Use of a digital camera as alternative method for non-destructive detection of the leaf chlorophyll content and the nitrogen nutrition status in wheat

- The potential of image analysis to assess leaf chlorophyll content was tested.
- Image analysis is an alternative to destructive determination or spectral methods.
- The method is applicable even at very low levels of ground cover.

In this paper, the use of a digital consumer camera for the non-destructive detection of the N nutritional status is compared with two alternative methods, namely SPAD and reflectance spectrometry in three field experiments. The image analysis method consisted of segmentation and successive analysis of the foreground color, i.e. only green plant parts. Thus, also analysis of canopies with small degree of ground cover is possible. All methods gave comparable results, while the effort necessary was considerably higher when using the chlorophyll meter. With spectral measurements, the biomass and leaf nitrogen content could not be clearly differentiated; chlorophyll measurements do not reflect biomass, whereas the described procedure of image analysis permits the consideration both. If used properly, digital image analysis is a valuable tool for the determination of the N nutrition status under field conditions, with low costs and labor requirements.