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Theme Leader and Staff
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G.
Trebuil, IRRI Photobank, |
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Increasing water scarcity and competition for the same water from non-agricultural sectors drive the need to improve crop water productivity to ensure adequate food for future generations with the same or less water than is presently available to agriculture. This can be achieved because available information indicates that there is a wide gap between actual and attainable crop water productivity, especially in rainfed environments. Quantifying crop water productivity reveals gaps in knowledge regarding the best ways to increase crop water productivity. Most of these gaps relate to our inability fully to quantify all flow components in the domain of interest, their interactions with the plants, agricultural inputs and the environment in the process of producing marketable yields. Interactions among the hierarchical scales add to the complexity of the problems. It is hypothesized that breakthroughs in molecular breeding and advances in modeling, information and communication technologies will accelerate our understanding of the above interrelated factors, and the identification of interventions that will lead to improved crop water productivity at various scale levels.
Source: CPWF Full Proposal p. 9-10 |
By John Bennett, 2003
Within the CPWF, the focus of Theme 1 is on farmers - how they
gain timely access to water, how they use it efficiently for crop
production, and how they produce more food with less water under
circumstances of actual or economic water scarcity. Research in
Theme 1 focuses on four outputs:
- Stress-tolerant crop varieties that produce more marketable
yield per unit of water consumed;
- Farm practices that optimize water use;
- Management techniques that give farmers timely access to water;
and
- Policies and institutions that help farmers to take advantage
of the above advances.
Progress towards these outputs will come partly by taking lessons
learned in one crop or river basin and generalizing them to others,
and partly by original research into novel ideas. The CPWF provides
a unique institutional structure for promoting both approaches in
a context that maximizes the interaction between stakeholders and
scientists, emphasizes the needs of the poor, particularly women,
and recognizes the interdependence of agriculture and the environment.
Theme 1 contributes to the CPWF’s overall goal of improving
water productivity in agriculture by promoting food production and
water savings. In the past, a clear distinction was usually made
between irrigated agriculture and rainfed agriculture. Under Theme
1 this distinction will be severely eroded. On the one hand, irrigated
systems will attempt to maintain production levels by reducing water
withdrawals and relying as much as possible on rainwater. On the
other hand, rainfed systems will attempt to increase production
by introducing supplemental irrigation as dictated by the needs
of the crop and the pattern of rainfall. An important aspect of
Theme 1 will be the use of modern techniques of water storage, weather
forecasting, information technology and plant breeding. The development
of salt-tolerant varieties of crops will enable more use to be made
of saline land and water, while varieties with increased tolerance
of short-term or medium-term water deficits will facilitate water
saving under irrigated conditions and reduce the need for supplemental
irrigation under rainfed conditions. Tolerance of water-logging
and flooding will reduce the impact of poor drainage. However, the
trait that has been most effective to date in increasing water productivity
in many of the crops under the CPWF is short duration, especially
when accompanied by seedling vigor to reduce the yield penalty associated
with short duration. Another important trait is high harvest index,
which, in conjunction with medium duration, is responsible for the
high water productivity of modern rice varieties compared with traditional
varieties.
Prepared by the CPWF Consortium, 2002
Plant Level
It is expected that DNA-assisted backcross breeding, using the
discovery of genes underlying water productivity-related traits,
will quickly enhance abiotic stress tolerance and crop water productivity
in new or already popular varieties. The success of breeding within
the CP for water productivity depends heavily on the use of physiological,
molecular and genetic tools to exploit useful alleles.
Key research questions
- What are the main impediments to translating an appraisal of
abiotic stresses present in a river basin into an integrated program
of breeding and natural resource management for improved crop
water productivity?
- Do the genes responsible for improving water productivity in
rice and wheat through higher harvest index and shorter crop duration
have equally effective homologues in other crops?
- To which traits should priority be given in using molecular
techniques to increase the efficiency of conventional plant breeding
to improve water productivity of the mandate crops of the CGIAR
?
- For rainfed and water scarce environments, how can the yield
numerator in water productivity be maintained for crops growing
under extended periods of mild water deficit or brief periods
of severe water deficit?
Outputs
Varieties with superior abiotic stress tolerance and improved water
productivity
Crop and Field Level
New information and communication technologies, such as remote
sensing, wireless transmission, and simulations, open new opportunities
for investigating complex crop–soil–water and environment
systems. Simulation models facilitate ex-ante evaluation of technological
interventions on crop response, crop yield, water productivity and
soil and water quality. They are also valuable in the identification
of possibility for out-scaling the experimental findings to new
environments. At the same time, improved and affordable new irrigation
techniques, tillage and land leveling offer farmers a wide range
of options for improving production and water productivity.
Key research questions
- How can advances in information technologies, simulations and
crop physiology help develop better frameworks to analyze/predict
crop water productivity in different environments? And to characterize
the environment for better matching the desirable traits of the
cultivar to the target environment?
- What are cropping patterns and management practices that enhance
production and farmers income without increasing water input?
- How can the trade-off between yield (land productivity) and
water productivity in deficit irrigation be managed to provide
win-win situations?
- In rainfed agriculture, especially in dry zones, what are the
key indicators of risks? What risk management strategies and technologies
(e.g. supplementary irrigation, water harvesting) are appropriate?
- What are appropriate management strategies for sustainable
use of water of marginal quality?
Outputs
Technologies that enhance farmers’ livelihood and water productivity
at field level
Agro-ecological Level
In moving from field to system level scale, the level of heterogeneity
increases. Environmental characteristics and land use vary spatially
and temporally. An integrative, regional approach is needed to ensure
that interventions that increase water productivity at a particular
locality will not reduce water productivity and production elsewhere
in the system.
Key research questions
- What research tools and methods are required for cost effective
data collection for water accounting and water productivity quantification
at hierarchical scales within the system, especially in data–sparse
environments?
- How can seasonal weather forecasting be used to reduce risk
and enhancing water productivity?
- What tools can be developed to optimize water productivity
in the system, taking into account the underlying process of interaction
among the hierarchical scales within the system (e.g. return flows)?
- How can the management of irrigation systems be improved to
match water supplies to field water requirements, and to make
more effective use of unevenly distributed rainfall and water
storages (groundwater, small reservoirs, drainage canals....)
in the system?
- What are sustainable strategies to improve production and water
productivity in land that is degraded due to water logging and
salinization?
Outputs
- Interventions that enhance water productivity at agro-ecological
system level;
- Tools and methodologies to assess the impact of interventions
on crop performance, water productivity, water balance components
Policies and Institutions
There are a number of technologies that have the potential to increase
water productivity. However, the rate of farmers' adaptation of
these technologies has been slow. Too often in agricultural research
the lead-time from study to field impact is decades. Considering
the current and anticipated problems arising from water scarcity,
such a lead-time is unacceptable.
Key research questions
- What type of policies and institutional arrangements will promote
farmers' adoption of water productivity-enhancing technologies?
- Which factors (environmental and socioeconomic) influence farmers'
adoption of improved technologies?
- How can lessons from experiences in participatory research
and extension in other areas be applied?
Outputs
Institutional arrangements that encourage farmers to adopt water
productivity enhancing technologies.
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©
Copyright 2003 Consultative Group on International Agricultural
Research