TY - JOUR

T1 - Microbial nutrient limitation and catalytic adjustments revealed from a long‐term nutrient restriction experiment

AU - Kumar, Amit

AU - Pausch, Johanna

N1 - This publication was funded by the Open Access Publication Fund of Leuphana University Lüneburg. Publisher Copyright: © 2022 The Authors. Journal of Sustainable Agriculture and Environment published by Global Initiative of Crop Microbiome and Sustainable Agriculture and John Wiley & Sons Australia, Ltd.

PY - 2022/6/1

Y1 - 2022/6/1

N2 - IntroductionMicrobial abundance and activities in soils are predominantly determined by soil carbon (C), nitrogen (N) and phosphorus (P) availability. Much research has focused on the effects of soil N than P availability on soil microbial biomass and enzyme activities as sensitive proxies of microbial ecophysiology highlighting the need to investigate how microbes will respond to P availability in soil, especially in cropping systems.Materials and MethodsThe effect of P fertilisation on microbial biomass-C, -N and -P, and the kinetic parameters (maximal velocity [Vmax], Michaelis constant [Km] and catalytic efficiency [Ka]) of β-1,4-glucosidase (BG; C-acquiring), leucine-aminopeptidase (LAP; predominantly N-acquiring) and acid phosphomonoesterase (PHO; P-acquiring) were measured in a nutrient-poor agricultural soil (devoid of fertiliser application since 1942).ResultsThis study showed that P fertilisation led to a 65% and 56% increase in microbial biomass-N and -P, respectively, indicating severe P limitation and inefficient N acquisition by microbes without P availability. Increased Ka values of LAP with P fertilisation further hint toward the production of efficient isoenzymes to avoid resource tradeoffs for nutrient acquisition.ConclusionsOverall, these results decipher microbial metabolic and catalytic adjustments mediated by soil P availability. Increased microbial biomass-N and -P with P fertilisation indicated microbial N and P colimitation that was partly overcome by the production of efficient enzymes for N acquisition with P fertilisation. We argue to incorporate microbial enzyme activities as a response to different management strategies to better inform us about soil biogeochemical cycles in cropping systems.

AB - IntroductionMicrobial abundance and activities in soils are predominantly determined by soil carbon (C), nitrogen (N) and phosphorus (P) availability. Much research has focused on the effects of soil N than P availability on soil microbial biomass and enzyme activities as sensitive proxies of microbial ecophysiology highlighting the need to investigate how microbes will respond to P availability in soil, especially in cropping systems.Materials and MethodsThe effect of P fertilisation on microbial biomass-C, -N and -P, and the kinetic parameters (maximal velocity [Vmax], Michaelis constant [Km] and catalytic efficiency [Ka]) of β-1,4-glucosidase (BG; C-acquiring), leucine-aminopeptidase (LAP; predominantly N-acquiring) and acid phosphomonoesterase (PHO; P-acquiring) were measured in a nutrient-poor agricultural soil (devoid of fertiliser application since 1942).ResultsThis study showed that P fertilisation led to a 65% and 56% increase in microbial biomass-N and -P, respectively, indicating severe P limitation and inefficient N acquisition by microbes without P availability. Increased Ka values of LAP with P fertilisation further hint toward the production of efficient isoenzymes to avoid resource tradeoffs for nutrient acquisition.ConclusionsOverall, these results decipher microbial metabolic and catalytic adjustments mediated by soil P availability. Increased microbial biomass-N and -P with P fertilisation indicated microbial N and P colimitation that was partly overcome by the production of efficient enzymes for N acquisition with P fertilisation. We argue to incorporate microbial enzyme activities as a response to different management strategies to better inform us about soil biogeochemical cycles in cropping systems.

KW - Biology

KW - Ecosystems Research

KW - catalytic efficiency

KW - enzyme activity,

KW - Kinetic parameters

KW - Microbial biomass

KW - phosphorus fertilisation

UR - http://www.scopus.com/inward/record.url?scp=85149449102&partnerID=8YFLogxK

U2 - 10.1002/sae2.12015

DO - 10.1002/sae2.12015

M3 - Journal articles

VL - 1

SP - 142

EP - 148

JO - Journal of Sustainable Agriculture and Environment

JF - Journal of Sustainable Agriculture and Environment

SN - 2767-035X

IS - 2

ER -