Veris Soil EC Maps Soil Variability

At just six feet wide, the Veris doesn’t look like much of a mighty machine, but don’t be fooled. This implement, when fitted with sensors and a GPS receiver, is a powerful field-mapping tool. Don’t fret if you’ve never seen one — it’s likely because there are only three in the Prairie Provinces.

Terry Aberhart, who farms at Langenburg, Sask., and is an agricoach with Agri-Trend Agrology, bought the Veris in 2009, and the tool is quickly gaining popularity with the precision farming crowd. Readings are affected by soil texture, drainage, compaction, organic matter and other factors, he says, adding that it maps only variability not soil texture. “This is where some people get confused,” he says. “It is our job (at Agri-Trend) to help the client understand and interpret what the data means.”

“The Veris gives a relative reading between areas of a field. A high number may correspond to a saline area on my field but a peat area on someone else’s field. The important thing to remember is that (the Veris) is measuring a relative difference between areas of a particular field on a given day, not soil texture,” Aberhart says. It means that once mapping is complete someone still has to get out there and “ground-truth” just what the ratings mean in each field.

Aberhart says they run the Veris in the middle of 50-foot swaths to create maps. “Others go in 60-or 80-foot swaths but the closer you run the machine, the more accurate the overall map,” he says. The software must extrapolate the readings between the actual data points — the closer the data points, the more accurate the final map.

The five or six layers of data the Veris provides is then interpreted by Agri-Trends geo-coaches to create multi-layered maps for determing field management zones for variable-rate applications. But Aberhart says the utility of the Veris goes far beyond that. “The main use is for VRT, yes, but we’re using it for ditching and water management, as well as for more accurate soil testing,” he says.

A SOIL TESTING GUIDE

Aberhart says the maps generated by the Veris have proven invaluable for more accurate soil testing and when creating precision- management zones and rates. “We’ve found that the soil variability map generated corresponds very accurately with yield potential, more than in-season imagery in most cases,” he says.

For example, in-season imagery might rate two areas of the field as “poor” based on biomass or crop colour (whether an NDVI rating or satellite/aerial imagery). Without digging down into the soil and finding out why, you may treat those two areas as one management zone. But what Aberhart has found since using the Veris is that two areas that show up as poor with imagery have very different readings with the Veris.

“One area may be saline and the other sandy,” he says. “How you manage those two soil types is very different. If treated the same, you may be leaving yield on the table or making a bad situation worse.” For example, Aberhart says low spots or saline areas aren’t going to produce much, however a sandy area may still hold some production potential. “We might up the seeding rate but dial back the nitrogen and up the S in saline areas, but we might choose slow release N, dial down the seeding rate and look to add manure later on on sandy areas.” The eventual yield potential of each of these areas could have been jeopardized if treated as the same zone, he says.

What’s more, when using in-season imagery to delineate manage- ment zones, you may render soil tests useless. How? In following the above example, if you were to collect samples from all of the “poor” management zones based on the imagery, where part was saline and part was sandy, then mix them together, what would that soil test tell you? Nothing all that useful.

That’s not to say in-season imagery doesn’t have its place, Aberhart says. It’s a very useful tool for variable rate fungicide or in-crop N applications, he says. Soil testing zones, however, are best mapped out using the Veris, in his opinion.

ELEVATION MAPPING

In this, a very wet year for parts of the Prairies, the Veris may pique the interest of those looking to tackle drainage issues as well. “We’re using an RTK signal for sub-inch accuracy, so between the soil reading and the GPS signal we can generate elevation maps as well,” Aberhart says. Poor drainage is the number one limiting factor on Aberhart’s farm, as it likely is for many. Even in more average years, Aberhart knows he could conserve substantially more yield if he could keep water from sitting in low spots.

Drainage is a big picture issue on Aberhart’s farm. The Veris has added another layer of data to work with when decided where to place drainage and where all that

water is going to go. It’s a work in progress, of course, and this year beyond tiles there’s likely nothing that would have helped.

Mapping with the Veris is more costly than in-season imagery, however Aberhart says it’s a one-in- 15 to one-in-20 year event. “Unless you significantly alter your soil, there’s no reason to head out there and do this again,” he says. As part of Agri-Trend, Aberhart says a farmer can hire them to run the Veris on their fields and provide a full package of data, maps and advice based on those maps for about $10 to $12 per acre. “It’s a complete service that includes consulting to make sense of the maps, and, again, not something you’d do every year or even every five years,” he says. Farmers also own the data, once mapping is complete, he says.

To date, Aberhart’s Veris has covered over 10,000 acres and he only sees that number climbing steadily. “It’s not a perfect scenario, but in general terms, the Veris adds a level of confidence and consistency to field mapping that makes splitting fields into management zones that much more precise,” he says.

For more information on the Veris visit www.veristech.com.

LyndseySmithiseditorofGrainews.Contact

herat [email protected]

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The Veris adds a level of confidence and consistency to field mapping that makes splitting fields into management zones that much more precise

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