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Integrated Natural Resource
Management at IRRI
Much of IRRI’s research in the past has been in the
area of integrated natural resource management
(INRM)—albeit under different names. The ultimate
goal of the Institute’s research on the more efficient
use of natural capital such as water and soil is to
protect and improve the environment while maintaining
and improving rice yields.
Long-term yield/productivity. In recent decades,
IRRI and other institutions have been concerned
about the sustainability of intensive irrigated rice
production. Based on IRRI’s own long-term
research, evidence suggested that, under continuously
flooded rice with three crops per year, yields
declined significantly.
However, with help from a 100-strong team of
researchers in China, India, Indonesia, the Philippines,
Thailand, and Vietnam, exhaustive long-term
experiments have shown that, in tropical and
subtropical Asia, yield declines seem to be less
common than previously thought. IRRI’s fields
proved to be one of the exceptional cases, probably
because of prolonged soil wetness at the experiment
station that is less commonly observed in farmers’
fields.
Nevertheless, the research also pointed out that
in farmers’ fields there has been a general slowdown
in gains in productivity, a measure of output in
relation to all inputs of rice production. Most studies
have found that productivity growth was healthy in
the 1970s, ’80s, and early ’90s, but it is not possible
to predict future trends. The findings point to the
need for continued research on ways to improve both
rice yield and productivity to ensure that rice production
is profitable for farmers and that rice prices
are low for consumers.
SSNM. Site-specific nutrient management or
SSNM is a tactic that has been successfully tested in
more than 200 on-farm experiments across Asia. The
generic approach is to make fertilizer applications
more efficient. By using a leaf color chart and a
fertilizer calculation chart, farmers can assess
whether and how much fertilizer is needed at any
time during the growth of the rice plant. Average
yields and profits have shown increases of 10–15%.
Pilot studies at the village level began in six Asian
countries in 2001. The leaf color chart, in particular,
has proven to be an inexpensive guide to nitrogen
fertilizer status and is catching on across Asia.
Land leveling. Proper leveling of farmers’
fields has potential for a major impact on rice
production in South and Southeast Asia. After
flooding, level fields drain much faster than
unleveled fields, reducing weed incidence and
improving the timeliness of land preparation and
crop establishment. Tests have shown that leveling
improves yields by 15% without fertilizer and up to
28% with recommended fertilizer use. Leveling also
provides a 40% reduction in weed biomass, a 5–7%
increase in crop area by removal of bunds, a 10%
reduction in water requirements, and an increased
opportunity for direct seeding, which dramatically
cuts labor needs.
Ongoing regional-level INRM research.
Together with other centers within the Consultative
Group on International Agricultural Research, other
advanced research institutes, nongovernmental
organizations, and national research institutions, IRRI
is involved in two initiatives that span different
ecological zones:
• Ecoregional Initiative for the Asian Humid and
Subhumid Tropics—using a systems approach
to develop research and operational methods
of INRM that can be used at the regional level.
The research uses a bottom-up approach, that
is, focusing on the implications and
cumulative effects of field and farm
interventions at higher geographical levels of
integration. A top-down approach is also used
in tackling resource-use issues.
• Rice-Wheat Consortium for the Indo-Gangetic
Plains—in a region (South Asia) of increasing
demand for food grains, where past sources of
productivity increases (e.g., modern varieties,
fertilizers, irrigation investment) have been
exhausted, and where soils are being degraded
and groundwater depleted, to improve yields
through integrated crop, soil, and residue
management. A holistic approach is being
taken to combine resource conservation
approaches for rice with promising wheat
production technologies that use reduced or
zero tillage.
New INRM research. IRRI’s new projects on
integrated natural resource management, outlined in
the Institute’s latest medium-term plan, became
operational in January 2001. As with the INRM
research results described above, with the exception
of the region-level work, the new studies, listed
below, are based at the field and farm level. They are
components of one or more of the four IRRI research
programs described in this section:
• Natural resource management for the rainfed
and upland ecosystems
• Managing resources under intensified ricebased
systems
• Enhancing water productivity in rice-based
systems
• Understanding rural livelihood systems for
research prioritization and impact assessment
• Ecoregional approaches to integrated resource
management and livelihood improvement.
48 Rice almanac