Automating Irrigation on an Indian Farm: A Practical Guide

Most irrigation automation tutorials water a single pot plant on a balcony. A farm is a different problem: the pump is hundreds of metres from the house, the Wi-Fi does not reach, power cuts are routine, and a pump that runs dry for an hour costs real money.

This guide covers what changes when you automate irrigation in the field.

What an irrigation controller actually does

Every system, simple or advanced, does three jobs:

1. Measures soil moisture, and sometimes tank level, flow or weather.
2. Decides when to water and for how long.
3. Switches the pump or valves through relays or contactors.

The difference between a hobby project and a field controller is how reliably it does those three things in heat, dust, monsoon rain and with patchy power.

Choosing soil moisture sensors

There are two common types:

Placement matters as much as the sensor:

• Bury the probe at root depth for the crop, not just under the surface.
• In drip irrigation, place it near a dripper, where the roots actually take water.
• Use more than one sensor across a field. Soil varies, and one probe can mislead.

Stopping the pump from cycling

A naive controller switches the pump on when moisture drops below a threshold and off again the moment it rises above it. Right at the threshold, the reading flickers, and the pump starts and stops every few seconds. That burns out motor starters and contactors quickly.

The fix is two thresholds (called hysteresis):

• Start watering when moisture falls below the lower level.
• Keep watering until it reaches the upper level, then stop.

Add a minimum run time and a minimum rest time as well. Good controllers also have a maximum run time, so a failed sensor or a dry well cannot run the pump all day.

Protecting the pump

• Dry-run protection: a float switch or flow sensor tells the controller when there is no water, so the pump stops before it is damaged.
• Voltage monitoring: low or unbalanced voltage on rural three-phase lines damages motors. A controller that watches supply voltage can refuse to start the pump when the supply is bad.
• Use contactors for motor loads. A small relay module on its own is not rated to switch a pump motor directly.

Connectivity: 4G, Wi-Fi or LoRa

For most farms, the pump house is the point that needs to be online, and 4G is the simplest way to get it there. If you need sensors spread over many acres, LoRa sensors reporting to a 4G gateway combine the two. We cover this in detail in choosing connectivity for a field device.

Watering schedule tips

• Water in the early morning or evening. In Indian summers, midday watering loses much of the water to evaporation.
• Combine sensor readings with a schedule, not instead of one. The schedule sets when watering is allowed; the sensor decides whether it is needed.
• Log everything. A record of moisture, pump run time and supply voltage tells you far more about your field than any single reading.

Power cuts

A field controller must handle power cuts gracefully: remember its settings, come back in a safe state (pump off) and report the outage. Battery backup for the controller and modem keeps you informed even while the pump cannot run.

Our controller

The KaspersLab™ Agriculture and Field Automation Controller is built for exactly this: an ESP32 controller with 4G LTE, relay outputs for pump and valve control, irrigation automation and a real-time monitoring dashboard you can check from your phone.

For a system designed around your own farm (number of zones, pump type, sensors), talk to our engineers.