10
Issue: 03.2013 (EN)
Operation and application
Starting up
–
Insert the batteries.
The device is ready for use.
Requirements for reliable measurements
▪
The N-recommendations apply only for certain
development stages.
▪
At least 30 measurements must be carried out on 30
different plants per field.
▪
In order to obtain a representative average reading, the
measurements must be carried out randomly
distributed across the field.
▪
When measuring, avoid any atypical areas of the field
(e.g. areas with distinctly different soil properties, such
as sand banks or similar)!
▪
Measuring point: The measurement must be carried
out in the middle of the leaf blade of the youngest fully
developed leaf. Measurements on not fully developed
leaves may lead to increased recommendations.
Example, BBCH 32: Measuring point at
stage ‘Stem
elongation (node 2 at least 2 cm above node 1)
’
Example, BBCH 47: Measuring point at stage '
Booting’
(flag leaf sheath opens)
▪
Variety: Differences in the varieties need to be
considered, e.g. by correction factors.
▪
Sulphur deficiency: S deficiency such as N deficiency
leads to the leaves being brighter. Therefore a
sufficient S supply has to be ensured when using the
N-Tester. Other nutrients do not have any significant
influence.
