estimating rice yield under changing weather conditions in kenya using ceres rice model
DESCRIPTION
Estimating rice yield under changing weather conditions in Kenya using Ceres Rice model. By: W.O. Nyang’au, B.M. Mati, K. Kalamwa R.K. Wanjogu, L. Kiplagat Presented at : NIB AND COLLABORATORS RESEARCH FINDINGS AND PROPOSALS WORKSHOP AT KSMS 04/07/204. Introduction. - PowerPoint PPT PresentationTRANSCRIPT
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Estimating rice yield under changing weather conditions
in Kenya using Ceres Rice model
By: W.O. Nyang’au, B.M. Mati, K. Kalamwa R.K. Wanjogu, L. Kiplagat
Presented at:
NIB AND COLLABORATORS RESEARCH FINDINGS AND PROPOSALS WORKSHOP AT KSMS
04/07/20421/04/23 1
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Introduction
•Agriculture is always vulnerable to unfavourable
weather events and climate conditions.
•Despite technological advances such as improved crop
varieties and irrigation systems, weather and climate
are important factors, which play a significant role to
agricultural productivity.21/04/23 2
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Introduction Cont…
• In past years, Kenya has experienced food shortages
arising from declining farm productivity owing to low
fertility levels, high input costs and unreliable
weather in the face of a rising population.
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Introduction Cont….
•Understanding rice production in relation to weather changes is of great importance to boost food productivity.
•Crop growth simulation models provide the means to qualify the effects of climate, soil and management on crop growth, productivity and sustainability of agricultural production
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Introduction Cont…..
• These tools can reduce the need for expensive and
time-consuming field trials and could be used to
analyze yield gaps in various crops including rice
( Pathak, 2005)
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Objective
• To assess the effects of change in weather conditions
(temperature, solar radiation and atmospheric CO2
concentration) in Kenya on Basmati 370 and IR 2793-
80-1 grain yield cultivated under System of rice
Intensification using the CERES modeling system.21/04/23 6
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Methodology
Description of the study area
• The study was conducted in the four national irrigation
schemes in Kenya namely; Mwea in Central province
region, Ahero in Nyanza province region, Bunyala in
Western province region and West Kano in Nyanza
province region. 21/04/23 7
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Methodology cont…
Material, Methods and Data collection
Plant material
•Basmati 370 and IR 2793-80-1 rice varieties were used
in this study. This is because they are the two
commonly grown varieties in Kenya.
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Methodology Cont….
Field selection and design
• From each of the four irrigation schemes under study,
two SRI farmers were randomly selected and their
farms used as research fields. The rice profile and
management practices from nursery till harvest were
monitored.21/04/23 9
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Methodology Cont….
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Methodology Cont….
The following data was collected;
•Daily weather data
• Soil data
•Management practices
•Plant profile data
• Latitude of production area21/04/23 11
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Methodology Cont….
Input files were created to run the model: •Weather file (FILE.WTH)• Soil file (FILES)•Rice management file (FELEX).• Experimental data file (FILEA) with measured data.•Genetic coefficients file (FILEC),
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Methodology Cont…
Data Analysis
The CERES-Rice model version 4.5 of the DSSAT modeling system
which is an advanced physiologically based rice crop growth
simulation model was used to predict rice (Basmati 370 and IR2793-
80-1) growth, development, and response to various climatic
conditions prevailing in the four irrigation schemes.
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Methodology Cont…
Model calibrationBy determination of genetic coefficientsModel Validation•RMSE•RMSEn•D – Index of agreement•R- Squared21/04/23 14
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Results ( Mean temperatures and solar radiation during the cropping seasons
Scheme Mean Tmax (oC)
Mean Tmin (oC)
Mean solar rad (MJ/m2 )
Mwea 27.4 19.2 16.5
Ahero 30.1 17.0 21.1
West Kano 27.4 17.4 18.2
Bunyala 29.4 17.8 19.821/04/23 15
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Results Cont… ( Genetic Coefficients)
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Results Cont.. ( Genetic Coefficients ..)• P1 - Time from seedling emergence to the end of juvenile phase
(GDD). • P2O - Optimum photoperiod • P2R - Rate of photo-induction • P5 - Time from grain filling to physical maturity• G1 - Maximum spikelet number coefficient. • G2 - Maximum possible single grain size under stress free conditions. • G3 -scalar vegetative growth coefficient for tillering relative to IR64. • G4 defines the temperature tolerance scalar coefficient
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Results Cont.. (Main growth and development variables for Basmati 370 under SRI in Mwea irrigation scheme, Kenya.
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Results Cont.. ( Main Dev. Variables for IR2793)
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Results Cont… ( Model validation)
RMSE =0.838, RMSEn =15.027% and D= 0.875
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Results Cont.. (Sensitivity analysis on climatic adaptations
Effects of temperature change on Basmati 370 grain yield in Mwea
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Results Cont….
Effects of temperature change on IR2793 grain yield in Ahero, Bunyala and West Kano
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Results Cont..
Effects of change in solar Radiation on grain yield
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Results Cont…
Effects of change in CO2 on Basmati 370 grain yield in Mwea
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Results Cont… ( Effects of C02 on IR2793 grain yield in Ahero, West Kano & Bunyala
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Conclusion and Recommendation
• Therefore to improve on rice production under
System of Rice Intensification in Kenya, proper
understanding of the prevailing weather conditions
and regular monitoring is necessary.•
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Acknowledgement
•NIB- For funding the project• JKUAT Community•All staff and farmers of Mwea, Ahero, Bunyala and
West Kano irrigation scheme•Prof. Gerrit of Washington University, USA for his
comprehensive support towards acquisition of the DSSAT
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END&
THANKS
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