Irrigation Practices as Alternative Means of Supporting Rain-fed Agriculture: A Case Study of Potato (Solanum tuberosum L.)

Estimation of evapotranspiration is important for study, design, determining crop water requirement and management of irrigation systems. Also it’s important for determining irrigation water requirement during dry spell and water shortage i.e. when the evapotranspiration is greater than effective rainfall. Based on this, the study was conducted in Cheha district, Gurage Zone with determine crop water requirement of potato. In line to this, ten years climatological recorded data (2008-2017) for Indibir station on (sunshine duration hr /day), maximum and minimum temperature (OC), humidity (%) and wind speed (km/day) at 2 meters height were used to determine ETo using Penman combination method. Secondary data were used to collect important soil parameters required for determination of crop water requirement. Lengths of growing periods, planting date and crop varieties data were received from the validation value of the local farmers and CDAO.  Crop coefficients (kc), rooting depth, critical depletion fractions, yield response factors and crop height were obtained from food and agriculture organization of the United Nations guidelines (No. 56). The analyzed data indicated that reference crop evapotranspiration ranged from 2.40 to 4.73 mm with a mean of 3.56mm. The assessment has showed that the water requirement of potato is 63.2, 84.1, 145.8 and 77.2mm during initial, development, mid and late growth stages, respectively. The effective rainfall contribution throughout the growing stage of potato in the area is 8.5, 23, 187.2 and 158.1mm all through initial, development, mid and late growth stages, whereas the net irrigation requirement of potato throughout the dry spell period is 52.9, 61.3, 14.9 and 0mm in initial, development, mid and late growth stages, respectively. Soil and water conservation management practice, water harvesting technology and agronomic practices should be applied, principally mulching is very important to save soil moisture during high heat stress and dry spell or water shortage. Key terms: reference evapotranspiration, crop water requirement, potato DOI: 10.7176/JAAS/55-03 Publication date:May 31st 201

Rainfall and Temperature Trend Analysis at Indibir Station, Gurage Zone, Ethiopia

In Ethiopia where crop production overly depends on rainfall and temperature, studying the trend of these climate variables at a local scale is essential to devise proper strategies that enhance adaptive capacity. In light of this, a study was conducted in Indibir station, Gurage Zone to analyze rainfall and temperature trend. Data on climate variables (1986-2015) were obtained from National Meteorological Agency of Ethiopia. Mann-Kendall test was used for the analysis of trend in rainfall and temperature from 1986 to 2015 time period and carried out by XLStata softwares. The analyzed data indicated the respective annual and kiremt rainfall amounts were found to increase by a factor of 4.5 and 6.15 mm/year. However, the seasonal belg rainfall amount decreased by -2.23 mm/year and it was not statistically significant for the study period of 1986 to 2015. Respective annual and belg maximum temperature showed an increasing trend by a factor of 0.03 and 0.06 OC/year, but a decreasing trend was observed in kiremt maximum temperature by -0.13 OC/year. Minimum temperature revealed a decreasing trend at annual, belg and kiremt seasons by a factor of -0.2, -0.16 and -0.1 OC/year, respectively. Development planners of the area should design strategies and plans by taking into account a declining belg rainfall and increasing temperature impacts on livelihood of local communities

Effect of climate variations on maize yields across Abeshge district in Ethiopia

The mean onset date, cessation date and length of growing period of the main rain season remained May 5, September 14 and 133 days, respectively across Abeshge district in Ethiopia. The dry spell is minimum during the peak rainy season (June to August or DOY 153-244) and switch upward once more around DOY 247 (September 4), indicating end of the season). Rainy days have a strong positive relationship (r=0.72) with maize yield, whereas total rainfall and rainfall cessation have moderately negative (r=-0.56) and positive (r=0.58) correlation, respectively. Increase in total rainfall caused a decrease in maize yield. However, increased rainy days, length of growing period and maximum temperature will result to increase in maize yield. Therefore, to minimize the effects of total rainfall, cutoff drain should be considered along the farmland