Boosting Accuracy and Detail of Soil Analysis – Precise – Oliver Wood

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Terra Map - Soil OptixAgronomy firm Hutchinsons claims the technology at the centre of its new soil scanning system offers a greater level of precision than is possible with established techniques.

When compared with traditional zone-based scanning or grid-based sample point systems, measurement of a wider range of soil quality properties and greater accuracy when measuring them are the key claims for new soil analysis technology introduced this season to the UK by agronomy company Hutchinsons.

Canadian Tech

The technology behind the firm's new TerraMap soil analysis system was first adopted for agricultural use in Canada almost a decade ago, and has since been introduced to a number of countries. For the 2019-20 cropping year, UK farmers will be the first in Europe to be able to benefit from its ability to gauge the levels of up to 21 different soil constituents and qualities.

“One of the key issues with electro-magnetic induction (EMI) scanning is repeatability, because its ability to consistently produce accurate results is affected to a great extent by the level of soil moisture,” explains Oliver Wood, precision technology manager for Hutchinsons.

“On the other hand, the weakness of the grid sampling alternative is that, by its nature, it doesn't provide as much data as there are fewer sampling points – usually one per hectare.

“TerraMap sensing technology is based on a scaled-down version of airborne sensors that have been used for many years in mineral prospecting. The system uses a gamma ray spectrometer manufactured by Canadian firm SoilOptix. This contains a sodium-iodine crystal which flashes when hit by radionuclides emitted by the natural gamma radiation that radiates from soil. These flashes are then measured by a photo multiplier tube, which provides the data from which a variety of soil constituents can be measured.

Radiation Measured

“The radiation measured is that from the best naturally-emitted isotopes for this purpose - caesium-137, uranium-238, potassium-40 and thorium-232 – which are very stable due to their long half-lives. Unlike EC scanning, this method of measurement and its accuracy are not affected by soil moisture, compaction, crop cover or cultivation state, meaning there are very few conditions in which TerraMap cannot be used, the only one really being post heavy rainfall, when emitted radiation is not as strong. As a result, this technology has a much wider operating window compared to other soil scanning systems.”

The system delivers a sampling resolution of over 800 points/ha, which the developer says is the highest resolution system currently available. By measuring those various isotopes, it is capable of providing high definition mapping of all common nutrient properties, plus pH, soil texture, organic matter and cation exchange capacity – which governs the soil's ability to retain nutrients – as well as elevation and plant-available water. The individual map layers for all of these can be overlaid for contrast and comparison.

Portable Data

Terramap-display1While TerraMap users do not have to also be users of Hutchinsons' Omnia precision farming software, and the industry-standard file types in which the data is recorded mean it is exportable to other platforms, the connection will help exploit the data to best effect, says Mr Wood. The results from TerraMap can be used to create maps within Omnia, which can then be overlaid with additional field information – yield mapping or blackgrass populations, for example – to create accurate, consistent and detailed variable rate plans, he suggests, which can help counter problem variability such as different soil types and related seedbed conditions, plus weed pressure and slug pressure in particular areas.

Consistency and reliability of the results are among the key attributes of TerraMap, claims Mr Wood.

“We have taken satellite imagery of fields that showed up areas of soil differences quite clearly and when we overlaid this with the texture maps created by TerraMap they were identical. This has been confirmed by in-field ground truthing across a number of sites.

“We've also tested the results between seasons and over different cultivations, and they have remained consistent.”

What's on Offer?

Oliver Wood with TerraMapTerraMap is available from Hutchinsons in a standard or premium service offering. The standard service measures nine criteria, comprising phosphate, potash, magnesium, pH, percentage of clay, sand and silt, texture and elevation. In addition to these, the premium service also measures calcium, manganese, boron, copper, molybdenum, iron, zinc, sulphur, organic matter, cation exchange capacity and plant available water, delivering 21 layers of data for each field.

“Trace element indication backed up with tissue testing is useful generally, but particularly in lighter soils and drier years. Organic matter measurement provides a good barometer of soil health, can allow targeted applications where required, and can be a good indicator of soil moisture capacity.

"Plant available water index, combining clay, silt and organic matter layers, is possibly one of the most exciting system assessments, with significant scope for management and manipulation, and possible implications for variable rate seed patterns. We see use of TerraMap as part of the route to square metre farming that's coming with things like individual nozzle operation. There is also potential for the system in field management of forage crops and of grassland, and we are continuing to investigate both areas."

The scanning service is fast, and has negligible land impact, suggests Alan Christie, of Agri-Tech, the firm to which Hutchinsons has contracted the actual process of getting fields scanned.

“In the field, data collection is carried out in two simple steps. Firstly, the field is scanned at 10-12m widths by driving over it with a lightweight all-terrain vehicle. Soil samples are then taken, at a rate of one per three to four hectares. This allows for each scan to be used to create the most accurate picture possible.

“There is no need for calibration of the system in the field or even between different fields," he says.

“One of the simplest advantages here is that the process is far swifter than alternative systems, meaning that fields and farms can be covered far faster, but with no effect on accuracy. If you're going to have your farm scanned, it makes sense to do it once and do it well.”

Pricing Structure

Hutchinsons says pricing of the system using the TerraMap service has now been determined. As a guide, the cost for the standard service is likely to be £24/ha, while for the premium version the figure rises to £32/ha.

While this is new sensing technology to the UK, its ability to produce robust data quality and repeatable data capture has been proven in a number of other countries, says Mr Wood.

The launch of TerraMap reflects the continued investment and subsequent development of tools offered within the Omnia Precision Agronomy system, says Hutchinsons. Since its launch in 2016, developments within Omnia have included drone imagery mapping, the Connect app, and mapping for cost of production and yields. Omnia now has over 620 UK users covering 375,000 hectares.

“We have been looking for a new method of mapping soils that provides more accurate and repeatable results, and can also leverage the multi-layer analysis within Omnia," says Mr Wood.

“With interest in soil health and management becoming a greater focus of farmers, TerraMap's launch is aimed at meeting the needs of those looking for that next level of accuracy in understanding their soils.”