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Tropentag, September 14 - 16, 2022, Prague

"Can agroecological farming feed the world? Farmers' and academia's views."

Evaluating soil carbon emissions from cup-plant and silage maize under drought-stressed conditions; Tower an effective carbon farming using perennial bioenergy crops

Khatab Abdalla1, Hannah Uther2, Johanna Pausch3

1University of Bayreuth, Agroecology, Germany
2University of Bayreuth, Agroecology
3University of Bayreuth, Agroecology, Germany


Agricultural intensification highly contributes to greenhouse gas (GHG) emissions, which escalate the current risk of climate change. Thus, crops with high carbon (C) sink capacities are crucial for agroecosystem sustainability, particularly those that have the potential to resist extreme events, e.g., drought stress. Therefore, this study aimed to evaluate the potential of a perennial cup-plant (Silphium perfoliatum L.) in reducing C output (as CO2) to be proposed as a promising alternative for silage maize (Zea mays L.) under drought conditions. for this purpose, a lysimeter experiment comparing these crops subjected to two watering regimes (well-watered and drought-stressed), replicated five-time was set up at the botanical garden of the University of Bayreuth, Germany. Soil CO2 efflux was measured using a Licor-6400XT gas exchange system (LI-COR, Lincoln, NE, USA)) twice a month during the growing season for three consecutive seasons. Soil respiration was correlated to soil moisture and temperature, biomass (aboveground and belowground), and soil C and nitrogen (N) to identify the main driver of C output. The final cumulative CO2 efflux was greater by 29% (P < 0.05) under drought-stressed cup-plant than in drought maize, which was explained by the higher belowground biomass production under cup-plant. Soil CO2 efflux was mainly driven by the below and aboveground biomass (r = 0.6; P < 0.05), rather than soil temperature and moisture content. The benefits of cup-plant cultivation are further supported by the higher dissolved organic C: dissolved N ratio (DOC: DN), implying a better environment for microbial growth and activities. Even though the microbial activity enhances soil respiration and C mineralisation, an effective C farming solution under cup-plant can still be expected in the longer term due to the continuous fresh C inputs of the perennial cup-plant.

Keywords: Bioenergy crops, carbon sequestration, climate change, soil respiration

Contact Address: Khatab Abdalla, University of Bayreuth, Agroecology, Universitätsstraße 40, 95447 Bayreuth, Germany, e-mail: khatab.abdalla@uni-bayreuth.de

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