Evaluation of Wetting Front Detector on Water Productivity and Its Savings Under Pepper Production at Dugda District, East Shoa Zone of Oromia Region

Abstract

The limitation in water availability and also salinity and waterlogging related to over application of irrigation water resulted in low crop water productivity, which obliges to adopt alternative water management techniques. The work compared a simple on-farm water optimization technology called Wetting Front Detector (WFD) against computer program to estimate Crop Water Requirement (CWR) and farmers practice (FP). A field experiment was designed in Randomized Complete Block Design, replicated six times 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 FP. In comparison with FP, CWR saved irrigation water by 37% under pepper field. 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 (E_a), storage (E_r) 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 (E_a is 66.76%), followed by the WFD technique (E_a is 62.32%) and farmer practice (E_a is 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 3.67, 3.08 and 1.52. 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 E_r of 66.42% which can be beneficially used by the crops while the WFD of 50.85%. As a result, yield of the crop 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 (D_p) and this has environmental and economic implications. Although many indicators confirm the importance of CWR approach, 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.

DOI: 10.7176/JNSR/10-5-02

Publication date:March 31^st 2020