Details

Autor(en) / Beteiligte

• Kumar, Amit
• Pausch, Johanna

Titel

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

Ist Teil von

• Journal of sustainable agriculture and environment, 2022-06, Vol.1 (2), p.142-148

Ort / Verlag

Greater Western Sydney: John Wiley & Sons, Inc

Erscheinungsjahr

2022

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• Introduction Microbial 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 Methods The 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). Results This 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. Conclusions Overall, 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.