Earthworms increase available P turnover through microbial pathways: insights from δ18O in phosphate
Abstract
Reducing agriculture's dependence on finite mineral phosphorus (P) resources requires enhancing the use of soil legacy P by promoting the biotic cycling of P pools, such as organic P. Soil fauna, especially earthworms, may stimulate microbial activity, yet their role in regulating biotic P cycling remains unclear. Using 18 O-enriched water labelling and stable oxygen isotope of phosphate (δ 18 O–P) in two incubation experiments, we directly tracked biotic P transformations in soils with contrasting P availability with and without earthworms. The δ 18 O–P proved to be a sensitive tool, capturing earthworm-induced changes in microbial P transformations that conventional chemical extractions or enzymatic assays could not detect. We show that, regardless of their ecological group (anecic or endogeic), earthworms significantly increased the turnover of available P by increasing the exchange between the available and microbial P pools, despite having little to no effect on the size of these pools. In the soil with high P availability of the first experiment, earthworms doubled the proportion of microbial P entering available P, increasing it from 20% to 40%. In the soil with low P availability of the second experiment, earthworms with litter inputs stimulated the extracellular mineralisation of organic P, which appeared to be the dominant mechanism for replenishing available P, as indicated by the highest proportion of oxygen atoms (13%) incorporated into available P. These findings reveal that earthworms can stimulate microbial P turnover, a previously overlooked and unquantified mechanism. They also show that earthworms have the potential to mobilise legacy P in low P soils, provided a food source, such as crop residues or amendments, is supplied.
Related
- Increase in sea-level and shelf area positively influenced the development of Cenozoic biodiversity hotspots by modulating turnover rate in marine benthos
- Short-term BDD treatment of wastewater effluent reveals dissolved oxygen turnover and microbial community restructuring
- Plant genetic and root‐associated microbial diversity modulate Lactuca sativa responsiveness to a soil inoculum under phosphate deficiency
- Response of broiler chickens fed low-energy diets to increase levels of lysolecithin: linking growth performance with lipid metabolism gene expression, gut microbial modulation, intestinal morphology, and economic efficiency.
- Ecologically based agriculture benefits earthworms in Argentina’s large-scale systems: farm-level strategies matter
BibTeX
@article{pistocchi2026earthworms,
title = {{Earthworms increase available P turnover through microbial pathways: insights from δ18O in phosphate}},
author = {Chiara Pistocchi and A Burr and H M J Vos and F Tamburini and Claude Plassard and J W van Groenigen and Alexandru Milcu and Mickael Hedde and M B H Ros and A Vidal},
journal = {Soil Biology and Biochemistry},
year = {2026},
month = oct,
doi = {10.1016/j.soilbio.2026.110186},
url = {https://hal.science/hal-05805265v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Earthworms increase available P turnover through microbial pathways: insights from δ18O in phosphate
AU - Chiara Pistocchi
AU - A Burr
AU - H M J Vos
AU - F Tamburini
AU - Claude Plassard
AU - J W van Groenigen
AU - Alexandru Milcu
AU - Mickael Hedde
AU - M B H Ros
AU - A Vidal
PY - 2026
DA - 2026/10/19
JO - Soil Biology and Biochemistry
DO - 10.1016/j.soilbio.2026.110186
UR - https://hal.science/hal-05805265v1
AB - Reducing agriculture's dependence on finite mineral phosphorus (P) resources requires enhancing the use of soil legacy P by promoting the biotic cycling of P pools, such as organic P. Soil fauna, especially earthworms, may stimulate microbial activity, yet their role in regulating biotic P cycling remains unclear. Using 18 O-enriched water labelling and stable oxygen isotope of phosphate (δ 18 O–P) in two incubation experiments, we directly tracked biotic P transformations in soils with contrasting P availability with and without earthworms. The δ 18 O–P proved to be a sensitive tool, capturing earthworm-induced changes in microbial P transformations that conventional chemical extractions or enzymatic assays could not detect. We show that, regardless of their ecological group (anecic or endogeic), earthworms significantly increased the turnover of available P by increasing the exchange between the available and microbial P pools, despite having little to no effect on the size of these pools. In the soil with high P availability of the first experiment, earthworms doubled the proportion of microbial P entering available P, increasing it from 20% to 40%. In the soil with low P availability of the second experiment, earthworms with litter inputs stimulated the extracellular mineralisation of organic P, which appeared to be the dominant mechanism for replenishing available P, as indicated by the highest proportion of oxygen atoms (13%) incorporated into available P. These findings reveal that earthworms can stimulate microbial P turnover, a previously overlooked and unquantified mechanism. They also show that earthworms have the potential to mobilise legacy P in low P soils, provided a food source, such as crop residues or amendments, is supplied.
SN - 0038-0717
ER -