What's the difference between Watermark and Capacitance soil moisture probes?
Does it matter which one I chose?
Bridge is here to answer your questions like "how many inches of water are readily available to my crop?" or "how many days do I have left before the crop starts to stress?" We do the hard work to accurately deliver these same insights to you regardless of which technology you chose for the soil moisture probe. If in doubt, we recommend going with the capacitance probe, but for those of you who need a more detailed explanation I will try to give some of the theoretical and practical differences without going over-board on the technical jargon.
If in doubt, we recommend going with the capacitance probe
sensors are based on fairly old, but very well-researched principles. These sensors actually soak-in the moisture in the soil and determine how much pressure it takes to extract water from the soil. On it's own, this number is of very limited use for irrigation scheduling. When we take into account the texture of the soil, and combine the readings from several sensors at different depths, then we are able to put together the full picture of how much water your crop is going to have access to before it starts to stress. This article goes into much more detail about how these sensors work: http://extensionpublications.unl.edu/assets/pdf/ec783.pdf
- Decades of university research provide unmatched ability to interpret raw sensor readings into accurate soil moisture values.
- No in-season calibration required.
- The thing that they measure, soil water tension, is what actually affects the root's ability to take up water.
- Limited lifespan requires testing and replacement every few years. BUT we test each watermark sensor before installation and replace any sensor
that is “worn-out”, at no cost to you!
- Doesn't work as well in very sandy soils.
probes operate on entirely different principles. The individual sensors inside the probe each generate an oscillating (rapidly changing) electrical field that extends a small distance into the soil, and then measure how that field interacts with material around it. The amount of moisture in the soil has the greatest effect on the sensor readings, although soil texture, compaction, salinity, temperature, and other physical and chemical properties can all have an effect on the reading. This article has more information about capacitance probes as well as several other moisture probe technologies: http://extensionpublications.unl.edu/assets/pdf/ec3002.pdf
- Works great in any type of soil.
- More precise sensor readings result in a cleaner-looking graph of data.
- More sensors in the probe give a more accurate estimation of the inch-by-inch water content of the soil.
- Each probe must be manually calibrated each time it is installed, BUT as soon as the probe is installed, we start monitoring the data and fine-tune the calibration values so you don't have to!
How do I let you know when it's time to install my soil moisture sensors?
When you placed your order on Bridge Builder, we asked you which crop(s) you were planning to plant in that field. Based on your crop, geographic location, and our knowledge of how the season is progressing, we will be contacting you when we think ...
Soil Moisture Terms and Concepts
One quick note: When it comes to physiological processes in plants and physical processes in soils, there are never exact cut-off points or thresholds where something like crop stress begins or soil drainage stops. While all of the concepts below are ...
How far does the wireless connection between the gateway and probes reach?
When you place a Gateway on the map in Bridge Builder, you will see two circles. The green circle in the map shows the area that will definitely have adequate radio signal, even if there is rough terrain. The yellow circle shows where there should be ...
What's the difference between NDVI and EVI imagery?
Normalized Difference Vegetation Index (NDVI) is a popular way of using visible and near-infrared data to come up with a score that represents the health and biomass quantity of vegetation. This is how we can show you a map with red "bad" parts of ...
Can I use my existing probes or equipment with ServiTech Bridge?
We want Bridge to be a place that growers can view their sensor, crop, and equipment data regardless of the source! Unfortunately, it's not as simple as just flipping a switch to allow this to happen. It takes development resources for every source ...