Machinery & Technology: Pen and paper tactics to highlight map perks

Charley White, from Precision Decisions, performs test on soil in a farmer's field.           Picture: Gary Longbottom
Charley White, from Precision Decisions, performs test on soil in a farmer's field. Picture: Gary Longbottom
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GROWING A less yielding crop in one part of a field than another is something that many farmers have blithely accepted over the years as an uncontrollable aspect of their lives.

“Our soil varies not just from acre to acre but from yard to yard”, has been a commonly held view, but technology and methods associated under the umbrella of precision farming can now dispel the traditional image that certain areas of land will always underperform.

There are many hi-tech systems and products that allow for greater accuracy and efficiency with N Sensors, autosteer and controlled traffic farming now part of the arable farmer’s armoury but precision farming isn’t all about being hi-tech.

Charley White heads up the soil sampling division of Precision Decisions based in Shipton-by-Beningbrough and tells of how those who haven’t yet embraced precision farming will be surprised by what can be done.

“There’s a stigma around precision farming that means the mere mention of it can be very intimidating. Often we’re not showing farmers anything they don’t know. We’re just giving them information in a digital form that means they can make more informed decisions.

“I don’t believe that all precision farming needs to be hi-tech. When I took a digital yield map to a father-son operation they couldn’t see what it meant until I gave them a blank map of their fields and a set of highlighter pens and got them to show me the bits that always do well and those that didn’t. When they’d finished we set it alongside the digital mapping I’d brought and they could see how it married up.”

Soil sampling is a little more hi-tech than highlighter pens and paper but this provides one of the links to increased future production in traditionally weaker producing areas of a field that may have been taken for granted would never perform well.

“We carry out soil sampling using a buggy that is guided by GPS. Pressing a button in the cab simultaneously records the GPS location in the field and sends a message to the sampler to send the probes down into the soil. One soil sample is made up of 16 probes across a circle that has a 2.5-metre diameter and the probes collect the top 15cms of the soil. If it is grassland then the sample is a little shallower. Once the probes are retracted from the soil a barcoded reference label is automatically printed on the sample. This process carries on at intervals throughout the field allowing us to build up a conclusive picture that through the differing colours on the map determines the nutrient levels in the soil. The more frequently you sample, the more accurate the picture becomes.

“The farmer then has a template to work from in analysing the levels currently in the soil and what needs to be added to make it better yielding in the future. We then look at past yield maps to see how last year’s crop performed so that we can start creating ‘variable rate fertiliser recommendations’.

“Many farms have now been using yield mapping for years but perhaps then not acting on the areas that could be improved. This is where soil sampling can help.

“I get hold of previous years’ yield maps and put them into software we use called Gatekeeper. I clean up their maps because often there are fuzzy areas around the edges of the fields. These are where the combine header is lifting and yet people don’t take it out of their yield maps. It drives me nuts. So once I’ve cleaned up the mapping I can show a year-on-year performance and this married to the soil sampling can show quite clearly why one part of your field is only performing at perhaps 85 per cent of the field average. That’s when we can start working out what is happening and try to fix it.

“If we know there’s a limited part of a field we also then know to limit inputs rather than trying to push unnecessarily, but that’s where historic information also comes in.

“We had one field recently that was consistently yielding poorly towards its bottom end. It showed no significant change in soil type through our sampling except for a little soil deficiency but that wasn’t enough to explain it’s continued under performance. When we looked at old yield maps we saw a clear line where values changed across the field and it was only when we saw a more historic map that we saw the real reason. It had once been woodland. That’s what I mean about using hi-tech married with historic information.”

Precision Decisions, run by Clive Blacker, works with 4,000 farmers across the UK.