@article{SanzaMoral:9683,
author = "Sanza Moral, Beatriz and Casterad Seral, Mª Auxiliadora
and Quílez, Dolores",
title = "{Posibilidad de uso de imágenes aéreas multiespectrales
y radiometría de campo en la evaluación de la
disponibilidad de nitrógeno en cereales}",
year = "2012",
note = "The importance of nitrogen in agricultural production
generates investigations in the search of a diagnosis of
appropriate nitrogen fertilization in order to improve the
recommendations of sub-scriber in the crops. This paper
deals with obtaining information from airborne platforms
and mul-tispectral images of radiometry, as field support
to the management of nitrogen fertilization in cereals. The
study has been carried out in two trials of strategies of
nitrogen fertilization located in the province of Huesca,
one of corn in the municipal term of Almudevar and another
of rice in the municipality of Villanueva de Sigena.
Multispectral aerial images of very high spatial resolution
have been used with the purpose of having information that
will help to diagnose the nutritional status of the crop.
In addition, this information has been completed with
radiometric measures and data on the chlorophyll content of
the plants, taken in the field to validate the information
derived from the images, and to be able to establish
relationships between the content of chlorophyll and
reflectivity. In order to achieve this aims the development
of the sampling equipment, the design of the field sampling
and the development of measurement protocols have been
implemented. However, the acquisition of the multispectral
images with a high resolution has yet a high cost. Through
the analysis of the influence of the variation of the pixel
size on the information, derived from the images of the
work (indexes and bands) the use of lower resolutions in
the images without changes to the information contained
herein has been determined, thereby reducing the costs of
acquisition. Two models of radiometric calibration of the
images have been compared and information of the bands on
the green, red and infrared as well as two vegetation
indices, the NDVI and the GNDVI( information that relates
to the chlorophyll content of plants) has been extracted
from an image of the test of maize spectral. Some
preliminary results indicate the necessity to adjust
aspects in relation to the representativeness of the
samples and measurements performed, if you want to
characterize the behavior with the means in the plot of the
different variables studied. Moreover, the acquisition of
information has been plentiful even though it has to be
analysed in subsequent studies, and compared with different
parameters used in the line of research in which the work
is framed for the achievement of results.",
}