Forecasting of leaf blast using the dielectric leaf wetness sensor

Abstract

In this study, in order to predict leaf blast occurrence using a leaf wetness sensor, we examined the optimal sensor installation angle and location for the measurement of leaf wetness period in rice plant, the relationship between the wetness period and the occurrence of leaf blast severity, and the optimal threshold of the permittivity of a leaf wetness sensor to determine wetness in rice. The wetness period measured at an installation angle of 0 ° was significantly longer than the wetness period measured at 0 ° to 60 ° angles. Therefore, the optimal setting angle of the leaf wetness sensor was 0 °. There was no significant difference between the wetness period measured in the paddy field and the wet period measured in the plowed field. Therefore, it was considered that it was more practical to install the leaf wetness sensor outside the paddy field in consideration of the labor and maintenance required for the installation. The wetness period measured by the leaf wetting sensor was considered to be applicable to agriculture field sites because the estimation accuracy of the prediction of leaf blast occurrence was high. In rice, the wetting period evaluated at the threshold of 0.300V in permittivity was better than the threshold of 0.284V recommended by METER Group, Inc. to evaluate the occurrence of leaf blast.