| Summary: | This study was conducted to identify and visualise spatially the Nitrogen (N) status on immature oil palm area with an autopilot tractor-mounted active light sensor (ALS) in a Malaysian oil palm plantation. All the measurements taken by the ALS were assessed ‘on-the-go’ at every second while the tractor was moving on the field with autopilot steering mode. The N status was analysed based on 46% of the N content in urea and 40 kg ha–1 N application rate for a standard fertiliser requirement for immature oil palm. The ordinary kriging method was used to produce the interpolated maps of the N status by means of the ArcGIS 10.3 software. It was found that mean N-as applied rate per hectare read by the sensor was 1.62% lower than the recommended one. By showing such very small difference in mean rates, generally, the system showed its effectiveness in monitoring N status on immature oil palm. The interpolated maps also successfully displayed spatial variability of the N status on immature oil palm area, which are useable for reference in applying variable rate application (VRA) to economise the use of fertiliser on the said crop. © 2021 Lembaga Minyak Sawit Malaysia. All rights reserved.
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