Net ecosystem exchange of carbon dioxide on hayland with drained peat soil in central European Russia: mowing scenario analysis

Abstract

ABSTRACT Haylands are the mildest option for the agricultural use of drained peatlands in terms of CO2 emissions. However, CO2 fluxes and their balance may depend on various conditions including the frequency of mowing and amount of phytomass removed. Based on field measurements of CO2 fluxes using the chamber method and monitoring of environmental factors conducted in 2018–2020 on hayland and fallow on drained peatland in central European Russia, a mathematical model of CO2 balance was built. Numerical experiments showed that mowing of hayland, irrespective of the intensity, did not lead to an increase in CO2 emissions compared to fallow. Fallow and hayland after single mowing had closely modelled net ecosystem exchange (NEE) values: 9.9 ± 2.4 and 8.5 ± 2.7 t C ha−1 season−1, respectively. Furthermore, a single mowing turned out 2.8 t ha−1 of hay (0.8 ± 0.1 t C ha−1), and 4.4 (1.4 ± 0.1) after double mowing. The modelled NEE after double mowing increased to 9.4 ± 2.9 t C ha−1 season−1. A single mowing session in early summer is recommended. Compared to other uses, e.g. arable land, mowing on hayland is a compromise between reducing CO2 emissions and gaining economic benefits from drained peatlands.