Background and Objective

Peatlands drained for agriculture, forestry and peat extraction are a major source of greenhouse gas emissions. Therefore, sustainable utilisation systems are sought, which offer habitats for typical flora and fauna and have a long-term greenhouse gas balance similar to near-natural peatlands. At present, Sphagnum farming, i.e. the cultivation of peat mosses as a substrate for horticulture, is the only utilisation option of bogs which might combine ecological and economic goals.

The aim of our research project is the scientific evaluation of the commercial use of Sphagnum cultivation fields. The focus will be on biodiversity and greenhouse gas exchange. The project is comprised of the two projects “Großflächige Torfmooskultivierung in Niedersachsen als Folgenutzung nach Schwarztorf-Abbau und ihr Potenzial für Klimaschutz und Biodiversität (KlimDivMoos)“ and  “Auswirkungen großflächiger Torfmooskultivierung nach Schwarztorf-Abbau auf Biodiversität und Treibhausgasemissionen (MOOSKULT)“. KlimDivMoos (01.09.2015 until 31.12.2018) and MOOKULT (01.10.2016 until 30.09.2019) are funded by the Lower Saxony Ministry of Food, Agriculture, and Consumer Protection and by the German Federal Environmental Foundation (DBU), respectively.

Approach

Sphagnum farming depends on donor areas and an effective water management. Therefore, we will evaluate not only commercially used cultivation fields, but also a donor mire and propagation areas. The Leibniz University Hannover (Institute for Landscape Planning) will investigate the effects of moss “harvest” on the donor mire and the biodiversity (flora and fauna) of the propagation area and cultivation fields.  

The Thünen-Team is responsible for the measurement of greenhouse gas exchange. Using manual chambers, we will quantify the exchange of carbon dioxide (net ecosystem exchange), nitrous oxide and methane from the donor mire, the propagation area (including irrigation polders) and the cultivation fields. Using “Open Top Chambers”, we will test the resilience of different water management systems against increased temperatures. Furthermore, we will conduct an isotope study in the Sphagnum cultivation field to trace the newly sequestered carbon.

Our Research Questions

1. What is the greenhouse balance of the “peatland-based” production of Sphagnum substrates (donor mires, propagation areas, and cultivation fields)?
2. Which is the best irrigation method for optimizing the greenhouse gas balance?  
3. How resilient towards increased temperatures is Sphagnum cultivation compared to a semi-natural mire?  
4. Is there enough carbon dioxide sequestration to allow for peat growth despite Sphagnum harvest?