Gebeyhu Birara, Dagalo Samuel, Muluneh Mekuanent
Arba Minch Water Technology Institute, Faculty of Water Resources and Irrigation Engineering, Arba Minch University, Arba Minch, Ethiopia.
Arba Minch Water Technology Institute, Water Resources Research Centre, Arba Minch University, Arba Minch, Ethiopia.
Heliyon. 2024 Aug 10;10(16):e36089. doi: 10.1016/j.heliyon.2024.e36089. eCollection 2024 Aug 30.
The lack of soil moisture-based irrigation intervals, poor distribution of irrigation water among users, and the time-based and spatial variability of water supply have been challenges for the productivity of irrigation schemes in the Lower Kulfo catchment, Southern Ethiopia. This study was conducted to develop soil moisture-based irrigation intervals and to evaluate irrigation water delivery and field level irrigation efficiencies. Soil water content, and flow along the canal and in the field were measured directly, and irrigation duty was estimated by using CropWat 8 model. To minimize water stress or excess problems, irrigation needs to be applied when soil water content drops to 35.7 % for onion and pepper, 34.4 %% for watermelon, and 32.5 % for wheat and maize from field capacity. However, irrigation was applied at 36.2 % for onion, 35.4 % for watermelon, 36.4 % for pepper, 36.2 % for maize, and 35 % for wheat in the existing irrigation scheme that increased irrigation amount in the field. The average percentage of soil moisture depletion (p) at time of irrigation was 27.4 %, which was below the recommended value. The average adopted irrigation and design irrigation interval were 4 & 6 days for onion and pepper, 5 & 7 days for watermelon and wheat, and 6 & 7 days for maize, respectively. The mean irrigation adequacy and dependability of the irrigation scheme in the lower Kulfo catchment were 1 & 0 for Arba Minch irrigation scheme, 0.5 & 0.2 for Arba Minch University farmland, 0.4 & 0.25 for private farmland and 0.1 & 0.43 for Kollashara farmland, respectively. The value of irrigation equity was 0.7 in January, 0.6 in February, and 0.8 in March which indicates the highly temporary variation of irrigation adequacy. The mean value of canal conveyance was 82.7 % and the average on-farm irrigation efficiency also was 56.6 %. The average value crop yield in the present study were 0.5ton/ha for wheat, 4.9ton/ha for onion, 6.2ton/ha for pepper, 0.6ton/ha for watermelon, 4.2ton/ha for maize that was very low compared with other control irrigation in the study area. Inadequate soil moisture-based intervals, inequitable water distribution, and variable supply hinder irrigation in the Lower Kulfo catchment; adopting optimized practices and robust management can enhance efficiency, equity, and crop productivity.
土壤湿度灌溉间隔缺失、灌溉用水在用户间分配不均以及供水的时间和空间变异性，一直是埃塞俄比亚南部下库尔福集水区灌溉计划生产力面临的挑战。本研究旨在制定基于土壤湿度的灌溉间隔，并评估灌溉水输送和田间灌溉效率。直接测量了土壤含水量以及渠道和田间的水流，并使用CropWat 8模型估算灌溉定额。为了尽量减少水分胁迫或水分过多问题，当土壤含水量从田间持水量降至洋葱和辣椒的35.7%、西瓜的34.4%、小麦和玉米的32.5%时，需要进行灌溉。然而，在现有的灌溉计划中，洋葱的灌溉含水量为36.2%、西瓜为35.4%、辣椒为36.4%、玉米为36.2%、小麦为35%，这增加了田间的灌溉量。灌溉时土壤水分消耗的平均百分比（p）为27.4%，低于推荐值。洋葱和辣椒的平均采用灌溉间隔和设计灌溉间隔分别为4天和6天，西瓜和小麦为5天和7天，玉米为6天和7天。下库尔福集水区灌溉计划的平均灌溉充足率和可靠性，阿尔巴明奇灌溉计划分别为1和0，阿尔巴明奇大学农田为0.5和0.2，私人农田为0.4和0.25，科拉沙拉农田为0.1和0.43。1月的灌溉公平值为0.7，2月为0.6，3月为0.8，这表明灌溉充足率存在高度的短期变化。渠道输水平均值为82.7%，农场平均灌溉效率也为56.6%。本研究中小麦的平均作物产量为0.5吨/公顷，洋葱为4.9吨/公顷，辣椒为6.2吨/公顷，西瓜为0.6吨/公顷，玉米为4.2吨/公顷，与研究区域内的其他对照灌溉相比非常低。基于土壤湿度的间隔不足、水分配不均和供水变化阻碍了下库尔福集水区的灌溉；采用优化措施和强有力的管理可以提高效率、公平性和作物生产力。
