Irrigation Instincts vs. Insights: Making use of sensors to make the right irrigation decision!

Abhay Bharadwaj
Fasal Engineering
Published in
5 min readApr 20, 2020


The way water is used (or wasted) is as good a test as any to judge whether the farming practice is sustainable or not. We all know that water is a precious resource and reducing water wastage should be the utmost priority for all!

Alright, you may not be aware that you may be using excess of water for your irrigation, but have you ever considered how over-irrigating (or under-irrigating) your crops leads to lower quality and lower quantity harvest? Also, have you ever considered the number of resources and money (by way of water cost, electricity cost, etc.) you are wasting by irrigating based on your “Instincts” (Guesswork)?

If the answer is “no”, then you need to improve your irrigation practices by utilizing “insights” rather than “instincts” to get better yield and reduce wastage.

Soil may look dry on the top level, but you will never know how much water is still available at the root zone of the plant under the soil!

Optimal irrigation leads to better quality and a better quantity of crop yield. You can read more about it here:


The only way to reach “Optimal Irrigation” is by eliminating guesswork and using a “Data-Driven” approach. How can you achieve this? Well, that's where Fasal comes into the picture. Using Fasal device, you get numerous field-level parameters right in your palms 24x7x365. Below the soil parameters like soil water tension at multiple root zones is one such critical data point that we collect.

One of the best ways to measure a soil’s water content is by using the gravimetric measurement approach. But this is a time consuming and costly approach and cannot be done at regular intervals. Hence, a sensor-based approach is the most ideal way to measure soil moisture in real-time.

Types of Sensors to Measure the Moisture of Soil

There are primarily two types of sensors to measure soil moisture:

  1. Tensiometric
  2. Volumetric

Tensiometric sensors measure soil moisture tension or potential soil moisture. Water potential is a way to understand how tightly water is bound to soil surfaces. This tension determines whether or not water is available for uptake by roots and provides a range that tells whether or not water will be available for plant growth. Whereas volumetric sensors measure the actual volume of water in the soil.

There are various sensors available in each category. And generally, Volumetric based sensors cost considerably more when compared to the former. Also, getting to know the actual volume of water in the soil is useless if the plant is unable to absorb it! And hence, measuring how difficult it is for the plant to extract water from the soil becomes more relevant.

There are other types of sensors that are simple “resistive” or “capacitive” based that are really cheap. But they can never give any meaning full data and their operation life is less than a year.

Fasal Sense uses one of the most reliable and industry-accepted sensors called the Irrometer Watermark 200-ss.

Image: Irrometer Watermark 200SS sensor (courtesy:

These sensors perform soil moisture measurements based on the tensiometric method. The Watermark200ss sensor is based on the “Gypsum Block” also called an electrical resistance block. A porous block, typically made of gypsum, is placed in the soil while maintaining firm contact with it. The block contains two embedded electrodes into which wires are inserted. As water moves through the block to maintain equilibrium with the soil moisture, the electrodes measure the electrical resistance that the water generates. A suitable reader converts the resistance readings to water tension values. The reading we get from the sensor is correlated to the values between 0 and 200 KPa (or CB).

These sensors have a working life span of 5 to 10 years and do not require any calibration of maintenance once installed in the field.

Using these sensors, Fasal algorithms are able to see how much water is available exactly for the plants to absorb. You can view this data live on your mobile app and our AI systems give you Irrigation advisories (Light Irrigation, Normal Irrigation or Deep Irrigation) based on a combination of live moisture levels along with many other parameters like Evapotranspiration, VPD, RDI, and Micro-climatic conditions.

Image: Soilmoisture graphs (courtesy:
Image: Irrigation Advisory alerts (courtesy:

Case Study

A progressive farmer in Raipur was able to save thousands of rupees in one crop cycle by following Fasal's irrigation advisory. He was also able to get an overall increase in yield by 15% compared to his previous crop cycle. Using Fasal, he was able to get an ROI in just one crop cycle!

A grape farmer in Sangli was able to save around 8.5 Lacks liter of water and got an increase in yield of about half a metric tonne during harvest getting him higher profits from last season.

Mr. Bhupendra Parmara, C.G.

We have seen and heard many such similar success stories from our farmers who use Fasal’s services and most of them get an ROI in a single crop cycle itself. There are numerous farmers now who have been using Fasal across multiple agro-climatic zones, soil textures and crops, and all of them share the same results as with the farmers mentioned above.

Thus, by managing irrigation, you are able to get better quantity and better quality of crop yield thereby getting better income and also save cost on water and electricity which translates to overall higher profits from your farm. Grow more, grow better with Fasal.

Also read —



Abhay Bharadwaj
Fasal Engineering

Senior Embedded Engineer | Full Stack IoT Developer | Technology Trainer | Orator