Chameleon Card System by VIA

The Virtual Irrigation Academy

About this app

The Chameleon Card System has to be the simplest way to measure soil water. Touch the two sensor wires on the card and the LED lights up.

Chameleon soil moisture sensors provide a simple, accurate measurement of soil moisture for farmers and home gardeners alike. This App allows users to collect, store and visualise the readings from their Chameleon sensors and map that as a pattern against the respective crop, field or garden over a period of time. By comparing patterns and their associated yields, it is possible to explore ways to save more water and get higher yields. Learning helps us to test our assumptions about when to water and strive for continual improvement.

This App is designed to be used with the Chameleon Card system. To purchase the system please visit https://shop.via.farm/

The sensors use colour to indicate how thirsty a plant is, allowing the user to apply water more effectively. Blue = wet soil, Green = moist soil, Red = dry soil and Pink indicates the presence of salt. Precise application of water helps to reduce plant stress, improving growth, yields and reducing fertiliser runoff. Irrigating when the sensor is blue wastes water and leaches nutrients. There are some exceptions, such as plants in pots with restricted rootzones may need to be kept blue, as well as leafy vegetables on hot days.

The majority of the horticultural crops should be watered in the green zone. Be aware that the green zone does not last for long! A soil may have been blue for many days and then move from blue to red in just a day or two of hot weather. Most horticultural crops will lose yield in the red zone. This is particularly the case for leafy crops or if the red colour coincides with flowering and fruit set of other crops.

Responding to the colours does depend on how deep the roots are compared to where the sensor is located. A fruit tree with a red sensor at 20 cm depth will likely be happy enough if there is water below. If a high salt level is detected, then the colours need to be interpreted differently. Due to the presence of excess salt, the plant is under more stress in the green than normal. Irrigation may be necessary in the blue zone and definitely in the green zone.

Different crops have different sensitivity to water stress, and the irrigator must decide the optimal colour patterns. This requires some experimentation.

When the rootzone is completely wet the array will read blue at all depths.
As roots start to extract water, they will turn the shallowest Green.
As roots continue to grow into the rootzone they will turn each layer to green, then to red.
If there is no irrigation the rootzone will go all red.

The best combination depends on the type of crop and how frequently you have access to water.

Irrigating when all layers are blue is a waste of water, time, energy and fertiliser. Waiting until they all turn red will likely cause yield loss. There are 25 other combinations of blue, green and red.

The Chameleon sensors have been created by The VIrtual Irrigation Academy Ltd, a registered charity.