The accuracy of the technology is the key selling point.

Debates surrounding soil- and tissue-testing methods continue to cloud adoption rates and usage. With soil tests, it’s timing based on crop rotations: is fall best for gauging nutrient usage in a crop or should you rely on spring testing for what the coming crop will need? With tissue testing, it’s gathering samples and sending them to the lab for conventional testing, or perhaps an end-of-season stalk test to determine the nutrient demands for next year.

All methods have their advocates and detractors and much of the reasoning revolves around cost-efficiency.

A new system is still being tested, called the Leaf-Evaluated-Nutrient-System (LENS), designed by Picketa Systems, based in Fredericton, New Brunswick. The technology is in its fourth year of use in potato crops in the province and has now expanded into 13 U.S. states, including Ohio, Indiana, Illinois and California for use in corn and potatoes. It’s been favourably reviewed and adopted by McCain Foods for developing management strategies on new potato varieties. In 2023, Picketa Systems expanded its network of testers in the United Kingdom.

According to company literature, nutrient efficiency in most fertility programs is a 50/50 split: half of nitrogen-based fertilizer applied to crops is used effectively by the plant. But the remainder is lost to the environment and for many farmers and advisors, the preference defaults to over-application of nutrients as a necessary cost, based on concerns that under-applying nutrients might lead to yield losses. Higher land and equipment prices plus the effects of the carbon tax are more recent developments affecting growers’ decisions on fertilizer rates.

Timely technology
The designers of the LENS technology may have found an answer to grower demands for more cost-effective testing for nutrient use in plants, with the end-goal of improved performance in terms of yield. The company literature refers to “chemometrics”, which uses reflectance of plant tissue across a wide spectral range, then applies machine- learning algorithms to analyze the samples, almost instantaneously. Ten to 15 tissue samples are collected from the field, with leaves that are free of visible damage or disease, and then input into the unit.

“The point was to have a system that could give agronomic feedback in the field,” says Xavier Hébert-Courturier, co-founder and chief executive offer of Picketa Systems. “And not just for nitrogen but 13 nutrients, with ratings for nitrogen, nitrate nitrogen, potassium, phosphorus, and micronutrients like calcium, boron, manganese and magnesium. They’re all the ones you’d get from a typical lab test.”

Based on results from 2021 through 2023 with potatoes, the accuracy is encouraging. The average error was less than two to three per cent for N, P and K, compared to standard laboratory results. With micronutrients, accuracy was six to eight per cent error on average, but Hébert-Courturier notes those might have resulted from contamination by fungicide applications (especially for magnesium), or differences in calibration relative to a lab test.

Continuing reach
The company tested the unit in corn in New Brunswick in 2023, with added sites using it in potatoes in Quebec, Ontario, Manitoba and Alberta. The latest map outlining its reach now includes British Columbia and Prince Edward Island. During the winter of 2023-24, the company took a unit to Chile where they worked to calibrate it for corn.
Eventually, the plan is to adapt the LENS technology for canola, soybeans, cereals and eventually in all crops.

Hébert-Courturier says they’ve tested the unit through different growth stages in corn, starting at V2 through to tassel. In potatoes, agronomists and crop advisors were testing every week or once every two weeks.

“What we’ve heard in talking to farmers is that if you have it, you’re going to use it right before an application -maybe the day of,” says Hébert-Courturier. “Then you’re waiting five to seven days after to determine the uptake. We’ve seen people take more data points but typically, they’re planning on using it two or three key times during the season.”

Benefits
It’s the speed with which results are generated that’s the biggest advantage. Decisions on spray applications can be made quickly with above-average accuracy. One challenge with conventional lab testing is that samples can begin to decompose before reaching a lab, leading to inaccurate analysis.

The LENS unit itself is simple to operate -it requires a one- to two-hour training session -but most users are agronomists, researchers and retailers, since they’re scouting and assessing crops in the field. In using the unit in 2023, some of those working with the technology took as many as 1,500 samples.

“It’s for businesses that have the dedicated staff and the trucks serving 20 to 30 farmers,” says Hébert-Courturier. “It’s not the farmer who has to go out and learn this new system and take the samples, it’s for the agronomist who can fit it into their workflow and are used to sending samples to the lab.”

For more information on the LENS technology, go to www.picketa.com/contact