Meteobot® Hydro is an irrigation automation system. It measures continuously soil moisture and rainfall and automatically turns on watering pumps and valves according to the water needs of plants.
Meteobot® Hydro consists of:
- Volumetric water content sensor
- Rain sensor
- Soil temperature sensor
- Wind speed sensor
- Air temperature, relative humidity and barometric pressure sensor
- Controller module for up to 16 valves/pumps
- 230 V adapter
- Back-up power battery
- Mobile application for remote control from anywhere and anytime
- Subscription with data sharing (for 1 year)
- Connection with external irrigation controllers (e.g. Rainbird, Hunter, etc.)
Price: EUR 1030 (excl. VAT)
- SIM card (with fees included for 1 year): 36 EUR (excl. VAT)
- Leaf wetness sensor: EUR 230 (excl. VAT)
- Solar radiation sensor: EUR 370 (excl. VAT)
- Wind direction sensor upgrade (if a wind speed sensor has been ordered): EUR 110 (excl. VAT)
- Volumetric water content sensor at an additional depth: EUR 170 (excl. VAT)
Meteobot® Hydro works in the following way: the volumetric water content sensor measures the available soil moisture every 10 minutes. When it falls below a certain minimum, the controller module automatically turns on the irrigation pump and opens the corresponding valves. When the soil moisture reaches the designated maximum, the controller turns the pump off and shuts the valves.
Meteobot® Hydro can work in automatic, remote or manual mode:
- In automatic mode the irrigation is turned on when the soil moisture decreases to the specified minimum value. Respectively, when the moisture reaches the maximum value, the watering automatically stops;
- In remote mode you receive a notification on your mobile device when the specified minimum or maximum soil moisture value is reached, and you can turn the irrigation on or off using the Meteobot® mobile application;
- In manual mode you can turn the irrigation on or off using the regular switches on your switchboard.
Meteobot® Hydro provides very flexible settings. It can automatically turn the irrigation off:
- If it starts raining. (Of course, if the rain is not enough, Meteobot® Hydro will resume the irrigation until the necessary soil moisture is reached);
- If the wind speed exceeds a certain value (e.g. 4 m/s). This may be necessary in case you use watering guns;
- If the temperature gets too low (danger of freezing) or too high (plant stress).
Meteobot® Hydro can control directly up to 16 devices (for example, one pump and 15 valves). If you already have an irrigation controller such as Rainbird, Hunter, etc., Meteobot® Hydro can be connected to it, so that you can save water. In this case, the advantage is that you can irrigate when and as much as the plants need, and not according to a strictly determined schedule.
Meteobot® Hydro uses sensors that measure the volumetric water content. They show what percentage from the volume of a certain soil layer is filled with water.
Let’s take, for example, a soil layer which is 10 cm deep. If the sensor shows 25%, this means that one fourth (2.5 cm) from these 10 cm are water. The rest is soil, air pores, plant residue, etc. This way we can calculate the soil water content. If we use the above example: 2.5 cm = 25 mm = 25 liters / sq. m.
Each soil type can hold different amount of water, depending on the soil particles, the pores between them, the organic matter (humus), etc. Clay soils that are rich in organic matter have the highest soil holding capacity; sandy soils have the lowest one. The maximum quantity of water, which the soil can retain after it has been saturated from above and the gravitational water drains down is called “field capacity”.
Not all the soil water, however, is available for the plants to use. When the soil moisture falls below a certain level, the roots cannot access it and the plants wilt. This is the so called “wilting point”. The difference between field capacity and the wilting point is the plant available water.
On the following chart you can see approximate values of field capacity and wilting point for some common soil types:
In order to monitor the amount of water in the soil horizon, where the plant roots are, you can intall up to 5 volumetric water content sensors. Depending on the crop type they could be placed at 10, 30, 50, 70 and 90 cm depths, for example. The sensors have to be as close as possible to the plant’s roots. In case of drip irrigation, they have to be placed “between two droplets”, in order not to show incorrectly high values.
Meteobot® Hydro can be equipped with the soil moisture sensors of the leading Australian manufacturer – Sentek. They show the soil water content every 10 cm depth – e.g. at 10, 20, 30, … down to 120 cm. The water content is displayed in litres (mm) per square meter. This way you have information how much water you have available in the soil at any given moment.
Sentek sensors are especially suitable for deep rooted crops – for example, corn, irrigated with pivot (or other sprinkler-type) systems.
Sentek uses as a “sensor” the root of the plant. On the following chart you can see how the soil water content drops steeply during the day and gradually during the night. The reason for that is that during the day the plant “pumps” water from the ground and evaporates it through the leaves. This does not happen during the night. That is why the chart looks like stairs whenever the soil moisture is within the optimal range.
When the soil dries so much that plants cannot extract water from it any more, the chart goes straight and levels out. This is exactly the moment when another irrigation is necessary. When the soil is saturated, plants cannot use water from it in an optimal way and the chart is flat.
This way you can see when to irrigate – when soil moisture drops below the lower limit, under which plants get stressed. In the case on the next chart, this means one irrigation every 6-7 days.
How much to irrigate?
Sentek sensors measure soil water content at every 10 cm depth. This way you see how much water is necessary to provide optimal soil moisture down to the depth of the roots at the current moment. On the following chart you can see soil water content from 0 to 60 cm depth. In the middle of July (where the left arrow points), water is used from a depth of 20 cm (i.e. the roots reach down to 20 cm). This means it is necessary to irrigate that much, so that the water reached this exact depth. More irrigation would mean a waste of water, because roots will not be able to reach the greater depth and use the water from there.
Towards the end of August however, roots use water from 40 cm depth, because plants have already developed. That is why in August you would need to irrigate more, so that the water goes down to 40 cm in the soil.
This way you see exactly how much to irrigate at any given moment.
If, for any reason, the installation of soil moisture sensors in unpracticable in your case, your Meteobot® can be equipped with a solar irradiance sensor. By taking into account solar irradiance data, as well as temperature, air humidity and wind, Meteobot® calculates how much water is evaporated from the soil and transpired by the plants every day (so called “evapotranspiration”). When you know the water losses from the soil for a certain period, you can find out how much you need to irrigate (e.g. 5 days x 4 liters evapotranspiration per day = need for 20 liters of irrigation).