Energy Budget fo Rice Planted Paddy Fields, and Estimation of Its Water Temperature

Studies on water temperature and water management for paddy fields (I)

Abstract

Energy budgest of rice planted paddy fields are discussed, and a new water temperature estimation method is proposed to avoid cold weather damage to rice. Energy budgets and water budgets data were collected from the experimental paddy fields during the summer of 1984 in Fukagawa, Hokkaido. They show that the heat transfer coefficient is small at night, and big and fluctuating greatly during the daytime. Although it has been often treated as a wind function, its relation to time is clear than to wind. The new temperature estimation method, using the heat transfer coefficient as the time function, is in good agreement with the observed values. This method is applied to other paddy fields about 8 km from the experimental fields. The results show that this method also gives good estimates here, and prove its availability.