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Getting down to biology

Finally there may be a soil test to help you see your soil the way that your crop’s roots see it

Soil health is on everyone’s mind these days. Perhaps it’s tied to volatility in the commodity markets, or to the risk of consumer and government scrutiny. Or maybe more growers are interested in “doing things right.”

No matter the cause, there’s a long list of farm professionals welcoming the trend with open arms.

“Ultimately, the soil is the backbone of any farm operation — even if you’re producing livestock and you’re growing the crops to feed them,” says Jack Legg, agronomist and branch manager with SGS Agri-Food Laboratories in Guelph.

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“But,” Legg adds, “soil is also the easiest to put on the back burner. There are so many operational and management decisions that have to be made every spring and fall that the years can pass by between routine soil sampling.”

Legg agrees there are changes coming, particularly with environmental concerns, and he sees it happening quickly, including an emphasis on measuring what’s being done on the farm and proving that agriculture is doing things “correctly.”

Yet the question remains. How exactly are farmers supposed to show society they’re doing a good and responsible job?

New program

The new SoilOne Report provides an added parameter not found in most current soil tests, which are mostly based on chemical testing and less commonly on physical analyses. The SoilOne Report comes from the Soil Health Lab, a concept developed by Alpha-Agri in collaboration with SGS Lab.

The SoilOne Report adds a biological component to the final results, providing key indicators that create a more complex, multi-layered profile of a grower’s soil. Carbon dioxide respiration, potentially mineralizable nitrogen, root health, and organic matter are all included under the biological heading. Additional tests for mychorrizal infection rates, presence of nematodes and pathogenic fungi are also available.

The company says an initial SoilOne test provides a baseline or benchmark on a farm’s soil health. Subsequent tests every two to three years will add data on changes in soil quality.

This particular suite of tests was influenced by the Cornell (University) Soil Test, which Legg concedes has been a tough sell for growers, primarily due to its cost. Initially, the Cornell package looked at 70 different soil parameters, then reduced that number to make the test more practical, meaningful, and value-driven for farmers.

With the addition of Christine George, whose background is in microbiology, the development of the biological component has been completed, and the SoilOne Report is now available.

“There have been biological soil tests in recent years, but they’re difficult to reproduce,” says George, who works in research and development with Alpha-Agri, based in Bluevale, near Wingham, Ont. “We’ve been looking at the Cornell test and they’ve done a lot of work determining what tests are reproducible, and can be used as a reference as the years go on. We’re taking that and measuring the soil biology and the activity.”

Legg adds that with the three components — physical, chemical and biological — any enhancement of one invariably improves the others. If you boost the biology of the soil, it helps with chemical and nutrient-cycling and also helps soil structure.

The SoilOne Report adds a biological component to soil tests, with the understanding that all three are linked.

The SoilOne Report adds a biological component to soil tests, with the understanding that all three are linked.
photo: Used with permission of Alpha-Agri

Most growers, notes Legg, are familiar with the chemical interactions within the soil, just as they are with understanding the need for supplementary phosphorus with a low soil P test. But is there a clear link between poorer bulk density — meaning low porosity and low water infiltration — and the challenge of roots penetrating through some level of compaction?

It’s in line with a “total systems” philosophy, where instead of fixing one factor at a time, the focus is on improving overall soil health in order to nurture measureable improvement.

What it provides

On its own, the SoilOne Report won’t help growers to eclipse the 400-bushels-per-acre mark the first time they use it. Instead, George says the test provides many of the same components as any soil testing package that’s currently available. But what’s needed is a wider perspective on what this type of soil test can provide.

“Farmers can choose between chemical or physical, or there are the biological tests available now, and those must be requested,” she says. But growers also need to understand what they’re asking for, and the kind of information the test will yield. “What we’re doing with the SoilOne package is we’re testing these physical, chemical and biological components, and putting those together into a final grade, so they get weighed against each other. So, how are these physical components affecting the biological, and how are the biological affecting the chemical?”

At $320 for the combination biological, chemical and physical report, there is a cost, but if the popular business adage (i.e., that if you can’t measure it, you can’t manage it) is true of the soil as well, there may be few options.

Certainly, it can be argued that the timing is right for this type of deeper, layered analysis of the soil and its properties. More producers are examining their practices, justifying some while contemplating changes to others. The report establishes a baseline score that marks a starting point with the hope that a grower will track the results of any modifications in on-farm practices, whether that’s in three years or four, or longer.

One other important difference with the SoilOne Report is in its collection. Legg notes that with traditional bulk composite collection, soil samples are disturbed by the collection process. The goal with the new testing system is to obtain an undisturbed intact core for measuring bulk density, water infiltration and aggregate stability, among other potential tests.

Providing detailed information is becoming more important as consumers turn their attention to how crops are grown, including environmental issues such as runoff.

Providing detailed information is becoming more important as consumers turn their attention to how crops are grown, including environmental issues such as runoff.
photo: Supplied

“The argument could arise that if you’re taking a single core from your field, how representative is that?” asks Legg, adding that growers have to balance sampling intensity with cost and management practicality. “To best get around that, since all growers know their best- and worst-performing areas in their field, this could be a good comparison, not just from now to the future, but good versus poor production in the field.”

Changes in attitude

Legg and George agree there’s still some inertia to overcome in convincing growers of the value: soil testing remains a lower priority, with only about 25 per cent of growers performing soil tests as recommended every three years. But the agri-food landscape is changing rapidly, and growers are facing another of these “crossroads” that are talked about at meetings and trade shows. On one side of the farm, there are the positive programs such as the 4R Stewardship concept and environmental farm plans.

On the other side is the realization that there are more government restrictions and guidelines that are either in place or are in development, at the insistence of an increasingly demanding base of urban consumers.

Whether farmers are willing to accept these realities or use them as part of their exit strategy is a concern, yet it’s also becoming increasingly irrelevant. Traceability and all of its components — environmental, food-borne issues and soil health/sustainability — are seeing some level of manipulation, monitoring or dictating from non-farming interests. The SoilOne Report could be one tool that helps foster a greater level of accountability.

“That’s an important realization that I think more growers are recognizing — that the consumer is dictating what they want to buy,” says Legg. “That means the retailers have to provide that product and, ultimately, at the farm level, growers should recognize it as an opportunity. If you’re the first grower doing it, you’re the first guy in line to sell to the big retailers or exact a premium for that product.”

In an ideal world…

It’s an ongoing challenge, and there will be growers who refuse to comply with testing and the move towards sustainability or traceability. Yet a shift in attitude is often all it takes.

Arnold Wiegersma, principal with Alpha-Agri, acknowledges the difficulty with trying to convince growers that accountability has a value, especially in a time of low commodity prices, high land values and increasing rents.

“But I did have a young farmer tell me, ‘In 20 or 30 years when I sell my farm, if I control the history, not just chemically with what I’ve done and what I’ve put on, but what I’ve done to maintain this line, my farm has value at the point of sale,’” says Wiegersma. “‘Because I’ve done everything to show you that I’ve managed it well for 20 years.’ And he saw it as an asset.”

Another shift in attitude may come from what qualifies as “success” on the farm. Legg states that yield is the current yardstick on whether a farmer has had a good year, and that makes sense given that yield drives the economics in farming.

“But I think we’re due to start looking at quality, where maybe 170 bushels of a quality crop is better than 225,” he says, acknowledging the challenge of finding quality-based end-users in a least-cost buying environment.

Or maybe quality will mean the crop is less prone to disease or insect infestations, so that we’re minimizing risk by not just pushing the bushels but also by pushing the quality, Legg says. And something like a SoilOne Report should help the grower manage overall quality and health, he believes.

“And resistance to other things that we may not be able to control — like weather — but being able to control the health of your soil or at least direct the health of your soil, into helping your plant become more resilient to pests or drought or excessive moisture,” adds George. “If our soil is able to deal with those potentially catastrophic events, then it may not be catastrophic for the crop.”

The value of soil testing

Which is more important: where you go, or how you get there?

In agriculture, there’s the unmistakable allure of newer technology, with some growers upgrading every few years while others make do with what they have. The same may be said about soil health tests: some will argue that testing must be done in the fall, to determine what the crop has used in the previous growing season. Others make the case for spring testing to determine the nutrients that pending crops have available.

Yet most soil health experts and lab managers want only one thing: i.e. for farmers to test their soils on a regular basis. Whether it’s in spring or fall isn’t as important as being consistent and just “doing it.”

That’s the message that Adam Hayes, soil management specialist for field crops with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), wants to convey. He maintains that it doesn’t matter what soil health test you may take, whether it is a soil basic organic matter test or a comprehensive package of soil health indicators, there is still a lot of information to be gleaned.

“It is important to take the results from whatever the source, combine it with your knowledge of the field and your agronomist’s expertise to determine how to maintain or improve the field’s soil health,” says Hayes. “A simple organic matter test can tell a lot about the health of a soil — if it’s low, nutrient cycling, water-holding capacity and yields will be reduced.”

A low aggregate stability score for a soil means that a small clump of soil will fall apart into individual soil particles very easily, and that soil will be more prone to wind and water erosion. It will also crust more easily, sealing off the soil surface so critical rains run off instead of infiltrating the soil. Soil structure will likely be poorer reducing the number of pores in the soil, making root growth difficult.

A high potentially mineralizable nitrogen level in the soil is an indicator of higher biological activity and more nitrogen cycling in the soil. The carbon dioxide respiration indicator measures the activity of the soil biology. Higher numbers indicate more activity. Higher soil biological activity means more nutrient cycling, more crop residue breakdown and more release of the “glues” that help form soil aggregates.

If one or more indicators are low or the overall soil health is low then a change in soil management practices may be necessary to improve soil health.

About the author

CG Production Editor

Ralph Pearce



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