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Estimating biophysical properties of coffee (Coffea canephora) plants with above-canopy field measurements, using CropSpec®
- Putra, Bayu T. Widjaja, Soni, Peeyush, Morimoto, Eiji, Pujiyanto, Pujiyanto
- International agrophysics 2018 v.32 no.2 pp. 183-191
- Coffea canephora, chlorophyll, crops, field experimentation, light intensity, nitrogen, nitrogen content, remote sensing, trees, vegetation index
- Remote sensing technologies have been applied to many crops, but tree crops like Robusta coffee (Coffea canephora) under shade conditions require additional attention while making above-canopy measurements. The objective of this study was to determine how well chlorophyll and nitrogen status of Robusta coffee plants can be estimated with the laser-based (CropSpec®) active sensor. This study also identified appropriate vegetation indices for estimating Nitrogen content by above-canopy measurement, using near-infra red and red-edge bands. Varying light intensity and different background of the plants were considered in developing the indices. Field experiments were conducted involving different non-destructive tools (CropSpec® and SPAD-502 chlorophyll meter). Subsequently, Kjeldahl laboratory analyses were performed to determine the actual Nitrogen content of the plants with different ages and field conditions used in the non-destructive previous stage. Measurements were undertaken for assessing the biophysical properties of tree plant. The usefulness of near-infrared and red-edge bands from these sensors in measuring critical nitrogen levels of coffee plants by above-canopy measurement are investigated in this study.