Survey of Paddy Rice Growth in Agrivoltaic-systems

― A case study of the Kagawa breed rice “Oidemai” ―

Abstract

A survey of rice yield components was conducted in 2019 in several paddy fields where agrivoltaic systems were implemented in Marugame City, Kagawa Prefecture. Cnaphalocrocis medinalis (a type of pest) infestation was observed in all paddies except for Paddy b. Under the panels of the Paddy b, yield, number of rice ears, ripening rate, number of seeds per ear and thousand-grain weight were 54%, 64%, 86%, 98% and 99% respectively, compared to outside of the panels. However, there were no statistically significant differences among the factors other than yield. In 2020, a detailed distribution survey of rice ear numbers was conducted in Paddy b. The results revealed that the number of ears varied by more than 50 ears/m² within the rows under the panels, while the number of ears outside the panels increased as the rows moved away from the panels. It has been revealed that variations in rice growth occur depending on the location, both within and outside the panels, due to the continuous movement of panel shadows caused by the changing inclination of the sun based on seasons and time.