C. Zerbato, F. M. Carneiro, P. C. de Menezes, L. D. Gírio, C. A. Furlani, R. P. da Silva
UNESP
Sensors have shown great potential for development and are widely used in precision agriculture. Canopy sensors are tools that help in the application of variable rate of nitrogen fertilization, obtain accurate data in real time, and do not cause damage to the plant. These sensors are being used in agriculture to assess crop status, such as rice, corn, soybeans and wheat, by monitoring plant variability and assisting in management practices. However, there are still few studies on peanut culture comparing the efficiency of sensor readings with biometric parameters. The objective of this study was to evaluate the performance of canopy sensors in the detection of peanut variability at various stages of its development. The vegetation indices were collected in the 2016/17 crop in an agricultural area of a farm in the municipality of Dumont located at 21 ° 15'22.05 "S and 47 ° 58'15.00" W, state of São Paulo, Brazil. The canopy sensors used were GreenSeeker and OptRX, which allowed to calculate the vegetation indices NDVI and NDRE, respectively. Vegetation indexes and biometric parameters, dry shoot biomass and canopy width of the plants were evaluated at 30, 45, 60, 75 and 90 days after sowing (DAS) of the peanut. The statistical analyzes used were Pearson's correlation coefficient and descriptive analysis. The period that presented the highest correlation values was at 45 and 60 DAS, and these data were obtained from the NDRE. The NDVI values were lower in this period because of the saturation of their readings, this problem affects this index when the biomass increases and the physiological potential of the crop is higher, and these factors in turn affect directly the accuracy of the readings, and this was verified through the analyzes. However, at the beginning of the development of the crop for the biomass parameter NDVI presented the highest values of correlation compared to the NDRE, demonstrating greater efficiency in its reading. At 75 and 90 DAS there was no correlation between the parameters and the indices. The NDRE showed better performance in its readings to detect the variability of this crop, especially at 45 and 60 DAS, than NDVI, since the NDVI showed a problem in its readings due to saturation with the high development potential of the plant.