The Influence of Grain Legume and Tillage Strategies on CO₂ and N₂O Gas Exchange under Varied Environmental Conditions

• Main Authors: Emilie Marie Øst Hansen, Henrik Hauggaard-Nielsen, Eric Justes, Per Ambus, Teis Nørgaard Mikkelsen
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Agriculture
• Subjects: net ecosystem exchange; gross ecosystem production; mesocosm; rotation; soil tillage
• Online Access: https://www.mdpi.com/2077-0472/11/5/464

By this in vitro study addressing greenhouse gas (GHG) emissions from soil-plant mesocosms, we suggest a method to investigate the joint effects of environmental conditions, growth of plants, and agricultural soil management. Soils from two long-term agricultural trials in France were placed in climate chambers. The rotation trial was with or without grain legumes, and the tillage trial used plowing or reduced tillage. Environmental conditions consisted of two contrasting temperature regimes combined with ambient (400 ppm) or high (700 ppm) CO₂ concentrations in climate chambers. The plant growth went from seeding to vegetative growth. Carbon dioxide gas exchange measurements were conducted in both soil types for a period representing initial plant growth. The CO₂ exchange was influenced by the growing plants increasing the mesocosm respiration and gross ecosystem production. The environmental settings had no noticeable impact on the CO₂ exchange in the soils from the legume trial. The CO₂ exchange from the tillage trial soils exhibited variations induced by the environmental conditions depending on the tillage treatment. The N₂O emission measurements in the legume trial soils showed little variability based on rotation, however, in soils with legumes, indications that higher temperatures will lead to more N₂O emission were seen.