The AgriSmartGreen (ASG) irrigation control system includes IoT measuring stations that can operate in both GSM and LoRaWAN networks, depending on local communication conditions and possibilities. The measuring stations use sensors to measure soil and optionally weather parameters, and the measured data can be used to make manual or automatic decisions on the need for irrigation and its control. In the manual case the user starts and stops the irrigation, in the automatic case the irrigation control module controls the irrigation water dosage. The parts of the measuring system, its construction and the sensors used are described below.
Irrigation monitoring stations are installed in the irrigated area of the crop. The height and placement sequence should be adapted to the cultivation work (Figure a) to avoid the measuring station with the cultivators.
Irrigation monitoring stations are installed in the irrigated area of the crop. The height and placement sequence should be adapted to the cultivation work to avoid the measuring station with the cultivators.
The system consists of one or more irrigation monitoring stations per irrigated area, which measure the current values of precipitation, soil moisture, soil tension and soil temperature by continuous sampling. In addition, the parameters to be measured can be extended with additional sensors to meet the needs of producers.
The cloud-based application and database stores measurements and decoded data as a function of real time. In hindsight, the water dynamics of the root zone can be visualized and the most optimal water discharge program can be planned taking into account the forecasted weather conditions.
An embodiment of an irrigation monitoring station with an embodiment of a minimum set of sensors is shown in Fig. b. shown in Figure.
Partitions (identification markings in figure b):
❶Extrusion sensor, Precipitation gauge
❷Data logger and 4G radio GSM transmitter
❸Cable junction box
Sensors:
❹1 Teros 21v2 soil tension sensor
(onions: planted at 15-20cm depth)
❹2 SMT100 volumetric soil sensors
(onions: planted at 10cm and 20-30cm depth)
The patent application for the elements and operation of the system is based on the “ASH09 Model Specification” and the “ASH10 1sz. annexes, figures”. Other designs of plant and site-specific measuring station variants are also studied in the publication.
The functional sub-assemblies of the system variants are illustrated in the diagrams in the annex to the model publication.
Illustrative diagrams in Annex 1:
- Figure 1 shows a generalised set-up for pilot stations with a minimum set of sensors,
- Figure 1. Figure 4.1: Schematic of a version with optional environmental sensors for more detailed data collection needs, and
- Figure 3: Wiring diagram of a 5-sensor arrangement for deeper root zone crops such as maize.
How the ASG irrigation control system is built
The elements of the system are: the measuring stations, which measure the water status of the root zone and rainfall with sensors in the soil, and in some cases also the amount of water applied. Separately controlled areas, irrigated by separate machines, typically have a separate metering station.
The water source metering station, which measures the flow of pumped water, i.e. water consumption and water pressure, can be used to determine exactly how much water has been used for irrigation in a given area. If an automatic control irrigation system is installed, a remote zone control station manages the ON/OFF switching of the individual water supply (usually with electric valves) for each zone.
The pilot control systems are designed to monitor the irrigation of a given crop with a given irrigation machine and, based on this, to control manual irrigation, where multicropping may occur within the year.
The homogeneity of the soil in the area irrigated by the same irrigation machine is an advantage for precise irrigation control. If the soil of the treated area is inhomogeneous, it is possible to install several measuring stations in the same irrigation zone in plots with different soil types. By monitoring the water management factors of the soil in a given area with each monitor, you are free to influence irrigation according to the water management feedback of any soil type. But only one soil type can control the optimal irrigation dose at a time.
Precision irrigation metering station components, sensors
Ydoc ML-417ADS data logger and 4G transmitter
Solar panel and 6600 mAh built-in battery
SDI12 sensor interface
3x digital, pulse input
5x analogue input
sampling 1min – 24 hours
optional GPS receiver module
SIM card, GSM data transmission
MIS-RG1 Precipitation meter
0.28 mm resolution
Passive pulse transmitter type
The rain gauge serves a dual purpose in the system,
1: for sprinkler irrigation systems (micro-spray, linear, recirculation, irrigation drum), the water applied by the irrigation system is measured to check the water coverage parameter of the irrigation system and
2: measures the amount of natural precipitation. In the case of drip irrigation, only the rainfall is measured.
SMT100 TDT principle soil moisture sensor
Device available on SDI12 communication line
Three parameters are transmitted to the data logger:
Volumetric soil moisture (%),
Soil temperature (°C),
Pole voltage (V)
STM100 TDT sensors are installed at different depths to measure the water content and saturation of the soil layer.
Based on these measurements, we can determine whether the water saturation of the root zone has reached the irrigation cut-off point or not, so we can decide when to stop irrigation based on the measured data.
Meter Teros21v2 tensiometer
Device available on SDI12 communication line
Two parameters are transmitted to the data collector:
Matrix tensiometry value (5 …..-10.000 kPa)
Soil temperature (°C)
The tensiometer measures the force that the root needs to exert in a given soil and water condition in order for the plant to take up enough water from the soil matrix. As the water absorption capacity of plants differs, we can determine from the measured value whether a given plant can still absorb water without stress or whether the soil is too dry for it. At this point, the stock already requires irrigation to be started.
Optional additional sensor kit for irrigation metering stations
Acclima TDR 310, 315 soil moisture sensors
Device available on SDI12 communication line
Four parameters are transmitted to the data collector:
Volumetric soil moisture (%),
Soil temperature (°C),
Bulk EC (µS/cm)
Pore EC (µS/cm)
This soil moisture meter can be used instead of the SMT100, and its biggest advantage is that it also measures conductivity (EC) in the soil, providing fertilizer application data to aid in dose and application rate detection.
ATMOS14 TRH Air sensor
Device available on SDI12 communication line
Four parameters are transmitted to the data collector:
Air temperature (°C)
Air relative humidity (%)
Air pressure (kPa)
Vapour pressure from which the dew point can be calculated (kPa)
With this sensor, weather data can be sampled, and it can also be used for work management and crop protection purposes.
LWS01 leaf moisture sensor
Device available on SDI12 communication line
Two parameters are transmitted to the data collector:
Relative leaf humidity (0-100%)
Sensor internal temperature (°C)
Leaf wetness is mainly used as an input parameter for crop forecasting models.
Depending on user requirements, additional sensors can be installed on the measuring stations.
Publication ID:
Author:
Dr. Csaba Tóth
Tóth Tóth, electrical engineer, precision farming engineer
T-Markt Kereskedőház Kft.
2013 Pomáz Határ u 5/A
0626-525-500
www.agrismartgreen.com
