Water is scarce resource in Central Rift Valley of Ethiopia and is major limiting factor for crop production. The field experiment was conducted in 2018 at Melkasa Agricultural Research Center during the off-season to identify irrigation method and irrigation application level that maximizes productivity of onion per unit of water consumed and enhanced onion crop production. The experiment was carried out using split plot design in RCBD having three replications. The experiment consisted of two irrigation methods viz., furrow and drip irrigation as main plot and three levels of manageable allowable depletion viz., 120%, 100% and 80% as sub-plot. The ANOVA revealed that their interaction had a significant (p<0.01) effect on bulb diameter, total bulb yield, marketable bulb yield and water productivity. The maximum total bulb yield (41.76 t/ha), marketable bulb yield (38.39 t/ha), bulb diameter (6.02 cm) and water productivity (13.05 kg/m 3 ) were observed from drip irrigation method at 80% management allowed depletion application, while significantly lower of 34.48 t/kg, 31.6 t/ha, 5.11 cm, and 6.84 kg/m 3 respectively were recorded from furrow irrigation method at 120% management allowed depletion application. Among all tested treatments drip irrigation method with 80% MAD was the best practice because of its high yield, water productivity.

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The experiment was conducted during 2019 cropping season in six Peasant Associations (PAs) of Negele Arsi and Adami Tulu Jido Kombolcha Districts; with objectives of demonstration and scaling up the selected in-situ moisture conservation structures (Tied ridge and furrow closed at both Ends), awareness creation and analyzed the cost benefit. Totally twelve (12) FREG members were established and 600 farmers, 12 animator and 6 DAs were participated on training from six Peasant Associations (PAs). Two FREG members were established in each Peasant Associations (PAs). From these, 240 farmers were from FREG and 360 from non-FREG were participated on introductory training. Totally 100 farmers, 4 DAs and animator, 4 SMS and 32 others were participated on field day from both districts respectively. The mean yield obtained from tied ridge and furrow closed at both ends were 89.55 and 71.69 Qtha -1 at Negele Arsi district and 72.81 and 69.96 Qtha -1 were obtained from Adami Tulu Jido Kombolcha district respectively. The two-selected in-situ moisture conservation structures were gave a significant yield in both districts. The net benefit obtained from tied ridge, furrow closed at both end were 50,241 and 37,096 ETH Birr ha -1 respectively at NegeleArsi district. In addition, the net benefit obtained from tied ridge and furrow closed at both end were 38,119 and 35,896 ETH Birr ha -1 respectively at Adami Tulu Jido Kombolcha district. In-situ moisture conservation structures (tied ridge and furrow closed at both Ends) were more economical and better if it is more scale up in the study area and similar agro ecology. Agricultural and natural resource office should have give a great attention to popularized and scaling up this technologies in moisture deficit areas of the districts.

Irrigation land suitability assessment and mapping for irrigation purpose is important to utilize the land resources efficiently. This study was initiated to assess, evaluate and develop map of the land resources which is potentially suitable for surface irrigation in ziway micro watershed by using Geographic Information System (GIS). The evaluation of land in terms of the suitability classes was based FAO guideline for land evaluation. Multi-criteria decision evaluation method and suitability factors were used such as, soil data, slope, land use/cover for evaluate the physical land characteristics of the study area of surface irrigation and suitability map was developed. After evaluating the physical land capability for surface irrigation, irrigation suitability map was developed. The weighted overlay analysis gave 70.1 and 13.3% of the study area is lies in the range of very high suitable to marginally suitable for irrigation. Thus, the overall suitability shows that potentially irrigable land suitable for surface irrigation is about 83.4% of the area. Therefore, based on results, farmers, decision makers, investors, planners and policymakers at the local, regional and national levels and the government should invest in those suitable areas for irrigation.