| dc.description.abstract |
Drier parts of Embu County, Eastern Kenya, endure persistent crop
failure and declining agricultural productivity which have been attributed, in part,
to prolonged dry-spells and erratic rainfall. Nonetheless, understanding spatialtemporal
variability of rainfall especially at seasonal level, is an imperative facet to
rain-fed agricultural productivity and natural resource management (NRM). This
study evaluated the extent of seasonal rainfall variability and the drought characteristics
as the first step of combating declining agricultural productivity in the
region. Cumulative Departure Index (CDI), Rainfall Anomaly Index (RAI) and
Coefficients-of-Variance (CV) and probabilistic statistics were utilized in the
analyses of rainfall variability. Analyses showed 90 % chance of below croppingthreshold
rainfall (500 mm) exceeding 213.5 mm (Machanga) and 258.1 mm
(Embu) during SRs for one year return-period. Rainfall variability was found to be
high in seasonal amounts (CV = 0.56 and 0.38) and in number of rainy-days
(CV = 0.88 and 0.27) at Machang’a and Embu, respectively. Monthly rainfall
variability was found to be equally high even during April (peak) and November
(CV = 0.42 and 0.48 and 0.76 and 0.43) with high probabilities (0.40 and 0.67) of
droughts exceeding 15 days in Embu and Machang’a, respectively. Dry-spell
probabilities within growing months were high (81 %) and (60 %) in Machang’a and Embu respectively. To optimize yield in the area, use of soil-water conservation
and supplementary irrigation, crop selection and timely accurate rainfall forecasting
should be prioritized |
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