| dc.description.abstract | The study objective was to improve water use efficiency at
Sagana gravity fed sprinkler irrigation scheme. An optimal
cropping system for Sagana Irrigation Scheme was developed
using; climatic data, crops data, farmers preferences, and
market prices. An irrigation schedule to promote water use
efficiency was developed for crops in the optimal cropping
system using the FAD package CRDPWAT. French beans, which is
the main cash crop at Sagana Irrigation Scheme was subjected
to different water application depths and Nitrogen fertilizer
rates to:
i) determine the yield response factor; and
ii) study water and fertilizer interactions.
A line source sprinkler irrigation system was used to apply
different amounts of water with irrigation scheduling according
to the soil water balance. The water application depths were;
21.1 mm, 180.3 mill, 158.2 mm, and 138 mm. Four Nitrogen
fertilizer rates (0 kg/ha, 80 kg/ha, 120 kg/ha, and 160 kg/ha)
were randomized within the experimental plots.
The major findings of the study were:
i) Water use efficiency at Sagan a Irrigation Scheme can
be improved by designing an optimal cropping system
that exploits the existing climatic conditions.
.i i.) The developed optimal cropping system had a peak
water requirement of 114 mrn during the month of
January.
iii) For efficient water use under the optimal cropping
system, rotational irrigation as opposed to ondemand
irrigation is recommended.
iv) A yield response factor of 1.1 for French beans was
determined.
v ) Increased use of Nitrogen fertilizer at the same
water level had a positive effect on the yields of
French beans. | en |
