Abstract:
Spatial and temporal rainfall variability and unsustainable land use practices have always
been major hindrances in Ethiopian agriculture. Proper land evaluation for irrigated
agriculture is very important to combat such problems. This study was conducted to
assess irrigation potential in Guder river catchment, a sub basin of Abay river basin. The
study used FAO (1985) guideline: Land evaluation for irrigated agriculture. Five crops
(Maize, wheat, teff, sorghum and Barley) and three irrigation methods (surface, center
pivot and portable sprinkler irrigation methods) were selected as land utilization types.
Soil properties, land slope, land cover and water availability were evaluated against
requirements of each land utilization types. Crop water demand was estimated using
Penman-Monteith and Hargreaves methods. Surface water potentials of 45 sub
watersheds of Guder river catchment were assessed using SCS-CN method. The results
show that 54,800ha, 112,000ha and 442,000ha of land are marginally suitable
(provisionally irrigable area) for both maize and sorghum under three selected irrigation
methods (surface, center pivot and portable sprinkler irrigation systems) respectively. The
result for teff is 56,300ha, 116,200ha and 247,200ha under surface, center pivot and
portable sprinkler irrigation systems respectively. Whereas 59,500ha, 128300ha and
283,300ha of land is marginally suitable for wheat crop and 59,500ha, 125,500ha and
283,300ha of land is marginally suitable for barley crop under surface, center pivot and
portable sprinkler irrigation systems respectively. Major suitability limitation was found
to be land slope. Results of surface water potential analysis showed that without
considering any artificial water storage structures, surface water potential of Guder river
catchment can support 9423 and 15070ha of land for surface and sprinkler irrigation
systems respectively. When storage structures are considered surface water potential of
the study area can accommodate 532,622 and 798,934ha of land under surface and
sprinkler irrigation systems.
