How urban gardens help rebalance carbon: Q&A with PhD student Atefeh Movassagh

IZNE: What is the focus of your research?

Atefeh Movassagh: My research question is: How do land use and management practices in urban green spaces in the Bonn-Rhein-Sieg area influence soil organic carbon stocks (SOC), soil nutrients, and the potential to provide soil ecosystem services?

The aim is to assess how different land use and management practices affect SOC storage and nutrients in urban green spaces, with a focus on the Bonn and Rhein-Sieg districts.

IZNE: In a presentation last year, you said, “It’s not always about reducing carbon, but about rebalancing it.” Could you explain that?

Atefeh Movassagh: The total amount of carbon in Earth’s system remains nearly constant, but it continuously cycles between the atmosphere, oceans, and land. Climate change is not about having more carbon overall; rather, it’s about an imbalance in these carbon flows. Urbanization—through construction, industrial activities, and unsustainable soil management—exacerbates this imbalance. Restoring soil carbon and rebalancing these natural flows are essential for creating more sustainable and resilient urban environments.

IZNE: What are the most important findings so far?

Atefeh Movassagh: Our results indicate that urban green spaces in the Bonn–Rhein-Sieg district—such as house gardens, allotment gardens, and public green spaces—exhibit relatively high soil organic carbon (SOC) stocks and nutrients compared to global urban averages. We also found that vegetation type is a key factor influencing SOC storage, highlighting the importance of plant selection in enhancing carbon sequestration in urban soils.

IZNE: What practical recommendations do you have for gardeners?

Atefeh Movassagh:

• Grow more, not less: Increase biomass by planting diverse vegetation instead of leaving areas bare or dominated by lawn.
• Keep organic matter on site: Leave grass clippings and plant residues in your garden or turn them into compost.
• Support life below ground: Healthy soils depend on biodiversity—protect soil organisms by increasing plant diversity and managing irrigation and fertilization carefully.
   

IZNE: Thank you for these fascinating insights into your research. We wish you all the best for completing your PhD thesis!

The PhD project is supervisoned by: Prof. Dr. Martin Hamer (H-BRS, IZNE), Prof. Dr. Thomas Döring (University of Bonn), Prof. Dr. Florian Wichern (Hochschule Rhein-Waal) and Dr. Bibiana Betancur Corredor (Center for Development Research (ZEF) – University of Bonn).