Soils Primer Part 2 Transcription PDF

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Soils Primer Part 2 Transcription Slide 1: We've all heard about soil erosion, but we need to define the different types here, because this is a problem in turf, as it is in all the Earth. All the cropping systems we talk about, so we're going to define the terms and the different types. First one is splatter erosion. The effects of rain drop, we've got some pictures coming up to show that. We have sheet erosion, is when these rain drops build up, and the infiltration of rainfall, or irrigation, or any water falling on the soil. It infiltrates at different rates, depending on the porosity, the structure of the soil. But at some point, water can build up on the surface, and it can move, it particularly moves in relationship to gravity on a sloping surface, and as it moves, it picks up soil from the surface, and this is called sheet erosion, as a sheet of water moves across a soil surface. And then wind erosion, and you know what that is. It's important to note, that when we talk about erosion, in fact why don't we come back to me here for just a minute, I need to tell you more about this. We hear a lot about pollution. And we talk about, "Well, you know, “there's pollution from, “petroleum, from chemical fertilizers, “air pollution," whatever. But when we're talking about water pollution, what is washed into surface water, and that would be via sheet erosion, you have to understand that the biggest problem, the biggest pollutant, is soil that's eroded soil that comes in. Often times, that'll be more silty particles, we’ll define that in a minute. And when you think about it, you may not know, but when you dam up a river, you create any kind of reservoir, the depth of that reservoir is the greatest when the reservoir first fills up, and then from that point on, there will be soil washed into the reservoir, and because of the dam, it settles out. It's called "silting in." And this is a problem because it causes the depth to decrease. On the other hand, it keeps the soil from being washed down to the ocean, down into the deltas. That being a problem, that is why erosion control is so important. And the system, that best controls soil erosion, is turf. Its turf, turf holds the soil better than anything, that’s why you see road banks, covered with turf. That's the importance of lawns. Lawns keep soil from washing in, down into the curb and into the storm drains, and eventually into the rivers, and into the lakes. So that's a form of pollution. Slide 2: [photograph of a splatter of water] Okay, the three types, so here's some pictures. Here's splatter erosion. Time lapse photography, here, captures this. High-speed film here. So, it comes in, and just the impact of the droplet, makes a little tiny crater, and throws the soil out, so it translocates this soil, transports this soil from one spot to another. And this can happen from irrigation, it can happen from rainfall, and when we went to establishment, we had to control this during this establishment phase, because we don't have the turf yet, prior to establishment, and during the establishment phase, to counteract this. With a thick

stand of turf, it's just hitting the leaves, hitting the canopy. Then, when there's enough water there, you will get sheet erosion. Slide 3: [photograph of a roadside with sheet erosion] Talked about roadsides, this is where turf plays a part, right here. Obviously in this case, didn't get the turf in there, didn’t get the grass established fast enough. Slide 4: [photograph of a street along a farm with wind erosion visible over the field] And then wind erosion. Even baseball diamonds, the infield can suffer. What we call the "skin," can suffer from wind erosion, so wind erosion is a problem worldwide. Slide 5: How is soil formed? This has a lot to do with the chemical properties of a soil, what did it come from? Well, from a parent material, drives this, dictates this. The climatic conditions, we can throw rainfall in here, and of course, you know the resulting erosion. Relief or topography, once again, sheet erosion plays a big part in this, or driven by this parameter. And vegetation. Vegetation not only to hold the soil, but vegetation as it goes through its growth cycles, through the seasons, through the centuries, through the eons and the censing off of old tissue, as it increases organic matter over time. And there's time. Critical agents there. Slide 6: So, what are the weathering processes? Well, rocks. The parent material, which can be rocks, broken down by expansion and contraction. Then the temperature fluctuations, what we call the freeze-thaw cycles, would be the most extreme. But even where it doesn't freeze, these temperature fluctuations do cause expansion and contraction to occur, but certainly at a lesser degree. And then, friction from rivers, glaciers, and landslides. So, if we have this, particularly this river, there’s some eroded soil in there, there’s some sand part, whatever, that you're grinding down, you eventually end up with something like the Grand Canyon. The glaciers, kind of a frozen sheet erosion, if you will, much of the Midwest, up at Great Lakes, formed by glaciers. And then, of course, landslides. Just a violent translocation of soil from one site to another. Sandpaper action of wind, which is really kind of a sheet action there, from the wind. And then, corrosive compounds, that can come from the minerals in a certain parent material, acids are formed, in particular, that can cause further degradation, and subsequent compounds formed. Slide 7: [photograph of a damaged rock] Here's a picture of a rock, that’s been broken open, or cleaved, by a freeze-thaw cycle there. Freeze-thaw effect over many of them, but one, eventually, broke the thing apart. Slide 8: [photograph of a glacier]

Here's the glacial. Here's a glacier coming in, slowly moving over time, but as this move along, it picks up gravel and rocks and other things that grind the soil down as it moves along. Slide 9: [photograph of an orange colored rock] Here's wind erosion, the effect of wind erosion, from this parent material, here, this wind taking it off, where does that go? Who knows where the prevailing wind currents carry it? Probably to a desert. Slide 10: [photograph of a coast line] And then you have this salt effect in here, along the sea coast, and this salt weathers this parent material, increases the weathering process, through the salt and the sodium chloride, and then you have, weak acids form, and things like that, that increase the weathering process, the rate of weathering of this parameter, these sea coast rock formations here. Slide 11: So, what are the parent materials? Well, rocks and minerals, certainly. Glacial deposits. Loess deposits, and this would be what we're talking about, the wind carrying it, and that becomes, from a rock, can go to another area, and that becomes a parent material for the formation of soil in another place. And then alluvial and marine deposits, carried down into the deltas from the rivers, as it approaches the ocean, or a larger body of water, it tends to slow down and spread out, and you'll get deposits there, which, often times is excellent parent material for soil formation. And then, organic deposits. Things like, decomposed vegetation, maybe ferns from the dinosaur age or whatever, broken down over a long period of time. If it's underground, it might turn into oil, petroleum there, or even a natural gas. But if it's towards the surface, then it's what we call a peat bog, or something like that, a highly organic soil. Slide 12: [photograph of the ground] Now let's look at, here we have your minerals degrading here, your rocks, minerals, over time, you get topsoil built up over time, it continues, the process of soil formation going on there, your topsoil, your subsoil, and your parent material. Slide 13: [photograph of rolling plains] Here, loess deposits. Here, this is a rolling plain, where they're growing wheat. Slide 14: [photograph of a delta] You have your marine deposits, as it slows down in delta areas. Very rich soil. Often times you set up for crops and things that can tolerate soil saturation, such as rice. Slide 15: [photograph of a field full of turf]

And then you have, organic soil, and we have a lot of these in Michigan, these are often places where they grow either, in the past they've grown vegetables, such as carrots, celery, things like that, peppers, things like that, was a big part of Michigan, and continues to be on the west side of Michigan, but, as suburbia's crept out, more people planting lawns, it's a really good soil for sod farms, and we'll explain why that is the case later on in the course. So, we've formed our soil, we talked about the weathering processes, the parent material that it comes from, and as we move along in our little primer here, we’ll be right back at you....