Active proximal sensing has been increasingly used to provide information about canopy properties in a large range of crops. In this study a low cost, active multispectral optical device named Plant-OMeter (POM) was tested in real conditions at two experimental fields comparing it with the GreenSeeker handheld device. Treatments included five nitrogen (N) fertilisation rates applied during sowing. Maize was scanned between V5 to V8 growth stages. The results showed that measuring with the POM sensor within this growth stage window can provide good estimation of end-of-season yield, comparable to the GreenSeeker. This indicates that Plant-O-Meter exhibits strong potential for accurate plant canopy measurements and for real time variable rate fertilisation applications in maize

This study was supported by the project "Development of the device for measurement and mapping of nitrogen as the most important parameter in sustainable agriculture", contract no. 114-451-2794/2016-03, funded by Provincial Secretariat for Higher Education and Scientific Research of Autonomous Province of Vojvodina, Republic of Serbia