Definition
Precision Irrigation (Precision Irrigation, irrigation on demand) is an intelligent irrigation method based on soil moisture conditions, meteorological data, and crop water requirements. By monitoring soil moisture, evaporation, and rainfall in real-time through soil moisture sensors and weather stations, and combining this with crop growth stages and root depth, it precisely controls the amount of water, irrigation timing, and irrigation areas according to crop water needs, avoiding over-irrigation and water stress, achieving 20%–50% water savings, and increasing yield and efficiency.
Precision irrigation supports various irrigation methods such as drip irrigation, sprinkler irrigation, and micro-sprinkler irrigation, and can achieve precise fertilization when combined with water-fertilizer integration. Crop water requirements (ETc) are calculated using methods such as FAO Penman-Monteith.
Technical Features
The precision irrigation system consists of soil sensors, weather stations, irrigation controllers, solenoid valves, and cloud platforms. The irrigation controller receives irrigation plans or real-time commands issued by the cloud platform through IoT SIM cards and controls the opening and closing of solenoid valves. It supports multiple control modes such as scheduled, threshold-triggered, and remote manual control. NB-IoT and 4G are suitable for large fields and remote farms.
Use Cases
Precision irrigation is widely applied in large-scale farming, greenhouse agriculture, orchards, tea gardens, lawns, and landscaping. Devices such as irrigation controllers and solenoid valves receive instructions from the cloud platform via IoT SIM cards. SimtoLink provides stable network connectivity and dedicated APN for the precision irrigation system, ensuring timely delivery and execution of irrigation commands.
How fresh the moisture reading must be before a valve opens
In precision irrigation the IoT SIM carries whether a particular valve should open now. The decision uses soil moisture that has not expired, field weather, and the crop's current stage. It is not a remote button. If moisture has not updated within the agreed time, it must not trigger an automatic open. The surface may already be dry, or rain may just have fallen, and the old value no longer describes water around the roots. The probe must be buried at the depth that crop actually draws from. If a field has only one point, that point's command must not be sent to another field with different soil. Rain at the weather station should be able to stop the following irrigation plan, and rainfall and valve control must refer to the same plot. When field weather arrives late, the plan should become pending confirmation, not keep watering as before.
A command must name the valve, a target duration or a target volume, and an expiry time. An open command that arrives after expiry must be discarded. The controller runs locally. Cellular only carries the plan and the receipt. If the link drops and the controller already has today's plan, it may run that plan, but it must keep the actual open and close times. With no local plan, the default is to stay closed, not to repeat the last watering. Drip, sprinkler, and micro-spray have different flow rates. The same duration must not be converted into the same volume for all of them.
No valve receipt, yet recorded as irrigated
It is easy, after the platform sends an open, to treat a successful send as a finished irrigation. The solenoid never opened, the pipe has no pressure, the receipt never came back, and the soil is still marked as watered today. The next decision skips this field. A receipt must include a valve-position change or a flow-meter increment. With only a communication acknowledgement and no volume, the state should stay at "sent, not confirmed." Another mistake is a probe buried too shallow. The surface dries in the afternoon and the valve opens often, while the root zone is still wet. The record shows a lot of water, and the crop still looks short of water, or the field is standing in water.
When several valves share one SIM, a receipt that only says "controller executed" and does not name the valve books the neighboring plot by mistake. Clock error records a night irrigation as daytime, which no longer matches evaporation. For acceptance, pick one valve. Send a command from expired moisture: the controller should refuse. Send a normal command and disconnect the valve feedback: the platform must not mark it irrigated. Inject one short rainfall message: the following automatic plan should pause and keep the reason. All three results must be distinguishable in the record. They must not all show success.
Expired moisture must refuse to open the valve
When moisture has not updated within the agreed time, an automatic open should be refused and the plan marked pending confirmation. After a message that rain just fell, later automatic plans pause and record the reason. They must not keep watering. An open command that arrives after its own expiry is discarded. A receipt with no valve position and no flow increment stays at sent, not confirmed. The platform must not mark that field as irrigated today. A probe buried too shallow triggers often in the afternoon. Check the burial depth before changing the threshold.
When several valves share a controller, the receipt must name the valve, or neighboring plots are booked against each other. Drip and sprinkler must not share one duration-to-volume conversion. If the link drops and there is no local plan, stay closed. A plan already received for today may run, but the actual open and close times must be kept. Expired moisture refused, no receipt not counted as irrigated, and a plan paused after rain: when those three appear separately, the execution record for precision irrigation can be trusted.