EVALUATION OFWETTING FRONT DETECTOR ON WATER PRODUCTIVITY AND ITS SAVINGS UNDER PEPPER AND ONION CROP PRODUCTION AT DUGDA DISTRICT, EAST SHOA ZONE OF OROMIA REGION

Abstract

This work focuses on evaluating a simple on-farm water optimization technology called Wetting Front Detector (WFD). The work compared WFD against computer based tools to estimate Crop Water Requirement (CWR) and subsequent application and farmers practice. A field experiment was designed in Randomized Complete Block Design, replicated six times for pepper and five times for onion on farmers' fields. Results were compared on the basis of application, distribution storage and water use efficiencies, and water productivity. The results illustrate that there was a significant difference between the water used in the CWR, WFD and Farmer Practice (FP). In comparison with FP, CWR saved irrigation water by 37% under pepper and 35% under onion fields. The WFD technology also saved the irrigation water by about 16% than the farmer method. The differences between the water optimization techniques can be accounted for by to differences in the efficiencies of application (Ea), storage (Er) and irrigation water use which vary considerably from one type of irrigation water management to another at p<0.05. Generally, CWR technique is more efficient (Ea is 59.06 under onion and 66.76% under pepper), followed by the WFD technique (Ea is 53.78% under onion and 62.32% under pepper) and farmer practice (Ea is 49.26% under onion and 55.74% under pepper). On the basis of these values, the water saved by the CWR technique could irrigate 16.5% and the WFD 6-8% more area than the FP. Implicitly better crop production, also less competition between head and tail irrigators. The mean IWUE of CWR, WFD and FP were 114.79, 78.38 and 54.38 respectively for onion and 3.67, 3.08 and 1.52 for pepper. Based on this study, CWR technique appears to be a promising alternative for water saving without negligible trade-off in yield. The CWR had an Er of 65.09% and 66.42% under onion and pepper respectively which can be beneficially used by the crops while the WFD of 59.78% (Onion) and 50.85% (Pepper). As a result, yield of the crops from the CWR exceeds both techniques as it can provide sufficient amount of water for plants at their root zones. Considerable amount of water in FP is lost to Deep Percolation (Dp) and this has environmental and economic implications. Although many indicators confirm the importance of CWR approaches, its practicality at farmers level is questioning as it is computer based. Thus, WFD would be an important tool to be considered to improve the current on farm water optimization by smallholder irrigators.