This long chapter now consists of three parts: erosion1, erosion2, erosion3.
| concern | Soil erosion and degradation are so severe world-wide, that it threatens our agricultural base. | |
| degradation | Soil can degrade without actually eroding. It can lose its nutrients and soil biota. It can get damaged by waterlogging and compaction. Erosion is the visible part of degradation, where soil particles are transported down-hill by the forces of gravity, water flow or wind. Erosionand degradation are world-wide problems. | |
| damage | Soil erosion affects farming in detrimental ways. Physical damage is the most visible form of soil loss, and most likely to be remedied. | |
| gravity | Gravity pulls constantly at soil, nudging it down hill, causing soil slips, earth clips, cracks, creep and slumps. | |
| rain | Ironically, the most damaging of rainfall is the impact with which water droplets hit the soil. From there on, the flow of water causes sheet-wash, rilling, surface gullying, tunnelling and in rivers it scours banks. | |
| frost | Frost can cause frost-heave, a mysterious upward movement of soil. | |
| wind | In dry climates, wind blow is the main cause of erosion. | |
| estimating erosion | Soil erosion can be predicted from the kind of soil, what it is used for, how it is farmed, the lay of the land, and size of the field. | |
| affecting the sea | Ultimately, all soil ends up in the sea. It is a natural process that brings nutrients to the sea where it fertilises the coastal fishery. But too much of a good thing causes problems. | |
| least loss landscapes | The landscapes we see today have existed for a very long time. Under the influences of climate and cover, they have formed into shapes that minimise the loss of soil and nutrients. A new look. |
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