TY - JOUR

T1 - Soil microorganisms decrease barley biomass uniformly across contrasting nitrogen availability

AU - Munkager, Victoria

AU - Altenburger, Andreas

AU - Priemé, Anders

AU - Bang-Andreasen, Toke

AU - Rønn, Regin

AU - Vestergård, Mette

AU - Ekelund, Flemming

N1 - Publisher Copyright: © 2021 Elsevier Masson SAS

PY - 2021

Y1 - 2021

N2 - Aims: Microorganisms play a dichotomous role in the soil nitrogen cycle through mineralization and immobilization. We aimed to understand how nitrogen availability modifies the effect of microorganisms on plant growth. We hypothesized that soil microorganisms would increase plant biomass following amendment with a substrate rich in organic nitrogen (net mineralization), be neutral when adding inorganic nitrogen, and decrease biomass when adding organic nitrogen-limited substrate (nitrogen competition). Method: Barley (Hordeum vulgare L., cv. Evergreen) was exposed to either i) limited, organically bound nitrogen, ii) organically bound nitrogen or iii) inorganic nitrogen. In these amendments, we assessed the differences in plant biomass and physiology between plants with or without soil microbiome addition. Results: The soil microbiome reduced shoot biomass equally (12%) across all nitrogen amendments. However, nitrogen availability did modulate the effect of the soil microbiome on plant physiological parameters associated with nitrogen deficiency. Conclusions: The results indicate that the net negative effect of complex microbiomes on shoot biomass is independent of nitrogen availability. Thus, microbiome addition was deleterious to biomass even in a nutrient-stress-free environment. We suggest that strategies for improving plant growth through manipulation of microorganisms should not exclusively focus on beneficial and pathogenic microorganisms, but also include minimizing plant metabolic costs of microbiome interactions.

AB - Aims: Microorganisms play a dichotomous role in the soil nitrogen cycle through mineralization and immobilization. We aimed to understand how nitrogen availability modifies the effect of microorganisms on plant growth. We hypothesized that soil microorganisms would increase plant biomass following amendment with a substrate rich in organic nitrogen (net mineralization), be neutral when adding inorganic nitrogen, and decrease biomass when adding organic nitrogen-limited substrate (nitrogen competition). Method: Barley (Hordeum vulgare L., cv. Evergreen) was exposed to either i) limited, organically bound nitrogen, ii) organically bound nitrogen or iii) inorganic nitrogen. In these amendments, we assessed the differences in plant biomass and physiology between plants with or without soil microbiome addition. Results: The soil microbiome reduced shoot biomass equally (12%) across all nitrogen amendments. However, nitrogen availability did modulate the effect of the soil microbiome on plant physiological parameters associated with nitrogen deficiency. Conclusions: The results indicate that the net negative effect of complex microbiomes on shoot biomass is independent of nitrogen availability. Thus, microbiome addition was deleterious to biomass even in a nutrient-stress-free environment. We suggest that strategies for improving plant growth through manipulation of microorganisms should not exclusively focus on beneficial and pathogenic microorganisms, but also include minimizing plant metabolic costs of microbiome interactions.

KW - Bacteria

KW - Nitrogen competition

KW - Nitrogen mineralization

KW - Plant growth

KW - Plant-microbiome interaction

KW - Protists

U2 - 10.1016/j.ejsobi.2021.103311

DO - 10.1016/j.ejsobi.2021.103311

M3 - Journal article

AN - SCOPUS:85103387828

VL - 104

JO - European Journal of Soil Biology

JF - European Journal of Soil Biology

SN - 1164-5563

M1 - 103311

ER -