: What is soil degradation and what are the factors responsible for it?
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The soil usually contains a mixture of all sorts of elements.
There’s minerals, that’s the big part. and there’s organic matter (much smaller usually)
Plants dont really absorb a lot of minerals. They absorb some, but only tiny amounts.
But they absorb quite a big of the organic matter.
micro organisms break down the organic matter and the rain draws it into the soil. where the plant’s roots absorb it with the water they drink.
In nature, the plant then dies after a while and the organic matter is replenished.
But in agriculture, the organic matter from the plant is removed by harvesting the plants.
So the soil loses more and more of it’s organic matter.
This can be countered by fertilising the ground (adding organic matter)
You will always have degraded areas like desert or steppe, but in general there’s a lifecycle of decaying matter and growing plants that feed off the decaying matter with a free bonus food source of the sun.
The decaying matter can be leaf litter like in a rainforest, animal pooh like the heards of buffalo, spring bok, wilde beast (etc) create, which also churns up the soil with their hooves, dead trees that fungi break down, decaying animals, or whatever else I’ve forgotten or just don’t know.
This decaying matter revitalises the soil with minerals and other nutrients.
This sparks bacterial growth, which gives better quality food for the herbivores, encourages plant and reciprocal fungal growth which leads to more flowering and seeding, which creates more insect life. Flowers, seeds and insects attract birds. All of the above attracts predators which creates very nutrient rich pooh which is often buried creating more nutrients. Healthy predation on browsing animals like cattle or capybara produces a lot more pooh, and so on and so forth.
When you remove the chain of herbivores browsing and poohing, carnivores eating, poohing and dying, and plants reproducing you strip a lot of the nutrients from the soil.
When you get intensive farming practices which rely on fertilizer rather than the natural soil cycle, you strip the last remaining mineral content of the soil, which starves the bacteria and fungi of their food.
You end up with dust, like the dust bowl in the US in the 1930s. Nothing can really grow.
Farmers on the whole aren’t idiots. They know how to tend and care for their land in order for it to remain productive. When pressures of supporting your family, and paper thin margins created by large distribution and retail outlets, worst practices are not uncommonly resorted to “just to get by” for another year. These temporary measures can become permanent when the paper thin margins become even thinner.
**Edit** grammar and syntax
Organic matter compresses, dissolves, is absorbed or just washes/leaches away.
If you put a foot compost on a piece of land, by next year you will only have about six inches, one inch in 5 or six years and in 10 years won’t have any of it left.
Organic matter retains moisture which plants need as much as the minerals and organic bits they need.
plants grow and die and their bodies replace the organic matter they used up. Its not all vegetation, when they studied Mt St Helens that blew up 25 years ago they noticed that crevases in the raw dirt would get a drift of bugs that flew over, found nothing to eat and died. That was the start of nutrition for the wild seeds that also was carried by the wind.
Other factors include mechanical disruption, compression. over working the soil with tillers destroys the structure of the dirt allowing water to escape much easier (motorcycles on the desert, people walking across a lawn wearing a path) and heavy machinery can compress the soil even deep down, also damages roots of trees which is why construction of a house usually starts with the cutting down of the 100 year old oaks, they’ll die anyway.
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