PRONOVA Stelzner EC 2000, Technical Instructions

Page: 39 / 158

41
GB
Taken together, the EC value of the irri-
gation water and the EC value of the fer-
tilizer will result in the total EC value.
In water contaminated by salt, a low-bal-
last multi-nutrient fertilizer should be used.
High conductivity increases the salt content
in the soil and substrata. Soft water (≤ 8° dH)
lowers the pH, while hard water increases it.
2. The MULTI 2000 helps to determine the acti-
vity for all cultivated soils (measured in mg
salt/litre) using an AM probe. It can also
measure the conductivity in liquids (in mS/
cm) using the conductivity electrode.
Salt tolerance
I
low 500 – 1000 mg/l = 0,2 – 0,6 E.C. /mS
II medium 1000 – 2000 mg/l = 0,6 – 1,2 E.C. /mS
III high 2000 – 4000 mg/l = 1,2 – 2,0 E.C. /mS
3. The proportion of dissolved salts in the soil or
substrata and their activity is measured di-
rectly in the plant crops using the AM probe.
The measurement is dependent on the soil
density, soil characteristics, soil moisture
and soil temperature. The following guide-
line values are valid when measuring activity
values directly in the soil:
Nutrition need / salt tolerance
I low 0,2 – 0,4 activity in grams of salt/litre soil
II medium 0,4 – 0,6 activity in grams of salt/litre soil
III high 0,6 – 0,8 activity in grams of salt/litre soil
We recommend carrying out several measu-
rements at different depths and in different
plant crops. Since the activity is strongly
influenced by soil moisture, the moisture
content of the soil should remain constant
so that the measurements can be compared.
The activity measurement is not a physical
quantity. Rather, it is a practical value used
for testing the total salt content in the vicinity
of the roots.
Since the total salt content is mainly determi-
ned by nitrogen, a low value is indicative of a
lack of nitrogen or a lack of nitrogen/potash.
Activity measurement allows you to monitor
the decomposition of long-term fertilizers.
4. The pH value in the pot changes during the
growth period depending on the fertilizer
added, the water quality and substrata buffer
capacity. It is therefore important to maintain
the optimum pH values and track the values
during the growth period. The pH value in-
fluences the amount of nutrients absorbed
by the plants.
But the importance of the water’s pH value
should not be exaggerated. It should always
be considered in conjunction with the carbo-
nate hardness level.
Overview
The attached table shows the best pH and
activity levels for various plants in their main
growth phase.
In most cases, large containers are well sup-
plied in the topsoil layer; in the subsoil layer,
however, there may be major deviations.
Potted plants with thick root bales take up
fluid fertilizer within just a couple of hours.
Plants taking up fertilizer more slowly are
usually over-fertilized (primula acaulis, for
example). In the summer, farms using salty
irrigation water must take additional steps
to prevent salinisation. When growing ve-
getables under glass, too much fertilizer is
often used; in the open, however, plants are
often irrigated insufficiently.
Roadway damage caused by salt deposits is
a persistent problem when working in public
green spaces.
During the cultivation period, you can use the
MULTI 2000 to check whether enough fertili-
ser is used, whether the scheduled concen-
tration of fluid fertiliser in the soil reaches
the optimum AM values, or whether long-
term fertilizer is still available in sufficient
amounts.
What you see on the plant has already hap-
pened – but what you measure is actually
happening at the moment. Measurements
give you a head start so you can take imme-
diate action to prevent damage.
The MULTI 2000 is widely used during consul-
ting or soil inspections in garden centres.
MULTI 2000