Soil: The Invaluable Resource That Underscores Urban/Rural Disconnect. Part 2.


What is soil? How is it formed? Are all soils the same? Why do they differ? Why is it at risk? Why is it so important? Most Canadians, especially urban dwellers, take it for granted or don’t even think about it at all. Most people assume that because it is the second largest country in the world it has the second largest amount of soil. The truth is about one-third has none and the remainder only small pockets of agricultural quality soil. Sadly, we have very little yet, we bury some of the best soils in the world under our cities.

Years ago, I took students on a field trip west of Winnipeg. When we reached Portage la Prairie, we stopped for a break. A student said Dr. Ball you told us soils were very limited, but we just drove 50 km, and I saw tons of soil. I explained that volume does not mean the soil was fertile. You only need to lose a tiny portion of the soil for it to become infertile. It is like chewing gum without the flavor.  Another student from Hong Kong couldn’t get over how much land we have and don’t use. He calculated the amount of land in the 50 km divided highway and estimated the amount of carrots you could grow.

This is part of a Canadian problem that I call the complacency of superabundance. If you list every country in the world and what minerals they would like to have, you find Canada has all of them. We live off our resources far more than most people realize. Virtually all these resources are not visible. Fur trader Samuel Hearne was sent by the Hudson’s Bay Company (HBC) to the Coppermine River on the Arctic coast because large chunks of 94 percent pure copper were visible on the surface.  

We are not alone in failing to maximize food production potential. Watch a series available on the internet called Wartime Farm to see how much Britain increased food production and land under cultivation during World War II, when imported food was cut off.

Canada is the second largest country in the world, and that entire region has geologic opportunities. However, that doesn’t apply to soils. About half of the country has little or no soil as Figure 1 shows.

Figure 1

Only the first two soils listed, Chernozemic and Luvosolic, are good quality soils for any agricultural product. These represent at most approximately one-tenth of the total surface area. Notice that even with global warming there is no soil to support agricultural expansion to the north. When you look at this map, you understand why 60°N became the northern boundary of the Prairie Provinces. They knew as I discussed in Part 1, that you could not have an economy without soils and the ability to feed yourself.

Two large areas are marked Brunisolic and Podzolic. They underlie the vast boreal forest that creates the illusion that these are good quality soils and therefore could be adapted to agriculture. They are not. The only thing they grow naturally with any efficiency is the trees that cover them. The Hudson’s Bay Company had gardens at each post, and the only thing they grew successfully at boreal forest locations was potatoes.  

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Boreal forest

This idea that because there is vegetation the soil is suitable for agriculture is one of the great myths. The two biggest vegetation zones in the world are the boreal forest and the tropical rainforest. It is hard to believe, but soil under the rainforest is the most infertile. Most people know that trees are deciduous or evergreen, but those in the rainforest are deciduous evergreen. This point is essential to understand how the rainforest is created and maintained and appear to be growing on fertile soil.

The tropical rainforests exist in a climate with very high year-round rainfall over 2000mm and consistently high temperatures between 20°C and 30°C. This means the soils in the tropical region experience almost a complete washing out of minerals. What remains is mostly iron and aluminum, which makes the soils very red, but infertile. They are generally called laterites.

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Lateritic Soils

What happens in the rainforest is the trees are continually shedding and growing new leaves. Those leaves fall to the ground and immediately begin to decay in the hot, humid conditions. The rotting vegetation in the rainforest is one of the biggest sources of methane in the world. The trees immediately take up the minerals, and so maintain themselves. The soil is simply an anchor.

When you clear the trees, the soils are exposed. Two things happen, very heavy erosion if it rains, or the soil bakes literally iron hard. People who live in these forests practice what is called ‘slash and burn’ agriculture. They clear a small patch in the forest and burn the vegetation to add minerals to the soil. They grow crops for one or two years and then move to a new area.

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Tropical rainforest

The arrogance of outsiders who were fooled by the dense forest vegetation led to major agricultural development failures. By 1900 rubber trees taken from Brazil were flourishing in plantations in Malaya (now Malaysia). Before World War II industrial growth, particularly of motor transport, increased the demand for rubber. In 1928 Henry Ford built the town of Fordlandia in the center of the Brazilian rainforest. It was to be an industrial center around a rubber plantation. Ford wanted to control the production of every component of his newly massed produced cars.

During World War II Fordlandia became important because of the Japanese invasion of Malaya. However, he misjudged three things. First, the locals could not accommodate to an industrialized society. Second, the soil exposed by clearing the forest quickly lost its fertility without falling leaves. Third, the pressure of demand led to creation of a synthetic rubber.

The second failure to deal with tropical soils was known as the Tanganyika Groundnut Scheme. Groundnut is the English term for peanut. Most people don’t know that vegetable oils are the most important agricultural product in the world. During WW II, the British government realized they had to develop a reliable supply. Immediately after the War in 1946, a private company began looking for a site in Africa. They settled on 150,000 acres in Tanganyika (now Tanzania) and cleared the land. The project failed within five years and was completely abandoned by 1951. Labor difficulties were a problem, but the primary reason was the nature of the soil. These African Laterites baked rock hard, and they used machines that were part tank and part tractor to break it up. In addition, the soil also had quartz particles, and the combination of the iron and quartz ground a steel plow to nothing in a couple of days. Within 1 year, two-thirds of the imported tractors were out of service. It was a short-lived, expensive disaster.

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Rubber plantation

The third was called the Jari project and was the idea of US billionaire Daniel Ludwig. He bought 1.6 million acres to produce a rapid growing tree to produce pulp for paper. He anticipated a growing demand for paper that slower growing boreal forest-trees couldn’t provide. He even had a processing plant built on a huge barge and towed from Japan. The problems of the soils combined with health issues and forced him to quit the project in 1961 after just 10 years.

There are no tropical soils in Canada, and the ones we have are among the youngest most impoverished soils in the world. The ice sheet that covered Canada just 20,000 years ago was the most recent of four ice sheets that occurred during the Pleistocene period. It began 3 million years ago and ended about 12,000 years ago. As the ice formed and advanced it scraped Canada down to the bedrock. As the ice retreated and melted, it deposited the debris called till, and the meltwater filled every hollow to leave Canada with about one-third of the worlds freshwater. The trouble is it didn’t leave much agricultural quality soil, but more of that in Part 3.

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