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| Titel |
Scale and space dependencies of Nitrogen variability |
| VerfasserIn |
A. M. Tarquis, M. T. Castellanos, M. C. Cartagena, F. Ribas, M. J. Cabello, A. Arce, N. R. A. Bird |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250071314
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| Zusammenfassung |
| In this study we use the relative entropy (E(δ)) to investigate residual effects on wheat and
grain, biomass and nitrogen content, of fertigation treatments applied to a previous crop. The
wheat crop covered nine subplots from a previous experiment on melon response to
fertigation. Each subplot had previously received a different level of applied nitrogen and
plants from the previous melon crop had already taken up the applied nitrogen. Many factors
affect these variables, causing it to vary at different scales creating a non uniform
distribution. E(δ), and their increments between scales, were used to identify the scale at
which the variable had a maximum structure and compare with the scaling behavior
of the nitrogen applied. The E(δ)is particularly appropriate for this because of
does not require any prior assumptions to the structure of the data and it is easy to
calculate.
The results showed that the applied nitrogen through fertirrigation dominated the wheat
and grain biomass response as well as nitrogen content of the whole plant; surprisingly grain
nitrogen content didn’t show the same structure than the applied nitrogen. At the same time,
there was a noticeable structure variation in the biomass and nitrogen content at the
smaller scales that correspond to the melon cropping due to uptake of the applied
nitrogen by the previous crop. The E(δ) and the increments in E(δ) help us to
detect changes in the scaling behavior of all the variables studied, showing at which
scale there is a maximum structure. These results are in agreement with previous
studies.
References
Castellanos, M. T., Cartagena, M. C., Arce, A., Ribas, F., Cabello, M. J., and
Tarquis, A. M. 2010. Ef?ciency Indexes for melon crop optimization, Agron. J., 102,
716–722.
Milne, A.E., Castellanos, M. T., Cartagena, M. C., Tarquis, A. M. and Lark, R. M. 2010.
Investigating the effect of previous treatments on wheat biomass over multiple spatial
frequencies. Biogeosciences, 7: 2739-2747.
Tarquis, A.M., N.R. Bird, A.P. Whitmore, M.C. Cartagena, and Y. Pachepsky. 2008.
Multiscale analysis of soil transect data. Vadose Zone J. 7: 563-569.
Acknoledgements
This project has been partially supported by INIA-RTA04-111 and by Spanish Ministerio
de Ciencia e Innovación (MICINN) through project no. AGL2010-21501/AGR. |
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