August, 2015
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Strong plants - it's easy!

Growth and development of plants are dependent on the ratio of water and air in the soil

Soil moisture is one of the most important parameter involved in pedological processes and plant growth. There are three basic forms:

  • water that adheres in thin films to the surface of soil particles by molecular attraction is termed hygroscopic water. It is not available for plants;
  • water forming thicker films and occupying the smaller pore spaces is termed capillary water. Since it is held against the force of gravity it is permanently available for plant growth and it is this type of soil water which contains plant nutrients in solution;
  • water in excess of hygroscopic and capillary water is termed gravitational water, which is of a transitory nature because it flows away under the influence of gravity. When the excess has drained away the amount of water retained in the soil is termed its field capacity, when some of its pore spaces are still free of water.

Water and soil conditions

Saturated soil.
Spaces between the soil
particles totally filled with water.

Soil at field capacity.
Spaces between the soil
particles filled with water
and air.
Soil at wilting point.
Spaces mostly filled with air, with a small amount of water held tightly around the soil particles.

The water supply to of your plants has a fundamental influence in their development.  A sufficient moisture level in the root zone assures that the nutrients in the soil are at their best availability and supports a healthy plant nutrition and optimal growth.  In reverse, a lack of soil moisture disturbs the nutrient uptake of plants and often causes a nutrient deficit.

Reducing water stress of your crop comes with several profits for you: 
  • improving plant growth & quality
  • increasing your yield 
  • strengthening plant health and disease resistance

Ways of measuring soil moisture:
  • Volumetric Water Content shows you how much water is in the soil. It is usually expressed as a percentage. The measured results represent what percentage of total 'volume' of soil is water.
  • Soil Moisture Tension shows you how easy it is to extract water from soil. When a soil is saturated, there is plenty of water in the pore spaces and plenty of water coating the soil particles. All this moisture makes it very easy for plant roots to get water and the soil moisture tension is low.

Suggested tensiometer readings at which to start irrigation
(or Critical Soil Moisture Deficit)
Brussel sprouts
Reading in  hPa

STEP Systems has developed testing equipment which enables you to carry out quick and precise in-site soil moisture measurements.
MST 3000+
Hand-held Meter MST 3000+
and FDR sensor SMT 100

Mobil soil moisture measurement

Our newly developed hand-held meter MST 3000+ is suited for quick and accurate reading out of measurement data from the humidity and temperature sensor SMT 100. Its handling is very simple: by pressing a button, the values appear immediately on the LCD display.
The automatic switch-off prevents unintentional battery drain. The hand-held meter MST 3000+ can be used for direct, individual measurements in all soils and substrates.
MST 3000+
While using this measurement method it is essential to consider that equal measurement values can only be achieved at equal ambient conditions (soil density, penetration depth) of the sensor. It is therefore highly recommended to perform several measurements and to calculate an average value. The MST 3000+ can also be used merely as a display device for permanently installed sensors, that do not require frequent reading and documentation (in preliminary tests for irrigation control, for example).

Learn more...

Soil Moisture Guideline

Soil Type                   FC (%)            PWP (%)        ρb ( (g/cm3 )
Clay                            44.3                 21.7                            1.3
Clay Loam                  35.7                 16.9                            1.4
Loam                          31.1                 14.2                            1.4
Loamy Sand               18.4                   8.1                             1.6
Sand                           14.8                   6.3                            1.6
Sandy Clay                33.4                 16.3                            1.4
Sandy Clay Loam      29.4                 14.0                            1.5
Sandy Loam               21.3                   9.5                            1.5
Silt                              38.4                 17.2                            1.2
Silty Clay                    39.9                 19.2                            1.3
Silty Clay Loam          39.8                 18.7                            1.2
Silty Loam                  35.3                 16.0                            1.3
Instuments for an economic and effective water management:
SMT 100
Soil Moisture Sensor SMT 100

Due to the fast response of the sensors and universal applicability for all types of soil and substrate FDR sensors are most helpful for automation of irrigation control
Learn more
The conventional method of soil moisture measurement. The tensiometer is a device used to determine matric water potential, an indirect measure of soil water content
Learn more
Aquaterr M-350
Aquaterr is perfect for moisure measurements also in deeper soil layers, up to 70cm. It may be used in a variety of soils, and is un- affected by temperature, pH, dissolved salts, or metallic ions
Learn more

Around the world


Hortiflorexpo IPM Shanghai successfully

The Hortiflorexpo IPM Shanghai has ended with a new record number of visitors, 19,280 visitors from 27 countries came to the Shanghai New International Expo Center. The INDEGA was represented with a total of 11 companies on the German joint stand of the Federal Ministry of Food and Agriculture (FMFA). From INDEGA participated: STEP Systems, Gefoma, IPM Messe Essen, Lehei, Pöppelmann, Terracult and Ziegler.

This time Harald Braungardt acted as an official informant of the FMFA and was very pleased  that the Ministry was also present in China, with Tanya Geik as it’s official representative.
"The Hortiflorexpo IPM Shanghai has significantly succeeded to expand its leading position as the most important horticultural exhibition in China. The need for investment is enormous due to the high demand for flowers and plants. The show has benefited noticeably from this, and could at the same time set a new impetus for the green industry“, says Oliver P. Kuhrt, CEO of Messe Essen and thus a Co-organiser of the fair, about the successful event.

STEP Systems GmbH
Duisburger Str. 44
 90451, Nuremberg, Germany
Tel.: (1049-911)-96 26 05 0
Fax: (1049-911)-96 26 05 9
👉 Stay tuned for more useful information about our measurement technology
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