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Anticipated Climate Change and Impact on Kenyan Agriculture
E. Gacheru , P. GicheruE. Gacheru , P. GicheruC. K. Gachene .C. K. Gachene .and L. Claessen and L. Claessen
General overviewClimate change and Agriculture
• “Climate change. a serious global risks, demanding urgent global response” Stern review 2006)
• Global warming trend for Africa (0.50C-20C) % 10% reduction in rainfall
• Agriculture sector from developing countries most vulnerable
• Africa is the most affected by negative impacts (TAR ,IPCC 2001)
• Vulnerability and adaptation challenges highlighted by TAR IPCC 2001
• Contributing to further deterioration existing challenges ( PCC 2001; Mathews et al 2007, UNFCCC, 2007;DFID, 2006)
- land degradation- food and water insecurity
- poverty and HIV/AIDS
Observed Temperature Changes in Africa (Source: IPCC (2001) Climate Change 2001, Impacts, Adaptation and Vulnerability)
Kenya
• Situated at the Eastern coast of Africa• Neighbours, Sudan & Ethiopia, north; Somalia east;
Uganda, west; and Tanzania in the south• Area ~582 km2 ; Popn 28.7 mill (1999 census)
• Agriculture main stay of Kenyan economy-26% GDP-60% foreign exchange- Employment to 75% of counties labour force-Lifeline for 85% of population - Generates 60% of foreign exchange earnings
Agricultural production systems-Mainly mixed farming – raising of crops and livestock. - More intensive high potential areas
-Maize main staple food crop,-Dry bean most important legume crop.
- Coffee, tea, and sugarcane major commercial crops.- >75% agriculture practiced by small holder farmers
Importance of Potato and Sweet potato
Sweet potatoes (Republic of Kenya 2006) – important food security crop after cassava – Mainly grown in, Nyanza and western and central
province– Production increased from 546,309 in 2004, to
671,709 in 2005 • Irish potatoes (republic of Kenya 2006)
– Ranked second as staple after maize and 5th among the 20 most important agric commodities
– Grown in the high altitude zones of central province, eastern (Embu, Meru and Machakos*) and rift Valley
– Grows best between 1500m to 3000m– In urban areas, utilization indicates improving
standards of living
Kenya
ACZ CLASS RAINFALL
(mm)
I humid 1100-2700
II Sub-humid 1000-1600
III Semi humid
800-1400
IV Sh-SArid 600-1100
V Semi Arid 450-900
VI Arid 300-550
VII V Arid 150-350
Divided into seven agro-climatic zones (ACZ) based on suitable area for growing major food and cash crops. 18 % high agriculture potentials & 80% ASAL
Climate change concerns in Kenya
Period Temp ∆ (0C)
∆ in Rainfall (mm)
GCM Source
1869-2000 0.9 -91.8 ObservedFalloon et al 2007
2000-2100 5.9 +213 HadCM3LC
By 2030 (AEZ III-IV)
2.89 Variation LR(-) SR (+)
GFDLMati 2000
By 2030 (AEZ III-IV)
2.29 Variation LR(-) SR (+)
CCCM
By 2030 3.5 - CCCM Mariara & Karanja 2007; Karanja 2007
4.0 - GFDL
Mean for 1937-1968 vs 1981-2000 LM &LL Zones E. Kenya
0.35-0.5
- ObservedJaetzod 2006
Observed and anticipated Climate change in Kenya
Impacts of climate change; on agriculture productivity
– Increased temperature and reduction in precipitation expected to reduce crop
– Impact will vary from zone to zone– Increased temperature is more critical than rainfall (Mariara
& Karanja 2007)
Climate Scenario Medium & low potential Zones
High potential
All zones
+3.5 0C 80.05 (24%) -3.54 (-1%) 68.45 (20%)
+4.00C 108.79 (32%)
11.91 (3%) 93,04 (27%)
20% reduction in rainfall 69.54 (21%) 20.14 (7%) 24/39 (7%)
+3.5 0C+ 20% reduction in rainfall
149 (44%) 32.05 (27%)
92.84 (27%)
+4.00C+20% reduction in rainfall
178.33 (53%)
32.05 (9%) 117.43 (34%)
Predicted impacts on net revenue by Zones, Richardia analysis in (US$ ha-2)
source Mariara and Karanja 2007
Impact continued
Crop Scenario ET0
(mm)ETm (mm)
Ya Ym ETA (mm)
% ∆ in crop water use
IWR
Beans
Original 509 321 471 2500 94.4 19
CCCM-LR
559 352 471 2500 103.7 9.8 29.3
CCCM-HR
559 352 471 2500 103.7 9.8 21.5
GDFL-LR 566 357 471 2500 105.1 11.3 30.1
GDFL-HR
566 357 471 2500 105.1 11.3 22.2
Maize
Original 663 444 1137 9000 133.7 61.3
CCCM-LR
727 487 1137 9000 146.6 9.7 93.1
CCCM-HR
727 487 1137 9000 146.6 9.7 72.8
GDFL-LR 735 493 1137 9000 148.3 10.9 95.1
GDFL-HR
735 493 1137 9000 148.3 10.9 74.7
Increased temperatures and reductions in precipitation will increase crop water requirement
Impact of climate change in water use in Kwale district
(Adapted from Karanja 2007)
Adaptation • Policy/national level ( TNA 2000)
Increased frequency and intensity of extreme events has contributed to an increased awareness of impacts of climate
Examples of effort to responded include– Formation of the National Disaster mgt Authority– Crop early warning systems– Dissemination of weather & climate information ( Radio
internet& the formation of the Kenya Network of Journalists & Meteorologists
– Formation of a Inter-Ministerial Committee on Environment,,
– Plant breeding drought/disease tolerant crop varieties
At community level examples include– crop diversification, – different dates of planting, – irrigation, water – conservation and tree planting
Lack of capital/credit a constraint to adaptation
Predicted impacts and adaptation effects on maize Yield
Site Climate Model Yields for different planting dates
Original 15th Feb
1st March 15th March
1st April
15th April
Homa Bay
Normal climate
5813 4740 1500 0 77
CCCM ((2xCO2)
6684 5652 3534 296 0
GDFL( 2xCO2) 6609 5538 3724 474 0
Paponditi
Normal climate
1559 1407 1149 821 158
CCCM ((2xCO2)
1337 633 1416 1692 396
GDFL( 2xCO2) 1112 558 949 1644 554
Kichaka Simba
Normal climate
2056 2399 2393 2166 2190
CCCM ((2xCO2)
1988 2402 2566 1966 1861
GDFL( 2xCO2) 1820 2185 1800 1848 1217
Kampi ya Mawe
Normal climate
1153 343 123 0 0
CCCM ((2xCO2)
1881 1293 608 7 216
GDFL( 2xCO2) 1440 1306 420 0 322
Adapted from Mati 2000
Study Title
Effects of farmers resource endowment, anticipated temperature increase and
rainfall variation, on soil Organic carbon and intern its effect on potato
and sweet potato yields in Eastern Kenya
Justification• Exacerbation of existing vulnerability/ challenges of poor
farmers (land degradation, food insecurity, pests & diseases)
• Warmer temperatures /hydrological changes are likely to affect soil processes (SOM) mineralization and other processes that affect soil fertility (IPCC 2007).
• Technologies that may assist farmers reduce the anticipated global warming impact available
Impact of climate change on agriculture Ecosystem• Climate change may impact directly or indirectly on
ecosystems• Direct effects
• Temperature; Rainfall amounts/distribution• Indirect• Human activity as they respond to climate change
• Change of crop/diversification and change in mgt
• Som whose dynamics is driven by climate, plays an essential role in in determining soil fertility and productivity
Justification
Earlier studies on climate change and agriculture
• Looked at individual systems in isolation and failed to consider other interacting factors (Cohen et al 1994)
• Earlier studies on climate change and agriculture emphasized on crop response and impacts on food security and failed to consider other interacting factors like soil fertility (Parry 1990; Morton 2000)
• In Kenya most available information is on impacts; on agriculture in general or cereals
• Developing countries have different and unique circumstances, such as variable biophysical conditions, social cultural and economic situation that influence the impacts of climate change (Fischer and Velthuizen 2003).
• Shepherd and Soule 1998 reported variation on soil nutrient balances in western Kenya based on resource endowment; with low and medium resource endowment farms indicating negative nutrient balances,
Justification continued
In order to develop effective, such heterogeneity must be put into consideration when designing climate change adaptation strategies.
• Also the differences in adaptation capacity/options between the poor and wealthy need to be considered.
• Understanding on how systems will respond to change (Adaptation) is crucial in reducing vulnerability to climate change
• The relevance adaptive strategies to climate change impacts to a given region/community
• Agriculture should be managed to enhance ecosystem services beyond production (The millennium ecosystem service evaluation 2007 )
Objectives • Broad objectiveAssess the effects of temperature, precipitation and
farmers’ resource endowment and soil mgt on soil organic carbon and the effect of soil organic carbon on sweet potato and potato yields in different AEZ.
Specific objectivesTo assess the role of farmers’ resource endowment and
soil fertility mgt on soil organic carbonTo determine the impact of anticipated temperature and
precipitation due to climate change on soc and nitrogen dynamics in different AEZ
To determine the yield of potato and sweet potato varieties under varying soil organic matter content in small holder farms of Easten of Kenya
To assess the interaction effects of climate change and soil fertility on selected potato and sweet potato varieties yield in small holder farms in Kenya
To analyse the potential contribution of potato and sweet potato to climate change adaptation of small holder farms in Kenya
farming systems
Materials and Methods
• a) Literature review (Climate change analogies)
• Analogues scenarios represent possible future climate based on observed climate regime in space or time
• This method have advantages over controlled conditions (Lab and green house) by providing ecosystem microclimate dynamics and cheaper( Harts & Perry 1999)
• Even small changes in temperature will affect N cycling (Harts and Perry 199
• Using spatial analogue, Bottnier et al 2000, estimated a possible C mineralization of 25-25% with a temperature increase of 30C
Materials and methods continued
• Role of resource endowment and soil fertility mgt on SOC
Participatory wealth ranking, Participatory Learning and action research (PLAR) for soil fertility mgt classification and soil sampling
• Impact of climate change on socUsing PCV soil cores, soil will be tran-slocated across a AEZ
transect and soc and N dynamics monitored (See Harts and Perry 1999, Harts 2006, Bottner et al 2000)
• Potato and sweet potato yield trialsFarms will be selected on the bases of soc content and the
performance of yield performance of potato and sweet potato determined
Analysis of adaptation potential Using down scaled data from GCM, climate change analogue
procedures the impact of climate change on soc, N dynamics and adaptation potential of potato and sweet potato will be analysed
Study area (Embu,Mbere Meru districts
Characteristics District
Embu Mbeere Meru Central
Size (km2) 729 2097 2982
Administration divisions 6 4 11
Population 278196 170,953 498880
Population density 381 82 167
Arable land (km2) 300.1 1695 1952
Ave Farm size (ha) 0.86 4.8
Main AEZ UM1-3 LM3-5 UH1-2, UM1-3, UM2-5, LM2-5
Area cover (ha)/or % 133.9 (67%) 1813 (86%) Several AEZ
Altitude 600m in Mbeere - 2100m Embu
750M -2900
Mean temperature (0C) 15.8 in UH to 25.5 in LM 11.7-20.6
Rain fall (Bimodal) 640mm in Mbeere -2200mm Embu
500mm-2600mm
Farming system Embu and Mbeere
• EMBU– , mixed livestock system.– Land use varies with AEZ – Cash crops /tea and coffee(40%landa rea– Declining yields – Important food crops Maize, beans and potato – At individual farm occupies 30%, 15 and 7% respectively
• Mbeere -Most of the district is marginal land- 48% of population depend on mixed farming and 56% marginal mixed
livestock and farming - Main food crops-maize, beans, cowpea pigeon peas,
Meru central
• Land use • International level -Conservation of forest/national
parks• National level-part of national food and cash crop
basket• Cash crops-tea, coffee, tobacco, & horticultural crops• 1000 farms> 20 ha and 8100 less than 2 ha • In 2002, 39\000, 40,00 and 15700 ha grown to Maize,
beans and potato respectively• Potato production threatened by incidences of
bacteria wilt, blight & potato moth