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@PHDTHESIS{Kaloterakis:1050545,
author = {Kaloterakis, Nikolaos},
title = {{F}rom {S}oil {L}egacy to {W}heat {Y}ield {D}ecline:
{S}tudying the {P}lant-{S}oil {F}eedback {M}echanisms in
{W}heat {R}otations},
volume = {686},
school = {Bonn},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2026-00305},
isbn = {978-3-95806-874-2},
series = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
Umwelt / Energy $\&$ Environment},
pages = {XXIX, 188},
year = {2025},
note = {Dissertation, Bonn, 2025},
abstract = {Winter wheat is one of the most important crops cultivated
globally. The yield of winter wheat is stagnating in several
areas of the world since the 1990s. Continuous winter wheat
cultivation is associated with a marked yield decline that
is often attributed to the proliferation of the soil-borne
pathogen Gaeumannomyces tritici (take-all). However, it is
unlikely that this yield decline is solely due to take-all,
but rather it is the outcome of more complex
soil-microbe-plant interactions that drive plant-soil
feedbacks in the rhizosphere of winter wheat. The soil
legacy of the preceding crop is a major determinant of the
growth and development of the succeeding plant, and it can
be expected that the rotational position of winter wheat
will influence the productivity of the following winter
wheat. The aim of this thesis was to analyze plant-soil
feedbacks in successive winter wheat rotations and better
understand the observed yield decline. We specifically aimed
at investigating how the rotational position of winter wheat
affects the microbial communities and the associated
nutrient cycling and enzymatic activity in the soil, and how
the root system of winter wheat responds to these changes,
thereby affecting plant growth and productivity. Finally, we
looked into the potential of compost and plant
growth-promoting rhizobacteria to compensate for the growth
reduction in continuous winter wheat rotations and provide
farmers with a sustainable toolbox to safeguard plant
productivity and food production. We developed and used
novel mesocosms for growing winter wheat and employing
isotopic tracers to enable the quantification of important
rhizosphere processes and assess above- and belowground
carbon allocation, nitrogen uptake and water uptake from
various soil layers. We found that there was much higher
initial nitrate availability in the soil of winter wheat
after oilseed rape at the germination and tillering growth
stage compared to continuous winter wheat, especially in the
subsoil. This was associated with nitrogen immobilization by
the microbial community, which was associated with distinct
root plastic responses and reduced winter wheat growth early
in the growing season. Soil legacy of the preceding crop
also had a strong influence on soil enzymatic activity and
nitrogen cycling as indicated by changes in the activity of
nitrogen-related enzymes and the abundance of microbial
nitrogen-cycling genes. We also found a higher and sustained
belowground allocation of freshly assimilated carbon at the
flowering and grain ripening growth stages of winter wheat
growing after oilseed rape that was available for microbial
use, revealing a higher rhizodeposition in nonsuccessive
winter wheat rotations. Non-successive winter wheat
converted more of the freshly assimilated carbon into
biomass and achieved higher yields than continuous winter
wheat. Winter wheat after oilseed rape exhibited distinct
patterns in shaping its microbial community, with a higher
abundance of taxa involved in important nutrient
mineralization processes and capable of conferring plant
protection against important soil pathogens. Application of
both compost and plant growth-promoting rhizobacteria caused
a positive plant-soil feedback in continuous winter wheat
cultivation, compensating the growth reduction and yield
decline. This work thus demonstrated that yield decline in
successive winter wheat rotations is dependent on several
key rhizosphere processes and that soil legacy of the
preceding crop is an important driver of the productivity of
the succeeding plant. By understanding this phenomenon, we
can design resilient, productive and multifunctional farming
systems that can cope with the increasing adversities of
climate change without compromising yield production and
food security.},
cin = {IBG-3},
cid = {I:(DE-Juel1)IBG-3-20101118},
pnm = {2173 - Agro-biogeosystems: controls, feedbacks and impact
(POF4-217)},
pid = {G:(DE-HGF)POF4-2173},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
urn = {urn:nbn:de:0001-2601271048169.512365216362},
doi = {10.34734/FZJ-2026-00305},
url = {https://juser.fz-juelich.de/record/1050545},
}