# Minimizing CO2 and N2O emissions from urban lawns through sustainable management strategies.

Tom Künnemann, Patrice Cannavo, Vincent Guérin, Paul Legain, R Guenon

► To cite this version:

Tom Künnemann, Patrice Cannavo, Vincent Guérin, Paul Legain, R Guenon. Minimizing CO2 and N2O emissions from urban lawns through sustainable management strategies. SUITMA 13, Research Institute on Terrestrial Ecosystems (IRET); Italian National Research Council (CNR), Oct 2025, Pisa, Italy. **hal-05515585**

HAL Id: hal-05515585

https://hal.inrae.fr/hal-05515585v1

Submitted on 17 Feb 2026

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Distributed under a Creative Commons CC BY 4.0 - Attribution - International License
# Minimizing N₂O and CO₂ Fluxes from Urban Lawns through Sustainable Management Strategies

T. Künnemann¹, P. Cannavo¹, V. Guérin², P. Legain²,³, R. Guénon¹

(1) L'Institut Agro Rennes-Angers, UP EPHor; (2) INRAE, IRHS; (3) INRAE, UMR EcoSys

October 6th, 2025, Pisa, SUITMA

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L'INSTITUT
agro Rennes-Angers

Unite propre de recherche EPHor

INRAE

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ADEME

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AGENCE DE LA
TRANSITION
ECOLOGIQUE

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**Lawns** cover up to 50–70% of urban green spaces (UGSs) worldwide (Ignatieva et al. 2020)

**Conventional practices**

- Increase soil N₂O emissions

- Nutrient and C losses

- Indirect GHG emissions

**Alternative practices**

- Reduce N₂O emissions

- Nutrient and C storage

Organic fertilization and litter recycling can result in **GHG emissions** (Xia et al., 2018).

**Conventional practices**

**Alternative practices**

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**Knowledge Gaps**

Few references on GHG emissions
for alternative practices

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**Objective**

Assess the impact of **11 conventional and alternative** lawn
management practices, on **CO2 and N2O fluxes**.

* Organic vs mineral fertilization

- Litter recycling vs exportation

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H1

The use of **organic fertilizer reduces N₂O fluxes** compared to mineral fertilizer.

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Reduced N₂O fluxes

Low

N availability

H2

**Recycling tree litter** on the soil surface **increase CO₂ and N₂O fluxes** compared to exporting it.

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Increased CO₂ and N₂O fluxes

High

C availability

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Experimental site

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Angers, France

2023 - 2024

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430 m²

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<table><thead><tr><th></th><th>0-20 cm</th></tr></thead><tbody><tr><td>Organic C (%)</td><td>1.8</td></tr><tr><td>Total N (%)</td><td>0.2</td></tr><tr><td>pH H₂O</td><td>7.4</td></tr><tr><td>Bulk density</td><td>1.2</td></tr><tr><td>Soil texture</td><td>Sandy loam</td></tr></tbody></table>

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**Fertilization rate :**
**6.3 g N m⁻²**

**Mineral**

NPK 21-5-10

**Organic**

NPK 8-2-2

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**Sprinkler; VWC < 15%**

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**Litterfall recycling**

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+ Varying mowing frequency

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**Grass recylcing**

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**Grass exportation**

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**Control** without
fertilization and
irrigation

**Fertilization +
irrigation +
grass exportation**

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**Litter input : 3.8 Mg ha⁻¹**

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**3 litter treatments**

Quercus

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Pinus

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Mix

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**GHG measurements :**

* FTIR spectrometer → CO₂ and N₂O fluxes

* Over spring-summer-automn

* For 11 treatments → weekly measurements

* For 2 fertilized + control treatments → daily measurements

* During 7 days

* Mineral N → NH₄⁺, NO₃⁻

* Biomass sampling

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**Soil T°C and WFPS**

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**Climatic conditions :**

* Rain

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* Air T°C, relative humidity, global radiation

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Global CO₂ and N₂O fluxes

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Similar CO₂ fluxes across treatments.

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H1

N₂O fluxes were mainly detected in the plots where **mineral fertilizer** was applied.
Mineral fertilization is the main contributor to N₂O fluxes

<figure><img src="image_40.png" /><figcaption>NO₃⁻ (mg N kg⁻¹)</figcaption></figure>

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H1

N₂O fluxes are linked to N availability

Lower soil N use efficiency by lawns in early spring ?

<figure><img src="image_42.png" /><figcaption>Biomass production (g DW m⁻²)</figcaption></figure>

Organic fertilization sustains lawn productivity
Low CO₂ and N₂O fluxes for litter recycling practices

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Low N₂O fluxes on PIN and QUR_PIN when WFPS exceeded 50%

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Recycling litter on soil surface **did not induce higher CO₂ and N₂O fluxes**
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**Organic fertilization** greatly reduced N₂O emissions

Avoid **spring fertilization** to limit N₂O emissions and N leaching

<figure><img src="image_46.png" /><figcaption>Spring</figcaption></figure>

<figure><img src="image_47.png" /><figcaption>Summer</figcaption></figure>

<figure><img src="image_48.png" /><figcaption>Autumn</figcaption></figure>

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Recycling of senescent **litter** had a low N₂O emission potential

Enhance **ecosystem services**

<figure><img src="image_50.png" /><figcaption>Infiltration
(Fung et al. 2022)</figcaption></figure>

<figure><img src="image_51.png" /><figcaption>Fertility
(Ferlauto et al., 2024)</figcaption></figure>

<figure><img src="image_52.png" /><figcaption>Biodiversity
(Mills et al. 2020)</figcaption></figure>

**Perspectives**

C storage
potential of lawns

More organic
fertilizer types

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Thank you for your attention

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L'INSTITUT
agro Rennes-Angers

Unite propre de recherche EPHor

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