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| Titel |
Simulation with models of increasing complexity of CO2 emissions and nitrogen mineralisation, after soil application of labelled pig slurry and maize stalks |
| VerfasserIn |
Luca Bechini, Pietro Marino Gallina, Gabriele Geromel, Martina Corti, Daniele Cavalli |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111154
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| Publikation (Nr.) |
 EGU/EGU2015-15009.pdf |
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| Zusammenfassung |
| High amounts of nitrogen are available per unit area in regions with intensive livestock
operations. In swine farms, pig slurries are frequently incorporated in the soil together with
maize stalks. Simulation models may help to understand nitrogen dynamics associated with
animal manure and crop residue decomposition in the soil, and to support the definition of
best management practices.
The objective of this work was to test the ability of different models to simulate CO2
emissions and nitrogen mineralisation during a laboratory incubation (under optimal
soil water content and constant temperature) of maize stalks (ST) and pig slurry
(PS).
A loam soil was amended with labelled (15N) or unlabelled maize stalks and pig slurries,
in the presence of ammonium sulphate (AS). These treatments were established: unfertilised
soil; ST15 + AS + PS; ST + AS15 + PS; and ST + AS + PS15. During 180 days, we
measured CO2 emissions; microbial biomass C, N, and 15N; and soil mineral N (SMN and
SM-15N). Three models of increasing complexity were calibrated using measured data. The
models were two modifications of ICBM 2B/N (Kätterer and Andrén, 2001) and CN-SIM
(Petersen et al., 2005).
The three models simulated rather accurately the emissions of CO2 throughout the
incubation period (Relative Root Mean Squared Error, RRMSE = 8-25). The simplest model
(with one pool for ST and one for PS) strongly overestimated SMN immobilisation from day
3 to day 21, both in the treatments with AS15 and PS15 (RRMSE = 27-30%). The other two
models represented rather well the dynamics of SMN in the soil (RRMSE = 21-25%),
simulating a fast increase of nitrate concentration in the first days, and slower rates of
nitrification thereafter. Worse performances were obtained with all models for the simulation
of SM-15N in the treatment with ST15 (RRMSE = 64-104%): experimental data showed
positive mineralization of stalk-derived N from the beginning of the incubation, while models
strongly underestimated ST15 mineralisation until day 7. Due to model structure,
trade-offs exist between a good simulation of CO2 emissions and a good simulation of
SMN. Therefore, simulation performances of the three models are a compromise
between the errors in the simulation of C and N dynamics. Thus, some models
(especially the simplest one), overestimated or underestimated SMN to match CO2
measurements.
This preliminary work emphasised the importance of testing models with both C and N
measurements. This reduced the risk of obtaining model parameters suitable for the
simulation of N (or opposite C) dynamics that lead to unrealistic simulation of C (or N)
decomposition. The use of 15N-labelled materials will help to improve models for the
simulation of added organic matter decomposition.
Kätterer, T., Andrén, O., 2001. The ICBM family of analytically solved models of soil
carbon, nitrogen and microbial biomass dynamics—descriptions and application examples.
Ecol. Model. 136, 191–207. doi:10.1016/S0304-3800(00)00420-8.
Petersen, B.M., Jensen, L.S., Hansen, S., Pedersen, A., Henriksen, T.M., Sørensen, P.,
Trinsoutrot-Gattin, I., Berntsen, J., 2005. CN-SIM: a model for the turnover of soil organic
matter. II. Short-term carbon and nitrogen development. Soil Biol. Biochem. 37, 375–393.
doi:10.1016/j.soilbio.2004.08.007. |
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