Transcript Control and harvesting of excess water

Practical Methods for
Adaptation of Smallholder Farming
to Climate Change
in Belize
related to Agriculture and Conservation
Timo Baur
GIZ / CIM integrated Expert
Caribbean Community Climate Change Centre
Oktober 2012
ACICAFOC Taller Nacional Belize: “Construyendo una Estrategia
Agroforestal de Adaptacion al Clima”
Summary
• Change of climate - change of seasons
• Impacts
– Droughts and Flooding
– Stress on lifestock and yield, crops and soil
• Adaptation
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Rainwater harvesting and irrigation
Enhancing crop resilience
Rain and planting calendars
Protecting the soil
Quezungal method, agroforestry and hedgerows
Terracing
Impact
Change of Climate
• Detailed climate modeling projections for Belize
predict
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increase in average temperature;
increased occurrence of extreme events like heat waves;
decrease in average annual rainfall;
increase in heavy rainfall events which would lead to more
flooding events and reduce water quality and availability;
– potential for an increase in the intensity of tropical storms;
– increased Sea Surface Temperatures (SST)
Caribsave Risk Atlas Belize, 2012
Impact
Change of Seasons
• Higher likeliness projected for
– shorter rainy seasons
– longer or more intense dry seasons where rainfall is
unusually low or delayed
Green, 2000
Bates et al., 2008
Impact
Droughts
• In the dry season, drought-like conditions have become
more common in Belize
In an agricultural drought, the soil moisture at the roots of
crops is inadequate for their healthy growth and causes
extreme water stress
Impacts of drought
• Non-irrigated crops decrease in yields
=> all year water supply critical
• Drought can lead to infestation
– Drought weakens plants
– e.g. Pine Bark Beetle chewed up 80 % of the pines in
the Mountain Pine Ridge in 1999 - 2003
– Healthy trees can defend themselves by secreting a
resin, covering bore holes and frustrating beetles
Impact
Flooding
• Flooding is due to
– much rainfall in rainy season (May to November)
– tropical waves, depressions or storms
• Risk of frequent flooding in flat low lying
areas:
– much of the northern and southern coastal areas
– all of the islands and cayes
– several miles inland
(NMS, 2011)
Impact
Impacts of Flooding
• Floods
– cause significant losses in the agriculture, livestock and
transportation infrastructure sector (ECLAC, 2006)
– affect water availability and quality (BEST, 2009) (e.g.
brackish rivers)
– decrease soil quality (De-Campos et al., 2009)
– can contaminate various water sources (WMB, 2011) (e.g.
outdoor latrines overflow)
=> Control and harvesting of excess water
Impact
Stress on Lifestock
• Heatwaves
– e.g. Chicken, Cattle, Pigs
• In 2005, 40.000 chicken were killed in Belize by a heat
wave
• Warmer seawater
– Corals die and bleach
– Fish may move or migrate deeper
Impact
Stress on Yield: Crops
• impact on particular crops complex
• depends on
– photosynthesis properties of plants / the process of
absorbing and converting CO2
– tolerance of crops to heat
– resistance to drought
– resilience to stress (Rosenzweig & Hillel, 1995)
=> identification of more climate resilient crop varieties
and
diversification of crops
Richardson: Belize and Climate Change: The Cost of inaction, 2009
Impact
Example: Sugar Cane
- 45 % yield change due to
climate zone shift
CCRIF, Enhancing the climate risk and adaptation fact base in the Caribbean, 2010
International Centre for Tropical Agriculture (CIAT)
Impact
CCRIF, Enhancing the climate risk and adaptation fact base in the Caribbean, 2010
International Centre for Tropical Agriculture (CIAT)
Impact
Stress on Yield: Soil
• Intensified rainfall can lead to
– Soil degradation
– Erosion
– Runoff
Adaptation
Measures for Adaptation
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ensure all year water supply
control and harvest excess water
select more climate resilient crop
use different crops and planting times
provide shade for lifestock
conserve soil: prevent erosion, degradation
and runoff
Adaptation
Rainwater Harvesting
Water is everybodies
business
fields could have their own water
body for harvesting rain
Ponds
Rainwater Harvesting
• rooftop collectors
– Polythene sheets
– Banana-stems, royal palm leaves
– Tree trunks, rock cavities
Irrigation
• Irrigation channels and pipelines
Adaptation
Terracing
• One of the oldest means of saving soil and water
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Increases soil moisture
Reduce runoff and loss of soil
Stops or reduces soil erosion
Reduces slope steepness
• but: permanent soil cover and walls to be
maintained, requires much labour
• recent archaeological research: terracing was
widely used in Belize in ancient times
Dorren & Rey, A review of the effect of terracing on erosion, 200
Adaptation
Types of Terraces
• Bench Terrace: Cut benches in slope
• (Flat) Channel Terrace: Excavate soil from upper side to form a
channel, deposit downhill to form a bank
• Cajete Terrace in Mexico: small water reservoirs on terrace
plateaus
• Ridge Terrace: Excavate Soil from both sides, throw inwards
Adaptation
Enhancing Crop Resilience
• save seeds each year
• Identify and select crops that are more
resistant to droughts and pests
• Grow many different crops and varieties
• Share indigenous knowledge on best crop for
expected season (e.g. based on signs in
atmosphere)
TEBTEBBA Foundation: Guide on Climate Change & Indigenous Peoples, 2008
Adaptation
Enhancing Crop Resilience
• Polyculture
– Growing two or more crop species and wild
varieties
– Plant at different locations and times
=> reduced climate stress
(Lin 2011, Tengö and Belfrage 2004)
Adaptation
Rain and Planting Calendars
• Changes in growing seasons
• Changes in times of animal migrations and
reproduction
=> Adjust times of crop planting and harvesting,
wild plant gathering, hunting and fishing
TEBTEBBA Foundation: Guide on Climate Change & Indigenous Peoples, 2008
Adaptation
Protect the Soil
• Keep soil covered
– prevents runoff of nutrients
– Stabilizes soil moisture and temperature
– Improves soil structure; break compacted layers and
hard pans
– Permits rotation in a monoculture
– controls weeds and pests
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Use cover crops, e.g. tall grasses, Cowpea
Leave crop residue and plant litter
Controlled bush clearing
Protect river banks
Adaptation
Agroforestry
– Plant between trees
– Greater shade cover
• protects from heat and precipitation (Lin 2007)
• reduces storm damage (Philpott et al. 2008)
Adaptation
Quezungal Method
• traditional Quezungal farming method in Honduras:
– plant crops under trees whose roots anchor the soil
– prune vegetation to provide nutrient to soil, prevent too
much shading and conserve water
TEBTEBBA Foundation: Guide on Climate Change & Indigenous Peoples, 2008
Adaptation
Hedgerows
• Strips of vegetation along the main crop
– e.g. dense cover of trees or shrubs, 3-6 m apart
– reduces effects and velocity of soil erosion and runoff;
effective after two years
• crop yields higher than in control areas
• planted in ancient times in many parts of the world
Lin, 2007
Summary of Adaptation Methods
• Enhance fields
– Ponds and rainwater harvesting
– Irrigation Channels
– Terracing
• Enhance planted crop
– Save seeds and select more resistant crop varieties
– Adjust times of planting and harvesting
– Polyculture: Grow various crops at various locations and
times
• Protect the soil
• Plant near trees and shrubs
– Agroforestry, Quezungal Method, Hedgerows