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| Titel |
Investigating the effect of previous treatments on wheat biomass over multiple spatial frequencies |
| VerfasserIn |
A. E. Milne, M. T. Castellanos, M. C. Cartagena, A. M. Tarquis, R. M. Lark |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 9 ; Nr. 7, no. 9 (2010-09-16), S.2739-2747 |
| Datensatznummer |
250004968
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| Publikation (Nr.) |
 copernicus.org/bg-7-2739-2010.pdf |
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| Zusammenfassung |
In this study we use the maximum overlap discrete packet transform (MODWPT)
to investigate residual effects on wheat biomass 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. Many factors
affect wheat biomass, causing it to vary at different spatial frequencies. We
hypothesize that these will include residual effects from fertilizer
application (at relatively low spatial frequencies) and the local influence
of individual plants from the previous melon crop (at high frequency). To
test this hypothesis we use the MODWPT to identify the dominant spatial
frequencies of wheat biomass variation, and analyse the relationship to both
the previous fertilizer application and the location of individual melon
plants in the previous crop. The MODWPT is particularly appropriate for this
because it allows us first to identify the key spatial frequencies in the
wheat biomass objectively and to analyse them, and their relationship to
hypothesized driving factors without any assumptions of uniformity
(stationarity) of wheat-biomass variation.
The results showed that the applied nitrogen dominated the wheat biomass
response, and that there was a noticeable component of wheat-biomass
variation at the spatial frequency that corresponds to the melon cropping. We
expected wheat biomass to be negatively correlated with the position of
melons in the previous crop, due to uptake of the applied nitrogen. The
MODWPT, which allows us to detect changes in correlation between variables at
different frequencies, showed that such a relationship was found across part
of the experiment but not uniformly. |
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