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Lopez, F. D. S.

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tthe interest of, early a Id~dS
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,(E75- 10-23 3 )4 - IDENTIFI.CATION -OF :LARGE ..MASSES N52175
OF .CITRUS, FRUIT ,AND.- RICE FIELDS LIN EASTERNSPI (Pltcuc] nv f Madrid
~ (Spain).).6 ,p HC. $a3.- 25 CC 2 icaG-3/43 -00233
I~jL,IF IC A T0 W OF LARGS UmASs or CeT~ua
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SIS/902.6. :
https://ntrs.nasa.gov/search.jsp?R=19750013686 2020-03-22T21:27:15+00:00Z
The project Valencia PS-1-F -0463 fallz t-pcon the province
wi th tbz s~a 9,v70s a alaesical zone of intenaive hortiultum2 cultirA
tion and exrmsnie rice fields, the arborsous plantation of this area inolv-
de the bat spanish citric groves.
For that raason the mair. protect of this program, besidan others
questions, is the detection of phytosaritary oonditions of the citrieca.
Irrni project has an externs2ve ba--krod at-ay, but nothk'" reei
ved a periodic&I Lifo=-tation of ERTS imarneiy, it bas n~ot been pasible to maka
an acci~zative estirnats, ox wG first pr-tended.
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The zone selected to develop the third project (ERTS A-F.
0463) is located in the Valencia region of East Spain, It is
a classical zone of intensive horticultural cultivation and
extensive rice fields, where the best Spanish citric groves
are also found within the arboreous plantation of this area,
For this reason, in addition to the work aimed at possibly
differentiating these crops, according to their spectral signat-
ure and variation in time, the main project of this program i-s
to detect the phytosanitary conditions of the citrics to permit
adequate or recommended preventive measuras to he adopted in sach
case.
Howsver, i.m.ns. difficulties must evidc'tly bt ancountered
when trying to even remotely classify or differentiate the horti-
cultural culivatien considaring that thb L4ht is divided up into
a large number of private plots particularly in thia region. Added
to thiz, thair is a wide disparity of spccias grown with different
vegetative developments, intercalating with uncultivated plots,
whose density depends on the period of the agricultural year,.
In our case and for prior information, firstly considering
the restrictive factor of the resolutive power of the sensors
used, we reduced aerial photographs of the zone to scales of
approximately 1:100,000, 1:200,000 and I :400.000 etc., similar
to the ones taken from the ERTS negatives. As was expected,
these imagZs resembling a web or mosaic of dots in different
shades and sizsa corresponding to homogeneo4s masses or crops
of the same specie, are much fainter and diluted compared to
the ones corresponding to the aerial photograph redictions.
Certain broad zones can however be defined, ae in the case
of neglected rice fields, now replaced by hortdicultural crops
ORIGINAL PAGE I
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found between Sagunto and Rules, in a strip:parallel to the coast,
In addition, a zone of old rice fieldst where pear-trees
have now been planted could be identified and differentiated
from the former ones, comparing the images dn different wave
lengths.
The widespread rice farming which is characteristic of the
zone, grouped in low and humid land, is clearly differentiated
from the re.st espacially on bandsz SS -6 and MSS - 7, which as
we know correspond to wave lengths 0.7 - 0.8 and 0.8 - 1.1 microns
of the spectrum respactively.
On bands MSS - 4 and M4SS - 5, a small lake known as "La
Albufera" iS camouf1 jed and even i~stakn fr a ri2e field. The
reason for this is perhaps because it has a great density of sur-
face alga, as this effect disappears on the bands mentioned first
of all above.
Taking advantage of this clear definition which images
MSS - 6 and MSS - 7 provide us of "La Albufera", densitometric
stuidies are currently in progress to reach the most perfect
dcfinitiou possible of the rice zones, and to study the different
dcpths of their waters, as an encouraging definition of same has .
'been found in the images obtained with the isodensitometer, Photo'
Data Quantizer which has a graphic projection on vid:o streen,
To make an early diagnosis of plant diseasss, we are all
aware of the different aberbent or reflectant power of leaves,
according to th swelling of their cells, with regard to the
impinging infra-red radiations and ,the success achieved up until
now on numerous occasions.
o-G A
-3-
In our case, we are trying to apply it to detect new
sources, evolution and development of the infection and
assessment of damage in plantations affected by a virus disease
known commonly as "Quick Decline" due to the quick depression
and death of the oranges affected, which is usually confused with
other diseases that have a more or less similar symtomatology
but where trees may recover,
In this case, as with the horticultural crops, it is necessary
to consider the large way the property is divided up into plots,
where different citrus varieties are grown, with their corres-
ponding ample range regarding size and age in the plantations,
degree of sensitivity, etc, All.this, added to th, variations of
their vegetative development as a result of the fertilizer and
kind of soil where they have been grown, provoke a camouflaging of
the images which make it difficult for us to assess the phytosanitary
sta,e of the arboreous population.
On the other hand, out of .the numerous plagues and diseases
which affect the citrus, there are many (physiological diseases,
attacks by fungus and threadwor in roots, etc.) which at a given
moment produce depressions in the trees; these depressions inter-
fere with the spectrum radiation refledtance in more or lees a
similar way for all, with the consequent difficulty in diagnosing
the pathological producer cause,
From the above explanation and complementary work made up
until now, comparing the data taken on land, with the aerial or
land "false colour" photos, and other types of emulsion, we have
drawn the conclusion that only with a regular periodicity in
receiving information through satellites
. 
r aircrafts, shall we
be able to make a closer evaluation of the phytosanitary state of
the plan tions, which we can use as index to assess damages and
ORIGINAL PAGE JE
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-4-
forecast the products and average life.
Up until now, from the sole remittance of photos that
have been received, we have ascertained the aforementioned
difficulties as we have been unable to fit the land and aerial
data we possess easily in these photos, because of lack of
resolution and correspondence of shades.
O l AL Q
POOR, d


Identification of large masses of citrus fruit and rice fields in eastern Spain

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