Abstract
We have developed a liquid fertilizer application device that, utilizing irrigation water and inexpensive urea, can produce and apply the liquid fertilizer necessary for use in paddy fields onto the crop in a highly accurate manner. The drop flow rate of the fertilizer, and the nitrogen concentration rate, remained almost constant throughout field demonstration tests. After the fertilizer was applied, the leaf color, rice yield (calculated by crop cutting surveys) were the same as those achieved when a conventional fertilization method was used, namely, application of ammonium sulfate using a backpack-type spreader. In order to ensure accurate fertilizer application using irrigation water, it was necessary to first completely drain the field to expose the paddy, and to stop the flow of irrigation water after the application was complete.
