SOIL, WATER AND CLIMATE RELATED CONSTRAINTS … · SOIL, WATER AND CLIMATE RELATED CONSTRAINTS FOR...
Transcript of SOIL, WATER AND CLIMATE RELATED CONSTRAINTS … · SOIL, WATER AND CLIMATE RELATED CONSTRAINTS FOR...
SOIL, WATER AND CLIMATE RELATED CONSTRAINTS FOR CROP PRODUCTION
M. S. Khan, R. Sen, S. Noor, H. M. Naser and M. K. Alam
Soil Science Division, BARI, Gazipur-1701
Crop production situation in Bangladesh
becomes worsen due to various soil, water
and climate related constraints. Global
warming and climate change phenomena
exacerbate this situation.
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CO
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pm) 1.5
1.00.50.0
CH
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pb)
7501000
15001750
1250
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1000 1200 1400 1600 1800 2000
0.15
0.050.00
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N2O
(ppb
)Atm
osph
eric
con
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ratio
n
Rad
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efo
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g (W
m-2
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Year
Indicators of the human influence on the atmosphere during the industrial era
Source: IPCC 2001
Carbon Dioxide
Methane
Nitrous Oxide
Source: IPCC 2001
The contribution from each of the human-made greenhouse gas to the change in radiative forcing
CO2 60% CH4 20%
N2O 6%
CFCs & HCFCs 13%Others 1 %
1860 1880 1900 1920 1940 1960 1980 2000
Tem
pera
ture
Ano
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y (º
C)
0.6
0.4
0.2
- 0.2
- 0.4
- 0.6
0.0
Global TemperaturesFive year average
Year(Source: www.globalwarmingart.com)
Global warming: Causes and effectsCauses
Large-scale use of fuels, factories, & deforestation
Global warming: Causes and effects
Effects Effects
Causes
Large-scale use of fuels, factories, & deforestation
Warmer weather provides breeding grounds for insects
Damaging storms, drought and related weather phenomena
Global warming: Causes and effects
Effects Effects
Causes
Large-scale use of fuels, factories, & deforestation
During the past 100 years global sea levels have risen 4 to 8 inches
Increasing hot summers & intense thunderstorms
Terrestrial water storage,extraction of groundwaterbuilding of reservoirs,changes in runoff, andseepage into aquifers
Subsidence in riverdelta region,land movements, andtectonic displacements
Surface and deep oceancirculation changes, storm surges
As the ocean warms,the water expands
Exchange of the waterstored on land byglaciers and ice sheetswith ocean water
What causes the sea level to change?
(Source: IPCC 2001)
Asia's largest rivers, the Ganges and the Bramaputra, join in the world's most extensive delta and flow into the Bay of Bengal. Asia's largest rivers, the Ganges and the Bramaputra, join in the world's most extensive delta and flow into the Bay of Bengal.
Origin-Brahmaputra
GangesGanges
Possible Climate Change due to Global Warming
Variables of Climate Change and possible change of climateVariables Climate Change
Slow ExtremeAverage temperature increases (°C) + 02 + 04Sea level rise (cm) + 30 + 100 Rain fall (%)
Rainy seasonDry season
+ 18- 12
+ 33- 22
Evaporation (%)Rainy seasonDry season
+ 08+ 10
+ 15+ 20
River Water flow (%)Maximum flowMinimum flow
+ 06- 12
+ 13- 22
Storm Intensity (%) + 10 + 25
Climatic risks for BangladeshEnvironmental Impacts Socio-economic Resources &
Sector affected
• Changes in rainfall patterns Water resources
• Increased frequency and severity of : Agriculture and forestry
Floods Food security
Droughts Human health
Storms Infrastructure (e. g. transport)
Heat waves Settlements : displacement of inhabitants and loss of livelihood
• Changes in growing seasons and regions Coastal management
• Changes in water quality and quantity Industry and energy
• Sea level rise Disaster response & recovery plans
Major constraints to crop productivity in Bangladesh
Soil Fertility Decline Soil Erosion and land lossSoil Salinity Loss of water/Inefficient Use of Water Climatic stresses
In Bangladesh, major food crops remove about 2.98 m tons nutrients annually against a total addition of 0.72 m ton. According to an appraisal report on Bangladesh’s soil resources, soil of about 6.10 m ha contain very low (less than 1%) organic matter, 2.15 m ha contain low (1-2%) organic matter and the remaining 0.90 m ha contain high (more than 2%) organic matter.
Soil Fertility Decline
Name of AEZ Land type% Organic Matter (Mean) Depletion
of OM (%)(1970-2000)1969-1970 1989-1990 1999-2000
Madhupur Tract HL 1.78 1.20 1.02 42.7Barind Tract HL & MHL 1.45 1.15 0.76 47.6Old Himalayan Piedmont Plain
HL 1.32 1.2 1.04 21.2
Tista Meander Floodplain
HL & MHL 1.55 1.23 0.97 37.4
Northern & Eastern Hills
HL 2.04 1.32 1.05 48.5
Old MeghnaEstuarine Floodplain
HL 2.16 1.17 0.91 57.9
High Ganges River Floodplain
HL 1.21 0.98 0.83 62.4
Old Brahmaputra Floodplain
MHL 1.56 1.23 1.15 26.3
Changes of organic matter with time in Major AEZs.
H, high. M, medium. L, land Source: Karim et al., 2004.
The state of decline is also reflected in deficiency of N in almost all soil types, deficiency in P, Zn, S, B, etc. Five m ha of land suffer from S deficiency and 2 m ha from Zn deficiency.
Different types of land degradation and their extent in BangladeshTypes of land degradation Areas (in m ha) affected by different
degrees of degradationTotal area
(m ha)
Light Moderate Strong
1. Water Erosion-Bank erosion
0.1-
0.31.7
1.3-
1.71.7
2. Wind Erosion - - - -
3. Soil Fertility Decline- P deficient (for HYV rice)- P deficient (for Upland crops)- K deficient (for HYV rice)- K deficient (for Upland crops)- S deficient (for HYV rice)- S deficient (for Upland crops)Soil Organic Matter depletion
3.85.33.14.02.14.44.11.94
4.23.22.53.45.43.34.6
1.56
-------
4.05
8.08.55.67.47.57.78.7
7.55
4. Water logging 0.69 0.008 - 0.7
5. Salinization 0.29 0.43 0.12 0.84
6. Pan formation - 2.82 - 2.82
7. Acidification - 0.06 - 0.06
8. Active floodplain - - - 1.53
9. Deforestation - 0.3 - 0.3
10. Barind - - - 0.773Source: BARC, 1999.
High seasonal rainfall, low organic matter content in soils, poor soil management and steep slopes particularly in hilly areas contribute to soil erosion.
It is reported that about 1.74 m ha land is prone to soil erosion.
Land degradation result in part from deforestation both in hills and plains, occurring now at 5-6% annually.
Soil Erosion and Land loss
Shifting cultivationSoil erosionSoil fertility degradationEnvironment degradation
Months Soil loss (t ha-1) at different hill slopes10% 20% 30%
April 0.30 0.46 0.60May 1.64 2.10 2.56June 6.02 8.18 10.0July 4.18 7.06 9.11August 3.06 5.12 6.33September 1.28 2.05 2.82October 0.92 1.36 1.68
Month wise soil loss at different hill slope (average of 1998-2000)
Source: Khan, 2001.
Of the 2.85 m ha of coastal areas (some 30% of the total arable land of the country), about 0.87 m ha are affected by different degrees of soil salinity.
The problem has exacerbated in recent years, specially in Khulna-Jessore region as a result of reduced dry season water flow below the Farakka Barrage in India.
Water conductivity of 750 mmhos is damaging to human health while a rating of 2,000 mmhos affects yields of irrigated rice and many other crops.
Soil Salinity
Yield decrease EC on Rice(m mhos cm-1)
EC on Wheat (m mhos cm-1)
0 %10%25%50%
2,0002,6003,4004,800
4,0004,9006,4008,700
Source : FAP, 1993.
Effect on saline water on rice and wheat
Inefficient Use of Water
The water use efficiency in Bangladesh will hardly exceed 30%. It may be worthwhile to mention that irrigation water worth about Tk. 12 m is wasted annually in Bangladesh because of poor management practices and wrong setting of tubewells for irrigation.
Climate StressesClimate remains as the most determining factor for crop productivity although the impact of climate on productivity is not often appreciated by scientists.
Changes in climate have profound effect in crops specially grain crops.
i) Rainfall :
Crop production in Bangladesh is predominantly rainfed.
Hence the onset, duration, amount and the periodic aberrations of rainfall dictate the nature and type of crops to be grown and the activities of crop production.
The annual average rainfall of the country ranges from 1194 mm to 3454 mm.
Source: BARC
Early monsoon flood(Early June – Mid July)
Source: BARC
Late monsoon flood(Early Aug. – Mid Sept.)
1998 Flood ExtentDamages of 1998 Flood
32 districts affected100,000 sq km (66% area) affected575,000 ha of crops destroyed1,050 deaths reported30 million people affected25 million people left affected26,000 livestock lost20,000 schools and other edu. facilities damaged300,000 tube wells damaged16,000 km of roads flooded4,500 km of river embankments damagedSource: ActionAid, 1999
Natural hazards and affected area
Hazards Area affectedFloods (flash, rain water, river water and tidal floods)
1.32 mha of net cultivated area (NCA) severely affected5.05 mha of NCA moderately affected
Droughts 2.32 mha of crop affected in kharifseason1.20 mha affected in rabi season
Salinity and coastal surges
0.87 mha is affected
Cyclones and wind 2.80 mha of coastal area are subjected to damaging cyclones
Drought of different intensities occur in our country, which severely affects annually about 2.3 million ha in the Kharif season and 1.2 million ha in the dry (Rabi and pre Kharif) seasons.
iii) Drought :
Extent of Drought
Source: BARC/UNDP/FAO
Drought prone areas(Kharif season)
Drought Classes
Area (ha) Percent of yield reduction of cropsWheat Potato Mustard B. Aus
Very Severe 363855 60-70 >70 >50 >40Severe 864063 50-60 60-70 40-50 30-40Moderate 3284698 40-50 50-60 30-40 20-30Less Moderate
1457740 30-40 40-50 20-30 10-20
Slight 4352410 <40 30-40 <20 <10
Intensity of Rabi and Pre kharif droughts and yield reduction of crops
Source: Karim et al., 1990.
High temperature effect on key development stage of major agricultural crops
Crops Effect ReferencesWheat Temperature>30oC for more than 8
hours can reverse verbalizationEvans et al. 1975
Rice Temperature>35oC for more than 1 hour at anthesis causes high percentage spikelets sterility
Yoshida, 1981
Maize Pollen begins to lose viability at temperatures>36oC
Decker et al., 1986
Potato Temperature>20oC depress tuber initiation and bulking
Prange et al. 1990
Soybean It has great ability to recover from temperature stress
Shibles et al., 1975
Source : Acock and Acock (1993)
iv) Temperature:
v) Cyclone and tidal surges:Cyclone and tidal surges are also common in the coastal area and they cause severe loss to the crops and lives.
Salinity and tidal submergence tolerant rice varieties and appropriate cropping pattern with proven soil reclamation methods need to be developed to increase the cropping intensity of the coastal saline area.
Cyclone pathBangladesh
INDIA
INDIA
INDIA
MY
AN
MA
R
SIDR15 Nov. 2007
Loss of lives 3363
Monetary losses 6100 crores (Tk.)
Affected people 1 crore
Damages of crops 13 lacs m tons
Household’s affected 15 lacs(fully damaged 5.64 lacs)
Affected roads & highways 8000 km
Untraced people 871
Injured 55 thousandsAffected educational institute 8000 (4489 pri. Sch., 3750 H. sch. & coll.)
Affected sanitary systems 70%
Cyclone ‘SIDR’ inflicted losses
Sources: The Dainik Ittefaq, 18 December 2007.
SIDR15 Nov. 2007
vi) Hailstorms :
Hailstorms are usually associated with violent thunderstorms.
In Bangladesh, it mainly occurs during March to May and causes severe damage to standing crops like boro rice, wheat, jute, mungbean, summer vegetables, fruits etc.
Opportunities to Adaptation the Constraints
We have to face the challenges of the coming years by developing and applying technologies that can help increase yield to feed the growing population and this is to be achieved in ways that are economically viable and environmentally sustainable.
• Crop Management• Nutrient/Fertilizer Management• Water Management• Climate
ConclusionGlobal warming and climate change have detrimental impact on soil fertility and crop productivity.
Soil organic matter is decreasing due to rise of soil temperature.
Extent and severity of natural disaster like flood, drought, cyclone and tidal surges will be more in the coming years.
Increased drought and salinity, prolonged inundation and excessive soil erosion will reduce the crop area & yield.
Appropriate crop management practices should be followed in the climate change affected areas.
Selection of appropriate crop species/variety should be chosen for specific area
Thanks