Vol. XXXVIII, Part 7B
In: Wagner W., Székely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B
11
[N THE STATE
os Adami 1
tal.
e actions that harm the
ental protocols between
f Sao Paulo requires the
are used to monitor and
esting method (with or
le methodology utilized
harvest type was also
the 2006/07 season to
or harvest in the state is
?ion of the state had the
tute for Space Research
'paciais - INPE), the
ICA), the Center for
cs (CEPEA) of the Luiz
JSP) and the Center for
naintained the Canasat
Using remote sensing
s, the Canasat project
Initially, mapping was
o (Rudorff et al., 2005),
n extended to the other
of Brazil (Rudorff and
esponsible for 72.7% of
tate of Sao Paulo, is to
>r without burning the
; 2006/07 crop season,
is been utilized by both
¡. Beginning with the
l the type of harvest are
4A of Sao Paulo State,
nine if the straw burning
t the methodology of the
oring of the harvesting
Df the harvest areas with
)6/07 to the 2008/09 crop
:ct may serve as a basis
.ra et al., 2005), carbon
, public health studies
olicy in the agricultural
o allow evaluating the
> not harvested due to
issential information for
Figure 1. Location of the state of Sao Paulo within Brazil as
well as the area containing harvestable sugarcane in the 2008/09
crop year.
The identification of the harvesting method was performed by a
visual interpretation of TM (Thematic Mapper) sensor images
taken from the Landsat-5 satellite. In the case of cloud cover on
the TM images, CCD (Charge-Coupled Device) sensor images
taken from the CBERS-2 and CBERS-2B satellites were used as
an alternative (Epiphanio et al., 2007). For each orbit point of
the TM and CCD sensors, a database was created with the data
of interest from the images obtained by the two sensors. All
images were registered based on the orthorectificated mosaics
from TM/Landsat-7 images obtained by NASA (NASA,2007)
utilizing a first degree polynomial and nearest neighbor
interpolation.
Monitoring of the harvest type is only possible after producing a
map of available sugarcane for harvest. This is then utilized as a
mask for the remote sensing images and allows monitoring only
the sugarcane areas that available for harvested in the current
crop year. This map is prepared by the Canasat project at the
beginning of each crop season.
2. METHODS
Identification of the harvesting method, either burning or not
burning the sugarcane straw, is currently performed in the state
of Sao Paulo, the largest producer of sugarcane in Brazil. Sao
Paulo is located in Southeastern Brazil and has an area of
248,209 km 2 . Figure 1 shows the location of Sao Paulo State
and the area of sugarcane available for harvest in 2008/09.
1) Sep. 10 th , 2008
4a) May 24 th , 2009
2) Sep. 10 th , 2008
4b) Jun. 09 th , 2009
In contrast with other agricultural crops, sugarcane has a long
harvest season, lasting from April to December. The remote
sensing images allow to identify the harvesting method, either
burning or not burning the sugarcane straw, because the areas
where sugarcane is harvested after burning present dark tones in
response to soil exposure (Stoner and Baumgardner, 1981).
Areas harvested without burning present bright tones because
the ground is covered by dry leaves (Figure 2.1) (Aguiar et al.,
2009). In Figures 2.5 and 2.6, field photos of recently harvested
areas without straw burning and with straw burning,
respectively, can be seen. Both the accumulation of straw after
harvest and soil exposure from burnt straw may be observed in
these figures.
Over time, the correct identification of the harvest method
becomes less clear. Both weather and post-harvest agricultural
practices such as the burning of straw in the field after harvest
are the major factors that affect this identification (El-Hajj et al.,
2009). Figure 2.2 illustrates an area with plots harvested on
different dates. The difference in time and the use of different
post-harvest agricultural practices create changes in the color
and characterization of these plots, (which are differentiated in
the image). However, all plots were harvested without burning.
Figure 2.3a shows an image acquired in July of 2008 in which it
is possible to observe an area harvested without burning. This
same area, in September of 2008, possesses dark tones due to
either the straw being burnt following the harvest or due to the
soil being exposed (Figure 2.3b). Therefore, the less time that
has elapsed between the harvest time and the image acquisition,
the more likely it is to correctly identify the harvesting method.
Declivity is a limiting factor for mechanical harvest. For this
reason, in many crop fields, harvesting is performed using both
methods. In the part of the field where the declivity is over 12%,
burning is still used; however, in the part of the field with lower
declivity the mechanical harvest is performed. Figures 2.4a and
2.4b illustrate this situation in a sequence of two dates; in the
dark plots, with a high declivity, a manual harvest was
performed (after burning), and in the light areas, with a declivity
of less than 12%, the sugarcane was harvested mechanically
(without burning). It should be noted that Figure 2.4b shows the
presence of some clouds.
3b) Sep. 10 th , 2008
6) Jun. 03 rd , 2009
3a) Jul. 08 th , 2008
5) Jun. 02 nd 2009
Figure 2. Temporal sequence of TM/Lansat-5 images, color composition 4(R)5(G)3(B), illustrating different harvest types ( 2.1 and
2.2), the change in harvest characteristics caused by post-harvest agricultural practices (2.3a and 2.3b), different harvest types due to
declivity (2.4a and 2.4b), and field photos of recently harvested areas without straw burning and with straw burning (2.5 and 2.6).