The Field application efficiency Assessment of Paddy Field in Aceh Irrigation Scheme, Aceh, Indonesia

Abstract

The efficiency of project irrigation is the main factor in measuring the irrigation system’s effectiveness in conveying and distributing the water to a paddy field. The efficiency of irrigation projects in Aceh adopted from Indonesian irrigation standards is 65% which is much higher than generally used in some countries in Asia, i.e., 35-46%. This high value is caused by neglecting water losses in the paddy field when determining the project’s irrigation efficiency. This results in insufficient water for the overall irrigable areas planned in the irrigation scheme in Aceh. The study is aimed to assess the field application efficiency by investigating the water losses in paddy fields. To conduct the research, the paddy field in Pandrah Irrigation Project is plotted specifically. A drum technique instrument was installed in the plot to measure the evapotranspiration, percolation, and effective rainfall based on water balance analysis in the drum in one paddy growing season. The results showed that the field application efficiency is 75.34%. meaning some of the water supply could not be effectively consumed by the paddy. Based on the investigation, most water losses in paddy fields are caused by preferential flow through macropores in vicinity bunds which were triggered by the movement of rats, paddy roots, and bad plow of the field. Therefore, it is recommended to investigate the water losses that will occur due to the above assumption by continuing research in the future, so the project efficiency might be stated accurately when planning irrigation projects in Aceh.