14 Application of NIR in Agriculture
335
14.2.2 Crop Analysis—Direct Analysis in the Field
or Laboratory Analysis to Support Farmers
and Breeders
For the monitoring the crop before and during harvesting, NIR spectroscopy can be an
interesting solution. Indeed, it can be used for optimising the harvest date and for crop
management. NIR technology is used, among other things, for measuring moisture,
production yield, nitrogen status of the crop and to monitor the occurrence of plant
pests and diseases. Determining these chemical compositions and properties can be
done directly in the field during farm operations or at the harvesting stage for optimal
monitoring of crops throughout their life cycle. The objective is to support breeders or
farmers in their management. It can also be done in the field to support breeder observations or farmer choices, as well as at the receipt stages of storage facilities or of
industry. Today, there is a common effort by farmers, researchers, instrument manufacturers and farm advisory services to develop operational solutions for assessing
optimal crop management, to optimise the use of inputs, to assure the best product
quality and to maximise the financial benefits [2]. Classical NIR benchtop instruments are also used by researchers and breeders for routine analysis of the dried and
ground aerial parts of the crop in order to determine key parameters such as nitrogen
and carbon content [12]. Moreover, near-infrared microscopy (NIRM) has also been
proposed as a rapid technique to predict the chemical composition (e.g. nitrogen
content) of dried and ground materials when the material quantity is insufficient to
perform analysis by classical instrumentation. It has been demonstrated with very
small samples (1 g) of tomato (Solanum lycopersicum L.) leaf powder coming
from experiments. The calibration model obtained for nitrogen content proved to be
excellent, with a calibration coefficient of determination (R
2
c ) higher than 0.9 and a
ratio of performance to deviation (RPD c ) higher than 3. It appears that NIRM is a
promising and suitable tool for a rapid, non-destructive and reliable determination
of nitrogen content of tiny samples of leaf powder [13]. The use of the NIR hyperspectral imaging instrument for crop analysis seems to be an increasingly interesting
approach as it provides spatial information in addition to chemical information from
the spectral data. In that sense, this approach is being investigated to build phenotyping strategies useful in breeding programmes that focus on wheat varieties (e.g.
PhenWheat project; http://www.cra.wallonie.be/fr/phenwheat), sugar beet varieties
(e.g. BeetPhen project; http://www.cra.wallonie.be/en/beetphen) and potato varieties
(e.g. First project; http://www.cra.wallonie.be/fr/first). Figure 14.2 shows the NIR
hyperspectral imaging device used at CRA-W. Challenges are presentation of the
device to the crop and the development of a robust protocol to calibrate and validate the system using spectral data not collected in the controlled environment of a
laboratory.
The potential of NIR hyperspectral imaging spectroscopy and chemometrics for
the discrimination of roots and crop residues extracted from soil samples has also been
demonstrated. The study of these materials in different field conditions is important
to identify suitable soil management practices for sustainable crop production. In
335
14.2.2 Crop Analysis—Direct Analysis in the Field
or Laboratory Analysis to Support Farmers
and Breeders
For the monitoring the crop before and during harvesting, NIR spectroscopy can be an
interesting solution. Indeed, it can be used for optimising the harvest date and for crop
management. NIR technology is used, among other things, for measuring moisture,
production yield, nitrogen status of the crop and to monitor the occurrence of plant
pests and diseases. Determining these chemical compositions and properties can be
done directly in the field during farm operations or at the harvesting stage for optimal
monitoring of crops throughout their life cycle. The objective is to support breeders or
farmers in their management. It can also be done in the field to support breeder observations or farmer choices, as well as at the receipt stages of storage facilities or of
industry. Today, there is a common effort by farmers, researchers, instrument manufacturers and farm advisory services to develop operational solutions for assessing
optimal crop management, to optimise the use of inputs, to assure the best product
quality and to maximise the financial benefits [2]. Classical NIR benchtop instruments are also used by researchers and breeders for routine analysis of the dried and
ground aerial parts of the crop in order to determine key parameters such as nitrogen
and carbon content [12]. Moreover, near-infrared microscopy (NIRM) has also been
proposed as a rapid technique to predict the chemical composition (e.g. nitrogen
content) of dried and ground materials when the material quantity is insufficient to
perform analysis by classical instrumentation. It has been demonstrated with very
small samples (1 g) of tomato (Solanum lycopersicum L.) leaf powder coming
from experiments. The calibration model obtained for nitrogen content proved to be
excellent, with a calibration coefficient of determination (R
2
c ) higher than 0.9 and a
ratio of performance to deviation (RPD c ) higher than 3. It appears that NIRM is a
promising and suitable tool for a rapid, non-destructive and reliable determination
of nitrogen content of tiny samples of leaf powder [13]. The use of the NIR hyperspectral imaging instrument for crop analysis seems to be an increasingly interesting
approach as it provides spatial information in addition to chemical information from
the spectral data. In that sense, this approach is being investigated to build phenotyping strategies useful in breeding programmes that focus on wheat varieties (e.g.
PhenWheat project; http://www.cra.wallonie.be/fr/phenwheat), sugar beet varieties
(e.g. BeetPhen project; http://www.cra.wallonie.be/en/beetphen) and potato varieties
(e.g. First project; http://www.cra.wallonie.be/fr/first). Figure 14.2 shows the NIR
hyperspectral imaging device used at CRA-W. Challenges are presentation of the
device to the crop and the development of a robust protocol to calibrate and validate the system using spectral data not collected in the controlled environment of a
laboratory.
The potential of NIR hyperspectral imaging spectroscopy and chemometrics for
the discrimination of roots and crop residues extracted from soil samples has also been
demonstrated. The study of these materials in different field conditions is important
to identify suitable soil management practices for sustainable crop production. In