PRONOVA Stelzner EC 2000, Technical Instructions

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50
GB
Manure should not be used for soil with
phosphorus concentrations over 800 mg/l.
The damage threshold for potassium is
reached when the upper limit is exceeded
by 50%.
Magnesium
Optimal K : Mg nutrient ratio is 2 : 1. An ex-
cess of magnesium prevents the absorption
of nutrients (K + Ca).
Salt content
When these thresholds are exceeded, the
crops should be flushed or the substratum
should be thinned out with peat. Causes:
use of in-house soil (for example, compost),
excessive use of mineral fertilizer or water
used.
Iron and manganese
The threshold values are only valid for the
optimal pH range corresponding to the crops.
As the pH value decreases, these values can
also be lower. The actual availability for the
plants is very dependent on the pH value.
Boron
The specified range is valid for garden crop
substrata. For mineral soils and ph values
over 6.5, the concentration may be higher
without causing growth problems. (For loamy
soil: 1.0 – 2.5 mg/l).
pH value and lime
The amount of lime needed to create a cer-
tain pH value is dependent on several fac-
tors, such as the starting pH value, the buffer
capacity, the degree of decomposition and
the origin of the peat. Refer to the large table
for the pH ranges. Use calcium carbonate
(CaCo
3
) or slag lime when adding lime to
plants growing under glass.
There is a risk of trace element toxicity when
using large quantities of slag lime in subs-
trata that have high peat content. The lime’s
granularity has a significant influence on the
reaction rate and thus the basicity impact.
The reaction speed increases when the lime
has a finer granularity. Only lime with a gra-
nularity of 0.1 – 0.2 mm should be used for
substrata.
Minimum concentration: 85 % CaCo
3
. Granu-
lar lime is not recommended when adding
lime to substrata. 1.5 kg calcium carbonate
per cubic metre rough peat, in the pH range
3.0 – 5.0, will raise the pH value about one
unit. The pH does not increase linearly.
Calculating the fertilizer quantity for concentration readings in mg/litre
Liquid fertilization
Group I Group II Group III
Interval fertilization
Alternating with irrigation, 1 or 2 times per week.
0,5 – 1,0 o/oo 2 o/oo 3 o/oo
Irrigation fertilization With each water dosage
0,3 – 0,5 o/oo 0,6 – 0,8 o/oo 0,8 – 1,0 o/oo