ON SOLID GROUND
PRAIRIE SOIL STILL AN UNDISCOVERED WORLD
BY STAN BLADE, P. Ag.
The United Nations has declared 2015 the International Year of Soils. The goal of this effort is to “raise awareness of the importance of sustainable soil management as the basis for food systems, fuel and fibre production, essential ecosystem functions and better adaptation to climate change for present and future generations.” I have noticed that the usual UN ambassadors (Angelina Jolie, David Beckham, Katy Perry) have not stepped forward to serve as the celebrity face of this important initiative. Perhaps they think there are limited possibilities for a “photo op” with saline seeps, chernozems and micronutrients.
Where do you stand on soil? No doubt it is the substrate that produces millions of tonnes of grains, oilseeds and forage across Western Canada. Our soil contains large pools of nutrients (and manages the complex chemistry of nutrient cycling) that can be accessed by plants to combine with light and water to generate a remarkable range of products. At times, I wonder if we appreciate that soil is also a finite natural resource—non-renewable on a human time scale. In addition to soil as the foundation for food, animal feed, fuel and natural fibre production, it also contributes to the supply of clean water and a range of ecosystem functions.
I am convinced that western Canadian producers are superb stewards of the land—but there are many things happening in that ground that science is just starting to discover. Every producer in Alberta knows that our soils are based on climate and parent material. The brown chernozems of southeast Alberta are dictated by their original grassland vegetation and limited precipitation. As we move north and west in the province, the soils reflect dark-brown and then black coloration determined by the associated vegetation based on higher precipitation. Further north in the province, limitations to productivity occur due to soils associated with mixed forest vegetation and shorter frost-free periods.
Soil research has a remarkable history. The Russian geologist Vasily Dokuchaev is considered the father of soil science. He was the first to make the case in the early part of the 20th century that soils should be considered a complex and distinct resource separate from geology and crop production. Although there has been a massive amount of research done in the intervening century, there are still new areas of research that are providing us with novel insights.
Data from Texas A&M University estimates that the total weight of soil organisms ranges from 1,160 to 12,700 pounds per acre—and that doesn’t include earthworms, nematodes, mites and springtails. State of Colorado researchers, using the newest genomic techniques, compared virgin prairie soil microbiota to current cropland—and the populations were radically different. New research from the University of Helsinki indicates that small changes in atmospheric temperature can reduce the amount of sequestered carbon due to micro-organism response. The work and studies go on.
How does this work relate to current production? The Grains Research and Development Corporation in Australia is investing in research to see what role soil microbiology might play in disease suppression, and to quantify the benefit of free-living nitrogen-fixing bacteria in soils. Producers have been rewarded from new technologies to gain benefits from nitrogen-fixing rhizobia and mycorrhizae. The soil health initiative in the United States is looking at new ways to encourage U.S. farmers to understand the value of soil microbes—noting that there is a remarkable symbiosis between plants and soil microbes. Ohio State data showed that typical crop plants give up 25 to 45 per cent of their total carbohydrate reserves to feed the microbes; in return, the microbes provide nutrients and water to the plant. The relatively new Haney Soil Test measures not only the existing pools of nutrients, but also the capacity of soil to deliver nutrients based on soil biological status.
We now have the tools to start to understand (and, in the future, maximize) the massive populations of organisms that are active just beneath our feet in the cropland across Western Canada. A recent survey of producers by the Alberta Crop Industry Development Fund indicated that soil health was high on the list of issues that are of concern to crop producers in Alberta. This is the time to start using new scientific tools to not only understand the complexity of soil biology on the Prairies, but also develop new crop management techniques to work with nature to achieve both higher yields and healthy soils.
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