EGU General Assembly 2022
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the Creative Commons Attribution 4.0 License.

The impact of liquid organic fertilization and associated application techniques on N2, N2O and CO2 fluxes from agricultural soils

Balázs Grosz1, Björn Kemmann1, Stefan Burkart1, Søren O. Petersen2, and Reinhard Well1
Balázs Grosz et al.
  • 1Thünen Institute , Climate-Smart Agriculture, Braunschweig, Germany (
  • 2Department of Agroecology, Aarhus University, Blichers Allé 20, Tjele, 8830, Denmark

Prediction of liquid manure effects on N transformations in soils and associated N2O and N2 fluxes is poor because previous investigations mostly excluded N2, the end product of denitrification. We address the questions, (1) how liquid manure fertilization and its application technique impact N2, N2O and CO2 fluxes from agricultural soil, and (2) how the water, mineral N and dissolved organic carbon (DOC) content of the manure amended soil change between the soil layers. A sandy arable soil was used in a 10 days laboratory incubation at constant 15oC, constant 40% and 60% water-filled pore space (WFPS) and amended with and without artificial slurry in three manure treatments (control, surface-applied, injected). N2O and CO2 fluxes were quantified by gas chromatography. N2 and source-specific N2O flux was quantified by isotope-ratio mass spectrometry. At 5th and 10th day, depth distribution of moisture, NH4+, NO3-, DOC, pH and 15N enrichment of NO3- was determined with destructive sampling. The N2+N2O flux of the surface-applied and injected 40% WFPS treatments were 75% and 110% higher than the control and at 60% WFPS treatments were more than 610% and 1690% higher than the control. The product ratio of denitrification showed enhanced share of N2 to the N2+N2O flux in the manure treatments, which we attribute to hot-spot dynamics of the manure layers. Our data demonstrate how the dynamics of moisture, labile C, NH4+-N, formation of NO3--N by nitrification and pH following manure surface application or injection interact and result in N2O cycling by various pathways. The data-set can thus be used to evaluate and further develop models to predict denitrification and respiration processes of the manure-soil hot-spots. Further progress in unravelling and modeling manure induced hot-spot dynamics can be achieved if temporal and spatial resolution of our measurements is improved and additional techniques to determine O2 distribution and distinguish gross N transformations and their gaseous N fluxes are included.

How to cite: Grosz, B., Kemmann, B., Burkart, S., Petersen, S. O., and Well, R.: The impact of liquid organic fertilization and associated application techniques on N2, N2O and CO2 fluxes from agricultural soils, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9113,, 2022.