灌溉排水系统工程

Optimization of Furrow Irrigation Decision Variables: The case of Wonji Shoa Sugarcane Plantation, Ethiopia.

Abstract

Tokuma Adamu1*, Mekonen Ayana2, Gebremeskel Aregay3

Surface irrigation type is one of the most widely used in the world due to its low cost investment. However it is complex methods of applying water to soil, because of extremely difficult to achieve good control over the highly variable nature of the movement of water across a soil surface and its infiltration into the soil over a season. This complexity leads low efficiency of the system because of failure in management and design. In this study, it is attempted to optimize furrow irrigation decision variables at Wonji sugar estate using field experiment and two simulation models. The hydraulic performance of the existing system was evaluated using two systematically selected furrows. Accordingly, an application efficiency of 43% and 25% were obtained. The performance of the system was evaluated as poor due to excess application of water and less management skills of irrigation application. One experimental site was selected at field number of 85 for optimization of decision variables. The field data (before irrigation, during irrigation and after irrigation event) of experimental site (at field number 85) was measured as input for models and simulated using the SIRMOD software and Win SRFR software package. Furrow length of 32m, 48m, and 64m, slope of 0.05%, 0.075% and 0.1%, and flow rate of 3l/ sec, 4l/sec and 5l/sec were analyzed with three replication using volume balance method and two simulation models. Therefore, from the current findings, the optimum decision variables that gave maximum application efficiency and distribution uniformity was slope 0.1%, furrow length 32m,and inflow flow rate 4 l/sec at cut-off time 15.79 minutes. Thus, to improve the performance of furrow irrigation practice, optimal furrow length, inflow rates and cut-off time found by this study could be adopted.