Using Digital Camera Image for Recommending Nitrogen Topdressing Rate at Panicle Initiation Stage of Rice

摘要

Crop growth and N nutritional status at panicle initiation stage (PIS) of rice have been reported to be highly related to the subsequent crop growth rate and, therefore, to the yield, yield components, and grain quality of rice. Model recommending nitrogen topdressing rate at PIS was constructed and validated for its effectiveness through a series of field experiments (Nguyen et al. 2007). The model employs shoot fresh weight and SPAD value of Y-leaf at PIS of rice to calculate the nitrogen top dressing rate at PIS. However, the monitoring of shoot fresh weight and SPAD value is destructive, time- consuming, and requiring expensive SPAD meter. We tried to employ digital camera, available universally to farmers, for non-destructive, timely, and cheapmonitoring of shoot fresh weight and SPAD value.