Cambridge, UK-based Delta-T Devices has been at the forefront of measurement technology for environmental science since 1971.
The company’s instruments are routinely used in leading climate change, food security and irrigation research. New AG International Editor-in-Chief, Luke Hutson asks the questions to Dr. John Newstead, director, soil and environmental scientist and technical sales engineer with Delta-T Devices.
Delta-T is a high-tech co-operative and was founded in 1971 by Cambridge University graduate Edmund Potter. By 1973 we were collaborating with one of the UK’s leading plant science professors, John L. Monteith, to create the world’s first automatic leaf porometer. The success of this product led to development of a comprehensive range of plant and soil science instruments over subsequent decades. Edmund still works at Delta-T Devices (in the same Burwell, Cambridge HQ) 50 years later!
As you can imagine, 50 years of research and development of precision instruments endows you with a lot of invaluable information about what works and what doesn’t. This means that each new sensor we release can be refined in terms of accuracy and durability. Our measurement sensor expertise falls into five categories: soil moisture, plant canopy, stomatal conductance, weather and solar radiation.
Talk us through your key areas of expertise and how this relates to your products.
You produce sensors for scientists, growers, and sports turf specialists. What are the different requirements for these different sectors
To be honest, the fundamental requirements across the markets you mention are actually very similar. All sectors simply require a sensor that they can trust – in terms of build quality and data quality. A soil science research team may require a slightly higher level of accuracy than a grower who wants to set up an effective smart irrigation system. But we’ve found that the key focus (across all customers) remains reliability – and a consistent level of data accuracy which is appropriate to their application goals.
What are the major recent technology advances that have enabled you and other technology companies to develop improved sensors?
In terms of soil moisture sensors, probably the most important recent tech development is the availability of high performance low cost/low power microprocessors. These are capable of processing huge arrays of data – making it possible to incorporate an SDI-12 interface – and to achieve unprecedented sensor accuracy over a very wide range of conductivities and water content levels.
Digital communications protocols like SDI-12 have also had a strong impact over the last couple of decades – meaning that sensor networks no longer require each sensor to be individually connected directly to a master device (such as an irrigation controller) via its own separate cable. Instead they can be “daisy-chained” via a single cable to just one input on a master device, dramatically reducing cabling complexity and volume. The ability to remotely view live polytunnel data on mobile devices has also been a hugely important breakthrough. It means farm managers can see the exact state of growing conditions (and environmental conditions) at any given moment, regardless of their location and, if required, make fast adjustments.
Your new WET150 sensor is designed specifically for integration into smart irrigation systems. What differentiates the WET150 from other similar sensors.
Unlike many standard soil moisture sensors, the WET150 simultaneously measures two crucial additional variables. These are temperature and electrical conductivity (EC). EC readings are a strong indicator of the general nutrient level in soil and substrates. A particular strength of the WET150 is its ability to reliably calculate pore water conductivity (ECp), which is the ion content of the water available to the plant. Another key WET150 feature is SDI-12 compatibility, allowing it to be easily installed into virtually any SDI-12 based irrigation system.
The technical innovations that went into developing the WET150 are numerous. To achieve our goals we collaborated with the UK’s prestigious National Physical Laboratory (NPL) on several key aspects of the sensor design – most notably on the creation of new dielectric fluids with permittivity and conductivity properties that are representative of those typically found in soils and soil-free growing media. This work enabled us to test and refine the performance of the sensor until we reached an impressive level of accuracy.
Perhaps the most unique feature of the WET150 though is the impressive price-performance ratio it provides. The overriding goal for this sensor was to produce a high-quality digital multi-parameter sensor at a price level that encourages increased adoption of smart irrigation system technology, with all
the sustainability, yield and profit increase benefits technology can bring. Our confidence in the sensor is reflected by the fact it comes with a five-year warranty – quite unusual for a product of this type.
Your end-users would be greenhouse producers presumably, but are you seeing more interest for open-field applications?
The majority of our horticultural soil sensor customers are indeed greenhouse growers, especially in the soft fruit and medical marijuana sectors. However, the rugged watertight design of the WET150 means that it is ideal for outdoor use where it can be left buried for very long periods of time, with no loss of performance. So, we believe that open field users will continue to increase once they discover what our sensor is capable of.
How do you view the future of smart irrigation technology, and what do you see as the barriers to increased adoption?
We regularly speak to growers at industry events around the world and there is a consensus that increased use of smart irrigation is needed to meet the challenge of sustainably providing food to a fast-growing global population. In terms of barriers to adoption, we think trust and cost are the two key issues. Thankfully, both of these areas are benefitting greatly from important technology advances and the quality of sensors is generally improving, whilst at the same time prices are moving downwards. We feel that gradually the horticulture sector will clearly see the costs involved in installing precision irrigation systems are far outweighed by the benefits in terms of improved produce quality and yields, reduced water and fertilizer wastage, and last, but definitely not least, increased profits.
There are undoubtably huge opportunities in the agritech sector. It’s clear growers are becoming increasingly sophisticated and are keen to adopt new technologies to improve their operations and produce. With the right technology at the right price, I’m sure we’ll continue to see very positive enhancements to the way food is grown●
Before we get into the 'tech', can you tell us a little about Delta-T and the history of the company? Why, for example, is it based in Cambridge, UK?
