Logo image
Back
The soil microbial community and plant biomass differentially contribute to the retention and recycling of urinary-N in grasslands
Journal article   Open access   Peer reviewed

The soil microbial community and plant biomass differentially contribute to the retention and recycling of urinary-N in grasslands

Michaela K. Reay, Karina A. Marsden, Sarah Powell, Leonardo Mena Rivera, David R. Chadwick, Davey L. Jones and Richard P. Evershed
Soil biology & biochemistry, Vol.180, 109011
2023
DOI: https://doi.org/10.1016/j.soilbio.2023.109011
pdf
Published3.16 MBDownloadView
CC BY V4.0,  Open Access

Abstract

Compound-specific Grassland soil Microbial biosynthesis Mineralisation-immobilisation turnover Nitrogen leaching losses
Urine patches in grazed systems are hotspots for nitrogen (N) cycling and losses to the wider environment. Retention and subsequent recycling of urinary-N is key to minimise losses and increase ecosystem nitrogen use efficiency. Biosynthesis into the microbial organic N pool is an important N pathway but this has not been directly quantified in a urine patch. Herein, we present the results of a time course experiment using soil mesocosms sown with perennial ryegrass (Lolium perenne L.) and treated with 15N-labelled sheep urine to determine partitioning of the applied N between plant, soil biomass pools and leaching losses following simulated rainfall events. 15N-tracing used bulk and compound-specific 15N-stable isotope probing (SIP) to determine the fate of urinary N. Initial high leaching losses (233 kg N ha−1) were comprised of native soil N, ammonium and nitrate derived from urine by urea hydrolysis and nitrification, respectively. Leaching subsequently decreased whilst uptake into plant biomass and microbial biosynthesis increased during periods of low rainfall. Uptake into above and belowground plant biomass was the largest fate of urinary-15N after 94 d (42%), although assimilation into microbial biomass dominated for ca. 1 month after urine deposition (34%). Compound-specific 15N–SIP of amino acids and amino sugars revealed immobilisation of urinary-N following mineralisation was the dominant pathway for biosynthesis, with incorporation into bacterial organic N pools more rapid than into the fungal biomass. There was also intact utilisation of glycine derived from urine. This study provides clear evidence that direct assimilation of urine-derived N into microbial organic N pools is an important process for retaining N in a urine patch, which will subsequently support plant N supply during microbial turnover. [Display omitted] •15N-labelled urine was traced into plant, microbial and leaching pools in a grassland mesocosm.•Leaching losses were reduced, and plant uptake increased during periods of low rainfall.•Microbial uptake of urinary-N occurred via mineralisation-immobilisation and intact pathways.•Microbial assimilation was dominated by bacteria over fungi.

Details

UN Sustainable Development Goals (SDGs)

This output has contributed to the advancement of the following goals:

#2 Zero Hunger
#13 Climate Action
#14 Life Below Water

Source: InCites

Metrics

8 File views/ downloads
62 Record Views
4 Times Cited - Web of Science

InCites Highlights

These are selected metrics from InCites Benchmarking & Analytics tool, related to this output

Collaboration types
Domestic collaboration
International collaboration
Citation topics
3 Agriculture, Environment & Ecology
3.45 Soil Science
3.45.397 Nitrogen Management
Web Of Science research areas
Soil Science
ESI research areas
Agricultural Sciences
Logo image