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| Titel |
Impact of the Application Technique on Nitrogen Gas Emissions and Nitrogen Budgets in Case of Energy Maize Fertilized with Biogas Residues |
| VerfasserIn |
Monique Andres, Manuel Fränzke, Carola Schuster, Thomas Kreuter, Jürgen Augustin |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090594
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| Publikation (Nr.) |
 EGU/EGU2014-4849.pdf |
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| Zusammenfassung |
| Despite an increasing cultivation of energy maize fertilized with ammonia-rich biogas
residues (BR), little is known about the impact of the application technique on gaseous
nitrogen (N) losses as well as N budgets, indicative of N use efficiency. To contribute to
closing this knowledge gap we conducted a field experiment supplemented by a laboratory
incubation study.
The field experiment was carried out in Dedelow, located in the Northeastern German
Lowlands and characterized by well-drained loamy sand (haplic luvisol). Two treatments
with different application technique for BR fertilization – i) trail hoses and ii) injection –
were compared to an unfertilized control (0% N). Seventy percent of the applied N-BR was
assumed to be plant-available.
In 2013, biweekly nitrous oxide (N2O) measurements were conducted during the time
period between BR application and maize harvest (18.04.-11.09.2013; 147 days) using
non-flow-through non-steady-state chamber measurements. To quantify soil Nmin status, soil
samples were taken from 0-30 cm soil depth in the spring (before fertilization) and
autumn (after maize harvest). Immediately after BR application, ammonia (NH3)
volatilization was measured intensively using the open dynamic chamber Dräger-Tube
method. Export of N due to harvest was determined via plant N content (Nharvest).
Based on the measured N gas fluxes, N soil and plant parameters, soil N budgets
were calculated using a simple difference approach. Values of N output (Nharvest,
NN2O_cum and NNH3_cum) are subtracted from N input values (Nfertilizer and
Nmin_autumnminus Nmin_spring). In order to correctly interpret N budgets, other N fluxes
must be integrated into the budget calculation. Apart from soil-based mobilization and
immobilization turnover processes and nitrate leaching, this applies specifically to
N2 losses due to denitrification. Therefore, we measured the N2 emissions from
laboratory-incubated undisturbed soil cores (250 cm3) by means of the helium incubation
approach.
With cumulative field emissions of 2.9±0.8 kg N2O-N ha-1 and 3.9±0.4 kg N2O-N
ha-1 after trail hose application and injection, respectively, our results showed no clear
application effect. NH3-N losses were higher for trail hose application (7.2 kg NH3-N ha-1)
compared to injection (5.2 kg NH3-N ha-1). The calculated N budgets showed
negative values (accumulative deficit) up to -6 kg N ha-1 and -32 kg N ha-1 for trail
hose application and injection, respectively. But differences between treatments
were not significant. Overall N budgets were more influenced by plant N uptake
(91-96%) than by gaseous N losses (4-9%). However, results from the laboratory
incubation indicate that N2 may also be a potentially important pathway of N loss,
contributing to 34% of total gaseous N loss, corresponding to 5 kg N2-N ha-1 yr-1. |
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