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In Cambodia and Lao PDR, general land-use maps are being developed
based on Landsat MSS data. Details are current1 being incorporated into these
maps to estimate the total and projected areas o ! land under various rice
ecosystems. The Cambodia-IRRI Rice Project has engaged the services of a landuse
specialist to develop a comprehensive set of rice ecosystem maps for
information gathered from 1:50,000 topographic maps, land-use images, and
available aerial photographs. A national rice-ecosystem map (scale 1: 1,000,000) and
a set of more detailed provincial maps (scale 1:250,000) are being prepared.
Site description
Considerable time and effort were spent in conducting baseline surveys in
Indochina. The output of these surveys has been used for farming systems
characterization and as a basis for farming systems zoning at the district level in
Vietnam. In addition, household surveys of farms have been conducted to get more
detailed information to better understand farmer problems and to better plan
agricultural development programs. The method compared the farming systems of
low-performing farms with the systems used by high-performing farms. From the
results, agricultural package outlines were developed as potential intervention
mechanisms to bring about rapid increases in production (Mandac 1990).
Baseline surveys have similarly been completed in three rice ecosystems
(rainfed lowland, deepwater, and irrigated) in Cambodia, and in rainfed and upland
environments in La0 PDR (Lando and Solieng 1991, Schiller et a1 1991).
Long-term cropping pattern and fertility
The objective was to develop sustainable rice-based cropping systems that included
increased production of nonrice crops and incorporation of grazing animals. In
developing these systems, emphasis was placed on ensuring that the workload of the
farm family was not unacceptably increased.
The research was undertaken in the context of the whole farm (including on-
farm or natural water storage and provision of feed for grazing animals). More
specifically, the research involved experiments that addressed low soil fertility, pest-
management strategies, and the introduction of proven appropriate models. An
example of the work done in Cambodia is shown in Table 4.
Component technologies
The components of the farming systems currently undertaken in Indochina are
shown in Table 5. They involve a range of activities, from varietal improvement to
crop combinations.