Is there a tool out there or a method for assessing and interpreting soil health? Research out of the University of Saskatchewan could provide such a tool, where farmers could put in their soil data, find out their soil health score, and receive interpretation and management advice.
“Soil health is defined as its capacity to function,” said Dr. Kate Congreves, assistant professor of environmental agronomy of the U of S. Congreves presented research findings at Saskatchewan Agronomy Research Update recently.
Soils support plant growth in order to produce food, feed, fibre, and fuel, she added, but they also move carbon dioxide from the atmosphere, cycle nutrients and water, support biodiversity, regulate pests and diseases, and serve both ecosystem and cultural services. The healthier a soil is, the more capable it is of performing these tasks.
But, how do we measure a soil’s health? There are tools that already exist, but the problem is they’ve been developed for other regions of the world — for example the Cornell Soil Health Assessment — and will not accurately assess soil health on the prairies. Having a more meaningful tool developed for Chernozemic soils, with more horizons than just topsoil considered, will be beneficial.
“Knowledge and understanding of how to best manage soils are based on soil measurements,” said Congreves. “Really, over the past century, research has given rise to great gains in soil health management,” she added.
The objective of one of Congreves’ latest projects is to create a Prairie-based assessment of soil health indices.
Soil was collected from 0 to 15 cm, 15 to 30 cm, and 30 to 60 cm in fields across Saskatchewan, hitting every soil zone and major cropping region. Soil chemical, biological, and physical attributes were measured. All the attributes that were measured contribute towards the final soil health score, but certain attributes are weighted more than others. For example, some of the most important attributes for soil from 0 to 15 cm were organic carbon, active carbon, total nitrogen, and soil protein.
“Across Saskatchewan, the average soil health score is about 65 per cent, and this seems really reasonable, this is a more meaningful number than having everything always show up as 95 or 100,” said Congreves. Some soils were lower than that average, and some were around 80 per cent, based on soils sampled from a variety of cropping systems.
For comparison’s sake, native prairie samples had a high soil health score, close to 90 per cent, which is the benchmark to compare to, said Congreves.
The next steps in the research are to refine the soil health tool by soil zone and create a grower-friendly tool. Another future objective is to determine if healthier soils can help to buffer the effects of a bad year on crop productivity.