The future of sampling
High-tech soil sampling is key to the future of precision agriculture.
September 27, 2019 by Madeleine Baerg
For decades, soil testing has required little more than a shovel, a bucket and a mailing address for a lab. That said, it can be challenging to find time for soil testing, it can be difficult to collect truly representative samples, and the composite nature of traditional soil testing – often a single sample represents 100 or more acres – means that results don’t always provide producers with enough certainty to influence major management decisions.
All of that is in the process of changing. Just like virtually every aspect of agriculture, soil testing is currently undergoing significant automation and technological innovation. In the very near future, expect to be doing a very different kind of soil testing.
A number of companies are currently working to automate sample collection beyond the already-common truck-mounted hydraulic probe. Among the simplest is the Falcon 5000 automated soil sampler, invented by North Carolina producer Allan Baucom and introduced to the market in 2015. This sampler uses a five, seven or 12-inch probe attached to a 675 pound (lb) hollow steel drum. As the drum rolls along the ground at up to 12 MPH behind a vehicle, its weight pushes the probe into the ground on every revolution. The slightly tapered probe catches the sample until, when it revolves to the top of the drum, gravity forces the sample to drop out of the wider end of the probe into the drum’s hollow centre. Once a specified number of samples are collected and mixed in the drum, a composite sample is sent down a slide into an automatic bagging and geo-referenced labelling system, after which it is ready to for mailing to a lab for conventional analysis. The Falcon 5000 can pick up samples every 15 feet to a maximum of about 40 samples per minute.
At the other end of the spectrum, multiple researchers are working on very high-tech automatic samplers using unmanned ground vehicles (UGVs). Though no unmanned solution is yet available on the market, Dr. Eero Väljaots, the research lead on UGV soil sampling project in Estonia, says he expects this type of technology to be the future of soil sampling on average farms in approximately five years.
“There is a growing need for taking samples and (the) time (available) for collection is quite limited; therefore, taking the workload off from authorized personnel is desired,” he explains. At a current cost of about $34,000USD, the purchase of an unmanned soil sampling vehicle for an individual farm is not economically feasible for most farms, so he says rental is more likely.
Along with automated sampling, in-field testing equipment and handheld analysis technology is also evolving. Multiple companies are researching and developing probes and scanners that can provide near instant results right to one’s smartphone.
Soil probes by Teralytic, a precision ag and soil health specialist, feature 26 sensors designed to read microclimate data (air temperature, humidity and light) collected at the soil surface, soil gas (aeration and respiration) data from six and 18-inch depths, and multiple soil characteristics (moisture, salinity, temperature, pH, nitrate, P and K) from six, 18 and 36-inch depths. The data can be transmitted wirelessly up to 10 miles and stored in the cloud, and can be translated via Teralytic’s analytics service into real-time guidance provided in chart format.
Already, some infrared and near-infrared soil testing tools are on the market, including those available from AgroCares and Bruker. AgroCares’ scanner is designed to analyze nutrient content in leaves, feed or soil at the touch of a single button, with results and analysis in your hands within 10 minutes.
Markus Weber, president of LandView, says his company’s new LabFlow soil testing spectrometer will be market-ready within the year. Already, the company has the technology in place to measure soil carbon via digital spectrometry. Now, LandView and partner company Stream Technologies Inc. is currently imaging thousands of soil samples to develop machine-learned algorithms for N, P, K and S.
“We used to joke that [sending soil samples away to a lab means] we’re sending Alberta to Ontario one box at a time. Moving away from chemical analysis and going instead to spectrometry means you can essentially get your results while you’re standing in the field,” Weber says.
And, he adds, results are more accurate. Because testing via spectrometer will be cheaper than analyzing soil tests at a lab, producers will be able to afford to get higher resolution or more representative results via multiple samples.
Hardware for a LandView spectrometer currently sits at approximately $30,000. Within three-to-five years, however, Weber expects that the equipment cost will be low enough to be affordable by individual farms.
“I spend a lot of time with people who are already in the precision ag world. They see incredible opportunity with this technology,” Weber says.
In an ideal world, laser-scanning will soon allow a vehicle to travel through a field, mapping precise soil nutrient levels as it goes.
Translating data into action
No matter how innovative and precise the soil testing technology, translating data to action may still be challenging, says Trevor Wallace, a nutrient management specialist with Alberta Agriculture and Forestry.
“You have to ask: Does the producer have the technology on their equipment to do anything about the results they get? It’s really nice to get a good soil map so you know where to target nutrients. But if you have no way to change nutrient application rates, what can you do with the information?”
From a manure spreading standpoint, adjusting application rates can be as simple as speeding up or slowing down one’s pump or gearing one’s machine up or down, so site specific manure application is achievable if nutrient zones are fairly simple and clearly identified. From a fertilizer application stand point, however, most farmers’ current air seeders may not have variable rate fertilizer application options, so a precise nutrient map may not be as fully actionable as one might hope.
Also, the short length of growing season, particularly in many parts of Canada, means timing is always of the essence.
“Everyone understands the dollar savings of precision agriculture. Farmers are … updating or retrofitting equipment or looking at adopting different methods of nutrient delivery so as to take advantage of this information. … But the more you have to change your system or the more complex it gets, the more time it takes. It has nothing to do with farmers’ ability or experience; sometimes they just need to get the seed in the ground as fast as possible.”
While the optimistic side of Wallace says advanced soil testing is coming, he says the realist in him know that not all equipment and not all farmers are ready.
“We’ve been talking about it for 10 years with the false sense that (large-scale uptake of precision technology) was right around the corner. We’ve been putting out promises that variable rate is the way of future, but we haven’t really delivered on it yet.”