GUELPH, Ont. – It is a frustrating dilemma for a provincial government soil management specialist like Adam Hayes.
Maintaining a healthy soil base is key to keeping Ontario’s diverse multibillion-dollar agricultural sector thriving as one of the province’s economic bases and the largest agricultural industry in Canada.
But how can you judge if soil is healthy if farmers are doing what is required to keep their operations productive?
“It is not something we have a good handle on because we don’t have a good reliable way to assess it,” Hayes said.
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“We have farmers approaching us all the time for advice and also for judgment of their soil quality. They do their best but they want scientific proof that what they are doing is working. So how do we do that?”
Hayes is in the second year of a three year effort at the University of Guelph’s Ridgetown campus to find a way to judge soil health before declining production shows there is a problem.
He is trying to determine if a 12-point checklist developed by soil scientists at Cornell University in Ithaca, New York, can be adapted for Ontario conditions.
The Cornell Soil Health Assessment started as a list of 39 indicators and has been trimmed down to a dozen.
The first is the soil’s aggregate stability.
“How does it stick together when the rain hits because that is a huge issue for soil erosion,” Hayes said.
Soil samples are tested for available water capacity, which assesses how much water is retained by the soil and made available to plants.
The soil compaction is tested to a depth of six inches for surface hardness and then six to 18 inches deep for subsurface compaction.
“Compaction can affect both water retention and the ability of roots to grow,” he said.
“Compaction, particularly in the surface layer, can be caused by passage of equipment or heavy loads through the fields.”
The next four measurements are biological: the amount of organic material, the presence of active carbon, the amount of nitrogen that is mineralizable and therefore available to plants and the health of roots in the soil.
The final four indices are chemical, including soil chemical composition, and the presence of phosphorus, potassium and secondary micronutrients.
Hayes said the Cornell test assigns points for the results of each test to a maximum of 100. A score of less than 30 indicates soil in trouble, 30 to 80 is considered adequate and more than 80 signals top quality healthy soil.
If the system becomes widely available, the assessments would be an indication to farmers of where their soil management practices need improving.
“It would be a very useful tool for producers,” Hayes said.
Some of the soil testing is done at Ridgetown and some in the field.
Hayes said the provincial agriculture ministry started by sending soil samples from test plots to Cornell for testing but now conducts the tests in Ontario.
“To get soil across the border, they need to sterilize it, and that doesn’t help with some of the soil content that we test.”
He said the issue of cost will have to be tackled if testing is ever to become widely available to farmers. It is an expensive test and would require multiple samples.
“Ideally, a private lab would be able to offer the service to farmers but because of the cost, I think to make it work would require some grants or subsidies to encourage farmers to use it,” he said.
“We will continue our assessment of the test and what is relevant here and at the end of next year, we hope to make some recommendations to government.”
Hayes said the Nova Scotia and Quebec governments are also expressing interest in assessing whether the Cornell system could be applied to their provinces.
SOIL HEALTH CHECKLIST
Soil can be tested for various indicators to determine its health, including:
• Soil texture
• Aggregate stability
• Available water capacity
• Field penetration resistance
• Organic matter
• Active carbon
• Potentially mineralizable nitrogen
• Root health assessment
• Chemical analysis
