yellowing and finally harvesting.
Figure 2 gives an outline of the proposed system.
An initial data base of potential rice producing
units has to be assembled. The irrigation unit, with
its uniform irrigation and vegetation timescale,
could be used as a base unit. This database will be
filled by data from satellite imagery, aerial
photography and fieldwork. The accuracy of this
database is therefore not exclusively depending on
the geometrical accuracy and resolution of satellite
imagery. The operational
system will then use the satellite data to identify
whether the fields are actually irrigated and wether
rice is growing and being harvested.
4.3 Assessment of yield and detection of pests and
diseases
Apart from the identification of rice fields, remote
sensing can also be used to detect the ratio between
the high yielding varieties and the convential varie
ties. Possibly a further detailed subdivision in
these varieties could be made, but this has to be
studied.
In areas where crop diseases or pests are
occurring, crop development monitoring can be used to
determine the spread of the disease. To make disease
and pest monitoring possible, the effect of the
disease should be such that crop colour and
associated structure have changed to such a degree,
that the image interpreter can conclude that the
cause of the change in crop appearance and associated
patterns, should be attributed to the outbreak of a
disease or pest. This information could be used to
improve the efficiency of field surveys and of the
measures to bring the diseases and pests under
control.
It is expected that the high repetition of obser
vation in combination with the high spatial
resolution and the spectral band selection optimized
for vegetation monitoring, can provide an excellent
tool for crop disease and pest control.
The information on the extent of pests and
diseases, in combination with the information on the
distribution of the different rice varieties, can
improve the yield forecasts and estimates. The
related benefits are the reduction of production
losses and the improved efficiency of pest control by
a reduced usage of pesticides. On the basis of remote
sensing data an early warning system could be
established in order to minimize economic losses due
to pests and diseases.
5 UTILISATION PREPARATION PLAN
Remote sensing as a source of information is already
used by a number of organizations in Indonesia (e.g.
Public Works, Transmigration, Forestry, Environment,
Central Bureau of Statistics, Bakosurtanal). The
projects of these organisations will benefit from the
direct reception of Landsat images by the LAPAN
groundstation, which will be operational in the near
future. In the past these images arrived with long
delays (and often too late) from foreign stations. By
upgrading the station in the future, it will be
possible to receive also the high resolution images
from Landsat 5 and Spot and lateron possibly TERS.
A requirement exists for an overall approach to the
application of remote sensing techniques in
Indonesia. Part of this should be an inventory of the
present practical applications of remote sensing in
Indonesia. In a large number of projects remote
sensing methods are already used as an important
source of information, especially in those cases
where other sources of data, like topographic maps
are outdated. In a stepwise development of remote
sensing all the different available sources of data
should be used in an integrative approach.
Important steps are designated by the present
Landsat station, for the reception of MSS data,
becoming fully operational and the updating of this
station to X-band for the acquisition of high
resolution data like Landsat Thematic Mapper (TM) and
Spot. On the one hand this station will supply data
for applications (and research) and on the other hand
it will produce on the job training in the handling
of large datastreams as will be provided by most
future satellites.
Although no requirement exists for a centralized
remote sensing institute, a coordinated national
effort is required to develop the remote sensing
techniques into operational tools for the Indonesian
development programs. The platform for such a
national program for the development of remote
sensing is already available in the different
organisations involved in the research and
development as well as in the practical use of remote
sensing.
6 CONCLUSIONS
Preliminary analysis of potential benefits of a
satellite remote sensing system with the capability
to monitor crops and forests indicates that multi
million dollar benefits may be expected. Such a
system is not yet in existence, but from imagery of
present satellites the feasibility of realising these
benefits can be demonstrated. Further studies are
pursued in order to substantiate these findings and
to arrive at conclusions, if and when such a multi
million dollar investment for a dedicated equatorial
earth observation system for the monitoring of
renewable resources is justified.
REFERENCES
Mears, L.A. 1981. The New Rice Economy of Indonesia.
Yogyakarta, Gadjah Mada University Press.
Central Bureau of Statistics. 1982. Statistical
Yearbook of Indonesia. Jakarta.
Central Bureau of Statistics. 1981. Products Tanaman
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Malingreau, J.P. 1980. A Detailed Indonesian Case
Study. Berkeley.
Malingreau, J.P. 1983. Remote Sensing in Indonesia, a
Review of the Available Technology and its
Applications of Resources Surveys. Berkeley.
Machin Ervan 1981. Use of Remote Sensing for Crop
Production Estimation in Indonesia. Jakarta.
Machin Ervan et al 1980. Remote Sensing for
Indonesia, Agricultural Assessment: Evaluation
Report for Pilot Survey in Lampung, Sumatra.
Jakarta
Cyril Ponnamperuma 1984. A case for the remote
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