PRONOVA Stelzner EC 2000, Technical Instructions

Page: 49 / 158

51
GB
If there are deviations out of the optimal
ranges, the previously specified concentra-
tions should be temporarily increased or re-
duced. You should also take into account the
season, growth phase, temperature control
and nutrient content in the water.
Fertilization can also be adjusted based on
the per-pot nutrient needs of the plants. The
following table shows the calculation for
nutrient quantities administered as individual
liquid fertilizers.
Fertilizer % Concentration
Liquid
fertilizer
Quantity/pot
Nutrient quantity
N P
2
N
O
K
2
O
15 : 11 : 15 0,5 o/oo = 0,5 g/l 100 ml = 7,5 5,5 7,5 mg/pot
15 : 11 : 15 100 ml = 15,0 11,0 15,0 mg/pot
15 : 11 : 15 100 ml = 30,0 22,0 30,0 mg/pot
6.4 Quick test
When the crops have very high AM values,
it is important to ascertain whether these
values are caused by an increased nitrate
concentration.
Process:
The soil must have the optimal moisture level
for the crop. If long-term fertilizers are used
(such as Plantosan or Oscmocote), then you
can be fairly sure of obtaining a stable mea-
surement over a long time period because
nutrients are being constantly released.
Additional fertilization is required only after
the measured values fall below 0.2.
Accompanying salts, such as chloride,
influence the measurements when the salt
measurements increase constantly.
However, you can use a nitrate measuring
rod to determine if the higher measured
values are being caused by nitrogen. A deci-
sive factor here is the crop state. The nitrate-
nitrogen quick test is quite simple. For a high
measured value, the test can determine
whether or not nitrate-nitrogen is present.
Use a spray bottle to moisten the area to be
measured with distilled or nitrate-free water.
Insert the nitrogen-nitrate measuring rod
simply by pressing in with your finger. Insert
into the same area where you took the AM
PET 2000 KOMBI measurement.
In order to keep the indicator display clean,
you should use a filter before inserting into
the soil. A Kleenex or thin double-layered
tissue paper is best suited for this purpose.
Simply rip off a small piece and then use it
to cover the indicator display so that is will
not get dirty.
After five to ten seconds, when the filter is
moist, pull out the rod and look for discolou-
ration. (Take the reading after one minute.)
No discolouration = no
nitrate-nitrogen
is present
Weak discolouration = a low level of
nitrate-nitrogen
is present
Strong discolouration = much nitrate-
nitrogen is
present
If high activity levels are shown by measu-
rements taken directly in the soil by the AM
PET 2000 KOMBI and by the discolouration of
the nitrate rod, this indicates that the accom-
panying salts and the portion of available
nitrogen in the measured crop are having an
influence.
In this way, AM PET 2000 KOMBI serves a
monitoring function. With this process, the
cultivator or consultant has an additional
control mechanism in the fertilization and
growth phase of cultivated plants.