Features Agronomy Soil
How healthy are Ontario soils?

Managing soils is an ongoing process and most growers are very aware of what they need to do to maintain soil health. Or, do they? It is possible to make all the right moves, but it may not be enough to maintain soil health. As well, an operation that seems like the right thing to do may not be. Now, two soil specialists at Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) are developing a soil test, based on a similar assessment developed at Cornell University, that will give growers the answers they need.

There have been methods to assess soil health introduced over the years, but the process has been complicated by the requirements on how to take the samples and relating the results to individual farm management. “We’ve been working with soil health for a long time,” says Anne Verhallen, who, along with Adam Hayes, is assessing the Cornell material and adapting it to Ontario. “The challenge is how to quantify soil health, but the Cornell test is much like fertility sampling, which is a system familiar to most growers. Our goal is to give growers a tool that allows them to assess their own soil.”

The research undertaken by Verhallen and Hayes will take three years and, after two years of the work, the soil specialists believe they may be able to identify a simpler system that can be put in place for Ontario growers. “Our hope is to have a recommendation of what an Ontario soil health assessment could look like using some or all of the 12 Cornell indicators,” continues Hayes.

“In our first year of the project, we sampled long term rotation and tillage trials in Elora and Ridgetown,” Verhallen says of how they began gathering the data they needed. “In the subsequent years, we have included growers’ fields and the long term tillage/cropping studies in Ottawa, Delhi and Woodslee.” They are assisted in this endeavour by Drs. Dave Hooker and Bill Deen of the University of Guelph.

Once they have compiled their data they will have a benchmark of the health of Ontario soils.

The Cornell system scores soil health on a green/amber/red scale with green being good, amber meaning caution and red standing for critical. The goal is to have the soil health test available to growers who request it for a reasonable addition to the usual soil test fee. Ideally, the test should be taken in the spring and the report will indicate if there are problems. Working with a crop advisor or extension personnel, growers could then determine what they need to do to build better soil health, if they have received a grade in the amber or red range.

“Growers can use the results of their assessment to make management decisions that will improve their soil health,” Verhallen explains. “Growers will only need to do this test every five or 10 years.” Doing a soil assessment every few years will allow growers to stay on track with their soil management plans.

“Soil health assessments could also be valuable when growers are planning to buy or rent land,” continues Hayes. “If a grower knows the soil health of the land they are considering is good, it may make the purchase or rental more attractive.” Conversely, he adds, a grower wanting to sell or rent land may want to highlight the health of the soil, if it is good. With premium land harder to come by, property with proven healthy soils may also have a higher value placed on it.

“The assessment is a means of quantifying some of the soil health issues beyond fertility,” Verhallen explains. The Cornell assessment evaluates four categories under physical, biological and chemical properties of the soil. Under physical, the soil is rated for available water capacity, aggregate stability, surface hardness and subsurface hardness. Chemical properties fall under pH, extractable phosphorus and potassium and minor elements. The biological properties examined include organic matter, active carbon, potentially mineralizable nitrogen and root health. Verhallen says that part of the OMAFRA research is assessing whether all these tests are necessary to assess the health of Ontario soils.

“Growers are concerned about soil health and often wonder if they are doing the right thing,” Hayes says. “They wonder if they are making progress with what they are doing. What we are trying to do is develop the benchmark and go from there to help growers understand the level of their soil health.”

Verhallen says they are likely a year or two away from having a test that can be ordered from a lab and the cost has yet to be determined. Their goal is to refine the Cornell test series to allow growers to benchmark their fields for all cropping situations in all areas of the province from no-till to conventional tillage and all compass points. The result will give growers answers to the soil health questions they have and assist them in improving their soil management. Then there will be a definite answer to the question: “How healthy is my soil?”

March 2, 2012  By Rosalie I. Tennison