agriculture, 949 76 Nitra, Slovakia; vladimir.simansky@uniag.sk
3
Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129,
165 21 Prague, Czech Republic; hnatkova@dekonta.cz (T.H.); trakal@fzp.czu.cz (L.T.)
4
Dekonta, a.s., Dˇ retovice 109, 273 42 Stehelˇ ceves, Czech Republic
5
School of Agriculture, Policy and Development, University of Reading, Reading RG1 1AF, UK;
m.lukac@reading.ac.uk
6
Department of Forest Management, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences,
16 521 Prague, Czech Republic
* Correspondence: jan.horak@uniag.sk
Abstract: Biochar may offer a substantial potential as a climate change mitigation and soil improve-
ment 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 N
2
O emission (+280%) and an interaction with biochar
were found. The cumulative N
2
O 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 N
2
O production. Biochar did not affect the temporal dynamics
of N
2
O evolution from either soil. The addition of digestate/crop biomass biochar has resulted
in a significant increase in CO
2
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, NH
4
+
availability was positively related to N
2
O efflux,
and CO
2
emission was positively correlated to both NH
4
+
and SOC content. An increase in GHGs
as a result of an increase in NH
4
+
availability was seen both in compacted and uncompacted soils,
while the rates of N
2
O 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.
Keywords: N
2
O emissions; CO
2
emissions; biochar; soil compaction
1. Introduction
Agricultural soils are one of the most important anthropogenic sources of GHG emis-
sions 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. Modern
agriculture is characterised by its reliance on mechanised agronomic operations and inten-
sive soil management practices. Heavy vehicular traffic accompanying these operations
increases the risk of soil compaction in arable soils [3–5], with a consequent change in GHG
emissions [6]. At the same time, soil compaction is among the most significant drivers of
Agronomy 2022, 12, 546. https://doi.org/10.3390/agronomy12030546 https://www.mdpi.com/journal/agronomy