In search of a standardized soil test for Ontario farmers

Thursday, May 1, 2014

What the province's farmers have long wanted is a relatively inexpensive, on-farm method of measuring soil health. And now, thanks to a three-year University of Guelph research project backed by the Ontario agricultural ministry, they may soon have it

by MARY BAXTER

There are a lot of ways Earl and Bill Elgie monitor the health of the soil on their 700-plus cash crop acres near Dresden in Chatham-Kent. Each year, roughly a third of the farm's acreage undergoes soil testing, so that every field has been tested within three years. "We look at nutrient levels, micronutrient levels, organic matter," says Earl.

They don't stop there. Calcium and magnesium levels are determined, as are the ratios between the two as well as ratios between other components that might indicate a good mineral balance, such as phosphorus to potassium. Heavy metal levels in compost acquired from other locations are tested annually before spreading.

But for Earl, nothing beats the smell test, where you dig in, grab a handful and savour the aroma. "There's a good sweet smell" to a good healthy soil, he says. It should break apart, have good aggregate structure, "a million roots" and "lots of life in there, whether it be earthworms or little bugs eating up some of the organic matter."

He also recommends establishing "0" test strips in the field to grow the crop without the aid of any soil amendments and weigh off the results in the fall. "That is the true factor of whether you've got a healthy soil in our opinion," he says.

Currently, these two brothers, named in 2010 as national soils champions by the Soil Conservation Council of Canada, define healthy soil as being weather-proofed. "It will withstand heat and drought a little bit better than one that is non-healthy," Earl explains.

But another way to measure and define soil health may soon be available: standardized Ontario-specific soil health tests.

Adam Hayes, Ontario's field crops soil management specialist, and Anne Verhallen, the province's horticultural crops soil management specialist, have spearheaded efforts to establish the standardized testing. "As a ministry we've been talking about soil health for probably 10 years now," Hayes says, and the ministry has had good results from its efforts to share with farmers ways to foster soil health. But, time and again, "farmers would come up to us and say, OK, you're telling me I need to get my soil healthy, so how do I know if it is?" What they wanted, Hayes says, was a relatively inexpensive, on-farm method of measuring soil health.

So Hayes and Verhallen began looking. They found a U.S. soil health quiz that helped farmers rate components, such as the presence of earthworm middens, and review management practices. Then they discovered a soil quality test kit developed by the U.S. Department of Agriculture. "But it had a multitude of tests in it and would probably take somebody with a bit of training a day to run" all of them, Hayes says.

Finally, they uncovered a test that seemed to fit the bill. Developed by Cornell University in New York State, it appeared fairly easy to do and, with some narrowing down, had the potential to be affordable. For the test, 30 to 40 six-inch cores from a representative area of the field and some penetrometer readings are needed to evaluate 12 indicators. "So it's very similar to a fertility test," says Hayes. "It's just taking a bit more soil to send away."

In 2009, the pair secured funding to buy some of the equipment involved in the testing and obtained the agreement of two University of Guelph field crop researchers, David Hooker and Bill Deen, to embark on a three-year project to evaluate the effectiveness of the test on 13 long-term research sites maintained by the university and Agriculture and Agri-Food Canada. In years two and three, they added in samples from about 200 farm fields, including ones from the Elgie brothers' farm.  

Three of the Cornell test's indicators have shown promise: analyses of soil aggregate stability and organic matter, as well as the mineralized soil nitrogen test. Others were more challenging to work with or simply didn't seem to be all that responsive to Ontario soils, Hayes says.

A graduate student is now running statistics on the long-term trial data and, once they've obtained management information from the farm fields tested, they'll run statistics on those as well.

Meanwhile, Hayes and Verhallen continue searching for another test that might give an indication of the soil's biological activity. In a research project with Chris Gillard, a dry bean researcher with the University of Guelph's Ridgetown campus, they've also added water infiltration measurements.  

They hope to conduct a workshop later this year to share the results of the studies with researchers, some representatives from agribusiness and laboratories and some farmers. They also want to brainstorm "to see if we could come up with what we might use as an initial soil health test for Ontario." Hayes predicts a test could be released in the next year or two.

Such testing probably would benefit the operation of his farm, says Earl Elgie, and he likes the idea of a test that "gives you an idea of some parameters to look at within your own farm operation." But he points out that, in order for farm operations to meet certain criteria for having healthy soils, they may need to engage in specific practices, such as adding manure or compost. Not that every farm operation might want to or be able to. And if they don't, would they be able to obtain a healthy soil score? "I'm not sure," he says.

There are still plenty of questions to answer, acknowledges Hayes, pointing out that they have yet to even establish the scoring ranges for healthy soil indicators. Once questions such as these are resolved, however, the test would provide farmers with a straightforward tool to benchmark their fields' soil health and monitor the effectiveness of efforts to improve or maintain soil health. BF

Three objectives for maintaining a healthy soil
During a presentation at last winter's Ontario Soil and Crop Improvement Association's annual meeting in London, Earl Elgie, who farms with his brother Bill near Dresden in Chatham-Kent, noted three main objectives for their farm operation: "keep our land covered, sensible tillage and feed the soil life."

The decision to focus on soil health came after a disastrous season in the late 1980s when they planted tomatoes in rented, "beachy" sand ground across the road. The soil was very low in organic matter, he recalled, and was no match for the spring winds. "The tomatoes got sandblasted. They were just toast. We replanted them and it came again. We ended up spreading bales of straw; we did everything to try and get the wind from blowing the tomatoes, but to no avail," he says.

The solution, they realized, was to keep the land covered. Since then, the brothers try to keep their soil covered as close to year-round as possible by employing cover crops such as red clover, buckwheat, oats and rye. What type of cover crop gets planted depends on what it follows. Oats usually follow sweet corn, although they've tried rye, too.

Systematic tile drainage and windbreak tree plantings are other components of their soil health strategy, as is an emphasis on minimal tillage, used mostly to incorporate manures shallowly, perform inter-row cultivation for weed control and increase their soil's carbon dioxide levels.

To feed soil life, the brothers try to add minerals to their soil and favour manures generated from their own livestock or compost or manures imported from other sources, such as mushroom farms. The manure or compost is not only a source of nitrogen, but also carbon for microorganisms.

"We really like to go for something that's consistent, load after load, because we're banking on that manure, that compost to provide nutrients for our crop for the next year," Earl says. BF