Rice research for drought affected rainfed lowlands

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Rice research for drought affected rainfed
lowlands

• S. Haefele and G. Atlin

2

• CURE WG1
• Objectives from planning meeting
• To develop, evaluate, and refine site-specific
  approaches to reducing drought risk
• To build on the progress made by national
  programs and the RLRRC
• To coordinate research planning on high-priority
  problems
• To facilitate exchange of information,
  experience, and technology.

3

• Key sites
• Raipur
• Short, variable monsoon
• 1240 mm
• Direct-seeding, beusani
• Limited irrigation
• Severe, frequent drought
• Highly skilled research groups

4

• Key sites
• NE Thailand
• 1100-1600 mm
• Both transplanting and direct seeding
• Drought at any stage.
• Large team with little participatory activity
  (breeders excepted!)
• Extensive but scattered documentation

5

• Satellite sites
• Savannakhet
• 1400 mm
• 100 transplanted
• Limited research capacity
• Drought at any stage
• Extensive previous research on fertility
  management

6

• Research themes emerging from initial planning
  meeting
• Reducing drought risk and increasing productivity
  in transplanted and direct-seeded systems
• Short-duration, drought-tolerant varieties
• Tolerance to delayed transplanting
• Integrated weed management systems for DDS
• Integrated nutrient management systems accounting
  for fluctuating water availability
• IPM for drought-prone areas
• Cropping intensification

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• Initial activities
• Team identification
• Initial discussions with researchers on progress
  to date, research issues
• Focus group discussions at 2 villages per site
• Experiments planned to test our understanding of
  research needs arising from steps 2 and 3
• Monitoring visits

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What farmers told us about nutrient management

• Farmers apply higher doses on upper fields (Th)

KDML105 Neck blast sensitive
RD6 Lodging-prone
leaching
Drought Flooding Low soil fertility
medium
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• NPK fertilizer use Laos (20-3-0), Raipur
  (68-12-0), Thailand (TR 65-13-12 DS 86-22-21)
• Fertilizer dose is reduced when weed pressure is
  high or on fertile soils (Th, DS)
• Farmers reduce dose on susceptible varieties
• Spot fertilizer application (Th, L)
• Farmers know benefits of organic fertilizers, but
  labor and availability constraints
• Organic matter 1 to 2 t / ha every season or
  every 2nd to 3rd year (except Sa Patoum)
• Considerable pressure to use commercial organic
  fertilizers (Th, L)

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Nutrient management what we observed

• Comparatively low soil fertility
• Low pH (Th, L)
• High percolation (Th, L)
• Severe N and P deficiency (Th, L, R)
• Frequent K deficiency (L)

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Heterogeneity of water resources

• Due to topography, season, ponds (Th), wells (I),
  irrigation limited to DS

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Possible impact of new varieties

• New KDML105 with shorter duration and
  improved blast resistance

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Lessons learned and research questions

• Adjust nutrient management to topography, water
  availability, variety
• Stepwise technology adoption
  new variety -gtnew crop management -gt
  synergies
• LCC for rainfed environments drought x Nconc
  interactions, application timing after drought,
  greenness targeted
• Drought, leaf N concentration, and insect pests
• Temporary drought and N application

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• Nutrient x water interactions?
• Improved nutrient status can improve yield with
  drought, but does it decrease fertilizer use
  efficiency?

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• Fertilizer use efficiency in rainfed lowlands?
• Internal efficiency, recovery fraction, Ypot
  influence optimal dose and the value/cost ratio

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Direct seeding what farmers told us

• Change to DS 15y ago due to labor shortage,
  earlier establishment, higher yields (Th)
• Interested in DS due to climate change and
  increasing problems with beushening (R)
• Clear advantage of DS in the 2002 season due to
  shorter crop duration (R)
• Weeds are perceived as major constraint for DS
  technologies (Th, R)
• Limited use of herbicides, little experience and
  lack of information

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Direct seeding what we observed

• In September visits, contrary to earlier
  discussion, farmers expressed little concern
  about weed pressure in PS varieties
• They appear to be right.

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• Unexpected interest in a rice mungbean system

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Direct seeding lessons learned and research
questions

• DS appears to be the most promising drought
  management tool.
• Many TP and beusani plantings failed in 2002.
• Weed management options must be provided

• Herbicide-based
• Mechanical?

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Direct seeding lessons learned and research
questions

• 2. Weed management options need to be adjusted to
  topography, water availability
• Are long-duration, PS varieties affected less by
  weed competition?
• Do we need to worry about lower fields?

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• Breeding what we learned
• Quality constraints greatly limit farmers choice
  of varieties (e.g. wide use of Swarna, KDML).
• Disease susceptibility is major constraint on
  fertilizer use. KDML backcross lines will change
  the system in Thailand
• Farmers will not sacrifice much yield potential
  for increased drought stress tolerance.
• Little effective drought screening is being done.

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Whose problem is this?
Drought-prone upper fields (or irrigated)
Upland
Imperfectly drained shallow lowland (Swarna, KDML)
Semi-deep Shallow deepwater Long duration
WG1
WG1 or WG2?
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Lowland drought screening?
UQ-NAFRI drought screening trial, Vientiane, Oct.
2003
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• Breeding
• Research needs
• Clear identification of shallow but poorly
  drained lowland (Swarna country) as a breeding
  target
• Varieties with improved blast and sheath blight
  tolerance
• Protocols for managed lowland drought screening
  must be improved and disseminated
• Farmer knowledge on potential donors
• Expanded PVS

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• What do we need to do?
• Develop and test integrated dry direct seeding
  systems, with a focus on weed management.
• Document risk reduction associated with direct
  seeding in severely drought-affected areas.
• Develop nutrient management recommendations for
  intermittently dry fields.
• Speed up development and participatory testing of
  disease-resistant, high quality lines for
  management intensification.