Soil: The Invaluable Resource That Underscores Urban/Rural Disconnect. Part 3.
Everything on the planet is part of a cycle that operates on various scales and over various time periods. Perhaps the slowest and the least obvious is the Geologic Cycle (Figure1). Humans look at primary landscapes, like rivers, lakes, hills, and mountains and see little or no change over time. This view was philosophically defined in the 18th and 19th centuries by Hutton and Playfair, in consort with Charles Lyell’s geology, as uniformitarianism – the belief that change is gradual over long periods of time. It provided the framework for Darwin’s Origin of Species, and yet it is wrong. Change is going on all the time and rapidly, even in geology. This false philosophical view is why the public was easily fooled about climate change. The reality is that climate changes all the time, quickly and significantly. For example, it was just 18,000 years ago that almost all of Canada was covered with an ice sheet larger in area than the current Antarctic ice sheet.
In the Geologic Cycle, the solid land is created from magma, the material in liquid form under the crust that, after it emerges at the surface, is called lava. It is extremely hot (900°C) but quickly begins to cool, as shown in Figure 2. Once it cools it forms the basic rock type called Igneous Rock. Nature doesn’t waste a minute and begins weathering, that is breaking down the rock into smaller pieces. The total weathering of rock down to the smallest particles is what creates soil.
We classify components of the weathering by size known as the Wentworth Scale (Figure 3).
Ironically, the weathering front, that is where the rock breaks down is not right at the surface but down at the face of the bedrock. You can see what I mean in Figure 4.
Layer C is called regolith and is where the bedrock at the bottom is being broken down. In layer B the water and chemicals filtering from above create the subsoil, which is not very fertile from a plant production view but is important for the subsoil moisture. Look at the roots reaching down to this level. When drought occurs, this layer becomes critical in the soils capacity to hold moisture. Layer A is the actual soil area because it contains the nutrients in the humus, or, rotting vegetation.
This is a static diagram, but in nature it is a constantly changing dynamic zone. Despite the vegetation cover, the soil is continually being removed from the surface by wind and water. That erosion is carried into the nearest stream and river for transportation to the ocean. Figure 5 shows a tributary bringing sediment to a larger river.
There it is deposited as sedimentary layers that eventually become the second rock type, Sedimentary Rocks. Eventually, those sedimentary rocks are dragged down back into the mantle. Under the pressures and heat, it is transformed into the third rock type Metamorphic Rocks. The Latin word metamorphosis means to change form.
It went by unnoticed by most, but 2015 was declared The International Year of Soils by the United Nations. Fortunately, many of the farmers and landowners, especially in Canada, were aware of the problem and introduced solutions a few decades ago. The problem became especially noticeable on the Prairies when drought in 1988 and 89 brought back the always accompanying wind erosion and last seen in full force in the 1930s. Figure 6 shows a picture taken in Regina in 1933.
It was estimated that the natural rate of soil loss on the Prairies under tall and short grass conditions was on average approximately 5 tons per acre per year. Primarily because of removing the turf and replacing natural grasses with humanly introduced grasses like wheat and barley among others. To reduce moisture loss from weed growth when no crops were planted they practiced summer fallow. This involved plowing the land to keep it ‘clean’ (Figure 7).
Estimates claimed the rate of soil erosion doubled under these conditions to 10 tons per acre per year. This was troubling, especially given the slow rate of soil formation when the ground is frozen for about half the year. In addition, it was a fraction of the 700 tons per acre per year eroded in parts of China. The Yangtze River translates to the Yellow River because of the coloration caused by the high sediment load. Figure 8 shows the sediment discharging from the Yangtze into the ocean.
Saskatchewan farmer, Herbert Sparrow, was appointed to the Senate and used his position to trigger his concern in a 1984 Senate report titled, Soil at Risk: Canada’s eroding future. It is reputedly the most extensively published book in Canadian government history. Its influence was international because it was translated into dozens of languages. It, along with the work of University of Manitoba Professor Elmer Stobbe, introduced and promoted the concept of Zero Till and a modified form called Minimum Till. Elmer was so successful, he worked under contract with the Chinese and a few African countries, and his students continued his work after he retired.
The action was effective in reducing soil erosion, but like all actions it caused reactions. Most people don’t know why plowing occurs. They think it is to prepare the ground by removing weeds that will compete with their seeds. That is a factor, and that continues, except the weed removal is now done with chemicals like Roundup. Some condemn the use of chemicals, but there was a positive side-effect.
Summer fallow was usually preceded by burning, and the combination removed most of the organic material that rotted and made up the important humus of the soil. Prairies soil saw a significant decline in organic material and the all-important nemotoda and other creatures that process and create the soil. Charles Darwin dramatically introduced the importance of these worms in soil formation. Toward the end of his life, he was asked what he thought was his greatest achievement. Without hesitation, he said his calculation of how much soil was passed through the earthworms in a single year in one acre of English soil.
The major reason for plowing was to turn the soil over in the spring so that the warm surface layer was put at the level were the seeds would germinate. Seeds need a minimum temperature to start sprouting, and it takes time for the soil to warm at depth. Soil is a good insulator and does not transmit spring solar heat down very easily. Just try it on a more porous soil like beach sand. The surface is almost untouchable on a hot summer day, but just an inch or two down it is remarkably cool. It is why basement temperatures are remarkably stable without artificial heat at about 10°C year-round. It is also why root cellars served our forbearer’s well for food storage. Farmers across more northern regions of Canada, where a week is critical, saw the impact of zero till on their already limited growing season.
Climate change is normal, just as all change is normal. Since the introduction and application of statistics to the human condition, many tried to measure this change. Starting in the 1930s, all the attention was on averages. Remember those height and weight charts we all conformed to so as to be considered average or normal. Then, in the 1970s attention switched to trends. Marketing people wanted to measure and anticipate trends. In climate, it began with the recognition that the trend since 1940 was cooling and that became the consensus until the 1980s when it became warming. Now, as it always does with global cooling, the variability of weather from month to month and year to year has increased. Because of uniformitarianism and exploitation of its view that change, and especially rapid change, is not normal, we see hysteria and misinformation in full flight. One thing that also changes is the number of doomsayers, the Chicken Littles; the ‘sky is falling’ gang. Right now, we have an unusually high number, but it will decline as their deceptions are exposed by the natural cycles, and the world cools down. The other good news is not one doomsayer was ever right. My proof? We wouldn’t be here if one was correct.