Australian soil water sensor popular among smallholder farmers

According to the Virtual Irrigation Academy – a charity started by CSIRO – 4,065 farmers and farmer groups are using Chameleon soil sensors. A total of 74,947 Chameleon sensors have been distributed to farmers in 23 countries.

Over time, the Chameleon has been refined. The starter kit of the latest version of the system includes three soil sensors and a Chameleon Card, lighting up to display whether the soil is wet, dry or moist. The system is now also available for farmers in Australia.

CSIRO has developed the Chameleon soil water sensor system in a project funded by the Australian Centre for International Agricultural Research (ACIAR). The Chameleon soil water system has been designed to be inexpensively manufactured, simple to install, and easy to understand.

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Informed management decisions

The Chameleon Soil Water Sensor mimics the way a plant experiences the amount of water in the soil by measuring how hard the roots have to suck (the tension required) to extract moisture. It is designed to be accurate in the range that most plants are sensitive to water stress. Because the Chameleon Sensor measures tension, it does not need to be calibrated to different soil types.

The Chameleon Card shows farmers a blue light when there is too much soil moisture. No irrigation will be required for some time, in that case. When there is too little soil moisture, a red light is visible, and irrigation is required. When there is an adequate level of moisture, the system shows a green light – farmers do not need to irrigate and should monitor the situation at different soil depths.

Farmers have seen large increases in their crop yields, as well as reductions in water usage

An additional suite of tools is also available to measure salt and nitrate levels. Combined, CSIRO says, the Chameleon soil water sensor system helps farmers make informed management decisions.

Agriculturally, many regions of Asia and Sub‐Saharan Africa can be defined by their poor access to water to grow crops, CSIRO points out, which makes efficient use of precious irrigated water a significant priority for enabling food security.

A number of benefits

Without economic access to advanced soil water probes, farmers in these regions are prone to over‐watering – often incorrectly seen as a way of ensuring a successful crop. This reduces the overall amount of water available for other farmers.

It also counterproductively reduces the yield of the crop. This occurs by washing away nutrients in the soil, saturating the plant’s root system and often resulting in root diseases such as rot and mould. Furthermore, manually irrigating by hand in many of these countries is also time consuming.

CSIRO says that – as a result of its research – many of the world’s most vulnerable smallholder farmers are already seeing a number of benefits for their farming operations. Through improved water use efficiency and the reduction of diseases previously promoted by over‐watering, farmers have seen large increases in their crop yields, as well as reductions in water usage by as much as 30 per cent.

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Better understand farming practices

As part of the project, CSIRO has also established the Virtual Irrigation Academy, enabling farmers to access communal knowledge, and better understand their farming practices. Farms utilising Chameleon sensors have witnessed improved labour productivity, with labour previously used for watering duties diverted towards other beneficial tasks such as removing weeds that further compete with crops for soil moisture and nutrients.

According to researcher Dr Richard Stirzaker, who developed the Chameleon, the sensor was created to assist farmers in developing countries to conserve water and improve food security. “Millions of people irrigate to grow food but do not have simple and accurate information to guide them. The Chameleon uses coloured lights to tell you when to irrigate”, he says. “Farmers using Chameleon sensors quickly changed their practices, many using less water to achieve higher yields.”

Farmers have also been able to reinvest their increased profits into on‐farm improvements such as wells – driving further economic development, and futureproofing their farms for the benefit of their communities.